نتایج جستجو برای: cretaceous

تعداد نتایج: 9055  

2004
Brian K. Horton Kurt N. Constenius Peter G. DeCelles

Figure 1. A: Map of Charleston-Nebo salient and northernmost Book Cliffs showing rock units, thrust faults (dashed where buried), key seismic coverage (gray lines), measured stratigraphic sections (1–7; 8 is location of additional Blackhawk sandstone samples), and wells. Rock units: KTs—Cretaceous–Tertiary strata (North Horn and younger formations), Kmv—Cretaceous Mesaverde Group (Blackhawk, Ca...

Journal: :Anais da Academia Brasileira de Ciencias 2011
Jonathas S Bittencourt Max C Langer

The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footpr...

1999
J. P. Hunter J. J. Sepkoski M. J. Novacek K. Gao M. A. Norell G. Rougier

In the continuing debate about the timing of the origin of major extant placental clades, both proponents of a divergence after the Cretaceous-Tertiary (K-T) boundary and those advocating divergence deep within the Cretaceous too often miss what the Late Cretaceous record of placentals actually shows. For example, Foote et al. (1) are correct that many Late Cretaceous reports of extant ordinal ...

1999
J. David Archibald

In the continuing debate about the timing of the origin of major extant placental clades, both proponents of a divergence after the Cretaceous-Tertiary (K-T) boundary and those advocating divergence deep within the Cretaceous too often miss what the Late Cretaceous record of placentals actually shows. For example, Foote et al. (1) are correct that many Late Cretaceous reports of extant ordinal ...

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: :Current Biology 2016
Derek W. Larson Caleb M. Brown David C. Evans

The causes, rate, and selectivity of the end-Cretaceous mass extinction continue to be highly debated [1-5]. Extinction patterns in small, feathered maniraptoran dinosaurs (including birds) are important for understanding extant biodiversity and present an enigma considering the survival of crown group birds (Neornithes) and the extinction of their close kin across the end-Cretaceous boundary [...

Journal: :دیرینه شناسی 0
فرشته بداقی فاطمه هادوی بهنام رحیمی

coccolithophores are important primary producers in the modern world ocean and were almost certainly important in the mesozoic oceans, prior to the evolution and rise of diatoms in the phytoplankton. calcareous nannofossils are abundant, planktonic, rapidly evolving and largely cosmopolitan, so they are a good tool for biostratigraphy and paleoecology studies especially in the cretaceous system...

Journal: :iranian journal of earth science 0
kamal h karim department of geology, university of sulaimani, iraq zardasht a taha department of geology, university of sulaimani, iraq

new simplified tectonic models and depositional history of late cretaceous rocks are established in a part of zagros orogenic belt that is located in the northeastern iraq. these rocks constutes the most important cretaceous oil reservoir in the middle east. the dependent tools are petrography, field study and the concept of drowning phases. this concept is relatively new and accurate in explan...

2002
THEO ANDREW ALASTAIR H. F ROBERTSON

The Beyşehir–Hoyran–Hadim Nappes crop out over 700 km from NW to SE. Above a regionally autochthonous Tauride carbonate platform the Beyşehir–Hoyran Nappes begin with a thrust sheet (c. 400 m) of mainly redeposited carbonates, quartzose sandstones and mudstones of Mid–Late Triassic age, interpreted as a proximal slope–base-of-slope succession. Above is a thrust sheet (c. 1 km) of Middle–Upper T...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1994
C C Labandeira D L Dilcher D R Davis D L Wagner

From well preserved leaf damage of the mid-Cretaceous Dakota Flora (97 million years ago), three distinctive, insect-mediated feeding traces have been identified and assigned to two extant genera and one subfamily. These taxa are the leaf miners Stigmella and Ectoedemia of the Nepticulidae and Phyllocnistinae of the Gracillariidae. These fossils indicate that within 25 million years of early an...

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