research project aims at establishing a detailed chronologic framework
for the Neogene sediments deposited in the Eastern Paratethys area,
with special focus on the middle Miocene of the Dacian Basin and
Euxinic Basin (today's Black Sea). This framework will be constructed
using an integrated magnetostratigraphic approach to the thick
sedimentary sequences of the Carpathian Foredeep and Black Sea
requisite is quantifying the proposed - and still poorly understood -
diachrony between deep-water halite and shallow-water gypsum formation.
Detailed geochemical proxy records are needed to reconstruct the mode
(instantaneous, gradual or stepwise) of salinity increase and to
evaluate the contribution of the gateways to the Mediterranean and
Indian Ocean, in collaboration with oceanic box modelling.
project will develop new proxy records to reconstruct variations in
hydrography (hydrogen and oxygen isotopes) and basin-to-basin and
basin-to-open ocean connectivity (SR, Nd isotopes). Paleosalinity
variations in Paratethys at times of dramatic environmental
changes will be reconstructed from the hydrogen isotopic
composition (âˆ‚D ratio) of the molecular biomarkers.
The compound-specific âˆ‚D ratios will be analysed,
measured on both terrestrial (e.g. n-alkanes) and aquatic biomarkers
(phytane, alkenones). Together they constrain the mixing between
freshwater and ocean water end-members, providing a quantification of
using his own data and the data of the other ongoing projects on
Paratethys, Dan will focus on modeling the paleogeographic maps of the
Eastern Paratethys realm during the Miocene.
circum-Mediterranean Miocene is marked by several occurrences of
extraordinary paleoenvironmental catastrophes during which large
water-masses were cut off from the open ocean, resulting in the
formation of hypersaline waters, complete destruction of biological
ecosystems, and deposition of massive (100-1000m) evaporite units in
both the deep and marginal basins. These so-called salinity crises
occurred in the Middle Miocene (~15 Ma) of the Red Sea, the Late
Miocene (~6 Ma) of the Mediterranean11 and the Badenian (~14 Ma) of the
Paratethys. They are commonly considered to have been caused by a
complex interplay of tectonic and glacio-eustatic processes that
resulted in progressive closure of the marine gateways, and hence in
the obstruction of the hydrological exchange between different basins.
Futhermore the reconnection of the basins coincides with dramatic
changes in the marine ecosystems due to factors we do not fully
sedimentary depostis that we focus on sampling consist of Middle
Badeinan evaporites, commonly underlain by Lower Badenian deep marine
siliciclastics and carbonates, and overlain by Upper Badenian marine
sediments and transgressive Volhynian deep marine to brackish
siliciclastic deposits. These deposits also contain several volcanic
ash levels, suitable for radiometric dating. Very good exposures are
found in the Carpathian foreland domain and the Northern and Western
Black Sea Coasts.
The Badenian and Volhynian sediments will be sampled on different
transects in Carpathian, Black Sea and Caspian Sea areas, for
integrated stratigraphy and geochronology.
The organic rich shales below and above the evaporites and the
transgressions will be studied for high-resolution proxy records
(âˆ‚D, Sr, Nd) that will reveal the rates of salinity
change and variations in connectivity with the open ocean system.
Quantitative estimates on paleosalinity and hydrology will be
determined to validate the depositional environments.
Paleoenvironmental proxy records will allow reconstructing through time the environmental response
of sea retreat (aridification, cooling, monsoon intensification, biotic
events) to tectonism (collision, exhumation, crustal deformation, basin
formation) and to global climatic trends (EOT).