Abstract
The western Anatolian Miocene volcano-sedimentary basins in the Gördes, Demirci and Şaphane regions host abundant heulandite/clinoptilolite (hul/cpt) bearing widespread zeolitized pyroclastic rocks. Lithostratigraphy of these zeolitic pyroclastic levels show comparable association. Petrography and geochemistry of all the samples show mainly rhyolithic and rhyodacitic character and ash size vitric tuffs. Polarized microscopy and X-ray diffraction determinations of the samples show composition of 55–95 wt % hul/cpt and accessory of smectite, illite/mica, opal–CT, quartz, K–feldspar, plagioclase and opaque minerals. Geochemical results obtained from the studied samples represent hul/cpt–rich facieses formed under the moderate alkaline conditions in these pyroclastic units. Correlation of geochemical results and concentration of hul/cpt in these pyroclastic rocks gives some chemical data on zeolitization process and on adsorption and ion-exchange character of hul/cpt type of zeolites. Depleted and enriched elements by zeolitization have similar ionic radii in general. Ca and H2O clearly increased, Si, Na and Si/Al ratio decreased in hul/cpt bearing Lower-Middle Miocene pyroclastic rocks of western Anatolia. Additionally, Sr, Nb, Th, Ni, Hf, Cs, Pb and Ta increased, and Zr, Co, W and most of the rare earth elements (REE) decreased in highly hul/cpt–rich pyroclastics.
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INTRODUCTION
The pyroclastic rocks having high content of volcanic glass and porosity are widely transform to zeolite–rich rocks in the nature. Numerous parameters play role for the formation of zeolites in the primary materials; such as fluid parameters (silica activity, cation concentrations, pH, Eh, alkalinity), temperature, pressure, chemistry of parent rock, rock–solution interaction time and types of the hydrological system/ geological environment (Iijima, 1978; Surdam and Sheppard, 1978; Barth–Wirshing and Holler, 1989; Hay and Sheppard, 2001; Chipera and Apps, 2001). As an isostructural zeolite mineral, hul/cpt are usually formed from volcanic glass fragments in pyroclastic rocks in closed or open hydrological systems, deep–sea sediments and hydrothermal zones (Gottardi and Galli, 1985; Hay and Sheppard, 2001). Although there has been a general concept that the cpt has higher Si/Al, Na + K/Ca + Mg ratios and thermal stability than hul, the Si and Al in framework and alkali and earth alkali cations in the extra-framework of hul and cpt are highly variable (Boles, 1972). Therefore, Ca–, Na–, K– and Sr–hul and Ca–, Na– and K–cpt are common in the nature (Coombs et al., 1997).
Zeolite content in rock sample effects its adsorption and ion-exchange capacities due to the open framework of zeolites. Especially, hul/cpt–rich tuffs are commercially attractive due to their low costs and widely uses for agricultural, commercial and environmental applications (Ames, 1961; Loizidou and Townsend, 1987; Mumpton, 1988). The selectivity series for cpt–rich tuffs in some studies are given as: Cs > Rb > K > Na > Li for the alkali elements and Ba > Sr > Ca > Mg for the earth-alkali elements (Hector, California; Ames, 1961); Pb > Cd > Cu > Co > Cr > Zn > Ni > Hg (Owyhee County, Idaho and Ash Meadows, Nevada; Zamzow et al., 1990); Pb > Cu > Zn > Cd > Ni (Beli Plast mine, Bulgaria; Shaheen et al., 2012).
During diverge tectonic of the western Anatolia (Turkey) several volcanic materials bearing deposits developed in E-W and NE-SW trending basins (Yılmaz et al., 2000; Helvacı et al., 2006; Helvacı, 2015). Simav, Gediz, Büyük Menderes, and Küçük Menderes basins are developed E–W trending and Bigadiç, Gördes, Demirci, Selendi, and Uşak-Güre basins are NE–SW trending (Helvacı, 2015). The basement rocks in these regions comprise of Paleozoic metamorphics of Menderes massif and Mesozoic ophiolite and carbonate of the İzmir–Ankara suture zone. Miocene sediment groups are generally originated from massif basement slope, alluvial fan and fluvial materials which continues with the lacustrine sediments. First pyroclastic levels of these basins were formed after deposition of coarse-grained in the lower part of the Miocene units. Most of these levels which were deposited in lacustrine environment have neoform mineral facii including high content of hul/cpt type of zeolites (Esenli, 1993; Snellings et al., 2008; Semiz et al., 2011).
A series of rhyolithic–rhyodacitic tuff including medium and high content of hul/cpt type of zeolite mineral from the pyroclastic levels of three Miocene basins in west Anatolia (Turkey) are the subject of this study (Fig. 1). Representative samples (Gördes: 6; Demirci: 5 and Şaphane: 6) are selected from the dust–ash, glassy tuffs to determine and correlate lithostratigraphic positions, mineralogical and geochemical compositions of pyroclastic rocks based on their concentration of hul/cpt. Although, numerous studies have been reported about major oxides of hul/cpt–rich natural samples, there are no detailed studies on their trace and rare earth elements compositions. Therefore, the aim of this study is to fill this gap and explain the major, trace, and rare earth elements in zeolite-rich tuffs from the west Anatolia in order to determine the chemical changes during the zeolitization processes. This new data on zeolite-rich rocks will provide a critical conclusion about the genetic relationship of hul/cpt group zeolites and their primary volcanic host units. Additionally, this research will guide future exploration and utilization of these zeolite deposits.
Location and generalized geological map including studied Miocene basins in west Anatolia (modified from Yılmaz et al., 2000).
