Results 61 to 70 of about 16,111 (210)

Lithostratigraphy of the Portfjeld Group (Ediacaran – lowermost Cambrian) of North Greenland

GEUS Bulletin
The Portfjeld Formation, as originally defined, is the lowermost lithostratigraphic unit of the mainly Lower Palaeozoic Franklinian Basin in southern Peary Land, central North Greenland.
Jon R. Ineson, John S. Peel, Sebastian Willman, Elias J. Rugen, Martin Sønderholm, Peter Frykman   +5 more
doaj   +1 more source

A vast Caledonian fan and an Ediacaran arc: the contrasting provenance of Devonian clastics of Brunia (Bohemian Massif) [PDF]

Solid Earth
Brunia is a distinctive crustal block within the European Variscides, composed of a late Neoproterozoic arc complex overlain by Ediacaran–early Cambrian cover sequences.
S. Collett, I. Soejono, T. Kumpan, P. Hanžl, J. Míková, N. Novotná, J. Sláma   +6 more
doaj   +1 more source

Rare Earth Element Potential in the Araí Rift Metavolcanic, Central Brazil: Gamma‐Ray Signatures, Mineralogy and Exploration Implications

Terra Nova, EarlyView.
ABSTRACT Although central Brazil hosts significant ion‐adsorption rare earth element (REE) deposits associated with A‐type granites, their coeval volcanic counterparts have been largely overlooked as exploration targets. This study demonstrates that acidic metavolcanic rocks of the Araí Group share strong radiometric, geochemical and mineralogical ...
Yuri Ribeiro, Nilson Francisquini Botelho, Valmir da Silva Souza, Diego Guilherme da Costa Gomes   +3 more
wiley   +1 more source

Considering a Neoproterozoic Snowball Earth

Science, 1999
P. F. Hoffman et al. and N. Christie-Blick et al. discuss Hoffman et al.'s paper that "developed a modified 'snowball Earth' hypothesis (2) to explain the association of Neoproterozoic low-latitude glaciation with the deposition of 'cap carbonate' rocks bearing highly depleted carbon isotopic values (δ13C ≤ −5‰).
Christie-Blick, Nicholas, Sohl, Linda E., Kennedy, Martin J.   +2 more
openaire   +4 more sources

Relics of ophiolite-bearing accretionary wedges in NE Brazil and NW Africa: Connecting threads of western Gondwana´s ocean during Neoproterozoic times

Geosystems and Geoenvironment, 2023
Neoproterozoic breakup of Rodinia resulted in the formation of several oceanic realms between dispersing cratons, which were later consumed during the assembly of Gondwana. In its western portion, the interior orogenic belts of Gondwana formed during the
Lauro Cézar M. de Lira Santos, Fabrício A. Caxito, Merlain H. Bouyo, Sonia Ouadahi, Kawther Araïbia, Geysson A. Lages, Glenda L. Santos, João Paulo A. Pitombeira, Peter A. Cawood   +8 more
doaj   +1 more source

Multi‐Mineral Geochronology Across the Neoproterozoic Brasília Nappe Stack: Constraints on Thermal Resetting and Metamorphic Architecture

Terra Nova, EarlyView.
ABSTRACT The Southern Brasília Orogen formed during Western Gondwana's final assembly and comprises nappe systems piled against the São Francisco Craton. We present new rutile U–Pb ages from the lowermost Canastra Group (> 2.2 Ga) and the uppermost Carrancas Group (~560 Ma), integrated with published zircon, monazite, garnet, and mica ages from the ...
Rodrigo Irineu Cerri, Alex J. Choupina A. Silva, Tamiris Pagotti Gonçalves Pinto, Rodrigo Prudente de Melo, George Luiz Luvizotto, Regiane Andrade Fumes, Fabrício de Andrade Caxito, Renato Moraes   +7 more
wiley   +1 more source

A palaeogeographic context for Neoproterozoic glaciation [PDF]

Palaeogeography, Palaeoclimatology, Palaeoecology, 2009
Abstract The distributions of 77 Neoproterozoic glacigenic formations are shown on global palaeogeographic maps for 715 Ma (Sturtian), 635 Ma (Marinoan) and 580 Ma (Ediacaran), constructed on grounds independent of palaeoclimatic indicators. The meridional distribution of Sturtian and Marinoan deposits is biased in favour of low palaeolatitudes ...
Hoffman, P., Li, Zheng-Xiang
openaire   +2 more sources

MAGMATIC SOURCES OF THE EVOLVING CONTINENTAL TECTONOSPHERE IN INDIA: GENERATION OF ALKALINE IGNEOUS COMPLEXES WITH CARBONATITES IN THE SAMALPATTI (SOUTHERN INDIA) AND AMBA DONGAR (WESTERN INDIA) MASSIFS

Геодинамика и тектонофизика
Neoproterozoic Samalpatti and Cretaceous-Paleogene Amba Dongar massifs are considered to evaluate the change of sources of carbonatite magmatism in evolving tectonosphere of India. The inherited character of Ba and Sr distribution components is traced in
S. V. Rasskazov, T. A. Yasnygina, K. R. Hari, I. S. Chuvashova, E. V. Saranina   +4 more
doaj   +1 more source

Comprehensive evaluation of Neoproterozoic source rocks formation

Georesursy
Based on comprehensive analysis of geological, geochemical, and paleotectonic settings, the conditions for the formation of Neoproterozoic oil and gas source rocks of the Earth are analyzed. A brief review of oil and gas fields in Eastern Siberia, China,
K. A. Sitar, B. V. Georgievskiy, M. A. Bolshakova, R. S. Sautkin   +3 more
doaj   +1 more source

Biological feedbacks as cause and demise of the Neoproterozoic icehouse: astrobiological prospects for faster evolution and importance of cold conditions. [PDF]

PLoS ONE, 2007
Several severe glaciations occurred during the Neoproterozoic eon, and especially near its end in the Cryogenian period (630-850 Ma). While the glacial periods themselves were probably related to the continental positions being appropriate for glaciation,
Pekka Janhunen, Hermanni Kaartokallio, Ilona Oksanen, Kirsi Lehto, Harry Lehto   +4 more
doaj   +1 more source