Abstract The Hispanic Corridor is a postulated marine seaway linking the eastern Pacific and western Tethyan oceans as early as Early Jurassic times. Two existing hypotheses relate the Pliensbachian-Toarcian bivalve extinction and recovery to immigration of bivalve species through the Hispanic Corridor. The extinction hypothesis implies that, in South America, the Pliensbachian-Toarcian extinction can be partly explained by the immigration of bivalves through the Hispanic Corridor and subsequent competitive replacement. The recovery hypothesis states that, in NW Europe, the renewed rise in diversity in the late Toarcian/Aalenian was largely a consequence of immigration of taxa from Andean South America via the Hispanic Corridor. To test these hypotheses, I calculated immigration and origination rates of bivalves per million years. In both regions, early Pliensbachian to Aalenian immigration rates remained at low levels, thus disproving both hypotheses. By comparison, the origination of new species generally played a much more important role than immigration in controlling overall diversity of both regions. Future research should investigate if this is a more general pattern in the recovery of post-extinction biotas. The apparently global Pliensbachian-Toarcian diversity crisis may be best explained by a combination of physicochemical factors, invoking intense volcanism, sea-level highstand and widespread anoxia, as well as biological factors. Recovery from this mass extinction commenced when origination rates increased again, which, in the Andean basins, was in the Aalenian and in NW Europe, the late Toarcian.

The Early Jurassic (late Hettangian to early Toarcian) bivalve fauna of the Sierra de Santa Rosa Formation of the Antimonio terrane (Sonora, NW Mexico) is analyzed taxonomically and biogeographically. Fifty taxa are recognized, representing 36 genera and subgenera. Thirty-four of these taxa have not been mentioned from the Jurassic of this region previously. This fauna is of great biogeographical interest, because Early Jurassic bivalves from low paleolatitudes of the tectonically complex western margin of North America are still poorly documented. About half of the described species are also known from other localities along the eastern Pacific margin. The second largest group is composed of widespread taxa, which, in addition to eastern Pacific occurrences, are also reported from other regions, particularly from Europe. The smallest group is endemic taxa that appear to be limited to Sonora during the analyzed time intervals. Geological evidence indicates that the Antimonio terrane was tectonically transported southeastward between the Middle and Late Jurassic from an original position at the southwestern margin of the United States by the Mojave-Sonora megashear. We calculated similarities of contemporaneous pectinoid bivalve faunas from seven eastern Pacific regions to independently constrain Early Jurassic paleolatitudinal positions of this terrane. Cluster analyses and similarity coefficients tentatively suggest that tectonic displacement of the Antimonio terrane toward lower paleolatitudes may already have started in Early Jurassic (Pliensbachian) time.

Abstract Basin-scale stratigraphic correlation is the fundamental base for successful reservoir exploration, and especially when dealing with cross-border areas. Differences in lithostratigraphic and chronostratigraphic nomenclature between sub-basins and countries often result in problematic estimations of reservoir geometries and potential. This study combines available biostratigraphic, biofaunal and lithofacies data, together with sequence-stratigraphical correlations of the Lower Jurassic from the Central European Basin (CEB), to propose a genetic-based framework of transgressive and regressive depositional units. The determination of four major biofacies environments, composed of (I) polyhaline open-marine/offshore environments, (II) upper mesohaline marine–brackish environments, (III) lower mesohaline brackish environments and (IV) low oligohaline to freshwater continental environments comprising very rare marine phytoplankton and terrestrial spores and pollens, were translated into 12 biofacies reconstructions of ammonite (sub-) chronozone levels. Variations of biofacies reconstructions in time and space were supplemented by biostratigraphically constrained large-scale progradational and retrogradational sedimentary architecture. Retrogradation is accompanied by increasing polyhaline environments and pinpoint basinwide third-order flooding events, whereas progradation is accompanied by decreasing polyhaline environments pointing to third-order regressions. The outcomes of this study support exploration of Lower Jurassic deep geothermal reservoirs or CO 2 storage sites in the eastern CEB (especially Germany and Poland). Supplementary material: A list of all documented Liassic ammonites known from the eastern European shelf area (Denmark, The Netherlands, Sweden, Germany, Poland; wells and outcrops) is available at https://doi.org/10.6084/m9.figshare.c.3923467

Abstract Central Skåne (Scania) in southern Sweden hosts evidence of extensive Jurassic volcanism in the form of mafic volcanic plugs and associated volcaniclastic deposits that entomb well-preserved macro-plant and spore–pollen assemblages. Palynological assemblages recovered from the Höör Sandstone are of Hettangian–Pliensbachian age and those from the overlying lahar deposits are dated as Pliensbachian–early Toarcian (?). Palynomorph assemblages from these units reveal significantly different ecosystems, particularly with respect to the gymnospermous components that represented the main canopy plants. Both palynofloras are dominated by osmundacean, marattiacean and cyatheacean fern spore taxa but, whereas the Höör Sandstone hosts abundant Chasmatosporites spp. pollen produced by plants related to cycadophytes, the volcanogenic deposits are dominated by cypress family pollen ( Perinopollenites ) with an understorey component rich in putative Erdtmanithecales (or possibly Gnetales), and collectively representing vegetation of disturbed habitats. Permineralized conifer wood attributed to Protophyllocladoxylon sp., belonging to plants that probably produced the abundant Perinopollenites grains, is abundant in the volcanigenic strata, and shows sporadic intraseasonal and multi-year episodes of growth disruption. Together with the relatively narrow but marked annual growth rings, and the annual and mean sensitivity values that span the complacent–sensitive domains, these features suggest growth within Mediterranean-type biomes subject to episodic disturbance.