ANALYTICAL METHODS
Seventeen samples from the pyroclastic levels of the Miocene sequences in the Gördes, Demirci and Şaphane regions were collected and studied petrographically, mineralogically and geochemically. A polarized-light microscope (Leica) were used for determination of petrographic thin sections of the samples; particularly for definition of texture and primary components. All samples were analyzed by X-ray diffractometer for definition of fine-grained neoform components. X-ray diffraction (XRD) analyses were performed by Bruker D8 Advance instrument with Ni–filtered CuKα radiation at a scanning speed of 1° 2θ/min and a tube voltage of 40 kV and current 40 mA at the laboratory of İstanbul Technical University (Turkey). XRD–reference intensity method (Chung, 1975) was used to determine semi-quantitative modal analyses of the samples by using the reference intensity constants for minerals and steps of methodology given by Ekinci–Şans et al. (2015). The detection limits of mineral concentrations are estimated at approximately 5%.
Chemical analyses of 17 tuff samples were determined by X-ray fluorescence (XRF) method for major elements and inductive couple plasma-mass spectroscopy (ICP–MS) for trace elements at the JAL laboratory of İstanbul Technical University (Turkey). Five grams of sample pulp was crushed to 100–mesh size for these analyses. Pressed discs prepared by binder and boric acid were analyzed using by Bruker S8 Tiger model XRF equipment. Trace element concentrations were determined using Perkin Elmer Elan DRC–e 6100 ICP-MS instrument. One-tenth gram of sample was treated by acid mixture (3 HCl + 1 HNO3 + 1 mL HF, 220°C, 40 bar, 1 hour). A 5% boric acid solution was added to the mixture during dissolution. Normalization of REE concentrations was carried out using the North-American Shale Composite (NASC) according to Haskin and Haskin (1966). REE anomalies were calculated from the normalized values of the neighboring REE (for example, the formula of Ce/Ce* = 2CeN/(LaN + PrN) given for the Ce anomaly; De Baar et al., 1985).
RESULTS
Geological Setting and Mineralogy
Lithostratigraphic correlation of the Gördes, Demirci and Şaphane regions are shown in Fig. 2. Mineralogical compositions and estimated percentages were determined by XRD semi-quantitative modal analysis method of the samples (Table 1; GR: Gördes, DM: Demirci and SP: Şaphane). Samples are stratigraphically ordered in this table (from bottom to top; 1 to 6 for GR and SP groups and 1 to 5 for DM group). The basement of the study area comprises of Paleozoic Menderes massif and generally limestone and ophiolite complex of Mesozoic İzmir–Ankara suture zone. These units are unconformably overlain by approximately 1000 m Miocene units. Pyroclastic units which is the subject of this study show about 100 m thickness in the regions.
Comparison of the Miocene stratigraphy of the Gördes, Demirci and Şaphane regions (gray colored ones are zeolite–rich pyroclastic units subjected in this study; MM: Menderes massif, İAZ: İzmir–Ankara suture zone).
Gördes. Miocene sequence comprises of block–pebble–sand materials at the lower level (lower coarse–grained unit) and continues upward with pebble–sand type sediments in the Gördes region (lower fine–grained unit) and overlain conformably by a volcanic tuff level (lower tuff unit) (Fig. 2; Esenli, 1993). Lacustrine sediments having fine–grain and thin–medium layers of clastic and tuffaceous layers (upper unit) and tuffs which partially mapable (upper tuff unit) overlay the lower tuff unit. Gördes zeolitic (hul/cpt) samples (GR in Tables 1, 2) are from the lower tuff unit. This unit is the main industrial raw material for mining zeolite today and have a continuous several kilometers N–S trending exposures. Thickness (<80 m) and grain size (agglomerate-ash-powder) decrease from north to south. They show rhyolithic-rhyodacitic character, and generally comprise of vitric and ash-dust tuffs. Abundant zeolitic glass shards associated with quartz, plagioclase (albite–oligoclase), K–feldspar, biotite and lithic fragment. K– and Ca–types of clinoptilolites having coarse grain size (10 × 5 × 2 mµ) and high stability (thermally stable up to 700°C) and heulandites having fine grain size and low stability were reported by Esenli (1993) and Esenli and Kumbasar (1998) from the lower tuff unit. XRD determination of GR samples reveal concentration of 70–90% hul/cpt associated with accessory opal–CT, quartz, feldspar, smectite, and illite/mica (Table 1).
Demirci. The lower part of Miocene sequence comprises of block–pebble–sand size of clastics and sandstone–conglomerate, tuffite, mudstone, marl, limestone, and shale in the Demirci region (Fig. 2; Kürtköyü and Yeniköy formations; İnci, 1983). These units continue upward with sandstone, claystone, marl and have lateral transition with pyroclastic rocks (Mahmutlar formation and Akdere tuff). Pyroclastic rocks are covered by sandstone, mudstone, shale (locally bituminous), limestone and tuffite bearing lacustrine unit (Demirci formation) that is laterally and vertically transects with rhyolite-rhyodacite lavas (Sevinçler volcanics). Demirci samples (DM in Tables 1, 2) are related to Akdere tuff. Akdere tuff is widely exposed at the north of Demirci; around Akdere village having approximate 60 m thickness of vitric-crystal and ash-dust tuffs and pumicites. Petrographic determination show that tuff samples composed of mainly glass shards that are completely zeolitized, and associated with K-feldspar, quartz, biotite, muscovite, amphibole, opaque minerals and coarse pumice and lithic fragments. XRD analyses of DM samples show concentration of 85–95% hul/cpt accompanied by opal–CT, feldspar, smectite, and illite/mica (Table 1).
Şaphane. The lower part of Miocene sequence in Simav–Şaphane–Gediz region (Kızılbük formation; Mutlu et al., 2005) consist of sandstone, conglomerate, claystone and tuff levels (Fig. 2). Rhyolithic Civanadağ tuffs and rhyodacitic Akdağ volcanics (Middle Miocene; 14.6 Ma; Seyitoğlu et al., 1997) are located over the Kızılbük formation. Zeolitic tuff level of Kızılbük formation is named as Karacaderbent tuff by Mutlu et al. (2005) and Snellings et al. (2008). Şaphane samples (SP in Tables 1, 2) were obtained from this tuff unit. Tuffs outcrop NE-SW trend between Köpenez and Çavuşoğlukayası hills, SW of Şaphane, having 1 km length and 200 m width. Yellowish green sandstone outcrops at the lowermost of the sequence and exhibit alternation with marl–limestone–claystone at the upper level and have conformable transition with Akdağ volcanics. These volcanics show beige, pale beige, beige-grey, pale green color and generally characterize as vitric rhyolite–rhyodacitic tuffs. Petrographical determination show presence of volcanic ash-dust size glass shard and trace of pumice and mineral fragments. Mineral fragments such as plagioclase, K-feldspar, quartz, and biotite generally show concentration of <10%. XRD analyses of SP samples show concentration of 55–95% hul/cpt accompanied by minor to trace opal–CT, quartz, feldspar, smectite, and illite/mica (Table 1). Smectite enhance up to 25% in only one level.
