Chromitite Deposits of Turkey in Tethyan Ophiolites

Abstract

Some parts of the Tethyan ophiolites of Alpine-Himalayan suture belt are located within Turkey. The Tethyan belt splits into two branches in Turkey. The northern branch follows the İzmir-Ankara-Erzincan Zone, while the southern branch extends along the Anatolide-Tauride and Bitlis-Zagros suture zone. The subsections of the latter reach Iran in the east and Oman ophiolites in the south east. These ophiolites are also the only environments in which chromitite deposits occur. Consequently, the ophiolites in Turkey are significantly rich in terms of Alpine type chromitite occurrences and they are the oldest metallic mine products.

There has been chromitite ore production in Turkey since the nineteenth century. With their refractory quality, chromitite produced in Turkey has always had a good standing in the market. Chromitite, which was exported as lump ore until mid-twentieth century, started to be used in the domestic market as the country’s industry developed, but still, even today an important part of the production is exported. In addition, since the chromitite developments near to the surface are almost completely exhausted, the chromitite ore production in the country has evolved to concentrated ore obtained from low grade deposits, through beneficiation. Although there are many active beneficiation plants in various parts of the country, there is still a significant amount of concentrate ore production; especially in the deposits of Adana-Aladağ region.

In this chapter, the mentioned chromitite occurrences are discussed in a specific order from west to east, taking into account the ophiolite sequences to which they belong. The North Anatolian Ophiolites are introduced in the first three sections whereas the other three sections present the chromitite deposits of the South Anatolian Ophiolites. Nevertheless, considering the historical records and future production potentials, Turkey’s most important chromitite production regions could be listed in order of priority as Guleman (Elazığ), Kopdağ region (Erzincan), Muğla-Fethiye region, Aladağ-Pınarbaşı (Adana-Kayseri), Orhaneli-Harmancık (Bursa)-Eskişehir region and Hatay. It is clear that these should all be taken into consideration for further prospecting targeting.

3.1 Introduction

This chapter has been prepared by making use of the wide literature on Turkish chromitites. The “Turkish Chromitite Inventory” project, which is being prepared using the Chrome-Nickel Prospecting reports, has been worked on by the General Directorate of Mineral Research and Exploration for many years. Most of the presented data (tables and maps) were derived from these prospecting reports. In the first part we provide brief information about Tethyan ophiolites of the Eastern Mediterranean. The second part includes general information about chromitites and general features of chromitites in Turkey. A summary of petrogenetic studies regarding ophiolites in Turkey is also presented here. The third part is the main body of this chapter. Chromitite occurrences of Turkey presented here are based on an inventory format in accordance with County administrative requirements in Turkey. In this way, related ophiolite sequences can be described in more detail.

This Chapter aims to work through the chromite occurrences associated with the Tethys Ophiolites, thereby becoming an essential overview and a guide for new scientific studies. We also hope to have opened a new window for our colleagues and students who are studying and working on mineral systems.

3.2 Tethyan Ophiolites of the Eastern Mediterranean

The Mesozoic Tethyan ophiolites of the Alpine-Himalayan orogenic belt include the Mid-Late Jurassic ophiolites of the Dinarides, Albanides and Hellenides in the western region and the Late Cretaceous ophiolites of Turkey, Troodos, Baer-Bassit, Khoy, Kermansah, Neyriz, and Oman in the eastern region (Fig. 3.1). The Mid to Late Jurassic ophiolites in the western region formed in a transitional tectonic settings from MORB to SSZ (Bebien et al. 1998; Bortolotti et al. 2002; Robertson 2002, 2012; Robertson and Shallo 2000; Höck et al. 2002; Dilek and Flower 2003; Saccani et al. 2004; Dilek et al. 2005, 2008; Tremblay et al. 2009), whereas the late Cretaceous ophiolites in the eastern region, from Turkey to Oman, are supra-subduction zone (SSZ) type (Aktaş and Robertson 1984; Pearce et al. 1984; Hebert and Laurent 1990; Lytwyn and Casey 1993; Yalınız et al. 1996; Collins and Robertson 1998; Dilek et al. 1999; Floyd et al. 2000; Parlak et al. 1996, 2000, 2002, 2004, 2009, 2013a; Al-Riyami et al. 2002; Robertson 2002; Robertson et al. 2006, 2007; Flower and Dilek 2003; Dilek and Thy 2009; Dilek and Furnes 2009).

Fig. 3.1

U-Pb ages of the Tethyan ophiolites in Turkey and surrounding areas (Data are from (1) Dilek and Thy (2006), (2) Dilek et al. (2008), (3) Liati et al. (2004), (4) Mukasa and Ludden (1987), (5) Konstantinou et al. (2007), (6) Dilek and Thy (2009), (7) Parlak et al. (2013a), (8) Karaoğlan et al. (2013a), (9) Koglin (2008), (10) Koglin et al. (2009), (11) Topuz et al. (2012), (12) Sarıfakıoğlu et al. (2012), (13) Karaoğlan (2012), (14) Robertson et al. (2013b), (15) Karaoğlan et al. (2013b)). LO Lesvos Ophiolite, AO Antalya Ophiolite, BHO Beyşehir-Hoyran Ophiolite, ORO Orhaneli Ophiolite, KO Kınık Ophiolite, EO Eldivan Ophiolite, MO Mersin Ophiolite, PKO Pozantı-Karsantı Ophiolite, OsO Osmaniye Ophiolite, GO Göksun Ophiolite, PO Pınarbaşı Ophiolite, IO Ispendere Ophiolite, DO Divriği Ophiolite, KmO Kömürhan Ophiolite, SO Sevan Ophiolite, plg plagiogranite, gb gabbro, dk dyke, tnl tonalite, rhy rhyolite. (Map modified after Dilek and Flower 2003; Çelik et al. 2011)

Neotethyan ophiolites in Anatolia are located along several east-west trending suture zones separated by continental blocks, metamorphic core complexes and sedimentary basins (Şengör and Yılmaz 1981; Robertson and Dixon 1984; Robertson 2002, 2006; Okay and Tüysüz 1999; Okay 2008). These suture zones are marked by ophiolites, ophiolitic melanges and ophiolite-related metamorphic rocks (Okay 1986, 1989; Parlak et al. 1995, 2006, 2009; Önen and Hall 2000; Vergili and Parlak 2005; Robertson et al. 2009; Pourteau et al. 2010; Okay and Whitney 2010; Dilek and Furnes 2011). These tectonic units were emplaced in the Late Cretaceous as a result of series of collisions of intra-oceanic arc-trench systems with the continental margins (Robertson 2002, 2004, 2006, 2007; Flower and Dilek 2003; Dilek and Flower 2003; Dilek et al. 2007; Dilek and Thy 2009; Dilek and Furnes 2009; Okay and Şahintürk 1997; Okay et al. 2006; Okay 1989).

The ophiolites in northern Anatolia occur in the İzmir-Ankara-Erzincan suture (Fig. 3.1), cropping out in western, central and northeastern Anatolia. The ophiolites are incompletely preserved, and crustal units display a supra-subduction zone geochemical character. In western Turkey, the ophiolites were emplaced over a subducted and exhumed passive margin of the Tauride-Anatolide platform in the Campanian (Okay 1989; Yılmaz et al. 1997a, b; Göncüoğlu et al. 2000; Robertson 2002; Robertson et al. 2009). The Late Cretaceous dismembered ophiolites above the Kırşehir/Niğde metamorphic massifs, and within the Ankara Melange are interpreted mainly as remnants of SSZ-type ophiolites formed in the Late Cretaceous within a northerly Neotethyan oceanic basin. The felsic intrusives and the volcaniclastics of Middle Turonian-Early Santonian age are indicative of contemporaneous arc volcanism (Yalınız et al. 1996; Yalınız and Göncüoğlu 1998). The Late Cretaceous Central Anatolian ophiolite was emplaced southwards from the Ankara-Erzincan suture zone onto the Kırşehir/Niğde metamorphic basement before latest Maastrichtian time. However, Early-Middle Jurassic isotopic ages were reported from the Ankara melange (Dilek and Thy 2006; Çelik et al. 2011). The Ankara-Erzincan suture zone includes large bodies of ophiolites and ophiolitic melanges in northeastern Anatolia (Rice et al. 2006, 2009; Sarıfakıoğlu et al. 2009; Parlak et al. 2013b; Topuz et al. 2013). These ophiolitic units display well-preserved oceanic lithospheric sections and accretionary melanges with local blueschist assemblages. Southward-emplacement onto the Tauride passive margin and northward emplacement onto the Pontide active margin has been proposed during Late Cretaceous-Early Tertiary (Okay and Şahintürk 1997; Yılmaz et al. 1997a, b; Rice et al. 2006, 2009). These ophiolitic units are unconformably overlain by Campanian-Maastrichtian sediments that were, in turn, imbricated with the ophiolitic rocks (Okay and Şahintürk 1997; Rice et al. 2006, 2009).

The Tauride belt ophiolites start with the Lycian nappes to the west and end with the Divriği ophiolite to the east. These ophiolites (Lycian nappes, Antalya, Beyşehir-Hoyran nappes, Mersin, Pozantı-Karsantı, Pınarbaşı and Divriği) are situated either on the northern or on the southern flank of the E-W trending Tauride carbonate platform axis (Juteau 1980). They mainly consist of three tectonic units namely, in ascending order, ophiolitic mélange, sub-ophiolitic metamorphic sole and oceanic lithospheric remnants. The ophiolitic mélange in tectonic contact with the underlying platform carbonates, is composed of ophiolitic rock fragments, limestone blocks ranging in age from Permian to Late Cretaceous, radiolarites, shale, and fragments of metamorphic rocks. This unit is, in turn, tectonically overlain by thin sheets of metamorphic rocks that display inverted metamorphic zonation from upper amphibolite to greenschist facies. The mantle tectonites, dominated by harzburgite, tectonically rest on the deformed metamorphic sole rocks. Well-preserved ultramafic and mafic cumulates are the most conspicuous features all over the Tauride belt ophiolites (Juteau 1980). The plutonic sections and the metamorphic soles of the Tauride ophiolites are crossed by numerous isolated diabase dykes at different structural levels. The dykes are not deformed, indicating that they were emplaced after the deformation of metamorphic soles, but they do not extend into the underlying melanges. Sheeted dyke complexes and volcanic sections are rarely present in some of the ophiolites such as Antalya, Mersin and Pozantı-Karsantı (Juteau et al. 1977; Parlak 1996; Parlak et al. 2001). The geochemistry of crustal rocks indicates SSZ origin for the Tauride ophiolites (Collins and Robertson 1998; Parlak et al. 1996, 2000, 2002, 2006; Andrew and Robertson 2002; Vergili and Parlak 2005; Çelik and Delaloye 2003; Çelik and Chiaradia 2008; Çelik 2007).

Two subparallel, NE-SW-trending belts of Upper Cretaceous ophiolitic rocks transect southern Turkey, extending through northern Syria, Cyprus and intervening offshore areas (Robertson 2002; Parlak et al. 2009). The southern belt includes the Troodos ophiolite (Cyprus), the Baer–Bassit ophiolite (northern Syria) and the Antalya (Tekirova and Gödene), Hatay, Amanos and Koçali ophiolites (southern Turkey). Geophysical evidence indicates that a submarine connection existed between the Troodos and Levant margin ophiolites (Baer-Bassit and Hatay ophiolites) via the Latakia Ridge (Ben-Avraham et al. 2006; Roberts and Pearce 2007; Bowman 2011). These ophiolites originated within the Southern Neotethys. Regional comparisons show that the Kızıldağ ophiolite has similar petrological and geochemical features to the Baer–Bassit and Troodos ophiolites. The Baer–Bassit ophiolite is the leading edge of a vast ophiolite that was emplaced southwards from the southerly Neotethyan Ocean in latest Cretaceous (Maastrichtian) time. The Kızıldag ophiolite to the north represents the undeformed, more northerly part of the same thrust sheet (Robertson 1986a, b, 2002; Al-Riyami and Robertson 2002; Al-Riyami et al. 2002). There are a number of similarities between the two ophiolites. Despite the strongly dismembered nature of the Baer-Bassit ophiolite, it can be reconstructed as a single complete ophiolite sequence from bottom to top, like the Kızıldag ophiolite (Robertson 1986a, b; Al-Riyami et al. 2002). The plutonic section of the Kızıldag ophiolite is lithologically similar to that of the Baer–Bassit ophiolite (Bağcı et al. 2005, 2008; Al-Riyami et al. 2002). Both ophiolites have well developed sheeted dyke complexes. The extrusive rocks in both ophiolites are mostly depleted and exhibit the geochemical features of island arc tholeiites (IAT) (Al-Riyami et al. 2002; Bağcı et al. 2008).

