Tephra marker horizons in loess records from southeastern Europe

Abstract

The use of volcanic ashes in addressing chronostratigraphic issues for terrestrial records such as loess has gained considerable advance. For example, the Campanian Ignimbrite/Y-5 tephra, the product of one of the largest late Quaternary explosive events in the Mediterranean is now the most important chronologic and stratigraphic marker for loess and other records from western Eurasia. Dated to 39-40 ka BP, it provides an independent basis for establishing age-depth relationships for the embedding deposits and for comparing records on a wider scale. Motivated by its widespread occurrence in the Danube loess, we conducted detailed paleoclimate investigations of selected loess sites corroborated by the dating through (mainly) luminescence dating methods. One aim was to test for the reliability of different luminescence dating methods in that narrow age-range around 40 ka BP. In general the luminescence age estimates confirm that the volcanic ash occurrences represent a regionally synchronous depositional event, around 40 ka in age, albeit considerable chronological variability has been observed. These results provide, however, the needed sedimentological framework for testing models of tephra accumulation, preservation and impact on the paleoenvironment. Further, comparison of magnetic susceptibility and grain size records from the longest measured loess profiles in the Danube loess, extending to Early Pleistocene, show that a number of macroscopically visible ash layers could be identified alongside a range of cryptotephra horizons. Albeit most of these tephra layers have been altered and preserve no glass shards, we show that they offer potential in providing correlation tie-points. Based on this, we explore the potential of tephrostratigraphic and tephrochronological investigations in linking loess profiles in southeastern Europe, as well as loess with other records such as marine and lake sediments.

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Bibliography

Veres, D., Hambach, U., Timar-Gabor, A., Wulf, S., Zeeden, C., Obreht, I., Bösken, J., Radakovic, M., Markovic, S., Lehmkuhl, F. (2018): Tephra marker horizons in loess records from southeastern Europe. INQUA-INTAV International Field Conference and Workshop - Crossing New Frontiers - Tephra Hunt in Transylvania, INTAV, 24.06.-29.06.2018, Moieciu de Sus, Romania