Geochemistry
Chemical analyses of hul/cpt–rich tuff samples from the Miocene Gördes, Demirci and Şaphane basins (GR, DM and SP groups) are given in Table 2. The samples from all regions have range of SiO2 (63.37–72.60), Al2O3 (10.11–12.75), Fe2O3 (0.43–1.71), MgO (0.39–1.16), CaO (0.70–3.66), Na2O (0.07–3.63), K2O (1.48–5.81), TiO2 (0.05–0.36), and LOI (7.65–14.93 wt %). Totals of MgO+CaO and Na2O+K2O vary from 1.09 to 4.11 wt % and 1.55 to 6.96 wt % and the ratios of SiO2/Al2O3 and Na2O + K2O/MgO + CaO vary from 5.02 to 6.41 and, 0.42 to 5.63, respectively. The samples show calc-alkaline (mainly high–K calc–alkaline) character according to K2O + Na2O–FeO–MgO (AFM) diagram (Fig. 3a; Irvine and Baragar, 1971) and K2O–SiO2 diagram (Fig. 3b; Peccerillo and Taylor, 1976). The samples appear in rhyolite–rhyodacite/dacite–trachyandesite–trachyte boundaries on the Nb/Y–Zr/TiO2 diagram of Winchester and Floyd (1977) (Fig. 3c). Compositions close to the trachyte and trachyandesite in this diagram are controversial because of the Y mobilization; decreasing during zeolitization in general (Christidis, 1988). Thus, the samples may be considered as rhyolite–rhyodacite that is supported by the petrographical determination.
Discrimination and classification diagrams for the zeolite (hul/cpt)–rich pyroclastic rocks from the Miocene Gördes, Demirci and Şaphane basins in west Anatolia: (a) K2O+Na2O–FeO–MgO (AFM) diagram (Irvine and Baragar, 1971), (b) K2O–SiO2 diagram (Peccerillo and Taylor, 1976), (c) Nb/Y–Zr/TiO2 diagram (Winchester and Floyd, 1977).
Demirci (DM) samples have higher alkaline characters among the three regions [Na2O + K2O/MgO + CaO: 0.93–5.63 (average 2.16) in DM; 0.84–1.51 (average 1.11) in GR and 0.93–2.91 (average 1.33) in SP samples; Table 2]. They have also higher ratios of SiO2/Al2O3 and lower Ca and Mg than GR and SP samples. This is probably related to the different chemical compositions of circulating solutions through the host rocks between the regions. In this manner, Demirci Miocene basin is underlain by Si–, Na– and K–rich metamorphics of the Menderes massif (MM) basement rocks (Fig. 2). Ca– and Mg–rich basement group; the Mesozoic İzmir–Ankara suture zone (IAZ) including limestone and ophiolite complex is absent in Demirci basin, while it is present in Gördes and Şaphane basins (Fig. 2). On the other hand, in the studied samples, Ba and Sr have elevated in Ca–rich samples probably due to Ba and Sr substituted for Ca easier than Na in the zeolite structure. Major oxides, Ba, Sr, Rb, Zr and Ni of all studied samples generally show low-medium negative correlation with SiO2 (Fig. 4). There is clear negative correlation between SiO2 with each of Al2O3, Fe2O3, MgO, CaO, and K2O. The SP samples show different accumulation on some diagrams and composed of low SiO2 and high Al2O3, MgO, K2O, TiO2, Ba, Sr, and Zr. GR and DM samples show wide but SP samples narrow distribution on Harker diagrams.
Harker diagrams for major oxides and some trace elements versus SiO2 for the pyroclastic rocks from the Miocene Gördes, Demirci and Şaphane basins in west Anatolia.
Trace and REE contents of the hul/cpt–rich pyroclastic rock samples were normalized to the N-MORB (Sun and McDonough, 1989; Fig. 5a) and chondrite values (Boynton, 1984; Fig. 5b). Trace element profile of the samples illustrates homogeneity and enrichment for light REE (LREE) and inhomogeneity for medium REE (MREE) and partly flat for heavy REE (HREE). The samples exhibit negative anomalies of high-field strength elements (HFSE), especially in Nb, P and Ti relative to adjacent LILE and LREE and UCC. Th, K and Pb exhibit positive anomalies. MREE and HREE generally show flat pattern. Samples of the Gördes, Demirci and Şaphane regions have negative Eu anomaly (Eu/Eu* = 0.14–0.99) relative to chondrite. Most of the trace elements were enriched in Şaphane pyroclastic rocks (SP samples) compared to the other regions. The ƩREE, LREE, MREE and HREE are higher in SP than GR and DM samples and also Eu/Eu* is clearly higher (0.87–0.99) than those of GR (0.14–0.42) and DM (0.19–0.85). Th/U ratios of the samples (Table 2; 4.07–15.54, except one sample; 0.66) revealed altered source according to the average Th/U ratio of UCC (3.8; Taylor and McLennan, 1985; Condie, 1993; McLennan, 2001).
(a) N–MORB normalized trace element (Sun and McDonough, 1989); (b) chondrite–normalized (Boynton, 1984) REE spider diagrams for the pyroclastic rocks from the three Miocene basins in west Anatolia.
