A journey on plate tectonics sheds light on European crayfish phylogeography

Abstract Crayfish can be used as model organisms in phylogeographic and divergence time studies if reliable calibrations are available. This study presents a comprehensive investigation into the phylogeography of the European stone crayfish (Austropotamobius torrentium) and includes samples from previously unstudied sites. Two mitochondrial markers were used to reveal evolutionary relationships among haplogroups throughout the species? distributional range and to estimate the divergence time by employing both substitution rates and geological calibration methods. Our haplotype network reconstruction and phylogenetic analyses revealed the existence of a previously unknown haplogroup distributed in Romania's Apuseni Mountains. This haplogroup is closely related to others that are endemic in the Dinarides, despite their vast geographical separation (~600 km). The separation is best explained by the well-dated tectonic displacement of the Tisza?Dacia microplate, which started in the Miocene (~16 Ma) and possibly carried part of the A. torrentium population to the current location of the Apuseni Mountains. This population may thus have been isolated from the Dinarides for a period of ca. 11 m.y. by marine and lacustrine phases of the Pannonian Basin. The inclusion of this geological event as a calibration point in divergence time analyses challenges currently accepted crayfish evolutionary time frames for the region, constraining the evolution of this area's crayfish to a much earlier date. We discuss why molecular clock calibrations previously employed to date European crayfish species divergences should therefore be reconsidered

Single Aliquot Regeneration (SAR) Optically Stimulated Luminescence Dating Protocols Using Different Grain-Sizes of Quartz: Revisiting the Chronology of Mircea Vodă Loess-Paleosol Master Section (Romania)

The loess-paleosol archive from Mircea Vodă (Romania) represents one of the most studied sections in Europe. We are applying here the current state of the art luminescence dating protocols for revisiting the chronology of this section. Analysis were performed on fine (4–11 µm) and coarse (63–90 µm) quartz extracts using the single aliquot regenerative (SAR) optically stimulated luminescence (OSL) dating protocol. Laboratory generated SAR dose response curves in the high dose range (5 kGy for fine quartz and 2 kGy for coarse quartz) were investigated by employing a test dose of either 17 or 170 Gy. The results confirm the previously reported different saturation characteristics of the two quartz fractions, with no evident dependency of the equivalent dose (De) on the size of the test dose. The OSL SAR ages are discussed and compared to the previously obtained results on quartz and feldspars. The previous reports regarding the chronological discrepancy between the two quartz fractions are confirmed. However, while previous investigations on other sites concluded that this discrepancy appears only above equivalent doses of about 100 Gy, here fine grain quartz ages underestimate coarse quartz ages starting with equivalent doses as low as around 50 Gy

SAR-OSL dating of Late Pleistocene loess in Southern Romania using fine and coarse-quartz

Loess deposits cover significant areas in Europe, extending from NW-France and Belgium through to central Europe, the Ukraine and Western Russia. The loess palaeosol sequences of the Carpathian Basin-Lower Danube region (Romania, Serbia and Bulgaria) are thought to represent the most continuous and high resolution archives of regional climate and environmental change during the Late and Middle Pleistocene in SE Europe and a link between similar deposits in central Europe and Eurasia. However, in comparison to other loess sequences elsewhere in Western, Central and Eastern Europe, the deposits in Romania have been much less extensively studied.Luminescence dating is, at present, the only method that allows establishing an absolute chronology for loess deposits by virtue of its ability to directly date the moment of sediment deposition. Moreover, the aeolian nature of loess ensures that the luminescence signal is completely reset prior to deposition, a prime requisite for luminescence dating. Thus, loess sediments are ideal materials for developing, testing and applying luminescence techniques. This approach is essential for securely linking loess records from Romania in a chronologically reliable regional framework and to extend this information to other sites from central and eastern European loess belt, in order to understand past paleoenvironmental dynamics at both regional and continental scales.</p

Temporal‐Geochemical Evolution of the Persani Volcanic Field, Eastern Transylvanian Basin (Romania): Implications for Slab Rollback Beneath the SE Carpathians

