Results 61 to 70 of about 16,262 (232)

Paleomagnetism of a lateritic paleoweathering horizon and overlying Paleoproterozoic red beds from South Africa: Implications for the Kaapvaal apparent polar wander path and a confirmation of atmospheric oxygen enrichment [PDF]

, 2002
The Olifantshoek Group in southern Africa contains Paleoproterozoic red beds that are exceptionally well preserved, lying unconformably atop a regionally extensive lateritic paleoweathering profile.
Beukes, N. J., Evans, D. A. D., Kirschvink, J. L.   +2 more
core   +1 more source

Sedimentology of silica granules and haematite in the 3.47 Ga Antarctic Creek Member, Mount Ada Basalt, Western Australia

Sedimentology, EarlyView.
ABSTRACT The Paleoarchean Antarctic Creek Member of the Mount Ada Basalt, Eastern Pilbara Terrane, Western Australia, includes beds of jasper and white chert composed of sand‐sized silica granules that often contain or are mixed with silt‐sized particles of haematite.
Donald R. Lowe, Gary R. Byerly
wiley   +1 more source

Paleoproterozic Icehouses and the Evolution of Oxygen Mediating Enzymes: The Case for a Late Origin of Photosystem -- II [PDF]

, 2008
Two major geological problems regarding the origin of oxygenic photosynthesis are: (1) identifying a source of oxygen predating biological oxygen production and capable of driving the evolution of oxygen tolerance, and (2) determining when oxygenic ...
Kirschvink, Joseph L., Kopp, Robert E.
core  

Vetreny belt as a geological heritage of unique paleoproterozoic tectonomagmatic processes in the Fennoscandin shield

Известия высших учебных заведений: Геология и разведка
We presented the history of discovery and development of geological hypotheses about the conditions of formation of one of the largest Paloproterozoic structures of the Baltic Shield  — the Vetreny Belt.
S. V. Mezhelovskaya, К. I. Yushin, А. D. Mezhelovsky   +2 more
doaj   +1 more source

Mafic-ultramafic intrusions of Matokulma, Palojärvi, and Hongonniittu within the Central Finland Granitoid Complex with special reference to their petrogenesis and ore potential [PDF]

Bulletin of the Geological Society of Finland
We describe three previously unknown or poorly studied mafic-ultramafic intrusions (Matokulma, Palojärvi, Hongonniittu) from the south-central part of the Paleoproterozoic Central Finland Granitoid Complex (CFGC).
Seppo Karvinen, Hannu V. Makkonen, Perttu Mikkola, O. Tapani Rämö, Hannu Huhma, Matti Niskanen   +5 more
doaj   +1 more source

Evolution Model for the Paleoproterozoic Talvivaara Mudstone‐Hosted Ni‐Zn‐Cu‐Co Deposit in Fennoscandia

Terra Nova, EarlyView.
ABSTRACT The Paleoproterozoic Talvivaara mudstone is a very large sulfidic Ni‐Co deposit that records enhanced organic matter accumulation during the global Shunga Event. Here, rock geochemistry and microscale S and Fe isotope composition of in situ pyrrhotites and pyrites are studied in well‐characterised, well‐preserved drill core samples.
Raimo Lahtinen, Jaakko J. Laitala, Joonas J. Virtasalo, Martin J. Whitehouse   +3 more
wiley   +1 more source

Ductile Extrusion Triggered by Continental Collision in NE Brazil

Terra Nova, EarlyView.
ABSTRACT The Borborema Province in northeastern Brazil hosts one of the world's largest strike‐slip shear zone networks, active during the late Neoproterozoic assembly of West Gondwana. Whether these shear zones initiated during active continental collision or as a post‐orogenic response to far‐field stresses remains debated.
L. R. Tesser, C. E. Ganade, C. R. Cioffi, J. B. Forshaw, M. Hueck, E. Celis, M. A. S. Basei   +6 more
wiley   +1 more source

Contrasted tectonic styles for the Paleoproterozoic evolution of the North China Craton. Evidence for a ~2.1 Ga thermal and tectonic event in the Fuping Massif [PDF]

, 2008
International audienceStructural analysis along with 40Ar–39Ar and U–Pb datings in the Fuping massif provide new insight into the evolution of the eastern part of the Trans-North China Belt (North China Craton), from 2.7 Ga to 1.8 Ga.
Bruguier, Olivier, Faure, Michel, Lin, Wei, Monié, Patrick, Trap, Pierre   +4 more
core   +2 more sources

Re-Os age of molybdenite from the Hannivka deposit, Kryvyi Rih structure, Ukrainian Shield

Мінеральні ресурси України
This article presents the results of isotopic dating of molybdenite using the Re–Os method to determine the age of mineralization at the Hannivka deposit.
Yu. Ye. Khomych, V. V. Sukach, L. V. Shumlyanskyy, S. M. Bondarenko, V. O. Syomka, S. Tessalina, M. M. Reshetnyk   +6 more
doaj   +1 more source

Paleoproterozoic post-orogenic magmatism in southern Finland; geochemical, geochronological and Sr-Nd isotopic constraints on origin and magmatic evolution [PDF]

Bulletin of the Geological Society of Finland
Fifteen post-orogenic, basic to acidic High-Barium-Strontium (HiBaSr) intrusions of shoshonitic affinity have been recognized in central and southern Finland.
Oliver Teräs, Kaisa Nikkilä, Perttu Mikkola, Anna Kotilainen, Olav Eklund, O. Tapani Rämö   +5 more
doaj   +1 more source