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Ahmet Evren Erginal - One of the best experts on this subject based on the ideXlab platform.
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cement fabrics and optical luminescence ages of Beachrock north cyprus implications for holocene sea level changes
Quaternary International, 2016Co-Authors: Muhammed Zeynel Öztürk, Ahmet Evren Erginal, Nafiye Güneç Kıyak, Tugba OzturkAbstract:Abstract CaCO 3 -cemented Beachrocks are widely found along the northern coast of Cyprus. In this study, we aim to discuss the cementation history of Beachrocks at ten particular sites within the context of Holocene sea-level changes. Cement fabrics, petrographic and geochemical characteristics, and optically-stimulated luminescence ages of buried quartz grains were studied. The seaward-inclined (∼5–10°) parallel-stratified beds are composed mostly of sandstone alternating with conglomerate. Ooids, benthic and planktic foraminifera, bioclasts of red algae, echinoid spines and gastropods make up a significant proportion of the cemented beds. With CaCO 3 content ranging between 37% and 65%, poorly-sorted grains are bonded by four distinct cements: circumgranular micritic coatings, sparry calcite infillings, pore fills, and meniscus bridges. This consecutive nature of cementation is typical of a marine phreatic and meteoric vadose environment when the sea level was lower than present but had a tendency to increase during middle to late Holocene. OSL ages ranging from 5.4 ka to 0.38 ka indicate that the deposition and ensuing cementation of the quartz grains occurred during two main stages; younger beds dated between 2.3 ka and 0.38 ka and older beds from 2.3 ka to 5.4 ka. A period devoid of Beachrock formation was attested between 3.5 ka and 2.3 ka.
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Beachrock formation on the coast of Gökçeada Island and its relation to the active tectonics of the region, northern Aegean Sea, Turkey
Quaternary International, 2016Co-Authors: Mustafa Avcıoğlu, Erdinç Yiğitbaş, Ahmet Evren ErginalAbstract:Abstract There are Beachrock formations in 5 different sections of the south coast of Gokceada, Turkey's largest Aegean island. These Beachrocks form two different groups in terms of layering characteristics, δ18O and δ13C stable isotope compositions, consecutive cementation structures, and 14C dating. The West Group Beachrocks, to the west, were dated to 4010–5830 BP, while the East Group Beachrocks were dated to 620–2390 BP. The Beachrock formations in both groups are separated by the NE–SW-trending Ugurlu Fault. The Ugurlu Fault is a right lateral, strike slip with reverse component oblique fault, and is an active fault within the North Anatolian Fault Zone. In the period between the formation of the two Beachrock groups (2390–4010 BP), an earthquake was responsible for the destruction of Gokceada Yenibademli mound and the development of two generations of Beachrock.
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Preliminary Assessment of Submerged Beachrock and Tsunamigenic Deposit, Hasır Island, Marmara Archipelago, Turkey
Journal of Coastal Research, 2015Co-Authors: Ahmet Ertek, Ahmet Evren Erginal, Elçin Kılıç, Yunus Levent Ekinci, Alper DemirciAbstract:ABSTRACT Ertek, A.; Kilic, E.; Erginal, A.E.; Ekinci, Y.L., and Demirci, A., 2015. Preliminary assessment of submerged Beachrock and tsunamigenic deposit, Hasir Island, Marmara Archipelago, Turkey. A preassessment of coexisted submerged Beachrock and a fossil-laden near-shore deposit on the coast of Hasir Island, SW Marmara Sea, is presented based on depositional characteristics, two-dimensional electrical resistivity tomography (ERT) survey and accelerator mass spectrometry (AMS) radiocarbon ages. ERT-derived geophysical images clearly showed the subsurface position and contact relationship of submerged Beachrock under the studied beach. Textural features of Beachrock are typical solely of marine-phreatic cementation, including consecutively developed cement fabrics, i.e. micrite coatings, radial aggregates consisting of scalenohedral high-Mg calcites, and reticulated needles of aragonite. The intertidal cementation of Beachrock took place between 2940 and 2470 YBP when the level of the Marmara Sea was a...