The more northerly belt includes the North Berit (Göksun) ophiolite, the İspendere ophiolite, the Kömürhan ophiolite, the Guleman ophiolite and the Killan ophiolite. These ophiolites originated from an ocean basin, here termed the Berit ocean, that was located between the Malatya-Keban platform to the north and the Bitlis and Pütürge continental units to the south (Robertson et al. 2012a, b). The SE Anatolian ophiolites are tectonically overlain by the Malatya-Keban platform and all intruded by late Cretaceous granitoid (Parlak 2006; Rızaoğlu et al. 2009). These ophiolites were thrust over the Maden Group at the end of Middle Eocene time. They include differentiated rock units in both the plutonic (quartz diorites) and the volcanic sections (i.e. basalt to rhyolite). They are also overlain by volcanic arc units (i.e. Elazığ Unit, Yüksekova Complex), suggesting that SSZ-type crust evolved into an ensimatic island arc as subduction continued (Rızaoğlu et al. 2006; Parlak et al. 2009; Karaoğlan et al. 2013b). The Guleman ophiolite shows similar features to the Kömürhan, İspendere and Göksun ophiolites. Although it was also accreted to the base of the Malatya-Keban platform during the Late Cretaceous, it was not affected by the intrusion of the granitoid. All of the evidence suggests that the Göksun, İspendere, Kömürhan, Guleman ophiolites and the North Berit (Göksun) ophiolite were related to the northern margin of the southern Neotethys (i.e. the Malatya–Keban Platform), whereas the Kızıldağ (Hatay) ophiolite was attached to the southern margin (i.e. the Arabian Platform) of the southern Neotethys in the latest Cretaceous time (Robertson et al. 2006, 2007; Parlak et al. 2009, 2013a).

U-Pb ages of the oceanic magmatism (gabbro) reported from the Western and Central Alps range from 164 to 158 Ma (Rubatto et al. 1998; Rubatto and Scambelluri 2003; Kaczmarek et al. 2008). But the youngest oceanic magmatism was reported as 93 Ma by Liati et al. (2003) in the Central Alps. Similar Middle to Late Jurassic crystallization ages were also documented from the Mirdita (plagiogranite: 165–160 Ma), in Albania (Dilek et al. 2008); Vourinos (plagiogranite: 172.9 ± 3.1 and gabbro: 168.5 ± 2.4 Ma), Pindos (gabbro:171 ± 3 Ma), Samothraki (gabbro: 159.9 ± 4.5 Ma), Evros (gabbro: 168.6 ± 1.8 Ma), Crete (gabbro/hornblendite: 162.7 ± 2.8 Ma) ophiolites in Greece (Liati et al. 2004; Koglin 2008); and Ankara melange (plagiogranite: 179 ± 15 Ma) in northern Turkey (Dilek and Thy 2006) (Fig. 3.1). In contrast, Late Cretaceous crystallization age of the oceanic crust is well documented in the Eastern Mediterranean region, including Troodos (plagiogranite: 90–91 Ma; Mukassa and Ludden 1987; Konstantinou et al. 2007), Kızıldağ (plagiogranite and gabbro: 93–91 Ma), Divriği (88.8 ± 2.5 Ma), Mersin (gabbro: 82.8 ± 4 Ma), Pozantı-Karsantı (Gabbro: 69.1 ± 2.1 Ma), Pınarbaşı (Isolated dike: 65.4 ± 3.2 Ma) ophiolites in Turkey (Dilek and Thy 2009; Karaoğlan et al. 2013a; Parlak et al. 2013a) and the Semail ophiolite (plagiogranite: 95 Ma) in Oman (Tilton et al. 1981; Warren et al. 2005).

3.3 Chromitites: Types, Occurrences, Petrological Features

3.3.1 Types of Chromitite Deposits

Chromitite deposits are usually associated with ultramafic rocks. Generally they are divided into three main types based on their origin, geological setting, mineralogy, texture, and chemical characteristics (Thayer 1960; Jackson and Thayer 1972)

• (a) Stratiform chromite deposits generally occur in mafic-ultramafic intrusions in stable continental regions: these are continuous deposits that usually have large reserves and show consistency in dip and strike, small grain size, smooth crystal shape (idiomorph), cumulate textures, high iron content, low Cr/Fe ratio. The most typical examples are deposits in the Bushveld (South Africa; Cawthorn 2015), and Stillwater (USA; McCallum 1996) complexes.

• (b) Alpine (podiform) chromite deposits: these consist of lenses or irregulalry shaped chromitite masses, with limited continuity in strike and dip, widely varying Cr content, and their reserves usually do not exceed a few hundred thousand tonnes. The chromite is coarse-grained, with irregular crystallinity and Cr/Fe ratios are generally high. Such deposits are usually found in countries located on the Alpine mountain belt such as the Former Yugoslavia, Albania, Greece, Turkey, Cyprus, Iran and Pakistan. Also, Kazakhstan, India, the Philippines and New Caledonia as well as some other countries where similar types of chromitite deposits are located.

• (c) Chromitite (and magnetite) deposits that have a concentric internal order, related to mafic-ultramafic rock assemblages: This type of chromite formation has no economic significance. The most typical examples exist in Alaska and are known as Alaskan-type intrusions (Johan 2002).

3.3.2 General Characteristics of the Turkish Chromitites

The chromitite deposits of Turkey are classified as “Alpine-Type” deposits. Thicknesses usually vary between 10 cm and 10 m with lengths of 100–200 m. However, in the Guleman (Elazığ) region, 1500 m long bodies were observed, boudinaged along strike, in the Uzun Damar and Ayı Damar ore deposits. Although the thicknesses of chromite masses can reach up to 50 m, it usually does not exceed a few meters.

The chromite mineralisation in Turkey can be found in the ultramafic rocks of both the cumulate and tectonite sections of the ophiolites and can be grouped according to their tectono-stratigraphic location (Engin et al. 1985). The chromite bodies of harzburgites (tectonites) are surrounded by dunite envelopes ranging in thickness from a few centimetres to a few meters (Fig. 3.2).

• (a) Chromitites within the deeper part of the mantle, harzburgites could be seen as in Ayıdamar and Uzun Damar deposits in Guleman (Elazığ) region,

• (b) Chromitites located below the tectonite-cumulate transition zone as in the Koca Ocak and Kıran Ocak in Harmancık (Bursa) region,

• (c) Chromitites located along the tectonite-cumulate transition zone as in Batı Kef Mine in Guleman (Elazığ) region,

• (d) Chromitites hosted in ultramafic zones (dunite), as in Pütyan Mine of Gölalan - Guleman (Elazığ) and Kızılyüksek (Pozantı-Karsantı) regions (Fig. 3.3).

Fig. 3.2

Location of chromitites in Turkey. (After Engin et al. 1985)

Fig. 3.3

Chromitites in Turkish ophiolites and representative ore deposits/mines. (After Engin et al. 1985)

The structural relationships of the chromitite bodies with the host peridotites are shown in Fig. 3.4. Chromite deposits in Turkey are mostly concordant with the foliation fabric of the peridotites (Fig. 3.4a). Although some deviations are possible due to the shape of the chromitite bodies, in general, the orientation of the chromite lenses and the foliation pattern in the peridotite are parallel to each other (Fig. 3.4a, b). However, later tectonics may have affected this primary fabric and the position of the chromitites (Fig. 3.4c–e).

Fig. 3.4

Wallrock/chromitite ores relationship typically found in Turkey: (a, b) chromitite bodies are concordant with the internal structure of the peridotite (Uzundamar and Western Kef Mines, Guleman-Elazığ; length of the orebody in dip direction is more than ten times than strike direction (Anik Mine, Fethiye); (c) Structural fabric of the orebodies in the fault zone are concordant with this fault zone, but they cut the internal structure of peridotite in a diagonal direction (Eastern Kef and Kapin Mines, Guleman); (d, e) Folded chromitite bodies in peridotite; chromitite bodies are plunging, foliation of the peridotite at the fold apex diagonally intersects these fabrics of the orebody (Kandak and Biticealan Mines, Köyceğiz-Muğla). (Redrawn after Engin et al. 1985)

Chromitites cutting the structural fabric of peridotites, are mainly located along fault zones (Fig. 3.4c). Some chromitite deposits although initially elongated along the foliation fabrics of peridotite, as a result of tectonic transportation and deformation, actually cut through the foliation planes (Fig. 3.4c), or are locally folded with the wall-rock ultramafics (Fig. 3.4d, e). These types of chromitites, as shown in Fig. 3.4, have been described only in few areas, such as Kavak-Bahtiyar (Eskişehir) and Guleman (Elazığ) regions (Engin et al. 1980–1981) in Turkey, but well studied in New Caledonian ophiolites (Cassard et al. 1981).

3.3.3 Geochemical Features of Turkish Chromitites and Platinum Group Element (PGE) Contents

Apart from whole rock geochemical features available through chromite mining operations, information related to chromite mineral chemistry and PGE contents of chromites was reviewed from published articles, post-graduate theses and public reports.

As mentioned above, Turkish chromitites typically are Alpine type (podiform) deposits. These deposits are characterized by high Cr₂O₃, Al₂O₃, Cr/Fe and MgO, and low FeO and Fe₂O₃ contents. Although the Turkish chromitites are generally of economic grade, their wide range of chemistry enables their use in the refractory and chemistry industries. The average wt% Cr₂O₃ grade of deposits ranges between 5% and 45%, with a maximum of about 58 wt% Cr₂O₃. Average grades of less than 40% Cr₂O₃ are accepted as “third quality”; 40–46% is accepted as “second quality”, and over 46% is accepted as “first quality” chromite ore in the market. In this regard, Turkish chromitites which are used in refractory industry should have approximately 30–40 wt% Cr₂O₃, 25–32 wt% Al₂O₃, >10 wt% SiO₂. On the other hand, the metallurgical industry needs at least 34–48 wt% Cr₂O₃, 8–15 wt% Al₂O₃, 8–12 wt% SiO₂, 16–22 wt% MgO. For the industry, average compositions should be at least 48 wt% Cr₂O₃ (base), 6–7 wt% SiO₂ and Cr/Fe rate should be 3/1 (typical) (Çiftçi et al. 2017; DPT 2001).

The chemistry of chrome spinel minerals in chromitites provides important data for genetic models of chromite formation and also for classification of chromite-bearing ophiolites. Chemistry of chrome spinels of Turkish chromitites varies significantly, and in this chapter, the average values of chrome spinel compositions are used.

Data of chrome spinel chemistry demonstrates classic features of these spinels. Turkish chromitites can generally be classified as Mg-Chromite/Chromite, according to their chromium and magnesium numbers; 0.5< Cr# (Cr/[Cr+Al], atomic ratio) and 0.4–0.8 <Mg# [100 Mg/(Mg + Fe), atomic ratio] (Fig. 3.5a) (Dönmez et al. 2014 and the references therein). Al₂O₃ wt% and Cr₂O₃ wt% contents support the podiform type generation of Turkish chromitites (Fig. 3.5b). Chrome spinels in Alpine type Turkish podiform chromitites have highly variable Cr# ranging from 0.2 to 0.9.

