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Equally warm but even drier Mediterranean region at the Miocene – Pliocene transition

Between 5.97-5.33 Ma, kilometre-thick evaporites were deposited in the Mediterranean Basin during the Messinian Salinity Crisis (MSC) under strongly negative hydrological budget. In the light of the IMMAGE initiative to drill the Mediterranean-Atlantic gateway, we present here the reconstructed continental mean annual temperatures (MAT) using branched glycerol dialkyl glycerol tetraether (brGDGT) biomarkers for the MSC Stage 3 (5.55-5.33 Ma) and compare them with continental temperature values obtained from Δ47 clumped isotope geochemistry of paleosol carbonate nodules from few Mediterranean locations. The biomarkers were extracted from outcrops onshore and offshore sites around the Mediterranean Basin. Calculated MATs for the 5.55 to 5.33 Ma interval show values around 16 to 19 ºC for the Malaga, Sicily and Cyprus outcrops. The MAT values for DSDP Leg 13 holes 124, 134 and Leg 42A holes 374 and 376 are lower, around 13 to 16 ºC. Comparing the brGDGT-MAT values with Δ47-MAT values from carbonate nodules, shows high congruence between both approaches. For the northern Mediterranean Δ47-MAT is 24.6 ± 1.6 °C and brGDGT-MAT is 19 ± 4.8 ºC. For Cyprus Δ47-MAT is 20.3 ± 1.7 °C and brGDGT-MAT is 18 ºC ± 4.8 ºC. Given the very different nature of the used paleoproxies, the similarity of the obtained MAT values provides a strong indication of (cross)validity in sampled sections. Additionally, the measured δ18O for the carbonate nodules used for the Δ47-MAT show high δ18O of the soil water (~ -5 ±0.7‰) indicating highly evaporative conditions for the two onland Northern Apennines and Cyprus locations.

Details

Author
Iuliana Vasiliev-Popa1, Konstantina Agiadi2, Katharina Methner3, Jens Fiebig4, Andreas Mulch5
Institutionen
1Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany; 2Department of Palaeontology, University of Vienna, Austria; 3Institute for Earth System Science and Remote Sensing, University of Leipzig, Germany; 4Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main, Germany; 5Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany;Institute of Geosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
Veranstaltung
GeoSaxonia 2024
Datum
2024
DOI
10.48380/pqta-rw25