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İçmecedere Beachrock (Bozcaada-Çanakkale-Türkiye): Results and Significance of Analytical Studies
2012Co-Authors: Mustafa Avcıoğlu, Ahmet Evren Erginal, Erdinç YiğitbaşAbstract:The Bozcaada, second biggest island in Turkey, is an interesting region in point of Late Pleistocene-Holocene geological formations. On the south coast of the island eolinites, Beachrocks and rhizolithes are widely observed. These geological formations are important for understanding of the paleo-coastal environment. In this study, Beachrocks occurring on both sides of the island namely Icmecedere Beachrock that was not mentioned before in the literature have been investigated. Petrographic, analytic (XRD and SEM-EDX) and 14 C dating studies have been performed in order to clarifying the age and facies of Beachrock. The outcrops of the Icmecedere Beachrock extends 20 meters parallel to the coastline and have heterometric structure with poorly sorted including block-sized and also fine clast. For geochemical analyzing and age dating samples have been taken from the three different points of Beachrock which have a maximum 40 cm thickness. Calibrated radiocarbon datings from youngest beds yield to 950-750 years and 3860-3560 years from the oldest layers. Based on thin-section studies, Beachrock is composed mainly of poorly sorted metamorphic rock fragments. Moreover, the cementing is weak and including cracked fossil shells among grains. SEM analyses were performed to determine the cement micromorphology among grains. The analysis, show that cementation started in intertidal zone and the grain surfaces were covered by micritic envelope. These micritic envelopes are covered by meniscus cement indicating the mixture of sea water and fresh water. Secondary cement which developed on the micritic cover states declining the sea level during the cementing. The older layers of Beachrock with bridge cement were cemented during this sea-level declining stage. This period should be contemporaneous the declining of the sea-level at -2m in the Aegean Sea. According to the result of EDX analysis; element abundances in weight percent of micritic envelope and inter-grain cement range as O>C>Ca>Si>Al>Mg>Fe>Cl>Na in decreasing order. The mean value of %MgCO 3 is 5.37 showing high Mg-calcite of cementing carbonate. Moreover, XRD analyses indicate the existence of dolomitic cement. According to stable isotope (δ 18 O and δ 13 C) cementing material is ranging from 1.75 to 2.38 for 13 C and 1.28 to -1.81 for 18 O. These positive values indicate enrichment in heavy isotopes and also increasing in temperature during deposition of cementing material. This period correspond to arid stage at the end of climatic optimum δon the Mediterranean (6-3 thousand years). This study is supported partly by 2010/162 project of COMU-BAP and includes preliminary results of the first author’s PhD thesis.
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First note on marine-like cementation of Late Holocene Beachrock, Iznik Lake (Turkey)
Geochronometria, 2012Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Erdinç Yiğitbaş, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Beyhan ÖztürkAbstract:Micro-fabric characteristics and optically stimulated luminescence (OSL) dating results are presented to discuss the controlling agents and timing of Beachrock cementation on the fresh-water Iznik Lake shoreline. The Beachrocks are made up of grain-supported polygenic conglomerate containing 20.42% carbonate with encrusted grains, basically as micrite coatings, isopachous aragonite rims, cryptocrystalline void fills and meniscus bridges. The optical ages of twelve samples yielded ages that range from 4.226±0.569 ka on the lowermost beds to 0.706±0.081 on the uppermost. This is the first report of precipitation of marine-like cements in Iznik Lake. The abundant aragonite-dominated cement is likely indicative of precipitation-prone dry evaporative conditions from the climatic optimum to the last millennia.
Muhammed Zeynel Öztürk - One of the best experts on this subject based on the ideXlab platform.
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cement fabrics and optical luminescence ages of Beachrock north cyprus implications for holocene sea level changes
Quaternary International, 2016Co-Authors: Muhammed Zeynel Öztürk, Ahmet Evren Erginal, Nafiye Güneç Kıyak, Tugba OzturkAbstract:Abstract CaCO 3 -cemented Beachrocks are widely found along the northern coast of Cyprus. In this study, we aim to discuss the cementation history of Beachrocks at ten particular sites within the context of Holocene sea-level changes. Cement fabrics, petrographic and geochemical characteristics, and optically-stimulated luminescence ages of buried quartz grains were studied. The seaward-inclined (∼5–10°) parallel-stratified beds are composed mostly of sandstone alternating with conglomerate. Ooids, benthic and planktic foraminifera, bioclasts of red algae, echinoid spines and gastropods make up a significant proportion of the cemented beds. With CaCO 3 content ranging between 37% and 65%, poorly-sorted grains are bonded by four distinct cements: circumgranular micritic coatings, sparry calcite infillings, pore fills, and meniscus bridges. This consecutive nature of cementation is typical of a marine phreatic and meteoric vadose environment when the sea level was lower than present but had a tendency to increase during middle to late Holocene. OSL ages ranging from 5.4 ka to 0.38 ka indicate that the deposition and ensuing cementation of the quartz grains occurred during two main stages; younger beds dated between 2.3 ka and 0.38 ka and older beds from 2.3 ka to 5.4 ka. A period devoid of Beachrock formation was attested between 3.5 ka and 2.3 ka.