Fig. 3.5

Geochemical properties of Turkish chromitites (explanations in text)

This compositional difference in chromitites, were reported by many researchers in the last decade and chromitites were divided into two groups according to their Cr# value intervals as high-Cr type (Cr# >0.6) and high-Al type chromitites (González-Jiménez et al. 2011; Pal 2011; Rollinson 2008; Uysal et al. 2009a, b; Zaccarini et al. 2011). Both types can exist in the same mantle source. The occurrences of high-Cr and high-Al types are still debated. Here, features that have a general consensus are addressed. In recent years, as a result of studies on Turkish chromitites, similar results were obtained about chromitites related to Muğla, Kastamonu and Van Ophiolites (Uysal et al. 2009b; Dönmez et al. 2014; Günay and Çolakoğlu 2011, 2016).

Turkish chromitites hosted in ultramafic tectonites, which dominantly consist of harzburgites and dunites. In these upper mantle rocks, chromite formations are strongly related to mantle stratigraphy. Stratigraphic levels of chromitites in an ophiolitic sequence, also appear to determine their chemistry. In this aspect, chromitites can be classified in an effective way on Rammlmair’s (1986) Cr# versus Cr/Fe diagram presented in Fig. 3.5c. It is clearly seen in this figure that Turkish chromitites mainly plot within (I) and (II) areas. These areas were defined as ultramafic tectonite (mantle peridotites) and are also consistent with their geological features. However, the chromitites related to ultramafic cumulate rocks that plot within (III) and (IV) areas, are bands which are also consistent with these rocks and their occurrences are highly limited.

Turkish chromitites that mainly occur in mantle peridotites, do not contain economic quantities of PGE. Chromitites in Turkey generally have low PGE content, ranging between 200 and 350 ppb. However, it was reported that elements such as Pt and Pd are locally enriched over 1 ppm in a few areas such as Muğla Ophiolite (Harmancık area; Uçurum and Koptagel 2006) and Kahramanmaraş Ophiolite (Berit area; Kozlu et al. 2014). There is no relation between whole-rock PGE contents of chromitites and mineral chemistry. In general, it is accepted that ophiolitic chromitites have high IPGE/PPGE (IPGE= Ru-Os-Ir; PPGE= Rh-Pt-Pd) ratios and low PGE contents (Economou-Eliopoulos 1996; Zhou et al. 1998; Proenza et al. 1998; Melcher et al. 1999; Ahmet and Arai 2002; Garuti 2004; Uysal et al. 2009a, b; González-Jiménez et al. 2011; Zaccarini et al. 2011). Turkish podiform chromite deposits exhibit enrichment in Ru-Os-Ir relative to Rh-Pt-Pd elements (Fig. 3.6a), similar to the PGE content of other ophiolitic chromitites around the World.

Fig. 3.6

PGE content and properties of chromitites in Turkey (explanations in the text)

On the basis of their PGE contents, Turkish chromitites show similar features with geochemical behaviours of PGE’s of ophiolitic chromitites in petrological processes. Total PGE contents of Turkish chromitites negatively correlating with PPGE_N/IPGE_N, are consistent with ophiolitic trends around the world (Fig. 3.6b; Melcher et al. 1999). In addition to this, Turkish chromitites display a trend compatible with partial melting rather than being fractionated in Pd/Ir versus Pt/Pt^∗[=Pt_N/(Rh_N ^∗Pd_N)^1/2] diagram (Fig. 3.6c; Garuti et al. 1997). It can be concluded that during the crystallization of chromites related to partial melting processes, Ir-group elements preferred chromite as the primary phase when compared to Pd-group elements.

3.4 Geological Properties of Chromitites in Turkey

Tethyan ophiolites located within the borders of Turkey are exposed mainly along the İzmir – Ankara – Erzincan, Inner Taurid and Bitlis – Zagros Suture Belt (Okay and Tüysüz 1999) (Figs. 3.1 and 3.7) and their principal features are discussed in Sect. 3.2. Chromitites, which are entirely related to these rocks, are considered in six related groups (Çiftçi et al. 2017) (Fig. 3.7). In this study, the chromite deposits of Turkey are introduced, together with the related ophiolite sequence, on the basis of this grouping, as follows:

• Region 1: NW Anatolian Region: (Balıkesir, Bursa, Eskişehir and Kütahya).

• Region 2: North Anatolian Region (Çankırı, Çorum, Kastamonu, Sinop, Tokat and Yozgat).

• Region 3: NE Anatolian Region (Sivas, Bayburt, Erzincan, Erzurum).

• Region 4: SW Anatolian Region (Antalya, Burdur, Denizli, Isparta, Konya and Muğla).

• Region 5: Central Anatolian Region (İçel, Adana, Kayseri).

• Region 6: SE Anatolian Region (Hatay, Osmaniye, Kahramanmaraş, Gaziantep, Elazığ, Malatya, Adıyaman, Diyarbakır, Siirt, Van, Hakkari).

Fig. 3.7

Major structural elements of Turkey; distribution of ophiolites and related chromitites (1: NW Anatolian; 2: North Anatolian; 3: NE Anatolian; 4: SW Anatolian; 5: Middle Anatolian; 6: SE Anatolian Sub-Regions). (IAES İzmir-Ankara-Erzincan Suture, TS Tavşanlı Suture, AS Afyon Suture, BFZ Bornova Flysh Zone, MM Menderes Massif, KM Kırşehir Massif, PS Pamphylian Suture, ITS Inner Tauride Suture, IPS Inner Pontide Suture, BZS Bitlis-Zagros Suture (Assyrian Suture), DSF Dead Sea Fault). (Modified After Okay and Tüysüz 1999) (Modified after MTA 2002)

Although the regional characteristics and the main features are discussed in the first section, it is necessary to describe them in more detail in terms of petrological and structural features because they are the primary wall-rock of chromitite ore deposits.

3.4.1 Region One: NW Anatolian (Balıkesir, Bursa, Eskişehir and Kütahya) Ophiolites and Related Chromitite Deposits

Ophiolitic rocks in this region and surrounding areas remain within İzmir-Ankara suture zone ophiolites (Fig. 3.7). The ophiolites that occur in the eastern border of Balıkesir province are part of the Yayla Melange (Ergül et al. 1980) and rocks belonging to the same section were examined under the Eydemirçay Formation towards the south (Konak and et al. 1980). In general, multi-colored units with different lithologies are in tectonic contact and form large and small blocks interpreted as ophiolitic melange (Pehlivan et al. 2007). The lithologies belonging to the Yayla Melange, which rests tectonically on the Bornova flysh, are also defined as a part of the Bornova flysch by other researchers (Ergül et al. 1980; Okay and Siyako 1993).

The chromite occurrences in the Balıkesir area are contained in harzburgites and dunites of the Harmancık Ophiolite, which is entirely composed of ultramafic tectonites. These units were cut partly by diabase dykes at different structural levels (Fig. 3.8).

Fig. 3.8

Distribution of the chromitite occurrences in Balıkesir segment: (a) Karacabayır hill; (b) Adaören; (c) Akçaalan-Sağir; (d) Boyalıca and (e) Çatalçam sub-regions. (Simplified and modified after MTA 2002)

Chromitite occurrences in Bursa province are associated with approximately E–W trending Orhaneli Ophiolite or Harmancık Ophiolite (Figs. 3.9 and 3.10). While the Orhaneli ophiolites are generally represented by ultramafic to mafic cumulates, the Harmancık ophiolite is usually characterized by variably serpentinized harzburgitic to dunitic mantle tectonites (MTA 2002; Sayak et al. 2009; Ortalan et al. 1984; Bacak and Uz 2003).

Fig. 3.9

Orhaneli sub-region and related chromitite occurrences and segments (A: Eskikızılelma; B: Çınarcık; C: Göktepe; D: Şeytanbudakköy; E: Çiviliçam; F: Ömeraltı; G: Letafet Köyü; H: Akçabük; I: Göynükbelen segments). (Simplified and modified after MTA 2002)

Fig. 3.10

Harmancık (Bursa) sub-region and related chromitite occurrences and segments (A: Piribeyler, B: Akçasaz, C: Delicegüney, D: Kınık, E: Yakuplar, F: Çakmak, G: Çeki Köyü, H: Harmancık, I: Balatdanış, J: Kocapınar-Kozluca, K: Eşen, L: Fındıcak, M: Gençel segments). (Simplified and modified after MTA 2002)

The ophiolites outcropping around Kütahya, have been studied by many researchers (Arni 1942; Holzer 1954; Brinkmann 1972; Okay 1981, 2011; Konak 2002; Önen and Hall 1993; MTA 2002; Önen 2003). In the Tavşanlı Zone they display an internally coherent unit, the Tavşanlı Ophiolite, and a disordered melange, the Dağardı Melange. The Tavşanlı ophiolite is located in the north of Tavşanlı village as an E–W trending tectonic unit which is underlain by the Dağardı Melange (Fig. 3.11).

Fig. 3.11

Chromitite occurrences of Kütahya region and its segments (A: Uluçam; B: Madanlar; C: Çamalan; D: Kargılı; E: Dereli; F: Nusretler; G: Karakaya; H: Elmalı; I: Karsak; J; Tavşanlı; K: Sobran; L: Muhatboğaz; M: Çukurören segments). (Simplified after MTA 2002)

Tavşanlı zone ophiolites rest tectonically on the Ovacik Complex and Orhaneli group in the region (Okay 2011). They comprise peridotites, gabbro, pyroxenite, and diabase dykes. These ophiolitic rocks were named as “Dağardı Ophiolite” by Bacak and Uz (2003) and this ophiolite section is known as the eastern extension of the Harmancık (Bursa) Ophiolite.

The Dağardı Melange covers a wide area between the Tavşanlı and Emet regions and consists of metamorphics, mafic to ultramafic magmatic and sedimentary rock assemblages trending NW-SE which are unconformably overlain by Tertiary sediments.

In Eskişehir province, ophiolitic units outcrop in three regions (Fig. 3.12). The first starts in the north of Eskişehir and ends in Sarıcakaya region as an E-W trending zone, and is named as Dağküplü Ophiolite. The second is Sivrihisar-Karaburhan Ophiolite Nappe outcropping in the north of Sivrihisar, and the third, the Dutluca Ophiolite, outcrops around Dutluca village. The ophiolitic rocks are made up of imbricated slices, and the assemblage from bottom to top is ophiolitic melange, mafic to ultramafic cumulates and tectonites (Özen et al. 2011).

Fig. 3.12

Chromitite occurrences of Eskişehir region and its sub-regions (A: Dağküplü; B: Kavak-Bahtiyar; C: Sivrihisar-Karaburhan; D: Bahçecik; E: Dutluca). (Simplified and modified after MTA 2002)

3.4.1.1 Balıkesir Region Chromite Deposits

The chromite deposits and formations in the Balıkesir province are located within the borders of Dursunbey District (Fig. 3.8). General features of the chromitites in Balıkesir Region are given in Table 3.1. As shown in this table, chromitite ores in the region are generally limited in shape and reserve, and do not have economic importance, although chromitite ore in Turkey was first mined in this region.

Table 3.1 General features of the chromitites in Balıkesir region

3.4.1.2 Bursa Region Chromite Deposits

3.4.1.2.1 Orhaneli Sub-region

Chromitite formations in this area are largely located in Eskikızılelma, Çınarcık, Göktepe, Şeytanbudakköy, Çiviliçam, Ömeraltı, Letafet Village, Akçabük and Göynükbelen sectors. These sub-regions correspond to the zones lettered from A to I in Fig. 3.9.