Some REE findings; particularly negative Nb, P and Ti and positive Th, K and Pb anomalies address contamination of crustal material and island arc volcanics and subduction-related origin (Weaver and Tarney, 1984; Hofmann, 1988). The samples plot completely on the active continental margin (ACM) field in the Th/Ta–Ta/Yb and Th/Hf–Ta/Hf geotectonic diagrams given of Schandl and Gorton (2002) (Fig. 6). Additionally, the samples plot as a line into the volcanic arc array on the Th/Yb–Th/Yb variation diagram of Pearce (2008) (Fig. 7). These results exhibit similarity to the Miocene calc-alkaline volcanics from the west Anatolia reported by Seyitoğlu and Scott (1992), Mutlu et al. (2005), Ersoy et al. (2008, 2014) and Kaçmaz (2016).
Plots of the pyroclastic rocks samples from the Miocene Gördes, Demirci and Şaphane basins in west Anatolia on the Th/Ta–Ta/Yb and Th/Hf–Ta/Hf geotectonic diagrams given by Schandl and Gorton (2002) (ACM: active continental margin, WPVZ: within–plate volcanic zone, WPB: within-plate basalt, MORB: mid–ocean ridge basalt).
Plots of the pyroclastic rocks samples from the Miocene Gördes, Demirci and Şaphane basins in west Anatolia on the Th/Yb vs Th/Yb variation diagram of Pearce (2008).
DISCUSSION
Zeolite (hul/cpt)–rich pyroclastic rocks from the Miocene Gördes, Demirci and Şaphane basins are probably stratigraphic equivalent of each other. Purvis et al. (2005) reported 19.16 ± 0.09–17.04 ± 0.35 Ma based on Ar/Ar radiogenic aging of biotites and sanidines from pyroclastic rocks of Gördes (lower tuff unit of this study; lacustrine tuff facii of Purvis and Robertson, 2004; Güneşli volcanics of Ersoy et al., 2011). The ages of 19.75 ± 0.07–19.06 ± 0.05 Ma (Ar/Ar) for dacitic Sevinçler volcanics and 17.58 ± 0.09 Ma (Ar/Ar) for andesitic Asitepe volcanics from the Demirci basin were given by Ersoy et al. (2012). Stratigraphically, zeolitic Akdere tuff in Demirci basin is located between these two volcanic units. Additionally, rhyolite of Akdağ volcanics in the Gediz-Şaphane region was aged as 20.30 ± 060–19.00 ± 0.2 Ma (K/Ar aging; Seyitoğlu et al., 1997; Helvacı and Alonso, 2000). Ersoy et al. (2011, 2014) reported 20.00 ± 0.20–17.90 ± 0.20 Ma (K/Ar and Ar/Ar) from the dacitic-rhyolithic Eğreltidağ volcanics at the bottom of andesitic-dacitic Yağcıdağ volcanics of Selendi Miocene basin, close to Demirci and Şaphane regions. The authors also explained these volcanics were equivalent to the Güneşli volcanics of Gördes and Sevinçler volcanics of Demirci and also Akdağ volcanics of Emet basins.
Generally, fluid composition and temperature are important factors on development of zeolite paragenesis. Also, alteration of volcanic rocks containing natural glass as a reactive phase generally associated with low-temperature (<300°C), neutral to alkaline waters, and most of the zeolite minerals were found only at temperature below 200°C (Chipera and Apps, 2001). Zeolitization processes in the studied basins possibly developed in the same or close periods, similar geologic-hydrologic lacustrine environments and also under the similar physico-chemical conditions at low-temperature. The lakes in the studied regions at the Miocene epoch can be defined as rift system alkaline lakes in the concept of closed hydrologic system (Surdam, 1977; Langella et al., 2001). Therefore, the waters feeding these lakes are derived from underground springs. Zeolite mineral paragenesis show similarity in the Gördes, Demirci and Şaphane regions. However, it is reported that the lower and upper levels of the zeolite-rich tuffs from Gördes and Şaphane basins partly contain different neoform minerals (opal–CT, quartz, smectite, K–feldspar) and hul/cpt with different exchangeable cations (Esenli, 1993; Snellings et al., 2008). Major oxides of the zeolite-rich tuff samples address Si–rich and K– and/or Ca–rich types of hul/cpt in the Gördes, Demirci and Şaphane regions. Although, SiO2/Al2O3 ratios show homogeneity, ratios of alkaline/alkaline-earth cations show heterogeneity. Na–rich hul/cpt levels are rarely found in the studied pyroclastic rocks. Increasing and decreasing of some elements are related to: (1) chemistry of the volcanic primary materials, (2) the stability constants of these elements in the solution after deposition of the pyroclastic rocks, and (3) the properties of atomic substituents in hul/cpt extra–framework structure.
Essentially, trace element chemistry of pyroclastic rocks from the Gördes, Demirci and Şaphane regions show some differences. For example, Ba, Hf, Sr, Zr, Mo, Cu, Pb, Zn, Ag, ΣREE, ΣLREE, ΣHREE, ΣMREE, ratio of ΣLREE/ΣHREE and Eu/Eu* are higher in the Şaphane (SP) samples (Table 2). Cs, Rb, Yb/Yb* values in Demirci (DM) samples are higher than those of the other regions. As a local or stratigraphic difference, chemical values of sample GR-1 from the lowermost of the lower tuff unit in the south of Gördes is different from the other Gördes (GR) samples (Fig. 2; Table 2). U, Y and ΣHREE values of this sample is about ten time more than the others, in contrast, Th/U and LaN/YbN values are about ten time less. It is known that the sandstones of the lower fine- and coarse-grained units (Fig. 2) are rich in U in the equivalent stratigraphic levels in the nearby region (south of Gördes; Köprübaşı uranium deposits; Yılmaz, 1982). U anomaly of this sample is probably related to this regional feature.