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First note on marine-like cementation of Late Holocene Beachrock, Iznik Lake (Turkey)
Geochronometria, 2012Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Erdinç Yiğitbaş, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Beyhan ÖztürkAbstract:Micro-fabric characteristics and optically stimulated luminescence (OSL) dating results are presented to discuss the controlling agents and timing of Beachrock cementation on the fresh-water Iznik Lake shoreline. The Beachrocks are made up of grain-supported polygenic conglomerate containing 20.42% carbonate with encrusted grains, basically as micrite coatings, isopachous aragonite rims, cryptocrystalline void fills and meniscus bridges. The optical ages of twelve samples yielded ages that range from 4.226±0.569 ka on the lowermost beds to 0.706±0.081 on the uppermost. This is the first report of precipitation of marine-like cements in Iznik Lake. The abundant aragonite-dominated cement is likely indicative of precipitation-prone dry evaporative conditions from the climatic optimum to the last millennia.
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Cementation characteristics and age of Beachrocks in a fresh-water environment, Lake İznik, NW Turkey
Sedimentary Geology, 2012Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Erdinç YiğitbaşAbstract:This paper focuses on the cement characteristics and optical luminescence age of late Pleistocene-Holocene Beachrock, exposed on the southeast shore of freshwater Lake Iznik in northwest Turkey, based on field observations, various spectroscopic analyses and optical dating results. The studied Beachrock is a poorly-sorted coastal conglomerate composed mostly of gravels derived from surrounding volcanic rocks and marbles as well as quartz and carbonate grains. We identified different types of cements; dominated by micritic envelopes, bladed isopachous aragonite rims, void fills, radial aggregates and meniscus bridges, implying no single origin. Cementation characteristics indicate that marine-like cement micro-fabrics may occur in freshwater lake environments where the lake-water chemistry favors carbonate precipitation. OSL data revealed the existence of older Beachrock dating back to 20.2 ka, together with younger Holocene-age Beachrock of between 5.6 and 2.4 ka. This suggests that younger Beachrocks have been superimposed on older cemented carbonates through the removal of carbonates by wave motion (splash and spray) during lower lake level conditions.Publisher's Versio
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Cementation characteristics and age of Beachrocks in a fresh-water environment, Lake İznik, NW Turkey
Sedimentary Geology, 2011Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Erdinç YiğitbaşAbstract:Abstract This paper focuses on the cement characteristics and optical luminescence age of late Pleistocene–Holocene Beachrock, exposed on the southeast shore of freshwater Lake Iznik in northwest Turkey, based on field observations, various spectroscopic analyses and optical dating results. The studied Beachrock is a poorly-sorted coastal conglomerate composed mostly of gravels derived from surrounding volcanic rocks and marbles as well as quartz and carbonate grains. We identified different types of cements; dominated by micritic envelopes, bladed isopachous aragonite rims, void fills, radial aggregates and meniscus bridges, implying no single origin. Cementation characteristics indicate that marine-like cement micro-fabrics may occur in freshwater lake environments where the lake-water chemistry favors carbonate precipitation. OSL data revealed the existence of older Beachrock dating back to 20.2 ka, together with younger Holocene-age Beachrock of between 5.6 and 2.4 ka. This suggests that younger Beachrocks have been superimposed on older cemented carbonates through the removal of carbonates by wave motion (splash and spray) during lower lake level conditions.
Nafiye Güneç Kıyak - One of the best experts on this subject based on the ideXlab platform.
