MEDMESS: Quantifying Mediterranean environmental change during the Messinian Salinity Crisis
Final Report Abstract
We reconstructed continental mean annual temperatures (MAT) using branched glycerol dialkyl glycerol tetraether (GDGT) biomarkers for the time period corresponding to MSC Stage 3 (5.55- 5.33 Ma). Additionally, for the same time interval, we estimate sea surface temperatures (SSTs) of the Mediterranean Sea using isoprenoidal GDGTs based TEX86 proxy. The excellently preserved organic biomarkers were extracted from outcrops and DSDP cores spread over a large part of the onland (Malaga, Sicily, Cyprus) and offshore (holes 124 and 134 from Balearic abyssal plane and hole 374 from Ionian Basin Mediterranean Basin domain. The calculated MATs for the 5.55 to 5.33 Ma interval show values around 16 to 18 ºC for the Malaga, Sicily, and Cyprus outcrops. The MAT values calculated for DSDP Leg 13 holes 124, 134 and Leg 42A hole 374 are lower, around 11 to 13 ºC. For samples where the branched and isoprenoid tetraether (BIT) index was lower than the 0.4 we could calculate TEX86 derived SSTs averaging around 27 ºC for all sampled locations. Where available (i.e. Sicily), we compared the TEX86 derived SSTs with alkenone based, Uk37 derived SST estimates from the same samples. The TEX86 derived SST values are slightly higher than the Uk37 derived SST of 20 to 28 ºC. For the Mediterranean region, values between 19 and 27 ºC of the Uk37 derived SSTs were calculated for the interval between the 8.0 and 6.4 Ma, close to our calculations for Sicily section (20 to 28 ºC). Independent of common pitfalls that may arise in using molecular biomarkers as temperature proxies, both SST estimates independently hint towards much warmer Mediterranean Sea water during the latest phase (Stage 3) of the MSC. These data will be further used for planning the exact sampling strategy of the future IODP drilling project initiative of ‘Demise of a Salt Giant’ (857C) led by Dr. Bertoni (University of Oxford) where the PI (Dr. Vasiliev) is a co-proponent.
Publications
- A warmer Mediterranean region at the Miocene to Pliocene transition? 13577, EGU 2020, 02nd-06th May
Iuliana Vasiliev, Daniela Böhn, Darja Volkovskaja, Clemens Schmitt, Konstantina Agiadi, Federico Andreetto, Andreas Mulch
(See online at https://doi.org/10.5194/egusphere-egu2020-13577)
