نتایج جستجو برای: Berriasian-Hauterivian
تعداد نتایج: 198 فیلتر نتایج به سال:
Benthic foraminifera at Ocean Drilling Program (ODP) Hole 692B were studied to understand variations in oxygen and organic-matter fluxes bottom waters during the Early Cretaceous. The upper Berriasian lower Barremian black shales, characterized by high concentrations of total organic carbon (TOC) ranging between 1.3 18%, deposited an outer neritic-upper bathyal environment (~200–500 m) accordin...
BACKGROUND Large ornithopod tracks are known from the Upper Jurassic to the uppermost Cretaceous rocks of all continents but Antarctica. They include the tracks historically called Iguanodon footprints, iguanodontid footprints, hadrosaur/hadrosaurid footprints, and other large ornithopod tracks that have been used to define ichnotaxa. More than 40 ichnospecies based on large ornithopod tracks h...
BERRIASIAN-HAUTERIVIAN SHALE SEQUENCE AND ASSOCIATED PINCH-OUT TRAP PROSPECTS OF THE YAMAL PENINSULA
BACKGROUND Ichthyosauria is a diverse clade of marine amniotes that spanned most of the Mesozoic. Until recently, most authors interpreted the fossil record as showing that three major extinction events affected this group during its history: one during the latest Triassic, one at the Jurassic-Cretaceous boundary (JCB), and one (resulting in total extinction) at the Cenomanian-Turonian boundary...
Modern and Cenozoic deep-sea hydrothermal-vent and methane-seep communities are dominated by large tubeworms, bivalves and gastropods. In contrast, many Early Cretaceous seep communities were dominated by the largest Mesozoic rhynchonellid brachiopod, the dimerelloid Peregrinella, the paleoecologic and evolutionary traits of which are still poorly understood. We investigated the nature of Pereg...
The Fahliyan Formation of the Khami Group is the most important oil and gas reservoir in southwestern Iran. The formation attains a thickness of 435.5 m at the oil well X2 in Dorood oil field, Persian Gulf. It is represented mainly by thin-bedded limestones. This formation unconformably overlies the evaporate late Jurassic Hith Formation and conformably underlies the Gadvan Formation. Integrate...
BACKGROUND Recent work on the Jurassic-Cretaceous transition of the Iberian Range (Spain) has opened a new window onto the interpretation of the trackmakers of some medium-sized tridactyl tracks. The ichnotaxon Therangospodus oncalensis has been described in the Huérteles Formation (Berriasian) and is one of the classical tracks from the area assigned to medium-sized theropods. METHODOLOGY/PR...
The non-marine trigonioidid bivalves show five phases of radiation in the Cretaceous of Pal-Asia: pre-Aptian (?Valanginian/Hauterivian-Barremian), Aptian, Albian, Cenomanian and Turonian-Maastrichtian. Their distribution patterns show two distinct palaeo-river systems feeding trigonioidids. Before the Cenomanian, the river system occupied the southwestern-southern-southeastern Pal-Asian contine...
Biostratigraphic data provided by the sections of the Caravaca–Cehegı́n region, SE Spain, have contributed decisively to the lively debate that has taken place in recent years concerning the Berriasian/Valanginian boundary. This work presents the results from new integrated stratigraphic analyses of these sections, based on the distribution of ammonites, calpionellids and calcareous nannofossils...
The Jurassic–Cretaceous boundary transition is widely distributed within the West Cameros Basin. This horizon constituted by Tera Group, consisting of two depositional sequences (DS1 and DS2) comprising four geological formations spanning Tithonian to Berriasian. Here, a combined sedimentological palynostratigraphic study was made covering Group. results for DS 1 differentiate three facies asso...
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