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cement fabrics and optical luminescence ages of Beachrock north cyprus implications for holocene sea level changes
Quaternary International, 2016Co-Authors: Muhammed Zeynel Öztürk, Ahmet Evren Erginal, Nafiye Güneç Kıyak, Tugba OzturkAbstract:Abstract CaCO 3 -cemented Beachrocks are widely found along the northern coast of Cyprus. In this study, we aim to discuss the cementation history of Beachrocks at ten particular sites within the context of Holocene sea-level changes. Cement fabrics, petrographic and geochemical characteristics, and optically-stimulated luminescence ages of buried quartz grains were studied. The seaward-inclined (∼5–10°) parallel-stratified beds are composed mostly of sandstone alternating with conglomerate. Ooids, benthic and planktic foraminifera, bioclasts of red algae, echinoid spines and gastropods make up a significant proportion of the cemented beds. With CaCO 3 content ranging between 37% and 65%, poorly-sorted grains are bonded by four distinct cements: circumgranular micritic coatings, sparry calcite infillings, pore fills, and meniscus bridges. This consecutive nature of cementation is typical of a marine phreatic and meteoric vadose environment when the sea level was lower than present but had a tendency to increase during middle to late Holocene. OSL ages ranging from 5.4 ka to 0.38 ka indicate that the deposition and ensuing cementation of the quartz grains occurred during two main stages; younger beds dated between 2.3 ka and 0.38 ka and older beds from 2.3 ka to 5.4 ka. A period devoid of Beachrock formation was attested between 3.5 ka and 2.3 ka.
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First note on marine-like cementation of Late Holocene Beachrock, Iznik Lake (Turkey)
Geochronometria, 2012Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Erdinç Yiğitbaş, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Beyhan ÖztürkAbstract:Micro-fabric characteristics and optically stimulated luminescence (OSL) dating results are presented to discuss the controlling agents and timing of Beachrock cementation on the fresh-water Iznik Lake shoreline. The Beachrocks are made up of grain-supported polygenic conglomerate containing 20.42% carbonate with encrusted grains, basically as micrite coatings, isopachous aragonite rims, cryptocrystalline void fills and meniscus bridges. The optical ages of twelve samples yielded ages that range from 4.226±0.569 ka on the lowermost beds to 0.706±0.081 on the uppermost. This is the first report of precipitation of marine-like cements in Iznik Lake. The abundant aragonite-dominated cement is likely indicative of precipitation-prone dry evaporative conditions from the climatic optimum to the last millennia.
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Cementation characteristics and age of Beachrocks in a fresh-water environment, Lake İznik, NW Turkey
Sedimentary Geology, 2012Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Erdinç YiğitbaşAbstract:This paper focuses on the cement characteristics and optical luminescence age of late Pleistocene-Holocene Beachrock, exposed on the southeast shore of freshwater Lake Iznik in northwest Turkey, based on field observations, various spectroscopic analyses and optical dating results. The studied Beachrock is a poorly-sorted coastal conglomerate composed mostly of gravels derived from surrounding volcanic rocks and marbles as well as quartz and carbonate grains. We identified different types of cements; dominated by micritic envelopes, bladed isopachous aragonite rims, void fills, radial aggregates and meniscus bridges, implying no single origin. Cementation characteristics indicate that marine-like cement micro-fabrics may occur in freshwater lake environments where the lake-water chemistry favors carbonate precipitation. OSL data revealed the existence of older Beachrock dating back to 20.2 ka, together with younger Holocene-age Beachrock of between 5.6 and 2.4 ka. This suggests that younger Beachrocks have been superimposed on older cemented carbonates through the removal of carbonates by wave motion (splash and spray) during lower lake level conditions.Publisher's Versio
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Cementation characteristics and age of Beachrocks in a fresh-water environment, Lake İznik, NW Turkey
Sedimentary Geology, 2011Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Erdinç YiğitbaşAbstract:Abstract This paper focuses on the cement characteristics and optical luminescence age of late Pleistocene–Holocene Beachrock, exposed on the southeast shore of freshwater Lake Iznik in northwest Turkey, based on field observations, various spectroscopic analyses and optical dating results. The studied Beachrock is a poorly-sorted coastal conglomerate composed mostly of gravels derived from surrounding volcanic rocks and marbles as well as quartz and carbonate grains. We identified different types of cements; dominated by micritic envelopes, bladed isopachous aragonite rims, void fills, radial aggregates and meniscus bridges, implying no single origin. Cementation characteristics indicate that marine-like cement micro-fabrics may occur in freshwater lake environments where the lake-water chemistry favors carbonate precipitation. OSL data revealed the existence of older Beachrock dating back to 20.2 ka, together with younger Holocene-age Beachrock of between 5.6 and 2.4 ka. This suggests that younger Beachrocks have been superimposed on older cemented carbonates through the removal of carbonates by wave motion (splash and spray) during lower lake level conditions.
