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83-618: The Aksu Basin has been gradually filling up with sediment since Neogene times. The Aksu Basin is located at an important intersection of several tectonic systems. To the north, the Anatolian continental plateau is undergoing uplift, while to the south the African and Eurasian plates are colliding, producing features like the Mediterranean Ridge and the Hellenic subduction zone . On the west,

166-691: A "right-lateral transform fault plate boundary" had formed between the Cyprus Trench and the Isparta Angle. This led to the creation of "a hybrid, terrestrial-shallow marine accommodation space" on the eastern side of the Isparta Angle, where sediments from the Antalya Complex further east were deposited. In the Middle Miocene ( c. 16-11 MYA), the Aksu Basin was formed as a graben cutting through

249-795: A decrease in global temperatures termed the Late Miocene Cooling (LMC) ensued, driven by decreases in carbon dioxide concentrations. During the Pliocene, from about 5.3 to 2.7 Ma, another warm interval occurred, being known as the Pliocene Warm Interval (PWI), interrupting the longer-term cooling trend. The Pliocene Thermal Maximum (PTM) occurred between 3.3 and 3.0 Ma. During the Pliocene, Green Sahara phases of wet conditions in North Africa were frequent and occurred about every 21 kyr, being especially intense when Earth's orbit's eccentricity

332-478: A formal stratigraphic term , "Tertiary" still sometimes remains in informal use. During this period, mammals and birds continued to evolve into modern forms, while other groups of life remained relatively unchanged. The first humans ( Homo habilis ) appeared in Africa near the end of the period. Some continental movements took place, the most significant event being the connection of North and South America at

415-409: A junction with another plate boundary, while transcurrent faults may die out without a junction with another fault. Finally, transform faults form a tectonic plate boundary, while transcurrent faults do not. Faults in general are focused areas of deformation or strain , which are the response of built-up stresses in the form of compression , tension, or shear stress in rock at the surface or deep in

498-545: A positive feedback as sea levels dropped and the ITF diminished and further limited the heat transported southward by the Leeuwin Current . By the end of the period the first of a series of glaciations of the current Ice Age began. Marine and continental flora and fauna have a modern appearance. The reptile group Choristodera went extinct in the early part of the period, while the amphibians known as Allocaudata disappeared at

581-404: A spreading ridge, or a subduction zone . A transform fault is a special case of a strike-slip fault that also forms a plate boundary. Most such faults are found in oceanic crust , where they accommodate the lateral offset between segments of divergent boundaries , forming a zigzag pattern. This results from oblique seafloor spreading where the direction of motion is not perpendicular to

664-418: A transform fault links a spreading center and the upper block of a subduction zone or where two upper blocks of subduction zones are linked, the transform fault itself will grow in length. [REDACTED] [REDACTED] Constant length: In other cases, transform faults will remain at a constant length. This steadiness can be attributed to many different causes. In the case of ridge-to-ridge transforms,

747-804: Is "poorly sorted with mostly rounded pebbles and clasts of Jurassic micritic limestone, and Triassic chert and basaltic rocks". The formation's maximum depth is estimated at 300 m. Akay et al. interpreted the Eskiköy Formation as a lateral equivalent of the Gebiz Limestone, meaning that they date from the same time. Fossils found in the Eskiköy Formation's marl include several species of planktonic foraminifera : Orbulina , Biorbulina , Globigerinoides (multiple species: trilobus , obliquus extremus , obliquus s.s. , bollii , emeisi , and aperture ), and Globigerinita incrusta . Based on these planktonic foraminifera fossils, Poisson et al. dated

830-501: Is about 1200 m. The Aksu Formation's type localities are in the northeast and northwest parts of the Aksu Basin. The formation's composition is somewhat varied in different places. The western part of the Aksu Formation consists of "poorly sorted conglomerate and conglomeratic sandstone ... composed of rounded clasts of fine-grained, beige micritic Jurassic limestone and Triassic light gray limestone and yellow sandstone". In

