Abstract A complex interplay of palaeoclimatic, eustatic and tectonic processes led to fragmentation and dissipation of the vast Tethys Ocean in Eocene–Oligocene times. The resulting Paratethys Sea occupied the northern Tethys region on Eurasia, grouping water masses of various sub-basins, separated from each other and from the open ocean through narrow and shallow gateways and land bridges. Changes in marine gateway configuration and internal connectivity affected regional hydrology, shifting most Paratethyan basins to extreme carbon-sink anoxic environments, anomalohaline evaporitic or brackish conditions, or even endorheic lakes. Paratethys gateway restriction triggered the onset of a long-lasting ( c. 20 myr) giant anoxic sea, characterized by stratified water masses and anoxic bottom-water conditions, resulting in thick hydrocarbon source rocks. Here, we review the geological evolution of the ‘dire straits’ of Paratethys that played a crucial role in the Eocene–Oligocene connectivity history of the Central Eurasian seas and we show that the main anoxic phases (Kuma and Maikop) correspond to restricted connectivity with the global ocean and a period of CO 2 depletion in the atmosphere. Paratethys represents one of the largest carbon sinks in Earth's history and may thus have played a prominent role in global climate change.

Abstract The continental Argana Basin of Morocco is the trans-Atlantic counterpart of the extensively studied Fundy, Hartford and Newark basins in north-eastern America, that have provided the astrochronologically tuned geomagnetic polarity timescale (GPTS) for the late Triassic and earliest Jurassic. The Argana red-bed successions also show astronomically driven time control, which allowed trans-Atlantic correlations and revealed that the interval towards volcanism of the Central Atlantic Magmatic Province (CAMP) is without any significant hiatuses. Here, we present palaeomagnetic results from the cyclically bedded upper Triassic red-beds and the intercalated volcanics associated with CAMP. Our composite Argana section comprises an interval of 3.5–4.0 Ma, but its magnetostratigraphic pattern does not allow a straightforward correlation to the Newark GPTS. The continental red-bed deposits of the Bigoudine Formation demonstrate a dominant magnetic overprint that could only be removed at temperatures above 600 °C. We suggest that this overprint could have been caused by a period of (Jurassic, c . 170 Ma) magmatism that caused pervasive overprinting of the Triassic palaeomagnetic signal. Correlations between the sections in the Tazantoute region are not straightforward, hampered by the presence of a magmatic sill. The CAMP lava sequences of Tazantoute are all of normal polarity and record secular variation in a manner that agrees with short-lived pulses of CAMP activity in Morocco. Our results indicate that the sedimentary successions of the Argana Basin have the potential to evaluate the Newark GPTS, but that detailed palaeomagnetic analyses of more suitable sections with long(er) cyclostratigraphic records are required.

Abstract The Oligocene–Miocene was a time characterized by major climate changes as well as changing plate configurations. The Middle Miocene Climate Transition (17 to 11 Ma) may even have been triggered by a plate tectonic event: the closure of the eastern Tethys gateway, the marine connection between the Mediterranean and Indian Ocean. To address this idea, we focus on the evolution of Oligocene and Miocene foreland basins in the southernmost part of Turkey, the most likely candidates to have formed this gateway. In addition, we take the geodynamic evolution of the Arabian–Eurasian collision into account. The Muş and Elazığ basins, located to the north of the Bitlis–Zagros suture zone, were most likely connected during the Oligocene. The deepening of both basins is biostratigraphically dated by us to occur during the Rupelian (Early Oligocene). Deep marine conditions (between 350 and 750 m) prevailed until the Chattian (Late Oligocene), when the basins shoaled rapidly to subtidal/intertidal environment in tropical to subtropical conditions, as indicated by the macrofossil assemblages. We conclude that the emergence of this basin during the Chattian severely restricted the marine connection between an eastern (Indian Ocean) and western (Mediterranean) marine domain. If a connection persisted it was likely located south of the Bitlis–Zagros suture zone. The Kahramanmaraş basin, located on the northern Arabian promontory south of the Bitlis–Zagros suture zone, was a foreland basin during the Middle and Late Miocene, possibly linked to the Hatay basin to the west and the Lice basin to the east. Our data indicates that this foreland basin experienced shallow marine conditions during the Langhian, followed by a rapid deepening during Langhian/Serravallian and prevailing deep marine conditions (between 350 and 750 m) until the early Tortonian. We have dated the youngest sediments underneath a subduction-related thrust at c . 11 Ma and suggest that this corresponds to the end of underthrusting in the Kahramanmaraş region, i.e. the end of subduction of Arabia. This age coincides in time with the onset of eastern Anatolian volcanism, uplift of the East Anatolian Accretionary Complex, and the onset of the North and East Anatolian Fault Zones accommodating westward escape tectonics of Anatolia. After c . 11 Ma, the foreland basin south of the Bitlis formed not (or no longer) a deep marine connection along the northern margin of Arabia between the Mediterranean Sea and the Indian Ocean. We finally conclude that a causal link between gateway closure and global climate change to a cooler mode, recorded in the Mi3b event (δ 18 O increase) dated at 13.82 Ma, cannot be supported.

We report paleomagnetic data from the northeastern margin of the Tibetan Plateau to help understand the timing and distribution of deformation (i.e., vertical-axis rotations) during the India-Asia collision. Paleomagnetic results throughout Xining Basin strata, recently dated using magnetostratigraphy to between 52 and 17 Ma, show that some 25° of clockwise rotation with respect to the stable Eurasian continent occurred at ca. 41 Ma. In view of a regional compilation of existing paleomagnetic data from the northeastern Tibetan Plateau, these results suggest that this region experienced clockwise rotations in the regional Paleocene-Miocene basin system, including rotation in the Xining Basin, ca. 41 Ma, thus establishing the existence of widespread deformation at this time. During a mid-Miocene phase, between 17 and 11 Ma, clockwise rotations were restricted to the Miocene-Quaternary basin system, implying that the Laji Shan thrust belt, which separates the two basin systems, was active during this time interval.