Multiple crises preceded the Mediterranean Salinity Crisis: Aridification and vegetation changes revealed by biomarkers and stable isotopes
نویسندگان
چکیده
During the Messinian (7.24–5.33 Ma), highly dynamic Mediterranean environment was concomitantly governed by global climate changes and regional tectonic activity affecting connectivity to ocean. The combined effects generated extreme rapid paleoenvironmental culminating in Salinity Crisis (MSC; 5.96–5.33 Ma). Here, we reconstruct conditions recorded Agios Myron section (Crete Island, Greece) between ?7.2 6.5 Ma that indicate marked eastern region prior onset of MSC. Hydrogen isotope ratios measured on alkenones produced haptophyte algae within water column, coupled carbon isotopes long chain n-alkanes higher terrestrial plants show three important dry periods peaking at 6.98, 6.82 6.60 accompanied shifts vegetation, transitioning from dominantly C3 markedly increased C4 contribution intermittent recurrence vegetation ?6.99 6.78 Ma. Mean annual air temperatures reconstructed using branched glycerol dialkyl tetraethers (brGDGTs) average 13 °C with an overall pattern permits orbitally-controlled pacing climate. Additionally, isoprenoid tetraether index bulk oxygen source(s) organic matter evolution basin towards a closed arid system. These results support model ongoing restriction Sea ?7 onwards reveal protracted aridification domain
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ژورنال
عنوان ژورنال: Global and Planetary Change
سال: 2022
ISSN: ['0921-8181', '1872-6364']
DOI: https://doi.org/10.1016/j.gloplacha.2022.103951