913-544: Is also conglomerate included in the formation's upper layers. Characteristic features of the Yenimahalle formation include "low-angle cross-bedding and lamination, trough cross-bedding, ripple lamination, fining upwards sand channels, and gravel/conglomerate lenses ". In some places, sandstone concretions are common. Tuff deposits can also be found in some places, caused by "local, small phreatomagmatic eruptions". The presence of "Margaritae and Punctulate zones" in lower parts of

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996-507: Is being created to change that length. [REDACTED] [REDACTED] Decreasing length faults: In rare cases, transform faults can shrink in length. These occur when two descending subduction plates are linked by a transform fault. In time as the plates are subducted, the transform fault will decrease in length until the transform fault disappears completely, leaving only two subduction zones facing in opposite directions. [REDACTED] [REDACTED] The most prominent examples of

1079-435: Is constantly created through the upwelling of new basaltic magma . With new seafloor being pushed and pulled out, the older seafloor slowly slides away from the mid-oceanic ridges toward the continents. Although separated only by tens of kilometers, this separation between segments of the ridges causes portions of the seafloor to push past each other in opposing directions. This lateral movement of seafloors past each other

1162-469: Is disputed – Üner et al. instead describe the Gebiz Limestone as being deposited after sea levels rose again; Kaya attributes the Gebiz Limestone to the "latest Miocene-early Pliocene", describing it as being deposited by a NW-SE-oriented lake that formed during this period. According to Kaya's interpretation, the Aksu Basin was a "fluvial, fluvial-delta, beach setting" during the Middle Miocene ( c. 16-11 MYA), then "a lacustrine and lagoon environment" by

1245-475: Is due to the comparatively fine divisibility of time units as time approaches the present, and due to geological preservation that causes the youngest sedimentary geological record to be preserved over a much larger area and to reflect many more environments than the older geological record. By dividing the Cenozoic Era into three (arguably two) periods ( Paleogene , Neogene, Quaternary ) instead of seven epochs,

1328-569: Is formed by a combination of several geological processes, including uplift of the Tauride Mountains to the north, rifting within the Isparta Angle, and relative subsidence of the region to the south that now forms Antalya Bay. According to Glover and Robertson, the upper Aksu Basin was formed by "erosion, then subsidence" in the Miocene: a foreland basin, after and related to the SE-ward emplacement of

1411-686: Is subdivided into two ages: The Miocene Epoch is subdivided into six ages: In different geophysical regions of the world, other regional names are also used for the same or overlapping ages and other timeline subdivisions. The terms Neogene System (formal) and Upper Tertiary System (informal) describe the rocks deposited during the Neogene Period . The continents in the Neogene were very close to their current positions. The Isthmus of Panama formed, connecting North and South America . The Indian subcontinent continued to collide with Asia , forming

1494-912: Is the San Andreas Fault on the Pacific coast of the United States. The San Andreas Fault links the East Pacific Rise off the West coast of Mexico (Gulf of California) to the Mendocino triple junction (Part of the Juan de Fuca plate ) off the coast of the Northwestern United States , making it a ridge-to-transform-style fault. The formation of the San Andreas Fault system occurred fairly recently during

1577-475: Is variously dated to the Messinian or Tortonian. Its maximum thickness is about 40 m, in its type locality near the town of Gebiz. The Gebiz Limestone consists mainly of bioclastic limestone, marl , claystone , and mudstone. In some areas, there are reefal limestone deposits. The largest continuous exposed stretch of the Gebiz Limestone lies along the southeastern edge of the Aksu Basin; it runs parallel to

1660-435: Is where transform faults are currently active. Transform faults move differently from a strike-slip fault at the mid-oceanic ridge. Instead of the ridges moving away from each other, as they do in other strike-slip faults, transform-fault ridges remain in the same, fixed locations, and the new ocean seafloor created at the ridges is pushed away from the ridge. Evidence of this motion can be found in paleomagnetic striping on

1743-507: The Himalayas . Sea levels fell, creating land bridges between Africa and Eurasia and between Eurasia and North America. The global climate became more seasonal and continued an overall drying and cooling trend which began during the Paleogene . The Early Miocene was relatively cool; Early Miocene mid-latitude seawater and continental thermal gradients were already very similar to those of

