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Upper Cretaceous volcaniclastic deposits of the Haţeg Basin (VDHB) (Southern Carpathians, Romania) consist of relatively poorly exposed products of multiple phreatomagmatic volcanic eruptions of andesitic to rhyolitic composition and crop out around Densuş, Răchitova, Peşteniţa, and Ciula Mică localities. These deposits are commonly associated with the Late Cretaceous Neotethyan magmatic activity that developed in Central-Eastern Europe, forming the Apuseni–Banat–Timok–Srednogorie (ABTS) belt. Since the geochemistry of these deposits has been investigated very little so far, this study provides petrographic and whole-rock geochemical analysis for twenty new different volcaniclastic rock samples, out of which sixteen samples represent lava clasts and the other four are samples of pyroclastic flow deposits. According to our geochemical data, the VDHB have a calc-alkaline and high-K calc-alkaline character, similar to the majority of rock samples from all sectors of the ABTS belt. A comparison between the Haţeg rock samples and Banat and Apuseni samples reveals comparable major and trace element abundances and REE patterns, supporting the idea that they originate from similar magmas. Trace element patterns suggest that the parental magmas were mostly derived from the melting of a metasomatized lithospheric mantle source, previously modified by an earlier subduction event. A combination of crystal fractionation and variable degrees of crustal assimilation during storage at higher and lower pressures was the principal mechanism driving calc-alkaline differentiation. Our geochemical analyses indicate that the VDHB were produced by magmas generated during two different magmatic events. Older, silica-rich melts produced the Peştenita and Răchitova ignimbrite deposits, while the Densuş and Răchitova andesitic–dacitic–rhyolitic rock suite was generated by younger, intermediate magmas. The individual melt production episodes are evidenced by the emergence of two different crystal fractionation trends: an amphibole-controlled trend at mid-crustal levels and an upper-crust plagioclase-dominated trend. The hydrous, calc-alkaline magmas arguably occurred in a post-collisional setting, in agreement with the orogenic collapse model, among others, proposed for the origin of the ABTS magmatic activity. Full article

The South-Pyrenean Basin (northeastern Spain) has yielded a rich and diverse record of Upper Cretaceous (uppermost Campanian−uppermost Maastrichtian) vertebrate fossils, including the remains of some of the last European dinosaurs prior to the Cretaceous-Paleogene (K-Pg) extinction event. In this work, we update and characterize the vertebrate fossil record of the Arén Sandstone and Tremp formations in the Western Tremp Syncline, which is located in the Aragonese area of the Southern Pyrenees. The transitional and continental successions of these sedimentary units are dated to the late Maastrichtian, and exploration of their outcrops has led to the discovery of numerous fossil remains (bones, eggshells, and tracks) of dinosaurs, including hadrosauroids, sauropods, and theropods, along with other tetrapods such as crocodylomorphs, testudines, pterosaurs, squamates, and amphibians. In particular, this fossil record contains some of the youngest lambeosaurine hadrosaurids (Arenysaurus and Blasisaurus) and Mesozoic crocodylomorphs (Arenysuchus and Agaresuchus subjuniperus) in Europe, complementing the lower Maastrichtian fossil sites of the Eastern Tremp Syncline. In addition, faunal comparison with the fossil record of Hațeg island reveals the great change in the dinosaur assemblages resulting from the arrival of lambeosaurine hadrosaurids on the Ibero-Armorican island, whereas those on Haţeg remained stable. In the light of its paleontological richness, its stratigraphic continuity, and its calibration within the last few hundred thousand years of the Cretaceous, the Western Tremp Syncline is one of the best places in Europe to study the latest vertebrate assemblages of the European Archipelago before the end-Cretaceous mass extinction. Full article