The chromitite ore is generally observed in highly fractured/crushed serpentinized dunites. It can be seen in dunites, alternating with wherlite and pyroxenites as in Göktepe Sub-Region (Fig. 3.9C), but can also occurs in sheared serpentinite zones as massive, disseminated and banded zones like in the Şeytanbudakköy Sub-Region (Fig. 3.9D). There are pyroxenites and diabases around Ömeraltı Village (Fig. 3.9F). Harzburgites and dunites are partly/completely serpentinized in this region. Chromitite ores are sometimes located in cumulate dunite sections, including wherlite and clinopyroxenite layers (Fig. 3.9G–I). Also, ophiolitic rocks around the Dağgüney region display a mélange character (Fig. 3.9I).

Although Orhaneli Sub-Region is characterised mainly by disseminated ore, occurrences of several other types (massive, nodules) also exist and alternate with disseminated ore as banded layers. These ore-zones exhibit quite different thicknesses varying from few centimetres to tens of metres. The lengths of these deposits are usually quite short because they are cut by several faults and thrusts, but some deposits are up to 100 and 150 m in length. The average grade of the chromitite ore in Orhaneli Region is around 20 and 30 wt% Cr₂O_3, but can reach up to 50% Cr₂O₃ in massive and banded sections.

3.4.1.2.2 Harmancık Sub-Region

The chromite deposits and occurrences in the lower part of Harmancık (Bursa) are shown in Fig. 3.10 and their features are summarised in Table 3.2. All chromite deposits and occurrences in this sub-region are related to the harzburgite and dunite levels of the ophiolitic rocks, which are described as “Harmancık Peridotite Massif”. These units are partly intruded by diabase dykes. According to Table 3.2, chromitite ores in this region have quite different shapes and dimensions, and include some large reserves. Since the nineteenth century it has included the most famous chromitite ore deposits in Turkey.

Table 3.2 General features of the chromitite deposits in Bursa region

3.4.1.3 Kütahya Region

Kütahya province chromitite formations were mainly observed within the Tavşanlı (Dağardı) ophiolite. This ophiolite body has been described above and interpreted as the eastern extension of the Harmancık peridotite. There are no notable chromitite occurrence within Dağardı Melange (Fig. 3.11).

Chromite and magmatic bands in this section of the Dağardı Ophiolite are coherent and oriented NW – SE (Ortalan et al. 1984). The SW section of the ophiolite, east of Tavşanlı and E-SE of Çamalan Village in the north of Emet, is lateritic in character, and post-ophiolite-emplacement magmatism in the region had partly altered ophiolitic rocks through silicification and listwanitization. Chromite textures indicate a tectonic origin for this section of Tavşanlı Ophiolite (Ortalan et al. 1984).

In general, chromite mineralisation in this region has similarities with the Bursa-Harmancık region. Mineralization is usually banded and disseminated, but massive and nodular types are also present. Mineralized zones have variable thickness of between a few cm and a few meters and the Cr₂O₃ grade of ore varies between 20% and 45%. Mining activities in this region were by open pit and underground mining. General features of the chromitites in Kütahya Region are given in Table 3.3.

Table 3.3 General features of chromite deposits in Kütahya region

3.4.1.4 Eskişehir Region

Other ophiolites around the Dağküplü Ophiolite are related to the North Anatolian Ophiolite Belt. These rocks are emplaced as imbricated slices of ophiolitic mélange, mafic and ultramafic cumulates and tectonites (Fig. 3.12). Chromitite ores are located within the harzburgitic and dunitic tectonites as well as within cumulate dunites. Ophiolites are strongly serpentinized and partly listwanitized in the region.

Chromite formations of Eskişehir are mostly located in Dağküplü, Sivrihisar-Karaburun, Dutluca and Kavak-Bahtiyar sub-regions (Fig. 3.12). Their general features are summarised in Table 3.4, in which it can be seen that no economically viable chromitite reserves exist in the region, except of the pipe shaped Kavak-Bahtiyar chromitite deposit. This deposit is one of the oldest chromitite mine in Turkey and operated since 1930s by Türk Maadin Company. According to the information given in the companies web-page, total production of chromitite ore (both massive and concentrated) is about 2.5 Mt and this is one of the deepest mine in the World (TMS 2017).

Table 3.4 General features of the chromitite occurrences in Eskişehir region

3.4.2 Region Two: North Anatolian (Çankırı, Çorum, Kastamonu, Sinop, Tokat and Yozgat) Ophiolites and Related Chromitite Deposits

3.4.2.1 Çankırı Region

3.4.2.1.1 Çankırı Ophiolites

Ophiolites around Çankırı and Çorum are examined under two names or labels in the literature. The first includes Eldivan Ophiolite Complex/Kargı Ophiolite Unit/Artova Ophiolite Complex (Özcan et al. 1980). The second is the Ahlat Ophiolitic Melange. The chromitite formations in the region are associated with peridotites of the Eldivan Ophiolite (Akın 1995). Akyürek et al. (1980) stated that the unit defined as Eldivan Ophiolite Complex, was emplaced as tectonic slices of oceanic crustal materials and upper mantle, separated by low angle overthrust planes (Hakyemez et al. 1986). The Complex consists of peridotite dunite, harzburgite and pyroxenite in the lower section; followed by oceanic crustal material consisting of gabbro, diabase dyke complex, pillow lava and pelagic sediment in the upper section (Akyürek 1981; Akın 1995). The internal structure of the Eldivan Ophiolite Complex is only partly known.

3.4.2.1.2 Çankırı Region Chromitites

Chromitite occurrences in Çankırı region are found in five areas: Eldivan Mountain, Çaparkayı, Sani Plateau, Yukarıöz Village and Gök Tepe sub-regions (Fig. 3.13). These occurrences are mostly in the eastern section of Eldivan County; a few are in the Northern sections of Korgun and Yapraklı Counties. General features of the chromitites in the Çankırı Region are given in Table 3.5.

Fig. 3.13

Chromitite occurrences of Çankırı region and its sub-regions (A: Eldivan Dağı; B: Çaparkayı; C: Sani Yaylası; D: Yukarıöz Köyü; E: Göktepe). (Simplified and modified after MTA 2002)

Table 3.5 General features of chromitites in Çankırı and Çorum regions

3.4.2.2 Çorum Region

3.4.2.2.1 Çorum Region Chromitites

Chromitites of Çorum Region are observed within dunitic and harzburgitic mantle tectonites (Ortalan and Taşan 1997). These occurrences, except for the Morsümbül Stream deposit, crop out along a tectonic lineament about 25 km NW of Çorum province (Fig. 3.14, Table 3.5).

Fig. 3.14

Ophiolites and chromitite occurrences of Çorum region (A: Uçarlık Tepe; B: Güllük Dere; C: Göl Sırtı; D: Yavşanlı Tepe; E: Derinseki; F: Tekçam Tepe and G: Morsümbül Dere chromitite occurrences). (Simplified and modified after MTA 2002)

Sub-economic chromitite occurrences was exposed in open pits within serpentinized dunites and harzburgites, and included massive ore fragments, with high Cr₂O₃ grades.. Most chromite occurrences are in breccia zones along faults, and as veneers on fault walls.

3.4.2.3 Kastamonu and Sinop Regions

As chromitites in Kastamonu and Sinop regions are observed in the same ophiolite body they are both introduced in this section.

3.4.2.3.1 Kastamonu and Sinop Ophiolites

Ophiolitic rocks in the region mainly consists of eclogite-bearing ultramafics, peridotite, serpentinite, gabbro, diabase, basaltic lava, chert, radiolarite and mudstones. Although these rocks were defined under different names by several researchers, we will follow the “Elekdağ Meta-ophiolite” name used by Yılmaz and Tüysüz (1984).

According to Yılmaz and Tüysüz (1984), meta-ophiolites in Elekdağ have a “complete ophiolite section” along the long axis of the Elekdağ Mountain. Ultramafic rocks are seen in lower levels and pass upwards into layered peridotite. Serpentinite is the most common lithology and can be foliated along shear planes. Mesh texture is common in serpentinites hosting chromite mineralisation.

Peridotite and serpentinites are overlain by gabbro and diabases. Traces of high-pressure metamorphism are observed in many places within the diabases. At the highest levels, basaltic pillow lavas, mudstone and cherts are observed.

3.4.2.3.2 Kastamonu and Sinop Region Chromitites

Chromitite occurrences in this region are concentrated in meta-ophiolite that was called “Elekdağ Meta-ophiolite”, and located mainly in Taşköprü territory (Fig. 3.15). The chromitite mineralisation occurs in ultramafic tectonites (harzburgite, dunite) and forms small bodies with little continuity and no economic potential. General features of the chromitites in Kastamonu and Sinop Regions are given in Table 3.6.

Fig. 3.15

Kastamonu (Elekdağ) chromitites and sub-regions (A: Olukbaşı; B: Belören; C: Çambaşı; D: Hacıali; E: Gündoğdu/Esentepe; F: Karapınar; G: Kovaçayır-Alıç; H: Kovaçayır-Türbe Tepe; I: Kovaçayır-Göçük Tepe; J: (Kovaçayır Alıç); K: (Örenbaşı); L: (Daday Hacıağa) ve M: (Araç Kavacık)). (Simplified and modified after MTA 2002)

Table 3.6 General features of chromitite occurences in Kastamonu-Sinop regions

3.4.2.4 Tokat and Yozgat Regions

3.4.2.4.1 Tokat-Yozgat Ophiolites

Two different ophiolites were identified around Tokat and Yozgat. The first one consists of mafic and ultramafic rock slices within a Permo-Triassic metamorphic sequence. The Tokat Massif or Turhal Group, as known in the literature, can be correlated with the Kargı Ophiolite association exposed around Çorum. These rocks are named as “Artova Ophiolite Complex” (Aktimur et al. 1990). The other one is “Tekelidağ Complex” and “Refahiye Ophiolite” consisting of epi-ophiolitic sediments and oceanic crustal components that partly have a melange character, exposed in the southern part of Tokat (Yılmaz 1981, 1985; Aktimur 1986).

3.4.2.4.2 Tokat and Yozgat Regions Chromitites

Some of the chromitite ores are located in the Artova Ophiolitic Melange, whilst others are in the Refahiye Ophiolite (Fig. 3.16). Key features of these deposits are summarised in Table 3.7. Around Arpacıkaraçay Village (A), Eşmebaşı Steam and Çukurtepe (B), and close to Doğlacık and Yağmur Village (C), occurrences of banded and disseminated chromite mineralization of no economic importance were observed.

Fig. 3.16

Tokat and Yozgat chromitites (A: Arpacıkaraçay; B: Eşmebaşı; C: Doğlacık-Yağmur; D: Artova-Kazbayırdere-Demirci; E: Yamaç; F: Ağılın Tepe; G: Artova Tepe; H: Bozsırt; I: Deveçıkmazı). (Simplified and modified after MTA 2002)

Table 3.7 General features of chromitite occurrences in Tokat and Yozgat regions

3.4.3 Region Three: NE Anatolian (Sivas, Bayburt, Erzincan, and Erzurum) Ophiolites and Related Chromitite Deposits

3.4.3.1 Sivas Region

3.4.3.1.1 Sivas Ophiolites

Ophiolitic rocks are exposed in three different areas around the Sivas province. These ophiolite sequences include different oceanic crustal components and cover sediments, and they are partly melange in character. In the literature, they are known as “Refahiye Ophiolite” that occur along the İzmir-Erzincan suture zone and were emplaced in the Late Cretaceous (Yılmaz 1985; Aktimur 1986, Aktimur et al. 1988) (Fig. 3.17). But the ophiolitic rocks cropping out in the north part of Kangal and west part of Divriği, are called “Divriği (Güneş) Ophiolite”, and are interpreted as products of the Inner Tauride Ocean (Bayhan 1980).