Chemical compositions and types of the zeolite-group mineral in between fresh and zeolitic rocks also depend on the character of their parent rocks. For example, chemical changes show difference between zeolite–rich andesitic–latitic parent rocks from zeolite–rich rhyolithic–dacitic ones (Walton, 1975; Barrows, 1980; Tsolis-Katagas and Katagas, 1989; Tsirambides et al., 1993; Esenli, 1993; Snellings et al., 2008). Some chemical changes during the zeolitization of tuffs are summarized in Table 3. All zeolitic tuff units are rhyolithic–rhyodacitic in character in Table 3. According to Iijima (1971), Walton (1975) and Tsirambides et al. (1993), although, some major oxides have different character, SiO2 and K2O significantly depleted from fresh host rocks to clinoptilolitic-bearing altered rocks of Japan, USA and Greece, respectively (Table 3). Esenli (1993) and Snellings et al. (2008) emphasized that CaO, MgO and H2O increased, while SiO2, Na2O and K2O decreased during zeolitization process of cpt-bearing tuffs in Gördes and Şaphane regions (Turkey), respectively (Table 3). Moreover, Esenli (1993) underlined that these changes are higher in hul–rich tuffs compared to cpt-rich ones and Ba, Sr, La, B, U, Th, As, P and Zn values are approximately double in hul/cpt–rich facii, while Mn, Co and W values increase in non–zeolite facii and Ba, Sr, La, and B values are relatively higher in hul–rich samples compared to the cpt–rich ones. Erdem–Şenatalar et al. (1992) concluded that K2O, CaO and MgO increased and SiO2 and Na2O decreased with increasing of zeolite content from Bigadiç zeolitic tuffs. Also, Gündoğdu et al. (1996) reported zeolitic (K– and Ca–cpt) and non-zeolitic (mainly glass + smectite) samples from Bigadiç and Emet basins (Turkey). Their zeolitic samples have higher SiO2, Al2O3, CaO and MgO values and lower Na2O, K2O and Fe2O3 values compared to that of non-zeolitic ones (Table 3). Recently, Kaçmaz (2016) explained a correlation between zeolitic and non-zeolitic tuffs from Demirci region (Yenice–Saraycık area). According to the author, rhyodacitic–rhyolithic tuffs with high amounts of hul/cpt contain higher Mg, Ca, P and LOI but lower K, Na and Mn than those of unaltered tuffs. The author also revealed that there is no big change in the REE abundances of unaltered and hul/cpt–rich tuffs although Ba, Sr, Cs, Pb, Zn, Ni, As, and Sb are higher in zeolitic tuffs and U in unaltered tuffs.
The studied zeolitic tuff samples from Gördes, Demirci and Şaphane show concentration range of 55–95 wt % hul/cpt (Table 1). Therefore, it is difficult to clear correlate zeolitic units with the pyroclastic parent rock. However, comparison of 55–75 wt % hul/cpt bearing samples (GR–1 and SP–3) and 75–95 wt % hul/cpt bearing other samples show that CaO and LOI increased, while SiO2 and Na2O decreased with increase concentration of hul/cpt. In Gördes samples Al2O3, CaO, K2O and LOI values are higher and SiO2, Fe2O3, MgO, and Na2O values are lower relative to enhance of hul/cpt. In Demirci samples SiO2 and Na2O values decrease, in contrast Al2O3, Fe2O3, MgO, and CaO values increase during zeolitization. It is difficult to determine Şaphane samples; partly MgO increasing with increasing of hul/cpt concentration is seen in these samples. It can be summarized that the total of alkaline–earth elements (particularly Ca2+) increased and alkaline elements (particularly Na+) decreased in pyroclastic rocks of the studied basins. These types of gains and losses reveal that hul/cpt type of zeolitization in the studied basins suggest development under the moderate alkaline conditions near the center of the basin (pH: 7–9; Mariner and Surdam, 1970; Hay and Sheppard, 2001). For example, high alkaline zeolites (analcime) and K-feldspar were reported from the center of the Gördes Miocene basin by Esenli (1993). Therefore, hydrolysis of volcanic glass in the pyroclastic rocks of Gördes, Demirci and Şaphane basins are controlled by the solution chemistry, rise of pH due to the reaction between the alkaline cations and water. Thus, devitrification of volcanic glass resulted firstly formation of gel-like phase and that is later of converted to hul/cpt types of zeolites.
In addition to the major oxide changes during zeolitization of the studied pyroclastic rocks, REE compositions show variable values. Although, LREE shows similarity, totally and individually all MREE and HREE increased in higher zeolitic sample SP-1 (90–95% hul/cpt) and SP-3 (55–60% hul/cpt) samples in Şaphane (SP) (Tables 1 and 2; Fig. 5). The mobility of MREE and HREE relative to LREE is also seen in the GR samples. DM samples show mobility for all REE. On the other hand, Ersoy et al. (2008) reported the chemical composition of non-zeolitic Eğreltidağ volcanics which is overlain by Akdere tuff in Demirci basin show different chemistry from Demirci and Gördes zeolitic tuffs. If we accept that Eğreltidağ volcanics is related with Demirci-Akdere tuff and also Gördes-lower tuff unit, thus, Sr, Nb, Th, Ni, Hf, Cs, Pb, and Ta increased and Zr, Co, and W and most of the REE and also some major elements (Al, Fe, Ca, Na) decreased by increase of hul/cpt via zeolitization process.
The sorption of some elements in hul/cpt–rich pyroclastic rocks should be controlled mainly by ion-exchange reactions. During or following zeolitization process some elements having similar ionic radii (e.g. Na–Ca, Ca–Sr, K–Ba and Mg–Fe) probably more easily substituted each other. Some trace elements showing depletion or enrichment have also similar ionic radii. Some other substitutions such as Mg–Cu–Ni–Zn–Co–Fe–Cr, Ca–HREE+Y, W–Ti–Zr–Hf and Pb–Th–U are probably controlled and resulted to depletion–enrichment in zeolitic rocks. Particularly, most of the radionuclides are higher in hul/cpt–rich facii of pyroclastic rocks because of the greater selectivity of zeolites for these elements. Simmons and Neymark (2012) also reported that sorption of Sr, Cs, Th, and U is also found in more pronounced in cpt-rich tuffs than vitric tuffs of Yucca Mountain (USA). REEs having smaller ionic radius i.e. heavier lanthanides easily exchanged by changeable major cations of hul/cpt and Y may be more effective among them. Thus, enhance of some major, trace and rare earth elements in west Anatolian hul/cpt–rich tuffs is a function of selectivity of zeolite minerals additionally to the parameters of geological environment.
