1.1 Introduction

Alpine orogenic belt with the whole of Turkey is located in the Mediterranean region (Eroskay and Günay, 1980). Some important conclusions have been made in this region regarding Turkey’s geology. The rock and sedimentary series that make up the country represent geosynclinal and orogenic facies and they are different from the peer series developed in the cratogenic shield areas and their shelf zones. Tectonic lines are orogenic origin. These structures are completely different from the formations that developed in the shield areas, which were subjected to no influence but slightly curved.

The very defective morphological surfaces, which are active in large parts of the country, are the result of intense tectonic movements and have not developed in the shield areas (Fig. 1.1).

Fig. 1.1
figure 1

Copyright © 2001 by V. H. WINSTON & Son, Inc. All rights reserved

International Geology Review, Vol. 43, 2001, p. 578–594.

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Mesozoic has been affected by only one orogeny, namely the Alpine orogeny. Mesozoic in Turkey is composed of carbonate, radiolarite and clastics. The Cretaceous is one of the most important paroxysms of the Alpine orogeny, perhaps the most important of which is composed of carbonate and conglomerate and flysch series deposited in the Middle and Upper Cretaceous.

It is developed as “Gypsum Formation” in the Oligocene, Central, and North Anatolia. Miocene deposits were deposited in epeirogenic basins and in the Southeast Anatolia foreground. The large transgression from the Mediterranean Basin invaded South, South Eastern, and Eastern Anatolia (Kaçaroğlu et al. 1997).

1.2 Tectonic of Turkey

The building lines were carried out by this orogeny and the young epeirogenesis that followed it. In this case, some important facts emerge; All regions of Turkey have been under the influence of Alpine orogeny and young epirogenic movment. The structures, which were previously developed during the Caledonian and Hercynian orogenesis, were folded again, rejuvenated, or completely erased during Alpine movement. Only the very limited remains of these old buildings have been preserved between Alpine folds. However, not only the current tectonic lines, but also the relief (topography) of the country were brought into being by the Alpine orogeny and the epirogenesis that followed it (Bozkurt and Mittwede, 2001).

Figure 1.1 Simplified tectonic map of Turkey showing major neotectonic structures and neotectonic provinces (from Bozkurt 2001). Abbreviations: K = Karliova; KM = Kahramanmaras; DSFZ = Dead Sea fault zone; EAFZ = East Anatolian fault zone, NEAFZ = Northeast Anatolian fault zone. Heavy lines with half arrows are strike-slip faults. Half arrows show relative movement sense. Heavy lines with filled triangles show major fold and thrust belt; tips of the small triangles indicate an active subduction zone; tips of the small triangles indicate polarity. The heavy hachured lines show normal faults; hachure indicates downthrown side. Bold filled arrows indicate relative movement direction of African and Arabian plates; open arrows indicate relative motion of Anatolian plate. The hatched area shows area of transition zone between the Western Anatolian extensional province and the Central Anatolian “ova.”

1.3 Tertiary Units

Tertiary desert deposits in some parts of the geosynclinal shale continued uninterruptedly into the Paleocene and then into the Eocene. Paleocene and Lower Eocene correspond to a rather quiet period that followed the Upper Cretaceous paroxysm. Compared to Upper Cretaceous, Paleocene-Lower Eocene formations have continuous and similar features. However, during the Cretaceous paroxysms, the topographic changes and exacerbated erosion that occurred in the inner part of the geosyncline also affected the accumulation conditions during the Paleocene-Lower Eocene. Therefore, sometimes very important facies differences are observed between the inner and outer parts of the geosynclinal area (Brinkman, 1976). Miocene deposits were deposited in epeirogenic basins and in the Southeast Anatolian foreground. The lithology and thickness of the series vary according to the size of the basins and tectonic developments. Besides the marine series left by the marine transgression, Lacustrine facies have developed (Atalay, 1987, 1988, 1996).

The Miocene had several important facies. Large transgressions from the Mediterranean Basin affected Southern, Southeastern, and Eastern Anatolia, where several large and many smaller Miocene basins were formed.

1.3.1 Karst in the Taurus Area

The Taurus Mountains are characterized by abundant water resources, large hydroelectric potential, some of the world’s largest karst aquifers, and the largest karst springs. These springs of exceedingly large discharge are formed by the channelized flow along with the fractures by water that cannot penetrate the deeper formations because of their low permeability (Günay and Yayan, 1979; Karanjac and Günay, 1980). Many large springs occur at this contact and flow along the fractures by the water that cannot penetrate the deeper formations because of the low permeability. The original heterogeneity of the aquifer formed by tectonism has been increased by the dissolution of limestone. This dissolution results from the infiltration of a significant amount of rain and snow in the Taurus Mountains, particularly at higher elevations. If the transmissivity of the carbonate aquifers was more homogeneous, and the aquifers were hydrologically connected to the underlying sediments, the entire system’s storativity would significantly increase, and diffuse flow would occur.