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1826-721: The Isthmus of Panama , late in the Pliocene. This cut off the warm ocean currents from the Pacific to the Atlantic Ocean, leaving only the Gulf Stream to transfer heat to the Arctic Ocean . The global climate cooled considerably throughout the Neogene, culminating in a series of continental glaciations in the Quaternary Period that followed. In ICS terminology, from upper (later, more recent) to lower (earlier): The Pliocene Epoch

1909-673: The Oligocene Period between 34 million and 24 million years ago. During this period, the Farallon plate , followed by the Pacific plate, collided into the North American plate . The collision led to the subduction of the Farallon plate underneath the North American plate. Once the spreading center separating the Pacific and the Farallon plates was subducted beneath the North American plate,

1992-642: The Phanerozoic . The Neogene is sub-divided into two epochs , the earlier Miocene and the later Pliocene . Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary . The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868). The earlier term Tertiary Period was used to define the span of time now covered by Paleogene and Neogene and, despite no longer being recognized as

2075-580: The mammoths and woolly rhinoceros were common in Pliocene . With lower levels of CO 2 in the atmosphere, C 4 plants expanded and reached ecological dominance in grasslands during the last 10 million years. Also Asteraceae (daisies) went through a significant adaptive radiation . Eucalyptus fossil leaves occur in the Miocene of New Zealand, where the genus is not native today, but have been introduced from Australia. The Neogene traditionally ended at

2158-492: The photic zone . The low species diversity – primarily colonies of Porites and Tarbaellastraea – may indicate a "stressed" environment. The shore was "medium-high wave energy -dominated", and the climate was temperate to subtropical. The presence of coral fossils among the fan delta deposits is likely from periods when sudden sea level increase left the deltas underwater. Traces of coral reefs at Kargı and Sütçüler have been dated to Late Tortonian times. Around 5.6 MYA,

2241-616: The Aksu Basin is bounded by the Bey Dağları platform carbonates , where the crust is extending to produce a series of grabens and horsts that are mostly east-west aligned. To the east, the Aksu Thrust separates the Aksu Basin from the Köprü Çay Basin. Part of the broader Antalya Basin , which is itself located within the Isparta Angle , the Aksu Basin can be divided into two sub-basins: in

2324-676: The Aksu Formation; in either case, the two are mixed together in many places. The Karpuzçay Formation mostly comprises alternating layers of conglomerate, sandstone, and mudstone . The conglomerate layers have clasts made of chert , serpentinite, and various types of limestone. Sandstones vary in color from grey to green to dirty yellow. They have cross-bedding , cross-lamination , and pronounced graded bedding . Layers of tuffaceous sandstone are commonly mixed in with conglomerate or conglomeratic sandstone layers. Mudstone layers are usually laminated and contain concretions ranging from 15 to 20 mm. The Gebiz Limestone unconformably overlies

2407-727: The Aksu River. The Aksu Basin is considered a sedimentary basin and a foreland basin . It has been infilling since Neogene times. There are five fan deltas in the Aksu Basin: Kapıkaya, Kozan, Karadağ, Kargı, and Bucak. There is also the Eskiköy alluvial fan . Along with the neighboring Köpru and Manavgat Basins, the Aksu Basin has been of interest to geologists since the 1910s thanks to its "rich tectonic complexities and well-exposed structural and sedimentary features". The Aksu Basin covers some 2000 square kilometers. The Aksu Basin

2490-468: The Earth's subsurface. Transform faults specifically accommodate lateral strain by transferring displacement between mid-ocean ridges or subduction zones. They also act as the plane of weakness, which may result in splitting in rift zones . Transform faults are commonly found linking segments of divergent boundaries ( mid-oceanic ridges or spreading centres). These mid-oceanic ridges are where new seafloor

2573-541: The Gelasian Age, which was formerly considered part of the Neogene Period and Pliocene Epoch. Thus the Neogene Period ends bounding the succeeding Quaternary Period at 2.58 Mya. Transform fault A transform fault or transform boundary , is a fault along a plate boundary where the motion is predominantly horizontal . It ends abruptly where it connects to another plate boundary, either another transform,