CONCLUSIONS
Field observation show that the lower tuff unit in Gördes, Akdere tuff in Demirci and Karacaderbent tuff in Şaphane show equivalent lithostratigraphic to each other. All of zeolitic pyroclastic rocks in the regions show similar petrographic characteristics; textures, glass shard (+pumice)/crystal ratio and significantly zeolite mineral types and zeolitization process. Based on both of mineralogy and major oxide chemistry from the studied pyroclastic rocks and related references, chemical gains and losses during the zeolitization (hul/cpt type) of rhyolithic/rhyodacitic tuffs are summarized as: (1) SiO2 decreases, in contrast Al2O3 increases and generally Si/Al ratio decreases. (2) Fe2O3 does not show clear change, but MgO generally increases. (3) CaO generally increases and enhance in hul-type alteration. (4) Na2O decreases and K2O shows slight changeable decrease. (5) LOI clearly increases. Also, enrichments and depletions of trace elements in hul/cpt–rich rhyolithic-rhyodacitic tuffs depend on the ionic substitutions between some elements having similar ionic radii. In general, Ba, Sr, As, Nb, Th, Ni, Hf, Cs, Pb, Ta, U, B, and HREE relatively enriched in hul/cpt–rich facii and Mn, Zr, Co, W, and most of the LREE relatively enriched in non-zeolitic facii in a lithostratigraphic level. The whole rock chemical compositions of Gördes, Demirci and Şaphane pyroclastic rocks and probably some other west Anatolian Miocene basins have been resulted by partly ion-exchange and -selectivity properties of hul/cpt. Generally, alteration of pyroclastic rocks to zeolites has a prominent effect on their chemical composition. Also, the compositions of zeolite (hul/cpt)–rich pyroclastics rocks in west Anatolia address secondary alteration chemistry not primary chemistry of volcanism, particularly for Si, Ca, Na and LOI and also for some trace elements.
REFERENCES
L. L. Ames, “Cation sieve properties of the open zeolites chabazite, mordenite, erionite and clinoptilolite,” Am. Mineral. 46, 1120–1131 (1961).
K. Barrows, “Zeolitization of Miocene volcaniclastic rocks, Southern Desatoya Mountains, Nevada,” Geol. Soc. of Am. Bull. 99, 199–210 (1980).
U. Barth-Wirsching and H. Holler, “Experimental studies on zeolite formation conditions,” Euro. J. Mineral. 1, 489–506 (1989).
J. R. Boles, “Composition, optical properties, cell dimensions and thermal stability of some heulandite-group zeolites,” Am. Mineral. 57, 1463–1493 (1972).
W. V. Boynton, “Geochemistry of the rare earth elements: meteorite studies,” in Rare Earth Element Geochemistry, Ed. by P. Henderson (Elsevier, 1984), pp. 63−114.
S. J. Chipera and J. A. Apps, “Geochemical stability of natural zeolites,” in Natural Zeolites: Occurrence, Properties, Applications, Ed. by D. L. Bish and D. W. Ming (Reviews in Mineralogy and Geochemistry 45, Mineral. Soc. of Am., 2001), pp. 117–161.
G. E. Christidis, “Comparative study of the mobility of major and trace elements during alteration of an andesite and a rhyolite to bentonite, in the islands of Milos and Kimolos, Aegean, Greece,” Clays and Clay Miner. 46, 379−399 (1988).
F. H. Chung, “Quantitative interpretation of X−ray diffraction patterns of mixtures III; simultaneous determination of a set of reference intensities,” Jour. of Appl. Cryst. 8, 17−19 (1975).
K. C. Condie, “Chemical composition and evolution of the upper continental crust, contrasting results from surface samples and shales,” Chem. Geol. 104, 1−37 (1993).
D. S. Coombs, A. Alberti, T. Armbruster, G. Artioli, C. Colela, E. Galli, J. D. Grice, F. Liebau, J. A. Mandarino, H. Minato, E. H. Nickel, E. Passaglia, D. R. Peacor, S. Quartieri, R. Rinaldi, M. Ross, R. A. Sheppard, E. Tillmans, and G. Vezzalini, “Recommended nomenclature for zeolite minerals: Report of the subcommittee on zeolites of the international mineralogical association, commission on new minerals and mineral names,” Canad. Miner. 35, 1571−1606 (1997).
H. J. W. De Baar, M. P. Bacon, P. G. Brewer, and K. W. Bruland, “Rare earth elements in the Pacific and Atlantic Oceans,” Geochim. Cosmochim. Acta, 49, 1943–1959 (1985).
B. Ekinci-Şans, F. Esenli, S. Kadir, and W. C. Elliott, “Genesis of smectite in siliciclastics and pyroclastics of the Eocene İslambeyli Formation in the Lalapaşa region, NW Thrace, Turkey,” Clay Miner. 50, 459−483 (2015).
A. Erdem-Şenatalar, A. Sirkecioğlu, I. Güray, F. Esenli, and I. Kumbasar, “Characterization of the clinoptilolite-rich tuffs of Bigadiç: Variation of the ion-exchange capacity with pretreatments and zeolite contents,” in Proceedings of Ninth International Zeolite Conference, Ed. by R. Von Balmoos, J. B. Higgins, and M. M. J. Treacy (Boston, 1983), pp. 223−230.
E. Y. Ersoy, C. Helvacı, H. Sözbilir, F. Erkül, and E. Bozkurt, “A geochemical approach to Neogene–Quaternary volcanic activity of western Anatolia: An example of episodic bimodal volcanism within the Selendi Basin, Turkey,” Chem. Geol. 255, 265−282 (2008).