Fig. 3.17

Chromitite occurrences of Divriği and Kangal (Sivas) regions (A: Gürgen Ağılı; B:Gülkanat; C: Sivritaştepe; D: Başçayır; E: Ortadağ; F: Bostan Dere; G: Çamlıburun; H: Galin; I: Karakuz; J: Kayabaşı; K: Karatepe; L: Asmalı Dere). (Simplified and modified after MTA 2002)

3.4.3.1.2 Sivas Region Chromitites

Numerous chromite occurrences in ophiolites of Sivas province were derived from both the Ankara-Erzincan Ocean and the Inner Tauride Ocean. Chromitite occurrences in the north have a genetic link with the Erzincan region ophiolites and are explained together with occurrences in Erzincan province. Whereas the chromite occurrences observed in the south, around Kangal and Divriği regions, as shown in Fig. 3.17, occur in disseminated and massive forms hosted in dunites. These chromitites are partly hosted in Refahiye Ophiolite and partly in Divriği Ophiolite, and are summarised in Table 3.8.

Table 3.8 General features of chromitite occurrences in Sivas region

3.4.3.2 Erzincan Region

The Erzincan Region is located on the Eurasian plate (Pontides) and Anatolian plate suture zone, along the “İzmir-Ankara-Erzincan Suture Zone” that was defined by Brinkmann (1966, 1968). The ophiolitic rocks along this suture zone are named as Refahiye Ophiolite and the defining unit (Refahiye Ophiolitic Complex, Yılmaz 1985) is exposed in the north of Erzincan and continues toward Mercan, Tercan and Çayırlı territories (Özen et al. 2008).

From its beginning north-northeast of Erzincan, along the Keşiş Mountains that extend eastward, the ophiolitic sequence consists of mantle tectonites (harzburgite and dunite), ultramafic to mafic cumulates (wherlite, dunite, pyroxenite, gabbro), isotropic gabbro, and sheeted dyke complex (Özen et al. 2008).

3.4.3.2.1 Erzincan Region Chromitites

There are numerous chromitite mines, quarries, open pits and outcrops of various size in Erzincan region (Fig. 3.18). These and some other occurrences to the NE of Sivas, that share the same features, are summarised below.

Fig. 3.18

Chromitite occurrences and sub-regions of Erzincan region (A: Refahiye; B: İliç-Kemah; C: NW of Erzincan; D: Üzümlü-Çayırlı; E: Pülümür; F: Otlukbeli-Tercan). (Simplified and modified after MTA 2002)

Ores in the Erzincan region (Fig. 3.18) are banded and lens shaped, and have mineralization styles of massive, spotted, disseminated and nodular type. The contacts between ore bands and lenses and wall rock dunite are generally primary, but structural in some cases. The chromitite bands and lenses are either primary or structural, and usually conformable with the internal structure of the peridotites. Mineralization in cumulate dunites is generally low grade (10–30% Cr₂O₃), whereas mineralization in tectonite dunites have relatively higher Cr₂O₃ grade (42–48% and above). In terms of their chemical components, they have good metallurgical characteristics (Cr/Fe ratios are high).

Chromitites in Erzincan region can be grouped in six sub-regions. These are Refahiye, İliç-Kemah, NW of Erzincan, Üzümlü-Çayırlı, Pülümür and Otlukbeli-Tercan (Fig. 3.18). The general features of these chromitites are given in Table 3.9.

Table 3.9 General Features of chromitites in Erzincan region

3.4.3.3 Erzurum and Bayburt Regions

These are located to the east of Erzincan and its border region (Fig. 3.19). Ophiolite sequences are located in Horasan and Narman regions, north and east of Tekman and outside of the Refahiye Ophiolite Complex exposures that line up to North of Aşkale in the west of the province. Ophiolitic rocks that lie between Tekman and Pasinler were defined as “Şahvelet Ophiolite”. This ophiolite sequence, from bottom to top, consists of ophiolite melange, tectonites and cumulates (Özen et al. 2008).

Fig. 3.19

Ophiolites, chromitite occurrences and sub-regions of Erzurum region (A: Kopdağ; B: Aşkale; C: Tekman; D: Narman; E: Horasan; F: Şenkaya; G: Karayazı). (Simplified and modified after MTA 2002)

Ophiolite melange at the bottom is characterised by podiform chromite mineralization within harzburgites, and dunites to a lesser extent. The tectonites consist mainly of dunites and harzburgites intruded by doleritic dykes. The cumulate sequence consists mainly of gabbros, and dunite with relatively lesser amounts of wherlite and clinopyroxenite. Moreover, the ophiolitic mélange unit also contains tectonites and cumulates around Karayazı region. The cumulate rocks in the region are characterised by dunite, wherlite, clinopyroxenite and gabbro alternations. The tectonites comprise harzburgite and dunites. The chromitite quarries, open pits and outcrops in this region occur in tectonite or tectonite-cumulate transition zones, but do not have economic potential when compared to chromite mineralisations between Pasinler and Tekman regions.

There is an ophiolitic melange at the base of the ultramafic rocks in Horasan region (Çolakoğlu et al. 2014). Above this melange, spilitic basalts with cover sediments come onto the cumulate section. Two different mélange units, namely Örükyayla and Gezenek Melanges, are observed in Kırdağ (Oltu-Erzurum) region and in successions overlain by ophiolitic units from bottom to top: cumulates, isotropic gabbros and epi-ophiolitic sediments with pillow lavas in the upper part.

3.4.3.3.1 Erzurum Region Chromitites

Ophiolites of Erzurum region are exposed mainly in four regions (Fig. 3.19), and seven groups have been recognised. A small part of ophiolites to the NW of Aşkale are located in the Bayburt province border and the “Kopdağ Chromitites” is one of the most important chromitite mines of Turkey. These occurrences are interpreted as part of the Refahiye ophiolite.

The second group of chromitites, close to the Kopdağ Deposit, is situated in the Erzurum province borders. These are known as “Aşkale West Chromitites”. They outcrop in an E–W trending belt. The Şahvelet Ophiolite, between the center of Erzurum province and Tekman, are considered as the third group under the name of “Tekman Chromitites”. On the other hand, the chromite occurrences hosted in dunitic-harzburgitic mantle west of Narman are the fourth sub-group: the “Narman Chromitites”. The fifth group was defined as “Horasan Chromitites”; the sixth group was defined as “Şenkaya Chromitites”; the seventh group was defined under “Karayazı Chromitites” in the west of Karayazı close to SE border of province. General features of the chromitites in Erzurum and Bayburt Regions are given in Table 3.10.

Table 3.10 General features of chromitites between Erzurum ve Bayburt regions

3.4.4 Region Four: SW Anatolia (Muğla, Denizli, Burdur, Isparta, Konya, and Antalya) Ophiolites and Related Chromitite Deposits

3.4.4.1 Muğla, Denizli and Burdur Regions

The Muğla region is located in SW Anatolia (Figs. 3.1 and 3.7). This region is at the south of the Menderes Massif and it is widely covered by metamorphic and oceanic crustal rocks.

3.4.4.1.1 Muğla-Denizli-Burdur Region Ophiolites

The distribution of ophiolitic rocks from Muğla to Burdur through Denizli, are shown on Figs. 3.1 and 3.20. Ophiolites in this area were defined as “Marmaris Ophiolite Nappe” (Şenel 1997a) and “Likya Ophiolite” (Şenel 2004). Their thicknesses are more than 2 km, and spread over a 45,000 km² area (Collins and Robertson 1997, 1998). Ophiolite units consist of serpentinized harzburgite, and lesser pyroxenite, podiform chromite and gabbro cutting by altered diabase dykes at different structural levels.

Fig. 3.20

Distribution of SW Anatolian Ophiolites (Marmaris and Yeşilova). (Simplified and modified after MTA 2002)

The Menderes Massif consists mainly of tectonite peridotites with the plutonic section completely eroded. Harzburgite is the most common rock type. Massive harzburgites exhibit foliation patterns on higher levels (Erendil 2002). Banding is defined by harzburgite-dunite or harzburgite-orthopyroxenite alternations. Banding planes are almost horizontal and it may indicate that the ophiolite nappe is close to the horizontal position.

The tectonites of Marmaris ophiolites are cut by isolated diabase and gabbroic dykes compared to the Yeşilova Ophiolite in NE areas. From the character of these isolated dykes, it was suggested that deeper sections of mantle are exposed in the massif (Reuber et al. 1984). The mantle peridotites are underlain by subophiolitic metamorphic rocks.

In the Denizli and Burdur Regions, ophiolitic rock groups are classified as Marmaris Ophiolite in the West and Yeşilova Ophiolite in the east, with the former discussed above. The general characteristics of the Yeşilova Ophiolite are as follows, the serpentinized ophiolitic rocks rich in chromite mineralization are located along the Çavdır-Tefenni-Yeşilova line. The ophiolites in this area are defined as “Marmaris Ophiolite Nappe” (Şenel 1997a) and “Likya Ophiolite” (Şenel 2004). The ophiolites that outcrop around Çavdır-Tefenni-Yeşilova were firstly defined as “Yeşilova Ophiolite” by Sarp (1976). Rock units within the ophiolitic sequence in Yeşilova region from bottom to top consist of tectonites, cumulates, dyke rocks and volcanic rocks (Döyen 1995). The tectonites are represented mainly by harzburgites and dunites. The chromites are enveloped by dunites. In mantle tectonites, beside harzburgite, lherzolite and wherlite are also observed (Döyen 1995).

Cumulate sections of Yeşilova Ophiolite, crop out in south and western part of Yeşilova Village. Dykes are generally represented by diabase. It is suggested that these isolated dykes cutting the Yeşilova opholites, can be interpreted as big dykes in tectonites (Reuber et al. 1984). The sheeted dyke complex could not be observed, instead mafic sills and basaltic volcanics were discovered by Koralay (2000).

3.4.4.1.2 Muğla Chromitites

Chromitites in the Muğla region are found in the Marmaris Ophiolite. Although these occurrences are less common in the Marmaris sub-region, there are numerous chromite quarries in the Köyceğiz, Dalaman and Fethiye areas, where significant Cr production has been recorded (Fig. 3.21). A number of quarries and open pits contain these chromites in Nergislidüz, Kazandere, Ilıkdere-Suçıktı, Sülek, Andızlık-Meşebükü-Erengediği, Dalaman-Ortaca and east of Fethiye (Fig. 3.21). The main features of these chromitite deposits are briefly explained in Table 3.11. Although this region is one of the major chromitite mining areas in Turkey, these deposits were almost mined out at shallow depths at the beginning of the twentieth century. This area was taken into consideration because of its economic potential and currently new exploration continues in deeper sections of the ancient ore deposits by using new methods and production technologies.

Fig. 3.21

Chromitite occurrences and sub-regions of Muğla region (A: Nergislidüz; B: Kazandere; C: Ilıkdere-Suçıktı; D: Akçaalan-Sülek; E: Andızlık-Meşebükü; F: Dalaman-Ortaca; G: Fethiye). (Simplified and modified after MTA 2002)

Table 3.11 General features of chromitite occurrences in Muğla, Denizli and Burdur regions

3.4.4.1.3 Denizli Chromitites

Chromitites in Denizli Region, as in the Muğla Region, are located within mantle tectonites, along the harzburgite-dunite level of Marmaris Ophiolite (Fig. 3.22). The chromite occurrences are mainly situated in the west and east sections of Beyağaç and Acıpayam. These occurrences are briefly introduced below (Fig. 3.22). The main Sub-Regions of the Denizli Region are Efekli, Topuklu, Karanfil, Çatak and Horozköy and the main features of chromitite deposits are briefly explained in Table 3.11. This region is much less active in terms of chromitite mining compared to the Muğla Region.