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2656-526: The Karabayir platform. Meanwhile, the surrounding continental areas were being pushed upward; erosion from these areas provided a lot of sediment that was poured into the emerging Aksu Basin. According to Kaya, this was especially the case with the rapidly uplifting Antalya Complex to the east; it "provided the topographic gradient and gravitational potential energy for the necessary fluvial erosion and transport for sediment supply". Poisson et al. instead highlight

2739-645: The Karpuzçay Formation at its type locality near the town of Gebiz in the southeastern part of the Aksu Basin. In some places along the basin's eastern edge, it is instead faulted against the Triassic-Jurassic rocks of the Antalya Complex . More within the basin, it is faulted against younger basement strata in some places. It is dated to the Upper Miocene, although the exact time period is disputed. It

2822-625: The Late Oligocene , and continuing through the Burdigalian , rising sea levels caused a marine transgression in the area. The shallow marine Karabayir Limestones were deposited in the north and west, forming a large platform around what is now the Aksu Basin. Meanwhile, to the south, a molassic basin was formed; this was the beginning of the Antalya Basin as a whole. By the Early Miocene ,

2905-621: The Lycian Nappes. Then in the Pliocene and Pleistocene there was crustal extension or transtension to form the lower Aksu Basin. The pre-Miocene basement primarily consisted of the Bey Dağlari platform, surrounded by the Antalya Nappes, and covered by a thin layer of Paleogene sedimentary deposition. This formed "an eroded flat surface [that] covered a large area in SW Turkey". Beginning in

2988-512: The Mediterranean region was hit by the Messinian salinity crisis . Sea levels dropped tremendously, and there was rapid erosion and desiccation. Growth of the fan deltas stopped as the receding coastline left the entire Aksu Basin on land. Deep gorges were carved in the areas that were now exposed as dry land. One of them, now a deep undersea canyon in the Gulf of Antalya , is still traceable in front of

3071-693: The Neogene and the Pliocene end at 2.58 Ma, that the Gelasian be transferred to the Pleistocene, and the Quaternary be recognized as the third period in the Cenozoic, citing key changes in Earth's climate, oceans, and biota that occurred 2.58 Ma and its correspondence to the Gauss-Matuyama magnetostratigraphic boundary . In 2006 ICS and INQUA reached a compromise that made Quaternary a sub-era, subdividing Cenozoic into

3154-513: The Pliocene or Upper Pliocene. Neogene The Neogene ( / ˈ n iː . ə dʒ iː n / NEE -ə-jeen , ) is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago ( Mya ) to the beginning of the present Quaternary Period 2.58 million years ago. It is the second period of the Cenozoic and the eleventh period of

3237-661: The San Andreas Continental Transform-Fault system was created. In New Zealand , the South Island 's Alpine Fault is a transform fault for much of its length. This has resulted in the folded land of the Southland Syncline being split into an eastern and western section several hundred kilometres apart. The majority of the syncline is found in Southland and The Catlins in the island's southeast, but

3320-633: The Yenimahalle-Çalkaya sub-basin underwater, leading to what Üner et al. describe as a shallow marine shelf environment. Üner et al. attribute the alluvial fan-delta of the Eskiköy Formation, and the "shallow marine siltstone-marl alternations" of the Yenimahalle Formation to this period. According to Kaya, the Yenimahalle and Çalkaya Formations were deposited during this period. In the Late Pliocene ( c. 3.6-2.6 MYA), sea levels dropped and

3403-483: The actively cutting Antalya canyon". Poisson et al. also argued that the Gebiz Limestone was formed during the Messinian, implying that there was still at least a pocket of sea in the Aksu Basin even while the sea retreated. They characterize this environment as "very shallow marine", with coral reefs, which then gradually became more restricted as it gave way to land and eventually dried up completely. This characterization

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3486-471: The basin from these basement rocks. In front of the mouth of the Aksu River, there is a broad, shallow marine shelf offshore where the present-day sediments of the Aksu River are deposited. In the past, this area was deeper; according to Poisson et al., there was likely a canyon, as there still is over by the Düden and Karaman mouths near Antalya, but this canyon has since been filled in by Quaternary deposition from