This area is characterized by abundant dolines, large poljes, coastal and submarine springs, sea caves, and large travertine terraces (Başar, 1972). One of the most unusual types of karsts is the one that is formed in an extensive conglomerate. The conglomerate is composed of cobbles of limestone with calcareous cement. The mode of transportation and deposition is not well understood (Erinç, 1960). As we can see at the Olukköprü springs area (Antalya—Beşkonak):

  • The formation of karst in the Southwestern Turkey is strongly influenced by the alternation of the Jurassic and Cretaceous limestones with ophiolites and Tertiary flysch in both horizontal and vertical planes, resulting from nappe structures. Many large springs are where carbonate rocks are exposed within ophiolite.

  • This region’s general characteristics reflect a combination of both humid and arid environments, a combination that does not occur in a tropical climate. The unusual combination in Turkey results from the Mediterranean climate, which is characterized by dry summer, wet winters, and a long period of snow cover in the mountains. Therefore, mechanical weathering is an essential chemical corrosion.

  • The hydrogeologic conditions of the karst indicate two types of recharge:

  • Systems recharged by poljes on lower plateaus are characterized by a high fluctuation of discharge, higher temperature, higher bicarbonate content, and extensive travertine deposition;

  • Systems recharged mainly from high mountains that are covered by snow for long periods are characterized by more stable regimes of discharge, lower temperatures, lower content of bicarbonate, and little or no travertine deposition. The Antalya travertine deposits were formed as a result of the precipitation of carbonate minerals due to the outgassing of carbon dioxide from the water initially saturated with respect to the carbonate minerals (Herman and Hubbard 1990). The source of the calcium and carbonate ions is the limestone of the Taurus Mountains to the north of the plain. The travertine in this plateau has a thickness of about 300 m and extends over an area of approximately 630 km2. These deposits exist because of three separate terraces: one at an altitude of 300 m, another between 50 and 150 m, and the third terrace is below sea level.

A spectacular waterfall (the Düdenbaşı waterfall) on these terrace deposits has an unusual hydrogeologic occurrence (Back and Günay, 1992). The water travels to the waterfall through three different pathways even though the original source is one major group of springs. Among these springs, Kırkgözler springs are about 25 km from the waterfall. Even though a hydrologic connection exists between Kırkgöz springs and the Bıyıklı Sinkhole, the sinkhole receives water only during a high flood.

Part of the water from Bıyıklı and Yağca sinkholes travels to Varsak directly to the Düdenbaşı waterfall. It discharges into the doline where the water enters on the up-gradient side of the doline and also discharges down-gradient to continue to the Düdenbaşı waterfall.

The water source is from a canal that carries water from Kırkgöz springs to the Kepez power plant. After the water is used for electricity production, it is diverted into other canals and reused for irrigation. The returned irrigation water is transported by canal to the Düdenbaşı waterfall. The water cascades over a cliff about 15 m high, where an extensive cave system has developed. It is possible to walk in the open cave system beneath the waterfall. The Düdenbaşı River, formed by a waterfall, empties into the Mediterranean again with a waterfall. The Düdenbaşı waterfalls are a major tourist attraction in the Antalya area.

Another major tourist attraction in the hydrogeologically significant area is the spectacular travertine deposit of Pamukkale, which means “The Cotton Castle.” It is on the ancient site of Hierapolis (an important city even before the time of the Romans). The travertine terraces are deposited from the series of geothermal springs brought to the surface along faults bordering the graben that forms the valley. The area has some potential for geothermal energy.

The major thermal spring source for the travertine terraces and ponds is a cave that was known as a road to Hades. The water from the thermal spring is 35 centigrade degrees, and originally, the spring was used for the medicinal qualities of the water. The atmosphere in the cave could not support life, probably due to the high concentration of carbon dioxide gas and consequent lack of oxygen.

The city’s reputation was further enhanced by the miracles that the priests would perform by using the cave. It was well known that the cave was dangerous, yet the priests could stay in for a long period of time, presumably by following the pathways where the upper chambers contained adequate oxygen, and then emerge with no adverse reactions. That would then give them the aura of immortality, and they could then exert their will on people. In the second century AD, the Romans diverted the warm mineral water into the buildings for the baths.

The Roman bathhouse is now a museum and the thermal springs are available to tourists at hotels’ swimming pools (Figs. 1.1 and 1.2).

Fig. 1.2
figure 2

Copyright © 2001 by V.H. WINSTON & Son, Inc. All rights reserved

Simplified tectonic map of the Taurus area. International Geology Review, Vol. 43, 2001, pp. 578–594.

Full size image

Figure 1.2 Simplified tectonic map showing major neotectonic structures and neotectonic provinces modified from (Sengör et al. 1992; Barka 1992), abbreviations: wbs = western black sea fault; wcf = west Crimean fault. Heavy lines with filled triangles show sutures: the tips of triangles indicate polarity. Heavy lines with open triangles indicate thrust belts: triangles point toward the vergence direction. Heavy lines with half arrows show relative movement along these faults. The Pontides and lesser Caucasus form the eastern extension of the Sakarya zone (from Sengör et al. 1985)