Results 231 to 240 of about 34,869 (280)

Neoproterozoic magmatism in eastern Himalayan terrane

Science Bulletin, 2017
Geochronological investigation on gneisses of granitic to leucogranitic compositions in Cuona, south Tibet, reveal that their protoliths formed at 808.8±7.9-816.4±3.4Ma and 855.8±7.0Ma, respectively. Zircon rims from the granitic gneiss record a metamorphic age of 739.4±4.3Ma.
Yuhua, Wang, Lingsen, Zeng, Li-E, Gao, Chunli, Guo, Kejun, Hou, Lifei, Zhang, Wei, Wang, Huiyi, Sun   +7 more
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 Distribution and significance of pre-Neoproterozoic zircons in juvenile Neoproterozoic igneous rocks of the Arabian-Nubian Shield

American Journal of Science, 2010
Igneous rocks of the Arabian-Nubian Shield (ANS) have lithologic associations (ophiolites, calc-alkaline igneous rocks, immature sediments) and radio- genic isotopic compositions consistent with formation as juvenile continental crust as a result of accreting intraoceanic arc systems during 880 to 630 Ma, with crustal differentiation continuing until ...
Stern, R.J, Ali, K.A, Liégeois, Jean-Paul, Johnson, Paul, Wiescek, F., Kattan, F.   +5 more
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The Neoproterozoic supercontinent Palaeopangaea

Gondwana Research, 2007
Abstract The Rodinia hypothesis for the Neoproterozoic Supercontinent reconstruction is associated with five major problems: (i) The palaeomagnetic test requires continental break-up hundreds of millions of years before the geological evidence for this event is recognised near the dawn of the Cambrian.
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Two or four Neoproterozoic glaciations?

Geology, 1998
A thick Neoproterozoic carbonate and glaciogenic succession of the southern Congo craton has yielded δ 13 C and 87 Sr/ 86 Sr records through the later Cryogenian (ca. 750–600 Ma) and earlier part of the Terminal Proterozoic (ca. 600–570 Ma). Sizeable negative δ 13 C excursions (to less than–5‰) occur above each of two glacial intervals and the 87 Sr/
Martin J. Kennedy, Bruce Runnegar, Anthony R. Prave, K.-H. Hoffmann, Michael A. Arthur   +4 more
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Neoproterozoic timescales and stratigraphy

Geological Society, London, Special Publications, 2009
Abstract The Infracambrian is a term for mostly Neoproterozoic successions in North Africa and areas to the east. Its base lies within the middle Neoproterozoic period, or Cryogenian, includes the youngest Neoproterozoic period, or Ediacaran, and continues into the early Cambrian to the level at which trilobites first appear.
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A Neoproterozoic Chronology

2007
Galen P ...
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Contributions to the Neoproterozoic Geobiology

2014
Ph. D.
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The Neoproterozoic glacial broom

Geology
Abstract Neoproterozoic snowball Earth events reflect globally frigid conditions thought to have stimulated changes in geochemical cycling with planetary biotic response. We investigated the impact of these events on sediment dynamics, focusing on the detrital zircon record within the Dalradian Supergroup of Scotland and Ireland ...
C.L. Kirkland, R.A. Strachan, D.B. Archibald, J.B. Murphy   +3 more
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Neoproterozoic glaciation in the Earth System

Journal of the Geological Society, 2007
The Neoproterozoic contains severe glacial intervals (750–580 Ma) including two extending to low palaeomagnetic latitudes. Paucity of radiometric dates indicates the need for chronostratigraphic tools. Whereas the marine 87 Sr/ 86 Sr signatures show a steady rise, δ 13
Fairchild, I., Kennedy, M.
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Neoproterozoic Geobiology and Paleobiology

2006
Chapter 1: The Proterozoic Fossil Record of Heterotrophic Eukaryotes Sussannah M. Porter 1. Introduction 2. Eukaryotic Tree 3. Fossil Evidence for Proterozoic Heterotrophs 4. Why Are Heterotrophs Rare in Proterozoic Rocks? 5. Conclusions Chapter 2: On the Morphological History of Proterozoic and Cambrian Acritarchs John Warren Huntley, Shuhai Xiao, and
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