3569-432: The basin's northern and western margins, where a series of fan deltas at prehistoric river mouths left thick sediment deposits – for example, the present-day Kapıkaya and Kargı fan deltas. The Aksu and Karpuzçay Formations were deposited during this period in what Kaya describes as "fluvial, deltaic to beach environments". Coral reefs fringed the coastline. These reefs lay on a "warm, well-aerated shallow marine shelf" in

3652-526: The beginning of the middle Pleistocene, global fluctuations in sea level increased, and a marine incursion may have eroded the lower part of the basin, although no marine sediments have been found in this area. Also around the mid-Pleistocene, a small fan was deposited at the mouth of the Karaman River. Also during this time, the most recent layer of the Aksu Basin was formed: the Belkis Conglomerate, in

3735-456: The constancy is caused by the continuous growth by both ridges outward, canceling any change in length. The opposite occurs when a ridge linked to a subducting plate, where all the lithosphere (new seafloor) being created by the ridge is subducted, or swallowed up, by the subduction zone. Finally, when two upper subduction plates are linked there is no change in length. This is due to the plates moving parallel with each other and no new lithosphere

3818-461: The corals Stylophora , Helliastraea , Plesiastraea , Favia , Tarbellastraea , and Porites . With a maximum thickness of 1500 m, the Karpuzçay Formation is the single most extensive formation in the Aksu Basin. It is approximately equal in date to the Aksu Formation, also being dated to the Langhian and Tortonian based on fossils. It is either slightly older or slightly younger than

3901-526: The distance between the ridges it separates; the distance remains constant in earthquakes because the ridges are spreading centers. This hypothesis was confirmed in a study of the fault plane solutions that showed the slip on transform faults points in the opposite direction than classical interpretation would suggest. Transform faults are closely related to transcurrent faults and are commonly confused. Both types of fault are strike-slip or side-to-side in movement; nevertheless, transform faults always end at

3984-499: The dominant terrestrial vertebrates, and took many forms as they adapted to various habitats. An explosive radiation of ursids took place at the Miocene-Pliocene boundary. The first hominins , the ancestors of humans, may have appeared in southern Europe and migrated into Africa. The first humans (belonging to the species Homo habilis ) appeared in Africa near the end of the period. About 20 million years ago gymnosperms in

4067-610: The early Pliocene, during the Zanclean period ( c. 5.3-3.6 MYA). The southern part of the Aksu Basin was submerged, while the northern part remained dry land. The Messinian canyons became filled in by new deposition. The Eskiköy canyon was at first completely submerged, as fossils of nannoplankton and planktonic foraminifera found in marl deposits suggest a shallow, "open-marine" environment. It then became "completely filled" by these marl deposits, then deltaic conglomerate deposits, and finally lacustrine marl deposits. Meanwhile, by

4150-475: The east, the formation contains "abundant clasts of red and green radiolarites , Triassic hallobia -bearing sandstone, and ophiolitic rocks ( serpentinite , dolerite , basaltic volcanic rocks". Near the eastern edge of the basin, the Aksu Formation directly overlies the Triassic basement rocks along an angular unconformity . Less commonly, blocks of reefal limestone are present. These blocks contain fossils of

4233-557: The edge of the basin. The main exposed outcroppings of the Eskiköy Formation are found in the middle part of the basin. Here, it generally sits on top of the Aksu and Karpuzçay Formations, separated from them by an unconformity. In some places, it instead lies on top of Triassic-Jurassic recrystallized limestones belonging to the Antalya Complex, either separated from them by an unconformity or faulted against them. The Eskiköy Formation primarily consists of sandy conglomerate and sandstone, with interspersed layers of mudstone. The conglomerate

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4316-405: The end of it. Neogene also marked the end of the reptilian genera Langstonia and Barinasuchus , terrestrial predators that were the last surviving members of Sebecosuchia , a group related to crocodiles. The oceans were dominated by large carnivores like megalodons and livyatans , and 19 million years ago about 70% of all pelagic shark species disappeared. Mammals and birds continued to be