Fig. 3.22

Chromitite occurrences and sub-regions of Denizli region (A: Efekli; B: Topuklu; C: Karanfil; D: Çatak ve E: Horozköy). (Simplified and modified after MTA 2002)

3.4.4.1.4 Burdur Region Chromitites

Distribution of ophiolitic rocks and chromitite deposits in Burdur region is shown in Figs. 3.21 and 3.23, respectively.

Fig. 3.23

Chromitite occurrences and sub-regions of Burdur region (A: Gölhisar; B: Çavdır; C: Tefenni; D: SW Yeşilova; E: Western of Yeşilova; F: NW of Yeşilova KB, and G: N and NE of Yeşilova). (Simplified and modified after MTA 2002)

The first chromitite prospecting in the region was done by Alpay (1951) around Salda, Horozköy, Bahtiyar and Işıklar Village of Yeşilova district. This was followed by large scale studies of Borchert (1960, 1962) and Denkel (1972). The chromite occurrences were studied in detail by Sarıkaya and Seyrek (1976) and Yıldız et al. (1976). Boyalı (1996) studied some occurrences in the north of Salda Lake, Antalya and Isparta provinces. Renewed studies were carried out by MTA (Mineral Research and Exploration Institute) in 1991, and the findings from these studies are reported here. It can be concluded that the ophiolites in the eastern section of the province are generally mélange in character and not related with chromitite occurrences (Fig. 3.23). The ophiolites which are important in terms of chromitites are serpentinized peridotites that belong to Marmaris Ophiolite along the Çavdır-Tefenni-Yeşilova line. Chromitite deposits in this region are significantly different in type and size (Fig. 3.23).

Chromite deposits in the Burdur region can be divided into six sub-regions. In each sub-region, features of a few representative and important deposits are given in Table 3.11. Chromitite mining has been stopped for a long time in the Burdur and Denizli Regions, but is still active in the Muğla Region.

3.4.4.2 Isparta-Konya-Antalya Regions

3.4.4.2.1 Isparta-Konya-Antalya Ophiolites

Isparta ophiolites generally consist of ophiolitic melange and peridotite bodies. The ophiolites from SE to NW reach the Sütçüler district, eventually ending to the S in the Serik (Antalya) district. These are parts of ophiolitic imbricates related to Antalya Nappes (Fig. 3.24).

Fig. 3.24

Isparta-Konya-Antalya ophiolites and locations of chromitite occurrences. (Simplified and modified after MTA 2002)

Peridotites exposed within the Isparta province, contain chromitites in the western part of Aksu district and of Şarkikaraağaç. The peridotites are accepted as a part of Beyşehir-Hoyran nappes that outcrop around Beyşehir (Konya) towards the SE of the Province. These ophiolite piles are part of the nappe beneath the Beyşehir nappes (Mackintosh and Robertson 2009). This structural imbrication is consistent with the nappe tectonics of the Taurides (Fig. 3.24).

To the southeast of Beyşehir Lake, metamorphic sole and ophiolitic rocks were observed. The mélange unit is mostly seen in the eastern part of the Middle Taurus Mountains (Özgül 1997). Also in this region, Mesozoic Taurus platform carbonates are tectonically overlain by the Late Cretaceous mélange unit. The melange unit comprises serpentinite blocks, basalt, chert and pelagic sediments. Regionally, the Beyşehir-Hoyran ophiolite nappe was obducted towards the south over the Taurus carbonate platform in Late Cretaceous. Later on, in the Late Eocene period, the ophiolitic rocks and the Mesozoic carbonate platform thrust southward due to closing of the suture (Andres and Robertson 2002; Mackintosh and Robertson 2009).

In Antalya nappes, a number of ophiolitic melange slices of different size are present. The melange unit within the Antalya nappes generally consists of serpentinites. Within the mélange unit, large blocks derived from harzburgite, dunite, wherlite, gabbro, amphibolite are also present (Şenel 1997b). Late Cretaceous Tekirova (Antalya) ophiolite is one of the largest nappes in Antalya of the Western Taurus and is represented by, from bottom to top, harzburgitic tectonites, ultramafic-mafic cumulates, isotropic gabbros and sheeted dyke complex (Bağcı 2004). In Tekirova (Antalya) ophiolite, volcanic complex was not preserved and rocks which belong to the metamorphic sole are seen as tectonic slices within the tectonites (harzburgite). A number of isolated dykes, and rarely pegmatitic gabbro dykes, cut the whole ophiolitic section (Fig. 3.25, Bağcı 2004).

Fig. 3.25

Tectono-stratigraphic column of Antalya (Tekirova) ophiolites. (Revised after Bağcı et al. 2006)

3.4.4.2.2 Isparta Region Chromitites

Chromite deposits and occurrences in the Isparta province are shown in Fig. 3.24A. Peridotite bodies are located around Sipahiler-Yuvalı-Bağıllı-Kocular in the south; around Belceğiz-Yenicekale-Salur-Çeltek and Yaniköy areas in the east; and around Atabey-Kapıcak-Barla areas in the west. General characteristics of chromite occurrences are summarized in Table 3.12. These chromitites have no economic importance in the Turkish chromite mining sector.

Table 3.12 General features of chromitite occurrences in Isparta, Konya and Antalya regions

3.4.4.2.3 Konya Region Chromitites

In the Konya region, chromite occurrences are found in two districts. The first is situated to the south of Çumra district (Fig. 3.24B1) and the second is located to the west of Seydişehir district (Fig. 3.24B2). Details of these deposits are summarized in Table 3.12. These chromitites also have no economic importance in the Turkish chromite mining sector.

3.4.4.2.4 Antalya Region Chromitites

Chromitite deposits and occurrences in Antalya are generally exposed to the SW of Antalya province center (Fig. 3.24C). One group of chromite occurrences belonging to dunite sections occur around Atbükü-Kemer and to the SE of Çavuş Village, and another group of chromite occurrences related to different sizes of dunites within harzburgites occur around Kumluca. A total of 19 chromitite occurrences occur in the Kemer and Kumluca districts. These chromitites also have no economic importance in the Turkish chromite mining sector.

All these chromitite ores and occurrences of the three Regions are summarized in Table 3.12.

3.4.5 Region Five: Central Anatolian (Mersin, Adana, Kayseri) Ophiolites and Related Chromitite Deposits

Thin slices of ophiolites from Mersin merge with the ophiolites of the IAEZ (Izmir-Ankara-Erzincan Zone) around Refahiye (Erzincan). These ophiolite slices in the eastern part of the Inner Tauride suture are discussed in the first section. Ophiolites related to this zone begin from the Mersin Ophiolite and continue to the NE as the Kızıltepe Ophiolite, Alihoca Ophiolite, Pozantı-Karsantı Ophiolite, Pınarbaşı Ophiolite and Divriği/Güneş Ophiolite (Fig. 3.26).

Fig. 3.26

Ophiolites and chromitite occurrences of Mersin-Adana-Kayseri and Sivas Regions (IAESZ Izmir-Ankara-Erzincan Suture Zone, IPSZ Inner Pontide Suture Zone, BZSZ Bitlis-Zağros Suture Zone, DSFZ Dead Sea Fault Zone). (Simplified and modified from MTA 2002; Suture Zones are adapted from Okay and Tüysüz 1999)

Although the Sivas Region ophiolites are associated with this suture zone, they are interpreted as part of the NE Anatolian Division. In this chapter, mainly chromitite deposits and related ophiolite sequences in Mersin, Adana and Kayseri provinces will be introduced.

3.4.5.1 Mersin Region

According to the map in Fig. 3.26, the ophiolites that cover the most SW part of the region are defined as the Mersin Opholite (Fig. 3.27).

Fig. 3.27

Chromitite occurrences and sub-regions of Mersin ophiolite (A: Kösbucağı; B: Köserelli; C: Sıraç – Yassıtaş – Mühlü; D: Poyrazlı – Hacıalanı; E: Avrangedik; F: Takanlı – Akarca – Demirışık – Yeniköy; G: Horozlu – Kızılbağ; H: Musalı). (Simplified and modified after MTA 2002)

3.4.5.1.1 Mersin Ophiolites

Mersin Ophiolite, exposed beneath a thick Miocene cover at the westernmost end of the Eastern Taurus Mountain, forms a large massif at the southern flank of the Bolkar Mountains. This ophiolite body rests tectonically on top of an ophiolitic mélange, named Aslanköy formation (Demirtaşlı 1984), and is covered by Eocene sediments in the north section (Ternek 1957; Demirtaşlı et al. 1975; Demirtaşlı 1984; Özgül 1976; Gedik et al. 1979) and partly by Oligocene conglomerates. Pillow lavas, volcanic breccias, hyaloclastics, radiolarites, pelagic limestones with lava intercalations (possible Triassic in age: Juteau 1979, 1980; Çapan 1980), limestones (Maastrichtian; Gedik et al. 1979) and serpentinite-gabbro blocks are the typical rock association within the ophiolitic mélange that was emplaced onto the Jurassic-Cretaceous carbonate platform (Erendil 2002).

The Mersin ophiolite represents an oceanic lithospheric section, about 6 km thick, which from bottom to top consists of; a metamorphic sole, harzburgitic mantle tectonites, ultramafic to mafic cumulates, basaltic pillow lavas (Parlak et al. 1996). Metamorphic sole rocks form a thin slice, 50–70 m thick, beneath the harzburgitic tectonites. It generally consists of amphibolite, mica-schist, amphibolite-schist and marble (Parlak et al. 1995, 1996). The mantle tectonites are represented by harzburgite and dunite. The cumulate rocks start with ultramafic units, namely wherlite, pyroxenite, dunite at the bottom, passing upwards into mafic units such as olivine gabbro, gabbro norite, troctolite and anorthosite at the top (Parlak et al. 1996). The volcanics are characterized by pillow basalts and basaltic lava flows. The metamorphic sole, mantle tectonites and cumulate rocks were intruded by numerous diabase dykes (Parlak and Delaloye 1996).

3.4.5.1.2 Mersin Chromitite Occurrences

The general distribution of chromitite occurrences in ultramafic rocks of the Mersin Ophiolite was given in Fig. 3.27. These occurrences are within eight sub-regions: Kösbucağı, Köserelli, Sıraç – Yassıtaş – Mühlü, Poyrazlı – Hacıalanı, Avrangedik, Takanlı – Akarca – Demirışık – Yeniköy, Horozlu – Kızılbağ and Musalı sub-regions and summarized in Table 3.13. Although several chromitite deposits are present in the Mersin Region, they are mostly small and almost totally mined-out.

Table 3.13 General features of the chromitite occurrences in Mersin, Adana and Kayseri regions

3.4.5.2 Adana Region

3.4.5.2.1 Adana Ophiolites

In Adana province, ophiolitic rocks form an important part of Aladağ Tectonic Unit that forms a belt through to the SE from Pozantı. These rocks extend to the northern borders of the province, and for about 30 km in the same strike on Kayseri province (Fig. 3.26). The most comprehensive studies about ophiolites in the region were conducted by Tekeli et al. (1984).

Pozantı-Karsantı Ophiolite or “Aladağ Ophiolite” has a nappe character sequence that includes metamorphic rocks at its base and ultramafic-mafic rocks. It is divided into two groups, based on the rock association. The first was defined as “tectonite” and is an ultramafic rock association with metamorphic texture, derived from the upper mantle. The other group is a cumulate type rock association, represented by ultramafic to mafic rocks (Fig. 3.28).

Fig. 3.28

Generalized lithostratigraphy of Aladağ ophiolite. (Re-constructed after Tekeli 1981; Çakır 1978; Bingöl 1978; Çapan 1980; Çataklı 1983)

The Aladağ Ophiolite Complex consists of three units defined by rock types, structural features and location. These are, from bottom to top, ophiolite melange, metamorphic sole and oceanic lithospheric section (Tekeli et al. 1981; Çakır 1978; Bingöl 1978; Çapan 1980; Çataklı 1983) (Fig. 3.28). The mantle tectonites are rich in chromitite mineralization. Even though the chromite occurrences in this area, firstly reported by MTA, are of low grade, they form one of the important chromite mineralisation regions in the world, at least in terms of mineral resources.

