نتایج جستجو برای: early cretaceous

تعداد نتایج: 692756  

2016
Valentin Fischer Nathalie Bardet Roger B. J. Benson Maxim S. Arkhangelsky Matt Friedman

Despite their profound adaptations to the aquatic realm and their apparent success throughout the Triassic and the Jurassic, ichthyosaurs became extinct roughly 30 million years before the end-Cretaceous mass extinction. Current hypotheses for this early demise involve relatively minor biotic events, but are at odds with recent understanding of the ichthyosaur fossil record. Here, we show that ...

J. MichalÌk

West Carpathian Mesozoic paleogeographic development indicates the effect of a left lateral shift of the Alpine- Carpathian microcontinent along the European shelf since the Early Jurassic. The evolution during Late Triassic/Early Jurassic was controlled by convergence along the border of the Meliata Ocean and by contemporaneous divergence along the Middle Atlantic/Penninic rift. During Mid-Cre...

Journal: :Proceedings. Biological sciences 2013
David M Grossnickle P David Polly

Fossil discoveries over the past 30 years have radically transformed traditional views of Mesozoic mammal evolution. In addition, recent research provides a more detailed account of the Cretaceous diversification of flowering plants. Here, we examine patterns of morphological disparity and functional morphology associated with diet in early mammals. Two analyses were performed: (i) an examinati...

2007
William C. McClelland E. Gehrels Jason B. Saleeby

Upper Jurassic and Lower Cretaceous bashal strata are preserved in a discontinuous belt along the inboard margin of the Alexander-WrangelliaPeninsular terrane (AWP) in Alaska and western Canada, on the outboard margin of terranes in the Canadian Cordillera accreted to North America prior to Late Jurassic time, and along the Cordilleran margin from southern Oregon to southern California. Nearly ...

Journal: : 2022

The Malmyzh ore cluster, which was revealed in 1970–1976, is located the central part of Khabarovsk territory, on right bank Amur River. deposits are timed to Late Cretaceous intrusions that break through sedimentary formations Early Cretaceous. Mineralization controlled by intrusive dome structures.

2017
Tom Brougham Elizabeth T. Smith Phil R. Bell

The fossil record of Australian pterosaurs is sparse, consisting of only a small number of isolated and fragmentary remains from the Cretaceous of Queensland, Western Australia and Victoria. Here, we describe two isolated pterosaur teeth from the Lower Cretaceous (middle Albian) Griman Creek Formation at Lightning Ridge (New South Wales) and identify them as indeterminate members of the pteroda...

2012
Dmitry A. Ruban

Angiosperms evolved rapidly in the late Mesozoic. Data from the genetic-based approach called ’molecular clock’ permit an evaluation of the radiation of flowering plants through geological time and of the possible influences of Mesozoic mass extinctions. A total of 261 divergence ages of angiosperm families are considered. The radiation of flowering plants peaked in the Albian, early Campanian,...

2017
Claire M. Belcher Victoria A. Hudspith

Angiosperms evolved and diversified during the Cretaceous period. Early angiosperms were short-stature weedy plants thought to have increased fire frequency and mortality in gymnosperm forest, aiding their own expansion. However, no explorations have considered whether the range of novel fuel types that diversified throughout the Cretaceous also altered fire behaviour, which should link more st...

2014
ERIC GORSCAK NANCY J. STEVENS ERIC M. ROBERTS

Whereas titanosaurians represent the most diverse and cosmopolitan clade of Cretaceous sauropod dinosaurs, they remain rare components of Cretaceous African faunas. Currently recognized continental African titanosaurians include Aegyptosaurus baharijensis and Paralititan stromeri from early Upper Cretaceous deposits near Bahariya Oasis, Egypt, and Malawisaurus dixeyi and Karongasaurus gittelman...

In the area SW of Arak, intrusives are emplaced into metasediments of early Mesozoic age. The intrusive rocks vary in morphology, structure and mineralogy, and exhibit various degrees of alterations; Rb-Sr geochronological data have been obtained to constrain their timing. There are three different groups of granitic rocks in the area: (a) the Astaneh intrusion, consisting of granite, biotite g...

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