Results 131 to 140 of about 292 (159)

Graptolite reflectance anomaly

International Journal of Coal Geology, 2022
Thermal maturation is traditionally evaluated based on vitrinite reflectance (VRo) measurements and its relationship to oil and gas generation and diagenetic transformation are ingrained in many basin modeling tools. However, vitrinite derives from higher land plants that evolved in Devonian.
Zheng, Xiaowei, Schovsbo, Niels H., Luo, Qingyong, Wu, Jia, Zhong, Ningning, Goodarzi, Fariborz, Sanei, Hamed; id_orcid 0000-0002-2961-9654   +6 more
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Mode of secretion of graptolite periderm, in normal and retiolite graptolites

Geological Society, London, Special Publications, 1986
Summary The construction of graptolite periderm is discussed with particular reference to the rival extra-thecal tissue (secretion) and pterobranch (mortaring) models, and it is concluded that only the former model fits the observed structures.
D. E. B. Bates, N. H. Kirk
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Migrations of the Graptolites

Annals and Magazine of Natural History, 1872
Most geologists are now prepared to admit that the occurrence of the same species of marine animals in strata very widely removed from one another in point of distance may be accepted as a proof of “migration” having taken place. It does not matter, from this point of view, whether the deposits of the two areas are approximately of the ...
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Molecular taphonomy of graptolites

Journal of the Geological Society, 2006
Graptolites are important fossils in Early Palaeozoic assemblages. Preserved graptolite periderm consists dominantly of an aliphatic polymer, immune to base hydrolysis. It contains no protein even though its structure, and chemical analyses of the periderm of the living relative Rhabdopleura
Gupta, NS, Briggs, DEG, Pancost, RD
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The Identification of Graptolites

Geological Magazine, 1944
There are unfortunately few graptolites that have retained their original chitinous periderm;when these are preserved in rocks of suitable composition they may be isolated from the matrix, and having escaped distortion, may then be studied more or less in their original condition, and much of our knowledge concerning the structure shown by this group ...
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Early Devonian graptolites and graptolite biostratigraphy, Arctic Islands, Canada

Canadian Journal of Earth Sciences, 2013
The Early Devonian graptolite fauna of the Arctic Islands comprises the highest species content (17 species) in the world. In spite of this richness, no new species have been recognized; instead already-existing species, scattered around the then-known continents, suggest that relatively complete cosmopolitanism held sway for graptolites.
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Graptolites in British stratigraphy

Geological Magazine, 2009
Abstract697 taxa of planktonic graptolites are recorded, and their stratigraphical ranges are given, through 60 biozones and subzones in the Ordovician and Silurian strata of England, Wales and Scotland, in the first such stratigraphical compilation for Great Britain since the synthesis of Elles & Wood (1901–1918).
Zalasiewicz, J., Taylor, L., Rushton, A., Loydell, David, Rickards, R., Williams, Mark   +5 more
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Graptolite preservation and deformation

PALAIOS, 1992
The preservation of graptolites as pale films is characteristic of many low grade metamorphic lower Paleozoic rocks. A study of such fossils at Abereiddy Bay, South Wales allows an interpretation of the abundant graptolite fauna under varying conditions of bedding-cleavage relationship. Similar phenomena are also documented from other localities.
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PROGRAMME‐EVOLUTION IN THE GRAPTOLITES

Biological Reviews, 1933
Summary.1. As an illustration of the occurrence of programme‐evolution among the graptolites, some of the series included within the “isolate” line of thecal elaboration in the monograptids have been selected.2. These are represented in the Lower Silurian (Valentian) rocks of Sweden, Britain, Germany and Bohemia.
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Molecular Preservation in Graptolites

2013
Graptolites are important fossils in the Lower Palaeozoic. Preserved graptolite periderm consists dominantly of an aliphatic polymer, immune to base hydrolysis. It contains no protein even though its structure, and chemical analyses of the periderm of the living relative Rhabdopleura, indicate that it was originally collagen.
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