Results 31 to 40 of about 2,704 (186)
The Cambrian Explosion: macroevolution and biomineralization
Academia Biology, 2023 Recent advances in our understanding of the Cambrian evolutionary diversification event (Cambrian Explosion) show that, although eumetazoan stem taxa were present in the late Proterozoic, a tremendous burst of macroevolutionary change occurred near the ...
Mark A. S. McMenamin
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ISOTOPIC-GEOCHEMICAL ASPECTS OF THE OCCURRENCE OF LIFE ON EARTH IN THE EARLY PRECAMBRIAN
Геохімія техногенезуThe time of the appearance of life and oxygen on Earth is debatable. In order to search for signs of the presence of life and the evolution of the Earth’s outer shells, in particular the time of the appearance of oxygen in the atmosphere,
Demikhov Yu.M. +4 more
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The early Proterozoic Saari-Kiekki greenstone belt: A representative of the Sariola Group at Kuhmo, Eastern Finland [PDF]
Bulletin of the Geological Society of Finland, 1989 The early Proterozoic Saari-Kiekki greenstone belt in Kuhmo, eastern Finland, is the deformed remnant of a NW‒SE-trending elongate structural basin c. 15 km long and up to 3 km wide.
E.J. Luukkonen
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International Journal of Geoheritage and Parks, 2019 The Pilbara region of Western Australia, covering some 500 km × 500 km, provides a diversity of Archaean to Proterozoic igneous rocks in a relatively compact area that records a younging southward crustal history of igneous activity, sedimentation, early
V. Semeniuk, M. Brocx
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Proterozoic, Archeam and other weeds in the Precambrian rock garden [PDF]
Bulletin of the Geological Society of Finland, 1970 The use of the terms Precambrian; Proterozoic, Algonkian, and Archean; Cryptozoic and Archeozoic; and Eocambrian, Infracambrian, and Subcambrian is discussed.
K. Rankama
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Evidence that the GOE was a prolonged event with a peak around 1900 Ma
Geosystems and Geoenvironment, 2022 The great oxygenation event (GOE), the first of two major rises in atmospheric oxygen in Earth history, was initially placed near the Archean-Proterozoic boundary (∼2500 Ma). More recently, the position of the GOE has been moved to between 2500 and 2300
Ross R. Large +5 more
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Geological Journal, EarlyView.Our petrochemical studies on ~1.2 Ga granitoids of the Natal Metamorphic Belt, South Africa, do not suggest any property similar to Phanerozoic‐style subduction‐related granitoids. Plot of Kotongweni Tonalite in Y versus Sr diagram (after Moyen 2011), note that most samples have Sr/Y < 50.
Palesa Leuta +2 more
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Geological Journal, EarlyView.U–Pb isotope and trace element geochemistry of apatite from carbonatites of Peshawar Plain Alkaline Igneous Province, western Himalaya shows Permo‐Carboniferous magmatism, an additional magmatic pulse during Cretaceous, and post‐magmatic hydrothermal/metasomatism during Oligocene. ABSTRACT U–Pb isotope and trace element geochemistry of apatite combined
Mehboob ur Rashid +9 more
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Tektonika, 2023 Higher than average thermobaric ratios (temperature/pressure) of metamorphic rocks and abundant ‘dry’ ferroan magmatism including massif anorthosite suites are two enigmatic features of the mid-Proterozoic (1.85–0.85 Ga) that have unclear origins.
Nick Roberts +3 more
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Sustainable Development, EarlyView.ABSTRACT Colorado's geologic, pedologic, topographic, hydrological, and climatic contrasts create strong but under‐synthesized opportunities for sustainable agritourism. This review investigates how geodiversity, and the broader environmental heterogeneity within which it operates, can be used to diversify farm income, strengthen place‐based visitor ...
Bonface O. Manono
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