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Investigation of Beachrock Using Microanalyses and OSL Dating: A Case Study from Bozcaada Island, Turkey
Journal of Coastal Research, 2010Co-Authors: Ahmet Evren Erginal, Nafiye Güneç Kıyak, Beyhan ÖztürkAbstract:Abstract We investigated the origin and absolute age of Beachrock samples on Bozcaada Island, located on the northern Aegean Sea coast of Turkey, using energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) analyses and optically stimulated luminescence (OSL) dating. Various types of cements were identified, such as micritic, meniscus, and biologic cements, revealing that the Beachrock could have occurred as a result of the combined effects of marine-phreatic and supratidal cementation conditions. Optical dating results showed that the formation of Beachrock ranged in age from 5.41 ± 0.58 ka BP to 0.33 ± 0.05 ka BP. However, much of the Beachrock body (about 3 m in thickness) is drowned or submerged today, suggesting that submerged Beachrocks extending to −5 m date to earlier times than the start of the cementation period discussed herein.
Erdinç Yiğitbaş - One of the best experts on this subject based on the ideXlab platform.
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Beachrock formation on the coast of Gökçeada Island and its relation to the active tectonics of the region, northern Aegean Sea, Turkey
Quaternary International, 2016Co-Authors: Mustafa Avcıoğlu, Erdinç Yiğitbaş, Ahmet Evren ErginalAbstract:Abstract There are Beachrock formations in 5 different sections of the south coast of Gokceada, Turkey's largest Aegean island. These Beachrocks form two different groups in terms of layering characteristics, δ18O and δ13C stable isotope compositions, consecutive cementation structures, and 14C dating. The West Group Beachrocks, to the west, were dated to 4010–5830 BP, while the East Group Beachrocks were dated to 620–2390 BP. The Beachrock formations in both groups are separated by the NE–SW-trending Ugurlu Fault. The Ugurlu Fault is a right lateral, strike slip with reverse component oblique fault, and is an active fault within the North Anatolian Fault Zone. In the period between the formation of the two Beachrock groups (2390–4010 BP), an earthquake was responsible for the destruction of Gokceada Yenibademli mound and the development of two generations of Beachrock.
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İçmecedere Beachrock (Bozcaada-Çanakkale-Türkiye): Results and Significance of Analytical Studies
2012Co-Authors: Mustafa Avcıoğlu, Ahmet Evren Erginal, Erdinç YiğitbaşAbstract:The Bozcaada, second biggest island in Turkey, is an interesting region in point of Late Pleistocene-Holocene geological formations. On the south coast of the island eolinites, Beachrocks and rhizolithes are widely observed. These geological formations are important for understanding of the paleo-coastal environment. In this study, Beachrocks occurring on both sides of the island namely Icmecedere Beachrock that was not mentioned before in the literature have been investigated. Petrographic, analytic (XRD and SEM-EDX) and 14 C dating studies have been performed in order to clarifying the age and facies of Beachrock. The outcrops of the Icmecedere Beachrock extends 20 meters parallel to the coastline and have heterometric structure with poorly sorted including block-sized and also fine clast. For geochemical analyzing and age dating samples have been taken from the three different points of Beachrock which have a maximum 40 cm thickness. Calibrated radiocarbon datings from youngest beds yield to 950-750 years and 3860-3560 years from the oldest layers. Based on thin-section studies, Beachrock is composed mainly of poorly sorted metamorphic rock fragments. Moreover, the cementing is weak and including cracked fossil shells among grains. SEM analyses were performed to determine the cement micromorphology among grains. The analysis, show that cementation started in intertidal zone and the grain surfaces were covered by micritic envelope. These micritic envelopes are covered by meniscus cement indicating the mixture of sea water and fresh water. Secondary cement which developed on the micritic cover states declining the sea level during the cementing. The older layers of Beachrock with bridge cement were cemented during this sea-level declining stage. This period should be contemporaneous the declining of the sea-level at -2m in the Aegean Sea. According to the result of EDX analysis; element abundances in weight percent of micritic envelope and inter-grain cement range as O>C>Ca>Si>Al>Mg>Fe>Cl>Na in decreasing order. The mean value of %MgCO 3 is 5.37 showing high Mg-calcite of cementing carbonate. Moreover, XRD analyses indicate the existence of dolomitic cement. According to stable isotope (δ 18 O and δ 13 C) cementing material is ranging from 1.75 to 2.38 for 13 C and 1.28 to -1.81 for 18 O. These positive values indicate enrichment in heavy isotopes and also increasing in temperature during deposition of cementing material. This period correspond to arid stage at the end of climatic optimum δon the Mediterranean (6-3 thousand years). This study is supported partly by 2010/162 project of COMU-BAP and includes preliminary results of the first author’s PhD thesis.
