Cement fabrics and optical luminescence ages of beachrock, North Cyprus: Implications for Holocene sea-level changes

WOS: 000374478500011CaCO3-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 (similar to 5-10 degrees) 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 CaCO3 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. (C) 2015 Elsevier Ltd and INQUA. All rights reserved.Turkish Academy of SciencesAEE wishes to thank the Turkish Academy of Sciences for their support in the framework of the Distinguished Young Scientist Award Program (TUBA-GEBIP). We also thank Graham H. Lee for checking the English of the earlier version of the paper

Structural controls on distribution of dolines on Mount Anamas (Taurus Mountains, Turkey)

Solution dolines are characteristic landforms on the high plateaus of the Taurus Mountains. In this study, the effects of tectonic structures, drainage and slope conditions on the distribution and morphometric properties of dolines in the western part of the Central Taurus are explained. To delimit the dolines, 1/25000 scale topographic maps were used. The uppermost closed contour lines were digitized as polygons and the elevation, long and short axes, elongation ratios, orientation angles of the polygons were calculated. The doline density is compared with drainage density and mean slope values. A total of 111 rose diagrams were created in order to illustrate the superficial distribution of orientation. As a result, a total of 10,652 dolines were detected in a 711 km(2) doline area and maximum density reaches 123 dolines/km(2). However, according to the doline density, two distinct regions were detected, high density (RI) and low density (R2). Correlations between drainage density, slope angle and doline density are negative in the two regions. According to negative correlations, the drainage density is not a determinant factor in RI, while it is a determinant factor in R2. A 30 degrees slope angle (in km2) limits doline distribution on the plateau surface

GIS based analysis of doline density on Taurus Mountains, Turkey

The Taurus Mountain is one of the most important karstic region of the world and dolines are characteristics landforms of this area. However, the number and distribution of doline are unknown in the study area. The aims of this study are to explain the total number of dolines, distribution of doline density, effects of slope conditions and the change of doline orientation in the Taurus Mountains. According to the 1/25000 scale topographic maps utilized in this study, a total of 140,070 dolines were determined in a 13,189 km(2) area on eleven high karstic plateaus bordered by steep slopes and deep gorges. These plateaus are substantially affected by highly-faulted and jointed systems and about 80% of each plateau is covered with neritic limestone. The dolines are located at an elevation between 10 and 2870 m. Average elevation of all dolines is 1842 m. 90% of dolines are located between 1300 and 2270 m and only 5% of dolines found under 1330 m. According to this results, the densest doline zone corresponds to the alpine and periglacial zone above the treeline. Doline density reaches > 100 doline/km(2) on Mt. Anamas and the Seyran, Geyik and Akdag ranges as well as the TaAYeli plateau. Maximum density (187 doline/km(2)) is found on the Akdag Mountains. However, 66% of the study area is characterized by low density, 29.9% with moderate density, 3.4% with high density and 0.7% with very high density. The highest doline densities are seen on gentle slopes (15A degrees-25A degrees/km(2)) and steep slopes (> 35A degrees/km(2)) are limited doline distribution. According to the rose diagram formed by the azimuths of the long axis of the dolines at the Central Taurus, two direction are dominant in doline orientations (NW-SE and NE-SW). However, dominant directions are NE-SW at eastern, NE-SW and NW-SE at central and NW-SE at western part of the Central Taurus. According to this elongations, doline orientations are formed an arc which is formed by tectonic evolution of the Central Taurus

Did Amphistegina lobifera Larsen reach the Mediterranean via the Suez Canal?

WOS: 000374478500007It has been accepted by many researchers that Amphistegina lobifera Larsen migrated to the Mediterranean Sea via Suez Canal like many other Indo-Pacific originated foraminifers and organisms. This idea was also supported in the studies performed on the Turkish Aegean and Mediterranean coast in the last ten years, due to the discovery of alien benthic foraminifers. However, during field research in the Akkuyu (Mersin) region, a rich benthic foraminifera assemblage was found in the sediment samples, in which Amphistegina lobifera Larsen was abundant. In the present study, when and how Amphistegina lobifera Larsen migrated to the Mediterranean was investigated. Most of the Amphistegina lobifera Larsen individuals observed are found to show similar morphological characteristics with recent samples collected from Turkish coastline, which at first indicated that the individuals from Akkuyu might also be of Holocene age, but the OSL method produced dates of 227.3 +/- 17.8, 87.7 +/- 9.6 and 6.0 +/- 0.6 ka. These ages are Middle Pleistocene, Late Pleistocene and Holocene. In one sample, aged 427.5 +/- 29.4 ka, Spiroloculina antillarum d'Orbigny, which was suggested to be introduced to Mediterranean via the Suez Canal, was found together with Articulina carinata Wiesner. The presence of Spiroloculina antillarum d'Orbigny with Amphistegina lobifera Larsen together with in an other sample, aged 227.3 +/- 17.8 ka, indicates that these foraminifers have been introduced to the Mediterranean in Middle Pleistocene and they might have been living in the Eastern Mediterranean since then. As a result, these age data show that Amphistegina lobifera Larsen individuals did not migrate to the eastern Mediterranean via the Suez Canal which was opened in 1869, but much earlier than that via a different natural water way connecting Indo-Pacific to the Eastern Mediterranean. (C) 2015 Elsevier Ltd and INQUA. All rights reserved

Eolianite and coquinite as evidence of MIS 6 and 5, NW Black Sea coast, Turkey

This paper discusses the implications of a lowstand carbonate eolianite and overlying transgressive sequence of coquinite at Sile on the Turkish Black Sea coast based on composition, depositional characteristics and optical age estimations. The cross-bedded eolianite is a mixed ooid quartz grainstone in composition, yielding a depositional age matching MIS 6. It formed at the backshore of the paleobeach with the supply of sediment the from the beach face and offering insights into the drift of mixed shallow marine carbonates and siliciclastics together with radial ooids by onshore winds from a subaerially exposed high- to low-energy ooid shoals and oolitic sand complexes which developed parallel to the shoreline on the shallow shelf margin. During this lowstand, a low-relief dune retaining a record of opposing paleowind directions than that of prevalent northeasterly winds of today appears to have been lithified to form dune rock (aeolinite) under drier conditions compared to the present. Coinciding with MIS 5e, shallow marine coquina beds resting unconformably on the eolianite indicate the occurrence of the Mediterranean transgression during the last interglacial, as confirmed by benthic foraminifera within the high-salinity tolerant coquina shells. (C) 2017 Elsevier B.V. All rights reserved