E. Y. Ersoy, C. Helvacı, and M. R. Palmer, “Stratigraphic, structural and geochemical features of the NE–SW-trending Neogene volcano-sedimentary basins in western Anatolia: implications for associations of supradetachment and transtensional strike-slip basin formation in extensional tectonic setting,” J. Asian Earth Sci., 41, 159−183 (2011).
E. Y. Ersoy, C. Helvacı, and M. R. Palmer, “Petrogenesis of the Neogene volcanic units in the NE–SW-trending basins in western Anatolia, Turkey,” Contrib. Mineral. Petrol. 163, 379–401 (2012).
E. Y. Ersoy, İ. Çemen, C. Helvacı, and Z. Billor, “Tectono-stratigraphy of the Neogene basins in Western Turkey: Implications for tectonic evolution of the Aegean Extended Region,” Tectonophys. 635, 33−58 (2014).
F. Esenli, “The chemical changes during zeolitization (heulandite-clinoptilolite type) of the acidic tuffs in the Gördes Neogene basin,” Geol. Bull. Turkey, 36, 37−44 (1993) [in Turkish with English abstract].
F. Esenli and I. Kumbasar, “X-ray diffraction intensity ratios I(111) / I(311) of natural heulandites and clinoptilolites,” Clays and Clay Miner. 46, 679−686 (1998).
F. Esenli, F. Suner, V. Esenli, and I. Kumbasar, “Relationship between trace element content and zeolitization of pyroclastic rocks in Gördes, west Anatolia, Turkey,” Mining Oilfield Chem. 2, 289−294 (2000).
G. Gottardi and E. Galli, Natural Zeolites (Springer-Verlag, 1985).
M. N. Gündoğdu, H. Yalçın, A. Temel, and N. Clauner, “Geological, mineralogical and geochemical characteristics of zeolite deposits associates with borates in the Bigadiç, Emet and Kırka Neogene lacustrine basins, western Turkey,” Miner. Deposita 31, 492–513 (1996).
M. A. Haskin and L. A. Haskin, L.A. “Rare earths in European shales: a redetermination,” Science 154, 507−509 (1966).
R. L. Hay and R.A. Sheppard, “Occurrence of zeolites in sedimentary rocks: An overview,” in Natural Zeolites: Occurrence, Properties, Applications, Ed. by D. L. Bish and D. W. Ming (Reviews in Mineralogy and Geochemistry 45, Miner. Soc. Am., 2001), pp. 217−232.
C. Helvacı, “Geological features of Neogene Basins hosting borate deposits: An overview of deposits and future forecast, Turkey,” MTA Bulletin, 151, 173−219 [in Turkish with English abstract].
C. Helvacı and R. N. Alonso, “Borate deposits of Turkey and Argentina; a summary and geological comparison,” Turkish J. Earth Sci. 24, 1−27 (2000).
A. W. Hofmann, “Chemical differentiation of the Earth: the relationship between mantle, continental crust, and oceanic crust,” Earth Plan. Sci. Lett. 90, 297–314 (1988).
A. Iijima, “Composition and origin of clinoptilolite in the Nakanosawa tuff of Rumoi, Hokkaido,” Molecular Sieve Zeolites 1, 334−341 (1971).
A. Iijima, “Occurrence of natural zeolites in marine environments”, in Natural Zeolites: Occurrence, Properties, Uses, Ed. by L. B. Sand and F. A Mumpton (Pergamon, 1978), pp. 175−198.
T. N. Irvine and W. R. A. Baragar, “A guide to the chemical classification of the common volcanic rocks,” Canad. J. Earth Sci. 8, 523−548 (1971).
U. İnci, PHD Dissertation, İzmir: Geology Engineering Department, Dokuz Eylül University, 1983.
H. Kaçmaz, “Major, trace and rare earth element (REE) characteristics of tuffs in the Yenice-Saraycık area (Demirci, Manisa), Western Anatolia, Turkey,” J. Geochem. Explor. 168, 169−176 (2016).
A. Langella, P. Cappelletti, and M. de Gennaro, “Zeolites in closed hydrologic systems,” in Natural Zeolites: Occurrence, Properties, Applications, Ed. by D. L. Bish and D. W. Ming (Reviews in Mineralogy and Geochemistry 45, Mineral. Soc. of Am., 2001), pp. 235−260.
M. Loizidou and R. P. Townsend, “Ion Exchange Properties of Natural Clinoptilolite, Ferrierite and Mordenite: 2. Lead-Sodium and Lead-Ammonium Equilibria,” Zeolites 7, 153–159 (1987).
R. H. Mariner and R. C. Surdam, “Alkalinity and formation of zeolites in saline alkaline lakes,” Science 170, 977−980 (1970).
S. M. McLennan, “Relationships between the trace element composition of sedimentary rocks and upper continental crust,” Geochem., Geophys., Geosyst. (G3) 2, 1021 (2001).
F. A. Mumpton, “Development and uses for natural zeolites: a critical commentary,” in Occurrence, Properties and Utilization of Natural Zeolites, Ed. by D. Kallo and H. S. Sherry (Budapest, 1988), pp. 333−365.
H. Mutlu, K. Sarıiz, and S. Kadir, “Geochemistry and origin of the Şaphane alunite deposit, Western Anatolia, Turkey,” Ore Geol. Rev. 26, 39−50 (2005).
J. A. Pearce, “Geochemical fingerprinting of oceanic basalts with applications to ophiolite classification and the search for Archean oceanic crust”, Lithos 100, 14−48 (2008).
A. Peccerillo and S. R. Taylor, “Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, Northern Turkey,” Contrib. Mineral Petrol. 58, 63−81 (1976).
M. Purvis and A. Robertson, “A pulsed extension model for the Neogene-recent E-W-trending Alaşehir Graben and the NE–SW-trending Selendi and Gördes Basins, Western Turkey,” Tectonophys. 391, 171−201 (2004).
