نتایج جستجو برای: fossils

تعداد نتایج: 14159  

N Abbassi

The Kashkan Formation (Paleocene to Middle Eocene), consists of conglomerate, sandstone, and siltstone in the Zagros Folded zone, southwest Iran. Type of the sedimentary facies, architectural elements and trace fossils show that Kashkan deposits were formed in a low sinuosity braided stream system, with north to south flow direction. The formation displays coarsening-upward succession reflects ...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1996
M A McMenamin

The Ediacaran biota is the earliest diverse community of macroscopic animals and protoctists. Body and trace fossils in the Clemente Formation of northwestern Sonora extend downward the geologic range of Ediacaran forms. Taxa present in the Clemente Formation include cf. Cyclomedusa plana, Sekwia sp., an erniettid (bearing an air mattress-like "pneu" body construction), and the trace fossils Lo...

2007
Habib G. Khosroshahi Trevor J. Ponman Laurence R. Jones

Using Chandra X-ray observations and optical imaging and spectroscopy of a flux-limited sample of 5 fossil groups, supplemented by additional systems from the literature, we provide the first detailed study of the scaling properties of fossils compared to normal groups and clusters. Fossil groups are dominated by a single giant elliptical galaxy at the centre of an extended bright X-ray halo. I...

Journal: :Nature 1890

2017
William Kitching James William Kitching

James William Kitching collected and studied fossils of dinosaurs and early humans [3] in the twentieth century. He worked at the Bernard Price Institute for Paleontological Research in South Africa. During the fifty-three years he worked at the institute, Kitching spent eighteen of those in the field uncovering fossils. Kitching recovered fossils of early human ancestors, later called Australo...

2015
Jacqueline S. Smilg Lee R. Berger Michael D. Petraglia

In the South African context, computed tomography (CT) has been used applied to individually prepared fossils and small rocks containing fossils, but has not been utilized on large breccia blocks as a means of discovering fossils, and particularly fossil hominins. Previous attempts at CT imaging of rocks from other South African sites for this purpose yielded disappointing results. For this stu...

Journal: :Molecular phylogenetics and evolution 2003
J David Archibald

Theria includes Eutheria and its sister taxon Metatheria. Placentalia includes extant eutherians plus their most recent common ancestor. The oldest eutherian is from 125mya (million years ago). Molecular studies place this origin at about 130-185mya. Older dates cannot be refuted based on fossil evidence as earliest eutherian remains are scarce. Earliest superordinal clades (hence Placentalia) ...

2016
Shixing Zhu Maoyan Zhu Andrew H. Knoll Zongjun Yin Fangchen Zhao Shufen Sun Yuangao Qu Min Shi Huan Liu

Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635-541 million years (Myr)), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1,560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossil...

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