Results 131 to 140 of about 2,704 (186)
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1992
First published in 1992, The Proterozoic Biosphere was the first major study of the paleobiology of the Proterozoic Earth. It is a multidisciplinary work dealing with the evolution of the Earth, the environment and life during the forty percent of Earth's history that extends from the middle of the Precambrian eon (2500 Ma) to the beginning of the ...
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First published in 1992, The Proterozoic Biosphere was the first major study of the paleobiology of the Proterozoic Earth. It is a multidisciplinary work dealing with the evolution of the Earth, the environment and life during the forty percent of Earth's history that extends from the middle of the Precambrian eon (2500 Ma) to the beginning of the ...
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Proterozoic Atmospheric Oxygen
2014This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history of continental growth and volcanic outgassing, as well ...
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A small marine biosphere in the Proterozoic
Geobiology, 2018AbstractThe riverine supply of the globally limiting nutrient, phosphorus, to the ocean accounts for only a few percent of nutrient supply to photosynthetic organisms in surface waters. Recycling of marine organic matter by heterotrophic organisms provides almost all of the phosphorus that drives net primary production in the modern ocean.
Thomas A. Laakso, Daniel P. Schrag
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Proterozoic Granitoids of Rajasthan
Journal of the Geological Society of India, 2005Abstract Two granitoid bodies each from Palaeo-, Meso- and Neo-proterozoic periods have been studied for their chemical, petrological and source characteristics The Proterozoic granitoids are megacrystic as well non-megacrystic with variable effect by tectonometamorphic events The Palaeo-proterozoic granitoids are peraluminous ...
S.K Bhushan, V.K. Chittora
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Tectonophysics, 1987
Abstract Proterozoic rifts at various stages of extension have been involved in different types of endogenous activity. As a result, the following evolutionary gradation of riftogenous structures is recorded: Aulacogens—continental paleorifts that are not affected by metamorphism and granite formation; intracontinental ensialic folded systems which ...
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Abstract Proterozoic rifts at various stages of extension have been involved in different types of endogenous activity. As a result, the following evolutionary gradation of riftogenous structures is recorded: Aulacogens—continental paleorifts that are not affected by metamorphism and granite formation; intracontinental ensialic folded systems which ...
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Paleobiology, 2005
Abstract A large, morphologically heterogeneous population of acanthomorphic acritarchs from the early Neoproterozoic Wynniatt Formation, Victoria Island, northwestern Canada, is ascribed to two form-genera, Tappania and Germinosphaera, but just a single natural taxon, Tappania. Analysis of Tappania morphology shows it to have been an actively growing,
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Abstract A large, morphologically heterogeneous population of acanthomorphic acritarchs from the early Neoproterozoic Wynniatt Formation, Victoria Island, northwestern Canada, is ascribed to two form-genera, Tappania and Germinosphaera, but just a single natural taxon, Tappania. Analysis of Tappania morphology shows it to have been an actively growing,
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Petrographic carbon in ancient sediments constrains Proterozoic Era atmospheric oxygen levels
Proceedings of the National Academy of Sciences of the United States of America, 2021Mark Van Zuilen +2 more
exaly