4399-414: The end of the Miocene (i.e. c. 5.3 MYA). Then, during the early Pliocene ( c. 5.3-3.6 MYA), there was a relatively brief (at least geologically speaking) period of tidal flat and very shallow marine conditions. Later, there was a "return to entirely terrestrial conditions", and deposition by the ancient Aksu River formed the Belkis Conglomerate during the Pleistocene period. Sea levels rose again in

4482-546: The end of the Pliocene Epoch, just before the older definition of the beginning of the Quaternary Period; many time scales show this division. However, there was a movement amongst geologists (particularly marine geologists ) to also include ongoing geological time (Quaternary) in the Neogene, while others (particularly terrestrial geologists) insist the Quaternary to be a separate period of distinctly different record. The somewhat confusing terminology and disagreement amongst geologists on where to draw what hierarchical boundaries

4565-442: The fault changes from a normal fault with extensional stress to a strike-slip fault with lateral stress. In the study done by Bonatti and Crane, peridotite and gabbro rocks were discovered in the edges of the transform ridges. These rocks are created deep inside the Earth's mantle and then rapidly exhumed to the surface. This evidence helps to prove that new seafloor is being created at the mid-oceanic ridges and further supports

4648-451: The form of some conifer and cycad groups started to diversify and produce more species due to the changing conditions. In response to the cooler, seasonal climate, tropical plant species gave way to deciduous ones and grasslands replaced many forests. Grasses therefore greatly diversified, and herbivorous mammals evolved alongside it, creating the many grazing animals of today such as horses , antelope , and bison . Ice age mammals like

4731-547: The formation near Gebiz indicate that the formation can be dated to the Lower Pliocene. A number of fossilized bivalve and gastropod mollusk shells have been found in the Yenimahalle Formation, including Acanthocardia , Ostrea , Cerastoderma edule , Paphia , Dentalis , Gibbula , Fusinus , and Pectens . Glover and Robertson interpreted the Yenimahalle Formation as "a fine-grained shallow-marine shelf deposit". There do not seem to have been many coarse-grained deposits in this area, leading them to conclude that

4814-412: The formation to the Upper Miocene, which is consistent with Akay et al.'s interpretation. The Yenimahalle Formation is best exposed in two areas: around Yenimahalle in the southwestern part of the Aksu River valley, and around Gebiz in the east. It lies conformably on top of the Gebiz and Eskiköy Formations; i.e. they are not separated by an unconformity. The Çalkaya Formation sits on top of it. Around

4897-418: The formation. These are typically 1 or 2 meters thick and are "pale, brown Mediterranean-type soils". Throughout the formation, there are thin layers of white, carbonate-rich claystone (less than 1 meter thick). According to Glover and Robertson, these claystones were deposited "from hypersaline waters in undisturbed isolated, evaporative lagoons and pools". Fossils found in the Çalkaya Formation are basically

4980-436: The latest Miocene/early Pliocene, continued tectonic activity had caused the Aksu Basin (specifically the present-day northern part, the Aksu-Karpuzçay sub-basin) to become uplifted and tilted towards the south. Deposition was now happening further south, forming the Yenimahalle-Çalkaya sub-basin. Sediment was now coming from the Bey Dağları platform to the west, which had been uplifted in the meantime. Rising sea levels had left

5063-533: The mid-oceanic ridge transform zones are in the Atlantic Ocean between South America and Africa . Known as the St. Paul, Romanche , Chain, and Ascension fracture zones, these areas have deep, easily identifiable transform faults and ridges. Other locations include: the East Pacific Ridge located in the South Eastern Pacific Ocean , which meets up with San Andreas Fault to the North. Transform faults are not limited to oceanic crust and spreading centers; many of them are on continental margins . The best example

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5146-425: The middle Pleistocene , by fluvial terraces . At the present day, tectonic activity in the Aksu Basin is minimal, and there is also relatively little sedimentary deposition. Instead, erosion is the primary activity, such as cave systems and sinkholes forming in the Antalya Tufa. The Aksu River also continues to form fluvial terraces along its course. The stratigraphy of the Aksu Basin is well documented, although

