Palaeoecology and sedimentology of the Miocene marine and terrestrial deposits in the “Medieval Quarry” on Devínska Kobyla Hill (Vienna Basin)

Dramatic tectonic and sea level changes of the Central Paratethys realm during the Middle Miocene resulted in changes of the coastal and seabed morphology affecting the composition of the marine association and the distribution of the facies along the coast. Three different episodes (marine-terrestrial-marine) in the environmental evolution are interpreted. A lower marine unit (Badenian; Lower Serravallian) reflects organodetrital sedimentation on and around an algal bioherm. Low terrigenous input maërl facies of typical rhodalgal carbonate factory type characterise the top of the algal mound. On the slopes, a rim of rhodechfor facies separated the bioherm from the rest of the bottom which had a seagrass cover. This high-energy rhodechfor carbonate factory is described from the Central Paratethys realm for the first time. It is composed mostly of coralline algae (Mesophyllum, Lithothamnion, Spongites and Lithophyllum), benthic foraminifers (Elphidium crispum, Neoconorbina terquemi, Miniacina sp., Borelis melo), echinoids (cidaroid, spatangoid and diadematoid groups) and bryozoans. Uplift of the Malé Karpaty Mts. resulted in tectonic activity in the vicinity, documented by the presence of clastic dikes and normal faults in the profile studied. Subsequent fluvial and terrestrial sedimentation is represented by regolith, palaeosoil and channel body deposits set discordantly on the top of lagoonal deposits. Finally, the third episode is represented by the Sarmatian transgressive marine sequence, which is characterized by coarse pebbly deposit eroded from an uplifted pre-Neogene basement. The strata studied originated in a warm temperate climate around the Badenian–Sarmatian transition

Constraining uplift of the southern margin of the Central Anatolian Plateau from biostratigraphy and 87Sr/86Sr stratigraphy on the highest marine sediments of the Mut Basin (Southern Turkey)

At the northern margin of the Mut-Ermenek Basin (Southern Turkey), well exposed, undeformed Miocene marine deposits cap the basement rocks of the southern margin of the Central Anatolian Plateau (CAP). From the Basyayla section, which ranges from 1781 m a.s.l. at the base to 1839 m a.s.l. at the top, we collected 24 samples, for a total thickness of about 40 m of the Köselerli Fm. Micropaleontological analyses were performed on calcareous nannofossil, ostracod, bryozoa, benthonic and planktonic foraminifera, and macroforaminifera assemblages to discern paleoecological characteristics of the marine paleoenvironment in the Basyayla area and to define the age of the Basyayla section. Also for this latter purpose, Sr ratios (87Sr/86Sr) were measured on tests of benthonic and planktonic foraminifera as well as on benthonic planar macroforaminifera (Heterostegina gr. costata and H. papyracea). The different ostracod assemblages recognized along the Başyayla section record a littoral marine environment with a depth between the outer infralittoral (40 m) to the inner circalittoral (120 m). Most of the identified ostracod species show a wide Neogene stratigraphical distribution, but the concomitant presence of Cytherella vulgata and Aurila freudenthali (last record in the Tortonian) and Semicytherura velata (late Tortonian-Present) constrains the age of the studied section to within the late Tortonian. Moreover, the occurrence in the upper part of the Basyayla section of both Globigerinoides extremus and Catapsydrax parvulus allow us to define the Globigerinoides extremus-Globorotalia suterae Interval Subzone (MMi 12a), which ranges from 8.35 to 7.81 Ma (upper Tortonian). 87 Sr/86Sr measurements were performed on 5 samples of the study section from tests of benthonic planar foraminifera (Heterostegina spp.), and benthonic and planktonic foraminifera. A total of 19 sample aliquots were analysed for 87Sr/86Sr measurements (11 Heterostegina spp., 3 planktonic, 5 benthonic) giving a range of values between 0.708821 and 0.708848 for a range of LOWESS IV estimated ages of 12.71 to 11.20 Ma. Three oysters sampled ~30 m above the top of the Basyayla section yielded 87Sr/86Sr ratio values between 0.708824 and 0.708833, for a range of LOWESS IV estimated ages of 12.58 to 12.17 Ma. The discrepancy between the 87Sr/86Sr estimated ages and the biochronology for the Basyayla section point to a strong departure from the global ocean Sr curve of the Tortonian seawater of the Mut Basin. The stratigraphical study of the Basyayla section, which represents the highest marine deposits capping the basement rocks of the Mut-Ermenek basin so far sampled, point to an age younger than the late Tortonian (8.35-7.81 Ma) for the start of uplift of the CAP southern margin