3.4.5.2.2 Adana Chromitites

Adana province is a region where low grade, large scale chromitite deposits occur. The Kızılyüksek-Yataardıç chromitite deposits (Table 3.13) are 200 m long with an average grade of 5.35% Cr₂O₃, according to MTA estimation. In addition, there are low grade chromitite deposits with reserves that vary between a few millions of tonnes and a few tens of millions of tonnes, embedded within cumulate dunites in this region. Rising demand for chromitite ore in the last decade has improved the economics of large, low grade deposits. Thus, Adana province is an important region in Turkey for low grade chromitite deposits, especially in terms of production capacity and potential.

The Adana chromitite deposits are shown on Fig. 3.29. The sub-regions are; Dereyurt-Gerdağı-Beyçamı, Cehennemdere-Kırcakatran, Gerdibi-Deveboynu-Kaklık Dere, Sivişli-Mencektepe-Çötlüktepe-Badırıklıtepe, Kütüklütepe-Tozlutepe-Kartalkale Tepe-Gavurgeri Tepe, Ziyaret Dağı-Kaltar Dağı-Duvarlı Tepe-Keşgöz Tepe, Çanakpınarı Tepe -Kızılyüksek-Yataardıç, Darılık Köyü-Akinek Dağı-Yapraklıtepe and Hova Tepe-Sulukerer Tepe-Üçsivri Tepe; and their characteristics are also summarized in Table 3.13.

Fig. 3.29

Chromitite occurrences and sub-regions of Aladağ (Adana) region (A: Dereyurt -Gerdağı-Beyçamı; B: Cehennemdere-Kırcakatran; C: Gerdibi-Deveboynu-Kaklık Dere; D: Sivişli-Mencektepe-Çötlüktepe-Badırıklıtepe; E: Kütüklütepe-Tozlutepe-Kartalkale Tepe-Gavurgeri Tepe; F: Ziyaret Dağı-Kaltar Dağı-Duvarlı Tepe-Keşgöz Tepe; G: Çanakpınarı Tepe-Kızılyüksek-Yataardıç; H: Darılık Köyü-Akinek Dağı-Yapraklıtepe; I: Hova Tepe-Sulukerer Tepe-Üçsivri Tepe). (Simplified and modified after MTA 2002)

3.4.5.3 Kayseri Region

3.4.5.3.1 Kayseri Ophiolites

Kayseri province ophiolitic sequences outcrop in two regions as shown in Fig. 3.30. One of them is located in the SW border of the province and this a NE extension of Aladağ Ophiolite.

Fig. 3.30

Tectono-stratigraphic section of Pınarbaşı ophiolite. (Modifies after Vergili and Parlak 2005)

The second ophiolitic sequence in Kayseri province is the Pınarbaşı Ophiolite that forms a belt with a NE-SW extension around Pınarbaşı (Fig. 3.30). According to Vergili and Parlak (2005), these ophiolites are allochthonous slices emplaced onto the Eastern Taurus Autochthonous. The ophiolitic rocks mainly consist of three different rock associations, such as ophiolitic melange, metamorphic sole and a regular opholite sequence (Fig. 3.30).

3.4.5.3.2 Kayseri Chromitite Occurrences

Some of the chromitite occurrences in Kayseri province are observed in the SW, in Aladağ Ophiolite (A, B, C, D). The other important part is seen in Pınarbaşı Ophiolite (E, F, G, H and I in Fig. 3.31). Table 3.13 presents the main characteristics of the chromitite deposits in Mersin, Adana and Kayseri regions.

Fig. 3.31

Chromitite occurrences and sub-regions of Pınarbaşı ophiolite (Kayseri) (A: Sarıtaş Tepe; B: Tatlar-Kanlıpınar-Zorkunlu Dere; C: Divrikçakırı; D: Ademi Mah.-Asar Tepe-Melengeçli Tepe-Delialiuşağı-Aşağı Delialiuşağı; E: Kadılı-Kızılören-Artmak, Avşarsöğütlü, Toklar; F: Kaman ve Diliciler; G: Kırımuşağı, Pulpınar, Demircili-Kireçlikyayla; H: Yusuflar, Bahçecik, Emeğil, Solaklar, Büyükpotuklu; I: Üçsivri Tepe). (Simplified and modified after MTA 2002)

3.4.6 Region Six: SE Anatolian (Hatay, Osmaniye, Gaziantep, Kahramanmaraş, Adıyaman, Elazığ, Siirt, Van, Hakkari) Ophiolites and Related Chromitite Deposits

Ophiolite sections of the SE Anatolian Region extend along the Bitlis-Zağros Suture Zone (BZSZ) and are named “SE Anatolian Ophiolite Belt” (Fig. 3.32). Some of the ophiolite sections, namely the Göksun Ophiolite, Berit Metaophiolite, İspendere Ophiolite, Kömürhan Ophiolite, Guleman Ophiolite, Baykan Ophiolite, and Gevaş Ophiolite, were accreted to the metamorphic Tauride platform (Malatya-Keban platform) in the north. Other ophiolites are situated on the top of the Arabian platform in the south. These are Kızıldağ Ophiolite, Kılan/Meydan Ophiolite, Koçali-Karadut Complex and Yüksekova Complex (Sarıfakıoğlu et al. 2014) (Fig. 3.32).

Fig. 3.32

Ophiolites in SE Anatolia along Bitlis-Zagros-Suture (BZS) Belt. (Simplified and modified after MTA 2002)

Although some of these ophiolitic sequences are very fertile in terms of chromite mineralisation, like the Guleman ophiolite, they generally lackchromitite deposits.

3.4.6.1 Hatay-Osmaniye-Gaziantep-Kahramanmaraş Regions

3.4.6.1.1 Hatay Region

3.4.6.1.1.1 Kızıldağ Ophiolite

The Kızıldağ Ophiolite is exposed at the south-western end of the Amanos Mountains and consists of ultramafic and mafic rocks in a NE-SW tectonic lineament (Fig. 3.32). It displays a well-preserved oceanic lithospheric section in southern Turkey, from bottom to top: mantle tectonites, ultramafic-mafic cumulates, isotropic gabbros, sheeted dykes, volcanic rocks and cover sediments. The Kızıldağ Ophiolite is located in the Mediterranean coastline and covers a wide area.

The mantle tectonites mainly consist of harzburgites, dunite with lesser amounts of lherzolite and wherlite. They are cut by number of dykes such as pyroxenite, pegmatite gabbro and rodingitized diabase dykes with chilled margins (Bağcı 2004). The harzburgites form 70% of the tectonites and, together with the dunites, weather to a brown colour. Both of these rocks are dark green-black in unweathered outcrops. The less common Lherzolites are mainly seen along the transition zone into the cumulate rocks.

The ultramafic and mafic cumulates form the lowest level of oceanic crust within Kızıldağ Ophiolite and are exposed along the southern flank of the Kızıldağ massif. The cumulates taper from southeast to northeast, are emplaced tectonically on tectonites at the base, and exhibit a transitional contact with isotropic gabbros in their upper levels (Bağcı 2004). The cumulate rocks are cut by diabase and pegmatitic gabbro dykes, ranging in thickness from 2 to 60 cm (Bağcı et al. 2005).

3.4.6.1.1.2 Hatay Chromitites

Chromite deposits in Hatay Region are located mainly in the central part of the Kızıldağ Ophiolite, in the area at the west of Belen and in the NE section of Dörtyol district. Most of these deposits and occurrences are hosted within ultramafic tectonites. Chromitite occurrences in Kızıldağ centre are mainly located in Çerçikaya, Aşağı Zorkum, Yukarı Zorkum, Sarıgöl, Gümüşoluk and Arapgediği quarries (Fig. 3.33A1). Chromite occurrences close to the NE of Dörtyol district (Fig. 3.33A2) mainly occur in Emirali Damları and Şehmahmut Pleateu/Yanık Hill areas (see Table 3.14).

Fig. 3.33

Chromitite occurrences of Hatay, Osmaniye, Gaziantep and Kahramanmaraş (A: Hatay Region; B: Osmaniye Region; C: Gaziantep Region; D: Kahramanmaraş Region). (Simplified and modified after MTA 2002)

Table 3.14 General features of chromitite occurrences in Hatay and Osmaniye regions

3.4.6.1.2 Osmaniye Ophiolites

Ophiolitic sequences in this region were emplaced during Late Cretaceous onto the Mesozoic Carbonate platform (Yılmaz 1984) (Fig. 3.32). They have characteristics similar to the Kızıldağ Ophiolite in the NE. Yılmaz (1984) considered these ophiolite sequences under different names based on their composition and tectonic position, with the Zorkun Ophiolitic Melange, Yarpuz Ophiolitic Melange, Tozaklı Ophiolite, Ispirler Meta-Ophiolitic Melange and Berke Ophiolite being the main sequences. The internal structures of these ophiolites are not considered in this section of Chap. 3.

3.4.6.1.2.1 Osmaniye Chromitites

The distribution of Osmaniye region chromitite occurrences is shown on Fig. 3.33B. They will be presented under four main groupings: Kanlıkoz Yayla – Kıvrıkoğlu Yayla, Konak Sırtı, Aşağıbağ Mevkii, Çamlık Sırtı – Karacaüstü, Ürün Mahallesi – Armuttarla Mevkii, Cevizlik Tepe (B1); Kayalı, Issızca, Davutlar, Çulhalı, Karayiğit (B2); Burgaçlı – Arıklıtaş (B3); and Beşağaç Tepe, Mezar Tepe, Gördüktarla ve Çamdenizi (B4), which are summarised in Table 3.14.

3.4.6.1.3 Gaziantep Region

3.4.6.1.3.1 Gaziantep Ophiolites

Ophiolites that were defined as “Allochthonous Series” and exposed in the west of the province, are mainly the Upper Jurassic-Early Cretaceous Koçali Complex, the Early-Middle Maastrichthian Karadut Complex, and the Middle-Late Maastrichtian Ophiolite Nappe (Fig. 3.32). These ophiolitic sequences were emplaced along the suture zone at different times and alternate with several magmatic and volcanic rocks of the Tethyan closure. Here we discuss only the chromitite deposits and not these ophiolitic sequences.

3.4.6.1.3.2 Gaziantep Chromitites

Chromite occurrences in Gaziantep province are generally centred in the Islahiye region (Fig. 3.33C1–C4). Ultramafic tectonites and cumulates of the Islahiye Ophiolite Nappe have small chromitite occurrences, reported by MTA in 1999 during chromitite-nickel prospecting surveys.

Little chromite was extracted from exploration quarries and no more than five deposits achieved a few thousand tonnes of production. The grade of chromite ores hosted in cumulate dunites, ranges from 10% to 30% Cr₂O₃ and many of these occurrences and deposits are not suitable for mining. The grade of chromitite occurrences in ultramafic tectonite basal dunite zones varies between 40% and 52% Cr₂O₃ and these higher grades have enabled a limited amount of production during periods of high demands and higher prices. The Gaziantep province chromitites and occurrences are shown as “Serial C” on Fig. 3.33. The general features of these chromitite deposits are given in Table 3.15.

Table 3.15 General features of chromitite occurrences in Gaziantep region

3.4.6.1.4 Kahramanmaraş Region

3.4.6.1.4.1 Ophiolites

There are many lithological associations that consist of ophiolite components in the Kahramanmaraş province and these are exposed in Malatya-Bitlis ophiolites group (Erendil 2002). Ophiolites of this belt occur as tectonic slices sandwiched between metamorphic massifs or unmetamorphosed younger deposits (Erendil 2002). Ophiolite slices of the Taurus Belt and Arabian Platform are shown in Fig. 3.32.

