Marine transgression(s) to evaporite basin:The case of middle Miocene (Badenian) gypsum in the Central Paratethys, SE Poland

The middle Miocene Badenian evaporite basin of the Carpathian Foredeep Basin was a saline lake, separated by a barrier from the sea and supplied with seawater seeping through the barrier or overflowing it occasionally in the form of short-lived marine transgressions. Such transgressions could leave behind marine microfossils in marly clay intercalations. One of them(2.3 m thick) occurs in the uppermost part of the sulphate sequence, in the unit ‘o’, in the Babczyn 2 borehole section. It contains marine palynomorphs(dinoflagellate cysts) and foraminiferal assemblages indicating a marine environment. The low-diversity benthic foraminiferal assemblages are dominated by opportunistic, shallow infaunally living species, preferring muddy or clayey substrate for thriving, brackish to normal marine salinity, and inner shelf environment. Dinoflagellate cyst assemblages, although taxonomically impoverished, consist of marine species;euryhaline forms that tolerate increased salinity are missing. Relatively common microfossils found in clay intercalations within gypsum have important palaeogeographical implications:they strongly suggest that there existed an additional inflow channel supplying the Polish Carpathian Basin from the south during the evaporite deposition and afterwards.

Impact of Topography and Land-Sea Distribution on East Asian Paleoenvironmental Patterns

Much geological research has illustrated the transition of paleoenvironmental patterns during the Cenozoic from a planetary-wind-dominant type to a monsoon-dominant type, indicating the initiation of the East Asian monsoon and inland-type aridity. However, there is a dispute about the causes and mechanisms of the transition, especially about the impact of the Himalayan/Tibetan Plateau uplift and the Paratethys Sea retreat, Thirty numerical sensitivity experiments under different land-sea distributions and Himalayan/Tibetan Plateau topography conditions are performed here to simulate the evolution of climate belts with emphasis on changes in the rain band, and these are compared with the changes in the paleoenvironmental patterns during the Cenozoic recovered by geological records. The consistency between simulations and the geological evidence indicates that both the Tibetan Plateau uplift and the Paratethys Sea retreat play important roles in the formation of the monsoon-dominant environmental pattern. Furthermore, the simulations show the monsoon-dominant environmental pattern comes into being when the Himalayan/Tibetan Plateau reaches 1000-2000 m high and the Paratethys Sea retreats to the Turan Plate.

The Silk roads: phylogeography of Central Asian dice snakes (Serpentes: Natricidae) shaped by rivers in deserts and mountain valleys

Influenced by rapid changes in climate and landscape features since the Miocene,widely distributed species provide suitable models to study the environmental impact on their evolution and current genetic diversity.The dice snake Natrix tessellata,widely distributed in the Western Palearctic is one such species.We aimed to resolve a detailed phylogeography of N.tessellata with a focus on the Central Asian clade with 4 and the Anatolia clade with 3 mitochondrial lineages,trace their origin,and correlate the environmental changes that affected their distribution through time.The expected time of divergence of both clades began at 3.7 Mya in the Pliocene,reaching lineage differentiation approximately 1 million years later.The genetic diversity in both clades is rich,suggesting different ancestral areas,glacial refugia,demographic changes,and colonization routes.The Caspian lineage is the most widespread lineage in Central Asia,distributed around the Caspian Sea and reaching the foothills of the Hindu Kush Mountains in Afghanistan,and Eastern European lowlands in the west.Its distribution is limited by deserts,moun-tains,and cold steppe environments.Similarly,Kazakhstan and Uzbekistan lineages followed the Amu Darya and the Syr Darya water systems in Central Asia,with ranges delimited by the large Kyzylkum and Karakum deserts.On the western side,there are several lineages within the Anatolia clade that converged in the central part of the peninsula with 2 being endemic to Western Asia.The distribution of both main clades was affected by expansion from their Pleistocene glacial refugia around the Caspian Sea and in the valleys of Central Asia as well as by environmental changes,mostly through aridification.

Central Asian aridification during the late Eocene to early Miocene inferred from preliminary study of shallow marine-eolian sedimentary rocks from northeastern Tajik Basin

The tempo-spatial development of the Cenozoic Asian aridification across the Eocene-Oligocene and its controlling factors are important scientific topics in Earth Sciences, which are pertinent to regional and global tectonic and climatic events. However, sedimentary rocks preserving the record of aridification during this time from central Asia(ACA) are rare. Here we present a preliminary analysis of sedimentary facies of the lower Paleogene in the northeastern Tajik Basin, which reveals that: the lower part of the studied section is dominated by shallow marine deposits of the Paratethys, the middle part is typical of alternations of eolian dune and fluvial deposits, the upper part is represented by eolian loess-sandy loess(L&SL) like facies, and the top exhibits alternations of fluvial-lacustrine and loess like facies. Based on a chronological framework derived from preliminary magnetostratigraphy, published U-Pb dating of a volcanic ash, and regional litho-stratigraphic correlations, we determine that eolian and L&SL facies accumulated in the northeastern Tajik Basin during the Late Eocene and through most of the Oligocene. These sedimentary units indicate that semi-arid to arid environments of ACA had developed at least since the late Eocene. This initial aridification is closely linked to the westward retreat of the Paratethys that was likely driven by a combination of tectonic activity and sea level changes.