5229-416: The north is the older Aksu-Karpuzçay sub-basin, and in the south is the younger Yenimahalle-Çalkaya sub-basin. The southern part of the basin is "now very heavily karstified and vegetated." The Aksu Basin overlies basement rocks of several types: Bey Dağları platform carbonates, Alanya Metamorphics , Antalya Nappes (made of ophiolite ) and Lycian Nappes (platform carbonate). An unconformity separates

5312-433: The offsets of oceanic ridges by faults do not follow the classical pattern of an offset fence or geological marker in Reid's rebound theory of faulting , from which the sense of slip is derived. The new class of faults, called transform faults, produce slip in the opposite direction from what one would surmise from the standard interpretation of an offset geological feature. Slip along transform faults does not increase

5395-401: The old classical Tertiary and Quaternary, a compromise that was rejected by International Union of Geological Sciences because it split both Neogene and Pliocene in two. Following formal discussions at the 2008 International Geological Congress in Oslo, Norway, the ICS decided in May 2009 to make the Quaternary the youngest period of the Cenozoic Era with its base at 2.58 Mya and including

5478-434: The ongoing geological processes in the region. Anatolia has been experiencing relative uplift, while the Aksu Basin has been experiencing relative subsidence to form an extensional graben. A fluctuating climate affected the river systems, and aggradation in the central part of the basin created fluvial terraces. Terra rossa -type soils formed on top of Mesozoic limestone and were redeposited into channels during flash floods. At

5561-505: The other continent. In his work on transform-fault systems, geologist Tuzo Wilson said that transform faults must be connected to other faults or tectonic-plate boundaries on both ends; because of that requirement, transform faults can grow in length, keep a constant length, or decrease in length. These length changes are dependent on which type of fault or tectonic structure connect with the transform fault. Wilson described six types of transform faults: Growing length: In situations where

5644-509: The periods are more closely comparable to the duration of periods in the Mesozoic and Paleozoic Eras. The International Commission on Stratigraphy (ICS) once proposed that the Quaternary be considered a sub-era (sub-erathem) of the Neogene, with a beginning date of 2.58 Ma, namely the start of the Gelasian Stage . In the 2004 proposal of the ICS, the Neogene would have consisted of the Miocene and Pliocene Epochs. The International Union for Quaternary Research (INQUA) counterproposed that

5727-425: The present day Düden and Karaman river mouths. A similar canyon likely existed on the Aksu, but it has since been buried by Quaternary sedimentation on the marine shelf. Poisson et al. reconstructed the course of the Aksu River around the end of the Messinian ( c. 5.3 MYA) this way: the river flowed through the Eskiköy Canyon, then "crossed the Antalya alluvial plain before joining the Antalya abyssal plain, through

5810-443: The present. During the Middle Miocene , Earth entered a warm phase known as the Middle Miocene Climatic Optimum (MMCO), which was driven by the emplacement of the Columbia River Basalt Group . Around 11 Ma, the Middle Miocene Warm Interval gave way to the much cooler Late Miocene. The ice caps on both poles began to grow and thicken, a process enhanced by positive feedbacks from increased formation of sea ice. Between 7 and 5.3 Ma,

5893-436: The river system depositing sediment here had a low gradient and relatively little bedload compared to total load. Based on foraminifera fossils, they estimated that the Yenimahalle Formation was deposited with a water depth under 150 meters, then gradually getting shallower to a depth of under 50 meters "for a significant period". The Çalkaya Formation rests on top of the Yenimahalle Formation. Glover and Robertson interpreted

5976-438: The same as those found in the Yenimahalle Formation. In general, gastropod and bivalve fossils in the Çalkaya Formation are larger than their equivalents in the upper Yenimahalle Formation. In some places, "exceptionally large" fossils of the gastropod Murex have been found. Other fossils found in the Çalkaya include foraminifera, ostracods , and "abundant" bivalve and gastropod mollusks. The Çalkaya Formation has been dated to

6059-444: The seafloor. A paper written by geophysicist Taras Gerya theorizes that the creation of the transform faults between the ridges of the mid-oceanic ridge is attributed to rotated and stretched sections of the mid-oceanic ridge. This occurs over a long period of time with the spreading center or ridge slowly deforming from a straight line to a curved line. Finally, fracturing along these planes forms transform faults. As this takes place,