To the north of Afşin and Kayseri border; the Göksun Ophiolite and the Berit Ophiolite are exposed between Andırın and Türkoğlu and can be described together. They consist of slices that were emplaced in the region at different times by overthrust nappe tectonics.

Chromite mineralisation in the region, occurs mostly in small deposits (Fig. 3.33D1–D3) which have been occasionally exploited with small-scale production.

In the Dağlıca Melange exposed between Afşin and Sarız, marketable chromitites occur in small deposits. To the south of Ekinözü, in the Berit Ophiolite, low Cr₂O₃ grade occurrences were identified with the “high aluminium” content depending on dunite abundance in the ultramafic cumulate units. The general features of these chromitite deposits of the Kahramanmaraş region are given in Table 3.16.

Table 3.16 General features of chromitite occurrences in Kahramanmaraş region

3.4.6.2 Adıyaman and Elazığ Regions

3.4.6.2.1 Adıyaman Region

Ophiolite sequences in the Adıyaman province are defined as the Karadut Complex, the Koçali Complex and the Opholite Nappe (Fig. 3.32).

3.4.6.2.1.1 Chromitites

Chromite deposits and chromitite occurrences in this region are located in the Ophiolite Nappe, within a sequence of peridotites referred as the Koçali Complex in previous studies (Yoldemir 1987).

The early chromite exploration programs in this region were carried out by MTA in 1973. Since 1989, information about chromitite occurrences in Adıyaman region was updated by field studies, and they are located mainly in Gölbaşı, Besni, and Tut central districts (Fig. 3.34). Within the framework of the data obtained during prospecting work, it can be concluded that the chromite deposits and occurrences in the Adıyaman territory are small with a potential of between a few hundred and a few thousand tonnes. The general features of these chromitite deposits in the Adıyaman region are given in Table 3.17.

Fig. 3.34

Chromitites of Adıyaman region and sub-regions (A: Harmancık ve Çorak; B: Besni; C: Tut; D: Yazıbaşı-Akçalı-Kotur). (Simplified and modified after MTA 2002)

Table 3.17 General features of the chromitite occurrences in Adıyaman region

3.4.6.2.2 Elazığ Region

The Elazığ-Alacakaya (Guleman) territory has the largest chromite resources and production in Turkey and accounts for about 45% of the total chromite resources. Mining in the Elazığ-Alacakaya territory started in 1936 and still operates today. Many scientific studies were conducted in the region aimed at the understanding the mechanism of chromitite genesis in order to improve exploration studies (Kovenko 1940; Borchert 1952; Ercan et al. 1970; İskit 1973; İzmir and Koç 1977; Ortalan and Erdem 1977; Özkan 1977, 1982a, b; Özkan and Sümer 1986, 1987; Engin et al. 1980–1981, 1987; Balcı 1986; Engin 1986; Engin and Sümer 1987).

The Guleman ophiolite unit covers an area of 200 km². About 65% of the unit is represented by tectonite and the rest is cumulate rocks (Fig. 3.35). The cumulate rocks are located within the tectonites, or generally surround them. Although there are chromite deposits in both rock groups, those in tectonites are more important.

Fig. 3.35

Geology of Guleman ophiolite and major chromitite deposits. (Modified after Özkan 1982b)

The dunite unit in Kef territory, is considered as a transition zone between tectonites and cumulates and the major Western Kef Deposit is exposed at the base of this dunite unit. Some other chromite deposits in the region occur in thin dunite envelopes within harzburgites.

Although the Guleman chromite deposits are classified as Alpine type, their continuity in terms of strike and dip directions make these deposits quite special. A large component of chromite mineralization is concordant with the internal structure of the host rocks. Figure 3.35 shows the major deposits in Guleman where mining was carried out by both open pit and underground mining operations. The principal features of these deposits are summarised in Table 3.18.

Table 3.18 General features of chromitite occurrences in Elazığ (Guleman) Region

3.4.6.3 Siirt-Van-Hakkari Regions Chromite Deposits

3.4.6.3.1 Siirt Region

3.4.6.3.1.1 Ophiolites

The Siirt ophiolites are part of the Bitlis Metamorphic Massif and occur as tectonic slices within this Massif. They are generally distributed around Baykan and Şirvan and rarely NE of Pervari (Fig. 3.32). The ultramafic unit was named Guleman ultramafics by Sungurlu (1974), whereas Perinçek (1978) referred to it as the Guleman group. The best outcrop of the unit is north of the Guleman settlement area in the east of Elazığ province, Maden district (Şenel 2007). This ophiolitic sequence was examined under different names, such as Guleman Group, Şimsin Formation (Açıkbaş and Baştuğ 1975); Guleman Metamorphics (Perinçek 1978); Guleman Peridotite Unit (Engin et al. 1980–1981); Guleman Ophiolite (Özkan 1981–1982, 1983) (Fig. 3.36).

Fig. 3.36

Ophiolites of SE Anatolia and major chromitite deposits (A: Siirt Region; B: Van-Özalp Region; C: Hakkari Region). (Simplified and modified after MTA 2002)

3.4.6.3.1.2 Chromitites

In the Siirt province, at Büzügan section, 41 chromitite outcrops have been identified. They occur mostly in serpentinized harzburgites in a melange environment, And exhibit limited continuity in both strike and dip (Fig. 3.36A).

Information for this region, is largely based on prospecting work conducted by MTA in 1974. Private companies subsequently carried out both exploration and production however, considering the geological structure of the region, the potential for substantial chromite production is considered limited.le.

3.4.6.3.2 Van Region

The Gevaş Ophiolite around Gevaş and the Özalp Ophiolite around Özalp and Saray areas, are the main ophiolitic sequences in the Van region. All chromitite occurrences in the region are located in the Özalp Ophiolite.

3.4.6.3.2.1 Özalp Ophiolite

This ophiolite outcrops in a wide region from Van in the centre to the east, near the Iran border (Fig. 3.36). Ophiolitic complex (melange) forms a layered structure around Özalp and Saray districts, consisting of basic components like deep-sea lavas (mostly spilitic), serpentinites and diabases, radiolarites-limestones-multicolored shales and marls (Ketin 1977). The Özalp Ophiolite is overlain by Neogene age sediments, suggesting that it was emplaced in Late Cretaceous-Paleocene time. The ophiolitic sequence is represented mostly by upper mantle harzburgites and minor amounts of gabbros. The tectonite peridotites are cut partly, or completely, by rodingitised diabase dykes (Günay et al. 2012).

3.4.6.3.2.2 Van Region Chromitites

Chromitite occurrences in Van Region are located in Özalp and Saray Villages, along the Land Border of Iran and Turkey (Fig. 3.36B). The main features of these chromitite deposits are summarized in Table 3.19. According to this table, chromitites in Özalp region are mainly in massive character, lens shaped, and banded in lesser amount. In contrast, the character of chromitites in eastern and SE part of Özalp Village are disseminated and they are mostly brecciated, partly lens shaped. Dimensions are also quite limited in both section, means that no significant chromite reserve has expected in the region.

Table 3.19 General features of chromitite occurrences in Van region

3.4.6.3.3 Hakkari Region

The ophiolites that are common in the Hakkari region (Fig. 3.36) are known as Yüksekova Complex and outcrop around Cilo Mountain of Hakkari and Yüksekova along the Bitlis –Zagros Suture Zone (Perinçek 1989). The Yüksekova Complex is mainly represented by spilitic basalt, agglomerate, volcanic sandstone, conglomerate, limestone, chert, granite, granodiorite, quartz diorite, tonalite and flysch facies rocks and in lesser amounts serpentinite, gabbro and diabase units (Sungurlu et al. 1985).

3.4.6.3.3.1 Hakkari Chromitites

Ophiolite occurrences in the Hakkari region are generally of melange character and they exhibit an orderly internal structure, belonging to a cumulate group, they show alternation of serpentinized dunite, wherlite and gabbro. In the ophiolitic melange extending for about 15 km SW of Yüksekova district in an approximate N-S direction, these bodies contain localised with chromitite occurrences. Due to lack of prospecting activity of the ophiolitic melange units to the east and NE sections of Yüksekova district, there is no detailed information about the structure of these sections (Boyalı and Sayın 1974; Sümer and Artan 1983).

Some prospecting and mineral exploration was conducted by MTA in 1983 in the Hakkari-Yüksekova Complex, with the specific aim of assessing the potential of the chromitites. This work showed that the chromitite mineralization is mainly associated with dunites in ultramafic cumulate units. Chromitites in peridotites are highly cataclastic and occur as discontinuous lens-shaped masses. The general features and potential for chromititite occurrences in the territory are presented below.

Ophiolite rocks in the Kışlacık village section in the Cilo Mountains are located in an area with a NW-SE trend in a 600–1000 m wide belt of cumulates alternating with dunite, wherlite and gabbro.

They are generally melange in character, but retain much of their internal structures. Chromitite lenses in serpentinized dunites, generally show a parallel sequence to ophiolite-limestone. Here, chromitites can be grouped as those between Kışlacık Village and Görhele Hill (2.718 m) and the ones between Alakan Village and Öküzölen Hill (2200 m).

Between Kışlacık Village and Görhele Hill, the serpentinized cumulate dunites, host about 24 chromitite lenses in 8 groups that have a general N-S trend. These lenses are generally in structural contact with serpentinized dunites, and are between 1 and 13 m long, with thicknesses varying between 0.5 and 7 m. The strike of these chromitite lenses is generally N60–65°E or 50–55°SE, but they have limited continuity along strike and down dip. Chromitites also occur in the form of large tectonic blocks. Chemical analysis of samples from chromitite lenses, indicate Cr₂O₃ grades of between 17.86% and 47.45% Cr₂O₃; SiO₂ content is between 1.66% and 17.74%. The dominant Cr₂O₃ content is around 30–35% (Sümer and Artan 1983).

Lens shaped chromitite bodies located mostly on the SW side of Öküzölen Hill (2.200 m, a.s.l.), SW of the Alakan Village, consist of two sequences, with a stratigraphic separation of 30 m, that continue in parallel, but with similar interruptions, for 400 m.

The chromitite lenses are between 0.5 and 30 m long and between 0.2 and 4 m thick. Strikes and dips are N25E, 40° SE; N55E, 46°SE and N50W, 42°SW. Chemical analysis of samples taken from chromitites in Öküzölen Hill, where disseminated chromitites are dominant, indicate that the Cr₂O₃ grade varies between 5.30% and 20.55%; SiO₂ content varies between 13.65% and 20.45% (Sümer and Artan 1983).

3.5 Conclusions

The demand from metallurgy and chemistry industries in Turkey are not sufficient to influence the chromitite market prices. As this sector is highly dependent in exploration, the fluctuations in the global market tend to affect Turkey’s chromitite production as well. Nevertheless, as the chromitite occurrences near the surface began to run out, junior mining companies in the country started to close down with the market scene being left to the larger companies with greater investment capabilities. In this circumstances, unless there is a global economic crisis, Turkey’s chromitite production may be stabilised. But, this would have a negative effect on a high number of employees who work for the junior mining companies, as they would be forced to find another sources of income.

In terms of high quality steel production, chrome is still an unmatched resource today. Therefore, chromitite as a metallic ore will always have a global demand in the short and medium term. All the same, it is evident that producing chromitite from shallow depths using traditional methods will soon no longer be desirable in Turkey. Aiming for deeper targets makes it necessary to invest more for research and exploration. Necessary operations have started in Turkey by using more sophisticated software technologies and modelling, more geological and geophysical data which can be helpful in reaching deeper levels of these ore deposits,. Historical mining activities and their records serve as a guiding source for these operations. In addition to this some important deposits which were abandoned without being processed before, are today being considered for producing concentrated ore. This can be taken as a hopeful development, paving the way for new opportunities in the chromitite mining sector in Turkey.