M. Purvis, A. Robertson, and M. Pringle, “40Ar–39Ar dating of biotite and sanidine in tuffaceous sediments and related intrusive rocks: implications for the early Miocene evolution of the Gördes and Selendi basins, W Turkey,” Geodyn. Acta 18, 239−253 (2005).
E. S. Schandl and M. P. Gorton, “Application of high field strength elements to discriminate tectonic settings in VMS environments,” Econ. Geol. 97, 629−642 (2002).
R. A. Sheppard and R. L. Hay, “Formation of zeolites in open hydrologic systems,” in Natural Zeolites: Occurrence, Properties, Applications, Ed. by D. L. Bish and D. W. Ming (Reviews in Mineralogy and Geochemistry 45, Mineral. Soc. Am., 2001), pp. 261−273.
B. Semiz, P. A. Schroeder, and Y. Özpınar, “Zeolitization of Miocene tuffs the Saphane-Gediz-Hisarcık regions, Kütahya-western Anatolia, (Turkey),” in European Clay Conference, Ed. by Z. Karakaş, S. Kadir, and A.G. Türkmenoğlu (Antalya, 2011), pp. 232.
G. Seyitoğlu and B. C. Scott, “Late Cenozoic volcanic evolution of the northeastern Aegean region,” J. Volcan. Geoth. Res. 54, 157−176 (1992).
G. Seyitoğlu, D. Anderson, G. Nowell, and B. C. Scott, “The evolution from Miocene potassic to Quaternary sodic magmatism in western Turkey: implications for enrichment processes in the lithospheric mantle,” J. Volcan. Geoth. Res. 76, 127–147 (1997).
S. M. Shaheen, A. S. Derbalah, and F. S. Moghanm, “Removal of heavy metals from aqueous solution by zeolite in competitive sorption system,” Int. J. Environ. Sci. and Develop. 3, 362−367 (2012).
A. M. Simmons and L. A. Neymark, “Conditions and processes affecting radionuclide transport,” in Hydrology and Geochemistry of Yucca Mountain and Vicinity, Southern Nevada and California, Ed. by J. S. Stuckless (Geol. Soc. Am. Memoir 209, Boulder, 2012), pp. 277−362.
R. Snellings, T. Van Haren, L. Machiels, G. Mertens, N. Vanderberghe, and J. Elsen, “Mineralogy, geochemistry and diagenesis of clinoptilolite tuffs (Miocene) in the central Simav Graben, western Turkey,” Clays and Clay Miner. 56, 622−632 (2008).
S. S. Sun and W. F. McDonough, “Chemical and isotopic systematics of oceanic basalts; implications for mantle composition and processes,” in Magmatism in the Ocean Basins, Ed. by A. D. Saunders and M. J. Norry (Geol. Soc. of London 42, 1989), pp. 313−345.
R. C. Surdam, “Zeolites in closed hydrologic system,” Rev. Mineral. 4, 65−91 (1977).
R. C. Surdam and R. A. Sheppard, “Zeolites in saline, alkaline-lake deposits,” in Natural Zeolites: Occurrence, Properties, Uses, Ed. by L. B. Sand and F. A. Mumpton (Pergamon, 1978), pp. 145−174.
S. R. Taylor and S. M. McLennan, The continental crust: its composition and evolution, (Blackwell Scientific Publication, 1985).
A. Tsirambides, A. Filippidis, and A. Kassoli-Fournaraki, “Zeolitic alteration of Eocene volcaniclastic sediments at Metaxades, Thrace, Greece,” Appl. Clay Sci. 7, 509−526 (1993).
P. Tsolis-Katagas and C. Katagas, “Zeolites in pre-caldera pyroclastics rocks of the Santorini volcano, Aegean Sea, Greece,” Clays and Clay Miner. 37, 497−510 (1989).
A. Walton, “Zeolitic diagenesis in Oligocene volcanics sediments, Trans - Pecos, Texas,” Geol. Soc. of Am. Bull. 86, 615−624 (1975).
B. L. Weaver and J. Tarney, “Empirical approach to estimating the composition of the continental crust,” Nature 310, 575–577 (1984).
D. L. Whitney and B. W. Evans, “Abbreviations for names of rock-forming minerals,” Am. Mineral. 95, 185−187 (2010).
J. A. Winchester and P. A. Floyd, “Geochemical discrimination of different magma series and their differentiation products using immobile elements,” Chem. Geol. 20, 325−343 (1977).
H. Yılmaz, “About natural radioactive disequilibrium in Köprübaşı uranium deposits” Geol. Bull. Turkey 25, 91–94 (1982) [in Turkish with English abstract].
Y. Yılmaz, Ş. C. Genç, O. F. Gürer, M. Bozcu, K. Yılmaz, Z. Karacık, Ş. Altunkaynak, and A. Elmas, “When did the western Anatolian grabens begin to develop?” in Tectonics and Magmatism in Turkey and the Surrounding Area, Ed. by E. Bozkurt, J. A. Winchester, and J. D. A. Piper (Geol. Soc. London 173, 2000), pp. 353−384.
M. J. Zamzow, B. R. Eichbaum, K. R. Sandgren, and D. E. Shanks, “Removal of heavy metals and other cations from wastewater using zeolites,” Sep. Sci. Tech. 25, 1555–1569 (1990).
ACKNOWLEDGMENTS
The authors are much indebted to Dr. S. Silantyev (Chief scientist of Vernadsky Institute of Russian Academy of Sciences) and Dr. Erik M. Galimov (Editor-in-Chief) for their extremely careful and constructive reviews and editorial comments that improved the quality of the paper significantly. Staff of the JAL laboratory of İstanbul Technical University (Turkey) are thanked for assistance with the chemical analysis.
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Fahri Esenli, Kadir, S. & Şans, B.E. Geochemistry of the Zeolite-rich Miocene Pyroclastic Rocks from the Gördes, Demirci and Şaphane Regions, West Anatolia, Turkey. Geochem. Int. 57, 1158–1172 (2019). https://doi.org/10.1134/S001670291911003X
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DOI: https://doi.org/10.1134/S001670291911003X