Investigating the Fluvial Response to Late Pleistocene Climate Changes and Vertical Deformation: Yesilirmak Terrace Staircases (central north Anatolia)

WOS: 000434463300010River terraces are remnants of former river floodplains that are fossilized above present-day river channels, often in staircase systems. The formation of terrace staircases is attributed to both tectonic, climate and sea/base level changes. Variations in tectonic and climatic conditions cause perturbations in the fluvial system, which, over time, lead to widening of valley floors, aggradation and incision, thereby producing terraces representing the complex response of the fluvial system to the chances in variables listed above. This study reports on the formation of terrace staircases at Yesilirmak River system of central northwest Anatolia, near Geldingen Plain (Amasya). The depositional steps reaching + 70 m (above today's recent floodplain), have been mapped and dated by using luminescence method which reveals that terrace formation started at early late Pleistocene and continued within Last Glacial Period. The terrace steps, namely T3 (+ 70 m), T2 (+ 35 m) and T1 (+ 15) were deposited during MIS5a, MIS3 and end of LGM. The correlation with the adjacent climate archives reveals that the terraces are formed primarily in response to climatically induced fluctuations in river discharge and sediment supply. Relative positions of the terrace risers and abandonment ages, enables us to calculate a long-term vertical uplift rate of 0.94 +/- 0.26 mm/year at the study area, located to the south of the North Anatolian Fault Zone

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

Age, composition and paleoenvironmental significance of a Late Pleistocene eolianite from the western Black Sea coast of Turkey

On the basis of field observations, thin section interpretations, microanalytical data, electrical resistivity survey and luminescence dating, the age, composition and internal structure of coastal eolianite on the west Black Sea coast at Sile, Istanbul, was studied for a combined interpretation of dune rock development and facies characteristics. Results demonstrate that the eolianite is made up of south-dipping, large-scale dune stratification, consisting mainly of quartz sand and, in particular, abundant ooids, as well as the binding cement which is composed of calcite and aragonite. Based on Electrical Resistivity Tomography (ERT) images, the eolianite has a thickness of between 3.5 m and 8 m and overlies a buried rugged topography that has developed on the Pliocene unit. This suggests the predominance of northerly winds that account for the landward removal of dune sands by offshore wind drift prior to carbonate cementation. Optically Stimulated Luminescence (OSL) dating estimations revealed that the initial deposition of the laminated eolianite layers on the underlying older unit took place at 138.57 +/- 13.65 ka, matching the Karangatian highstand or Marine Isotope Stage (MIS) 5e. (C) 2012 Elsevier Ltd and INQUA. All rights reserved

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