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First note on marine-like cementation of Late Holocene Beachrock, Iznik Lake (Turkey)
Geochronometria, 2012Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Erdinç Yiğitbaş, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Beyhan ÖztürkAbstract:Micro-fabric characteristics and optically stimulated luminescence (OSL) dating results are presented to discuss the controlling agents and timing of Beachrock cementation on the fresh-water Iznik Lake shoreline. The Beachrocks are made up of grain-supported polygenic conglomerate containing 20.42% carbonate with encrusted grains, basically as micrite coatings, isopachous aragonite rims, cryptocrystalline void fills and meniscus bridges. The optical ages of twelve samples yielded ages that range from 4.226±0.569 ka on the lowermost beds to 0.706±0.081 on the uppermost. This is the first report of precipitation of marine-like cements in Iznik Lake. The abundant aragonite-dominated cement is likely indicative of precipitation-prone dry evaporative conditions from the climatic optimum to the last millennia.
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Cementation characteristics and age of Beachrocks in a fresh-water environment, Lake İznik, NW Turkey
Sedimentary Geology, 2012Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Erdinç YiğitbaşAbstract:This paper focuses on the cement characteristics and optical luminescence age of late Pleistocene-Holocene Beachrock, exposed on the southeast shore of freshwater Lake Iznik in northwest Turkey, based on field observations, various spectroscopic analyses and optical dating results. The studied Beachrock is a poorly-sorted coastal conglomerate composed mostly of gravels derived from surrounding volcanic rocks and marbles as well as quartz and carbonate grains. We identified different types of cements; dominated by micritic envelopes, bladed isopachous aragonite rims, void fills, radial aggregates and meniscus bridges, implying no single origin. Cementation characteristics indicate that marine-like cement micro-fabrics may occur in freshwater lake environments where the lake-water chemistry favors carbonate precipitation. OSL data revealed the existence of older Beachrock dating back to 20.2 ka, together with younger Holocene-age Beachrock of between 5.6 and 2.4 ka. This suggests that younger Beachrocks have been superimposed on older cemented carbonates through the removal of carbonates by wave motion (splash and spray) during lower lake level conditions.Publisher's Versio
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Cementation characteristics and age of Beachrocks in a fresh-water environment, Lake İznik, NW Turkey
Sedimentary Geology, 2011Co-Authors: Ahmet Evren Erginal, Mustafa Avcıoğlu, Nafiye Güneç Kıyak, Muhammed Zeynel Öztürk, Mustafa Bozcu, Erdinç YiğitbaşAbstract:Abstract This paper focuses on the cement characteristics and optical luminescence age of late Pleistocene–Holocene Beachrock, exposed on the southeast shore of freshwater Lake Iznik in northwest Turkey, based on field observations, various spectroscopic analyses and optical dating results. The studied Beachrock is a poorly-sorted coastal conglomerate composed mostly of gravels derived from surrounding volcanic rocks and marbles as well as quartz and carbonate grains. We identified different types of cements; dominated by micritic envelopes, bladed isopachous aragonite rims, void fills, radial aggregates and meniscus bridges, implying no single origin. Cementation characteristics indicate that marine-like cement micro-fabrics may occur in freshwater lake environments where the lake-water chemistry favors carbonate precipitation. OSL data revealed the existence of older Beachrock dating back to 20.2 ka, together with younger Holocene-age Beachrock of between 5.6 and 2.4 ka. This suggests that younger Beachrocks have been superimposed on older cemented carbonates through the removal of carbonates by wave motion (splash and spray) during lower lake level conditions.