6142-607: The southern Aksu Basin once again became dry land. On the western side of the basin, the Antalya Fault spawned cold springs, which produced the Antalya tufa and travertine deposits. During the Quaternary period, the Aksu River cut a new gorge – not in the same place as the Eskiköy canyon; the river's course had changed in the meantime. Since in the early-mid Pleistocene, Earth has experienced an alternating series of glacial and interglacial periods , which "superimposed their effects" on

6225-506: The specific delineation of formation names, ages, and boundaries are varied. This article follows Kaya's terminology. According to Ersin Kaya, the Aksu Formation is the oldest layer of the Aksu Basin. It is mixed with the similar-aged Karpuzçay Formation. Based on fossil records, the Aksu Formation has been dated to the Langhian through Tortonian periods (i.e. c. 16-7 MYA). Its maximum thickness

6308-408: The theory of plate tectonics. Active transform faults are between two tectonic structures or faults. Fracture zones represent the previously active transform-fault lines, which have since passed the active transform zone and are being pushed toward the continents. These elevated ridges on the ocean floor can be traced for hundreds of miles and in some cases even from one continent across an ocean to

6391-419: The trend of the overall divergent boundary. A smaller number of such faults are found on land, although these are generally better-known, such as the San Andreas Fault and North Anatolian Fault . Transform boundaries are also known as conservative plate boundaries because they involve no addition or loss of lithosphere at the Earth's surface. Geophysicist and geologist John Tuzo Wilson recognized that

6474-429: The village of Dorumlar , the Yenimahalle Formation is overlain by the Belkis Conglomerate, with an unconformity between them. The total thickness of the Yenimahalle Formation is about 250 m. Evidence of a prehistoric river delta from this stage has also been detected offshore based on seismic lines. The Yenimahalle Formation is made up of "blue-grey siltstone with embedded sandstone and graded gravelstone ". There

6557-567: The Çalkaya Formation as "a combination of the Pliocene Alakilise and Eskiköy Formations", but Kaya interpreted it as a separate formation since there is "no observable direct contact between them". The Çalkaya Formation consists of marly siltstone, sandstone, and conglomerate.Its lower part is similar in composition to the upper part of the Yenimahalle Formation. Siltstone layers in the Çalkaya Formation are interspersed with coal seams measuring 25–30 cm in thickness. Common features of

6640-438: The Çalkaya Formation include "low-angle cross-bedding, through cross-bedding, ripple lamination, and hummocky cross-stratification . In some places, the sediment's grain size increases significantly as it goes towards upper layers, getting coarser and eventually giving way to conglomerate. The Çalkaya Formation's sandstone deposits are similar in composition to those of the Yenimahalle Formation. Glover and Robertson interpreted

6723-466: The Çalkaya Formation's conglomerate indicates that it was well-worked by waves. In some places, "small lenticular pebble bodies within well-sorted sands" may represent what Glover and Robertson described as "lag concentrations within the lower shoreface zone, possibly a result of accumulation in hollows, or as storm deposits". Some "channelized" conglomerates also contain evidence of prehistoric sandbars . Paleosols (prehistoric soils) are fairly common in

6806-582: The Çalkaya sandstone as "shallow marine in origin, subject to occasional storm activity". Throughout the Çalkaya Formation, there are small conglomerate deposits. Towards the south, around Çalkaya itself, there are "much larger conglomerate bodies" that "crop out as topographic ridges". Like the sandstone, the Çalkaya conglomerates are also "marine in origin, as indicated by the evidence of pebbles bored by sponges and marine bivalves". Some fossils of barnacles and bivalves attached to pebbles and marine shells are found. The "pebble segregation and low lenticularlity" in

6889-539: Was high. The PWI had similar levels of atmospheric carbon dioxide to contemporary times and is often seen as an analogous climate to the projected climate of the near future as a result of anthropogenic global warming . Towards the end of the Pliocene, decreased heat transport towards the Antarctic resulting from a weakening of the Indonesian Throughflow (ITF) cooled the Earth, a process that exacerbated itself in

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