First tephrostratigraphic results of the DEEP site record from Lake Ohrid, Macedonia
Abstract
A~tephrostratigraphic record covering the Marine Isotope Stages (MIS) 1-15 was established for the DEEP site record of Lake Ohrid (Macedonia/Albania). Major element analyses (SEM-EDS/WDS) were carried out on juvenile fragments extracted from 12 tephra layers (OH-DP-0115 to OH-DP-2060). The geochemical analyses of the glass shards of all of these layers suggest an origin from the Italian Volcanic Provinces. They include: the Y-3 (OH-DP-0115, 26.68-29.42 cal ka BP), the Campanian Ignimbrite/Y-5 (OH-DP-0169, 39.6 ± 0.1 ka), and the X-6 (OH-DP-0404, 109 ± 2 ka) from the Campanian volcanoes, the P-11 of the Pantelleria Island (OH-DP-0499, 129 ± 6 ka), the Vico B (OH-DP-0617, 162 ± 6 ka) from the Vico volcano, the Pozzolane Rosse (OH-DP-1817, 457 ± 2 ka) and the Tufo di Bagni Albule (OH-DP-2060, 527 ± 2 ka) from the Colli Albani volcanic district, and the Fall A (OH-DP-2010, 496 ± 3 ka) from the Sabatini volcanic field. Furthermore, a comparison of the Ohrid record with tephrostratigraphic records of mid-distal archives related to the Mediterranean area, allowed the recognition of the equivalents of other less known tephra layers, such as the TM24-a/POP2 (OH-DP-0404, 101.8 ka) from the Lago Grande di Monticchio and the Sulmona basin, the CF-V5/PRAD3225 (OH-DP-0624, ca. 162 ka) from the Campo Felice basin/Adriatic Sea, the SC5 (OH-DP-1955, 493.1 ± 10.9 ka) from the Mercure basin, and the A11/12 (OH-DP-2017, 511 ± 6 ka) from the Acerno basin, whose specific volcanic sources are still poorly constrained. Additionally, one cryptotephra (OH-DP-0027) was identified by correlation of the potassium XRF intensities from the DEEP site with those from short cores of previous studies from Lake Ohrid. In these cores, a maximum in potassium is caused by glass shards, which were correlated with the Mercato tephra (8.43-8.63 cal ka BP) from Somma-Vesuvius. With the tephrostratigraphic work, a consistent part of the Middle Pleistocene tephrostratigraphic framework of Italian volcanoes was for the first time extended as far as to the Balkans. The establishment of the tephrostratigraphic framework for the Lake Ohrid record provides important, independent tie-points for the age-depth model of the DEEP site sequence, which is a prerequisite for paleoclimatic and -environmental reconstructions. Furthermore, this age-depth model will help to improve and re-evaluate the chronology of other, both undated and dated tephra layers from other records. Thus, the Lake Ohrid record is candidate to become the Rosetta stone for the central Mediterranean tephrostratigraphy, especially for the hitherto poorly known and explored lower Middle Pleistocene period.
- Publication:
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Biogeosciences Discussions
- Pub Date:
- September 2015
- DOI:
- 10.5194/bgd-12-15411-2015
- Bibcode:
- 2015BGD....1215411L