Jin-long Sun - One of the best experts on this subject based on the ideXlab platform.
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Holocene coquina Beachrock from Haishan Island, east coast of Guangdong Province, China
Quaternary International, 2013Co-Authors: Jian-wei Shen, Jiang-ping Long, Kevin Pedoja, Hong-qiang Yang, Jin-long SunAbstract:Coquina Beachrock, with a thickness of 10 m and an exposed surface area covering 3.4 km(2), is well developed along the southern coast of Haishan Island on the east coast of Guangdong Province, South China. Part of the deposit not treated in this study also extends under the surface of the sea. The coquina Beachrock was deposited in a large embayment semi-enclosed by palaeocoastal hills and islands, but with good marine circulation. Holocene strata on Haishan Island demonstrate a mixed carbonate/siliciclastic regime in a series of fining- and deepening-upward shelly limestone successions. Mass accumulations of whole and fragmented mollusc shells are the most remarkable features expressed throughout the series. Coralline red algae are commonly found overgrowing the bivalve bioclasts. Other bioclasts include gastropods, coralline red algae, bryozoans, foraminifera, and scleractinian coral. Cement is well developed within the interstices formed by the bioclasts, showing two or three generations of development. On both a qualitative and quantitative basis, the consecutive coquina series document an overall shallowing-upward pattern of Beachrock deposition, which was strongly influenced by marine transgression on Haishan Island. Dating by AMS C-14 indicates an age in the Middle to early Late Holocene for these coquina Beachrock deposits. Siliciclasts incorporated within the Beachrock deposits mainly consist of quartz grains. Not fully hardened, the binding cement is high in calcium carbonate, including aragonite mud, fibrous aragonite and granular calcite. Such carbonate deposits dominated by mollusc bioclasts with quartz grains indicate a pattern of littoral sedimentation. The massive coquina Beachrock on the southern coast of Haishan Island formed during Middle to early Late Holocene time, and represents a highstand of sea level from 4000 BP to 2800 BP with short-lived and rapid sea level fall. (C) 2013 Elsevier Ltd and INQUA. All rights reserved.
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Holocene coquina Beachrock from Haishan Island, east coast of Guangdong Province, China
Quaternary International, 2013Co-Authors: Jian-wei Shen, Jiang-ping Long, Kevin Pedoja, Hong-qiang Yang, Jin-long SunAbstract:Coquina Beachrock, with a thickness of 10 m and an exposed surface area covering 3.4 km2, is well developed along the southern coast of Haishan Island on the east coast of Guangdong Province, South China. Part of the deposit not treated in this study also extends under the surface of the sea. The coquina Beachrock was deposited in a large embayment semi-enclosed by palaeocoastal hills and islands, but with good marine circulation. Holocene strata on Haishan Island demonstrate a mixed carbonate/siliciclastic regime in a series of fining- and deepening-upward shelly limestone successions. Mass accumulations of whole and fragmented mollusc shells are the most remarkable features expressed throughout the series. Coralline red algae are commonly found overgrowing the bivalve bioclasts. Other bioclasts include gastropods, coralline red algae, bryozoans, foraminifera, and scleractinian coral. Cement is well developed within the interstices formed by the bioclasts, showing two or three generations of development. On both a qualitative and quantitative basis, the consecutive coquina series document an overall shallowing-upward pattern of Beachrock deposition, which was strongly influenced by marine transgression on Haishan Island. Dating by AMS 14C indicates an age in the Middle to early Late Holocene for these coquina Beachrock deposits. Siliciclasts incorporated within the Beachrock deposits mainly consist of quartz grains. Not fully hardened, the binding cement is high in calcium carbonate, including aragonite mud, fibrous aragonite and granular calcite. Such carbonate deposits dominated by mollusc bioclasts with quartz grains indicate a pattern of littoral sedimentation. The massive coquina Beachrock on the southern coast of Haishan Island formed during Middle to early Late Holocene time, and represents a highstand of sea level from 4000 BP to 2800 BP with short-lived and rapid sea level fall.