The Ponto-Caspian basin as a final trap for southeastern Scandinavian Ice-Sheet meltwater

This paper provides new data on the evolution of the Caspian Sea and Black Sea from the Last Glacial Maximum until ca. 12 cal kyr BP. We present new analyses (clay mineralogy, grain-size, Nd isotopes and pollen) applied to sediments from the river terraces in the lower Volga, from the middle Caspian Sea and from the western part of the Black Sea. The results show that during the last deglaciation, the Ponto-Caspian basin collected meltwater and fine-grained sediment from the southern margin of the Scandinavian Ice Sheet (SIS) via the Dniepr and Volga Rivers. It induced the deposition of characteristic red-brownish/chocolate-coloured illite-rich sediments (Red Layers in the Black Sea and Chocolate Clays in the Caspian Sea) that originated from the Baltic Shield area according to Nd data. This general evolution, common to both seas was nevertheless differentiated over time due to the specificities of their catchment areas and due to the movement of the southern margin of the SIS. Our results indicate that in the eastern part of the East European Plain, the meltwater from the SIS margin supplied the Caspian Sea during the deglaciation until ∼13.8 cal kyr BP, and possibly from the LGM. That led to the Early Khvalynian transgressive stage(s) and Chocolate Clays deposition in the now-emerged northern flat part of the Caspian Sea (river terraces in the modern lower Volga) and in its middle basin. In the western part of the East European Plain, our results confirm the release of meltwater from the SIS margin into the Black Sea that occurred between 17.2 and 15.7 cal kyr BP, as previously proposed. Indeed, recent findings concerning the evolution of the southern margin of the SIS and the Black Sea, show that during the last deglaciation, occurred a westward release of meltwater into the North Atlantic (between ca. 20 and 16.7 cal kyr BP), and a southward one into the Black Sea (between 17.2 and 15.7 cal kyr BP). After the Red Layers/Chocolate Clays deposition in both seas and until 12 cal kyr BP, smectite became the dominant clay mineral. The East European Plain is clearly identified as the source for smectite in the Caspian Sea sediments. In the Black Sea, smectite originated either from the East European Plain or from the Danube River catchment. Previous studies consider smectite as being only of Anatolian origin. However, our results highlight both, the European source for smectite and the impact of this source on the depositional environment of the Black Sea during considered period

Hyalinea marmarica, a new species of benthic foraminifera from the Sea of Marmara (Turkey)

Traditionally, the benthic foraminifera Hyalinea balthica (Schröter) has been considered a species with high intraspecific variability, possibly related to climatic changes, and, therefore, a potential indicator of paleoclimate in the Mediterranean Sea. However, a stable and characteristic morphology very different from the syntype of the species can be observed in specimens from the Sea of Marmara. By identification and documentation of this morphology and a subsequent comparison to specimens similar to the type species, clear differences between the two groups have been established. Hyalinea marmarica n. sp. is proposed as an example of possible environment-related speciation in benthic foraminifera. It differs from H. balthica in having less numerous chambers in the last whorl (maximum of eight), depressed sutures at least in the last four chambers, a moderate increase in chamber size as added, a subacute profile and accessory apertures on the peripheral margin. Speciation could have occurred between 14 and 12 ka. At this time, increasingly efficient connections were progressively established between the Sea of Marmara and the Eastern Mediterranean Sea, allowing Hyalinea balthica to migrate into the Sea of Marmara. Here this species might have modified its morphology in response to the extreme environmental conditions

Application of micro and micro and meioorganisms to environmental problems [Mikro ve meioorganizmalarin çevre sorunlarina uygulanmasi]

The Second International on Conference "Applications of Micro- and Meioorganisms to Environmental Problems" was inaugurated at Winnipeg, Canada on August 28-September 1, 2000. It was the second in a series of conferences, which are carrying out on a regular 2-3 time interval. The previous one was held in Israel in 1997, and presented the results of innovative multidisciplinary research of the scientists from 49 countries in micro- and meioorganisms (e.g., bacteria, foraminifera, ostracoda, radiolaria, diatoms, calcareous nannoplankton, dinoflagellates, pollen and spores), to show their significance in solving environmental / paleo-environmental problems in the fields of biosciences, geosciences, environmental sciences, and agriculture. This Second Conference also aimed to introduce the utilisation of micro- and meioorganisms to a broader audience. Industries as well as regulatory environmental agencies still consider these applications "new", i.e. not proven. It is very important to bridge this gap between science, industries, and regulators

Tales set in stone

status: publishe

Geomorphological, depositional, and foraminiferal indicators of late Quaternary tectonic uplift in Iskenderun Bay, Turkey

Iskenderun Bay is a major shallow embayment in the eastern part of the Mediterranean Sea, where the African and Anatolian Plates converge. This tectonically active basin was investigated for oceanographic, sedimentological, geochemical, and foraminiferal parameters. On the basis of the data acquired, the distribution of living and fossil foraminifera in 284 grab and 54 gravity core samples was determined, the basin floor bathymetry of the bay constructed, radiocarbon ages of sediments and fossils ascertained, and depositional environments reconstructed. It has been discovered that for the last 13.5 k.y., water masses were stratified and sedimentation was discontinuous within the basin, which is characterized by irregular sea bottom morphology. The sedimentation rate was very slow, varying in time and space from 0 to 0.012 cm yr-1. The foraminiferal distributions were spatially varied and discontinuous and indicate a reversal from deep to shallow marine conditions in the cores. These irregularities were attributed to active tectonics in the bay and a major tectonic uplift of the bay since the late Pleistocene. © 2006 Geological Society of America

Geomorphological, depositional, and foraminiferal indicators of late Quaternary tectonic uplift in Iskenderun Bay, Turkey

Iskenderun Bay is a major shallow embayment in the eastern part of the Mediterranean Sea, where the African and Anatolian Plates converge. This tectonically active basin was investigated for oceanographic, sedimentological, geochemical, and foraminiferal parameters. On the basis of the data acquired, the distribution of living and fossil foraminifera in 284 grab and 54 gravity core samples was determined, the basin floor bathymetry of the bay constructed, radiocarbon ages of sediments and fossils ascertained, and depositional environments reconstructed. It has been discovered that for the last 13.5 k.y., water masses were stratified and sedimentation was discontinuous within the basin, which is characterized by irregular sea bottom morphology. The sedimentation rate was very slow, varying in time and space from 0 to 0.012 cm yr(-1). The foraminiferal distributions were spatially varied and discontinuous and indicate a reversal from deep to shallow marine conditions in the cores. These irregularities were attributed to active tectonics in the bay and a major tectonic uplift of the bay since the late Pleistocene