Nd-Sr isotopes, petrochemistry, and origin of the Siberian flood basalts, USSR

Journal Article · Mon Apr 01 00:00:00 EST 1991 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(91)90177-7· OSTI ID:5668379

Sharma, M; Basu, A R ^[1]; Nesterenko, G V ^[2]

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1. Univ. of Rochester, NY (USA)
2. Vernadsky Institute of Geochemistry, Moscow (Soviet Union)

The Siberian Flood Basalt Province (SFBP) of Permo-Triassic age is one of the largest flood basalt provinces with an estimated area of exposure of 337 000 km{sup 2}, average thickness of 1 km, and a magma volume of 337 000 km{sup 3}. Forty-seven basaltic rocks from two main subprovinces, Norilsk (5-10{percent} of area, thickness up to 3 km) and Putorana (90-95{percent} of area, thickness of more than 2 km), were selected, on the basis of petrography and volcano-stratigraphic relation, for major-element analysis. Twenty-six of these basalts, twelve from Norilsk and fourteen from Putorana, were analyzed for Nd- and Sr-isotopic compositions. The Norilsk and Putorana basalts show some contrasting behavior in terms of the ratios of the highly incompatible elements of Ti, P, and K as a function of their Mg. The Norilsk basalts are more variable, suggesting the role of fractional crystallization-assimilation in their evolution. In contrast, the Putorana basalts show remarkable uniformity in their bulk chemical compositions. In Nd- and Sr-isotopic space, most of the Siberian basalts also fall within the field defined by the ocean island basalts data, implying common mantle sources. It is concluded that the SFBP originated by hotspot volcanism due to the rise of a large and relatively primitive lower mantle-derived plume beneath the Siberian continent.

• OSTI ID: 5668379
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 55:4; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
BASALT
CHEMICAL COMPOSITION
PETROCHEMISTRY
PETROGENESIS
SIBERIA
GEOLOGIC DEPOSITS
CHEMICAL ANALYSIS
GEOLOGIC HISTORY
ISOTOPE RATIO
NEODYMIUM ISOTOPES
ORIGIN
STRONTIUM 86
STRONTIUM 87
TRIASSIC PERIOD
VOLCANISM
ALKALINE EARTH ISOTOPES
ASIA
BETA DECAY RADIOISOTOPES
DEVELOPED COUNTRIES
ELECTRON CAPTURE RADIOISOTOPES
EUROPE
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
GEOLOGIC AGES
HOURS LIVING RADIOISOTOPES
IGNEOUS ROCKS
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MESOZOIC ERA
NUCLEI
RADIOISOTOPES
ROCKS
STABLE ISOTOPES
STRONTIUM ISOTOPES
USSR
VOLCANIC ROCKS
580000* - Geosciences