The Quaternary Persani volcanic field (PVF) consists of alkali basalts formed in an extensional basin at the SE end of the Transylvanian basin, near an important anomaly in the European mantle, the Vrancea slab, a seismically active near-vertical lithospheric fragment of debated origin. The PVF is the only basaltic field regionally, has been studied geochemically in the past, and is also known for the presence of abundant mantle xenoliths. Here, we describe new geochemical data on rocks recently dated by Ar-Ar chronometry and show that while we can reproduce virtually all previous results, there is a clear temporal evolution of the magmatic system. There is an increase of over 80 degrees C in temperatures determined by the Si activity thermometer, from 1,300 degrees C to 1,380 degrees C during the similar to 0.5-Myr duration of volcanic activity, which is accompanied by several coherent trends in geochemistry, among which the decrease of Zn/Fe and Sr-87/Sr-86 ratios over time. Earlier, higher Zn/Fe ratios are indicative of a pyroxenite/eclogite-dominated source, which gradually changed to a peridotite-dominated source. These characteristics are typical of a dynamic mantle in which vertical mantle lithosphere tectonics, either due to slab rollback or mantle dripping plays a role and are not consistent with simple decompression melting of asthenosphere. Synchronous adakitic rocks found about 25-30 km east of PVF are presumed to be slab melts and are consistent with the Vrancea slab rollback as the trigger for mantle melting responsible for the PVF.Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii6 month embargo; first published online 16 April 2020This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The Campanian Ignimbrite tephra layer - a regional stratigraphic marker for the MIS 3 loess deposits of Romania

Loess deposits are widespread in Romania and many open profiles are found along the river valleys crossing the southern plains of the country, and these records are important resources for understanding paleoclimate dynamics and the Paleolithic cultural dispersal at the continental scale. However, loess deposits show significant lateral compositional variations, which bring about regional stratigraphic uncertainties, especially when site-to-site correlations still rely mainly on stratigraphic relationships, and only a handful of profiles having been investigated with more precise dating method

Late-Holocene landscape evolution and human presence in the northern Danube delta (Chilia distributary lobes)

International audienceThis paper documents the Late-Holocene environmental changes and human presence in the northern Danube delta using a multidisciplinary approach that combines geoscientific data with archaeological findings, historical texts, and maps. It follows the formation and progression of the Chilia distributary and the reconfiguration of socioeconomic activities. Sedimentary facies identified on five new cores by changes in texture properties, magnetic susceptibility, geochemistry, and macro- and microfauna composition together with the newly obtained chronology constrain the complex evolution of the Chilia branch as filling in a long-lasting bay and then of a giant lagoon (Thiagola) which covered most of the northern delta since the Old Danube lobe inception (ca. 7500 yrs BP) till modern Chilia development. It initiated during the Greek Antiquity (ca. 2500 yrs ar BP) at the delta apex, while in Roman times (ca. 1800 yrs BP) it pursued its slow flowing into the vast Thiagola Lagoon. The most dramatic transformations occurred in the last 800 years when the river passed east of the Chilia promontory, rapidly went through the present-day Matița-Merhei basin (several decades), and created its first open-sea outlet. Solid discharge increased in two distinct periods, once in the Middle Ages (ca. 750 yrs BP) and then in the Modern Period (ca. 150 yrs BP) due to human-induced land-use changes in the Danube watershed. The chronology of the cultural remains on the pre-deltaic Chilia promontory and the multiproxy analysis of a sediment core retrieved nearby downstream suggest the terrestrial connection of the island with the mainland in ancient times. The hitherto contended issue of the old Thiagola Lagoon and its location are redefined here, as are the original identifications of ancient and medieval toponyms and hydronyms, especially for Chilia-Licostomo, Byzantine, Genoese, Moldavian, Ottoman, and Russian trading point of great importance in the political and economic history of the Black Sea and neighboring regions

Crayfish Geological Calibration

These are the file associated with the geological time calibration analysis including the BEAST XML files

Nexus and partitionfinder

These are the nexus files for the 16S and COI data along with partitionfinder results

Strict Clock Files

These are the files associated with the strict molecular clock analyses including the BEAST XML files