Nd and Sr isotopic geochemistry of mafic layered intrusions in the eastern Baltic shield: implications for the evolution of Paleoproterozoic continental mafic magmas
Article Abstract:
The use of Sm-Nd and Rb-Sr isotopic data for two layered mafic complexes in the eastern Baltic Shield helps to study the effect of the age of host rocks and the post-crystallization metamorphic history on the isotopic signatures. Rb addition, during metamorphism 1.75-1.50 billion years ago, disturbed the Rb-Sr systems of minerals in the Olanga rocks. A mantle plume model with minor crustal and asthenospheric contamination explains the isotopic variations in Olanga. The undisturbed Sm-Nd systems of Burakovka are due to multiple magma injections, and complex mixing and contamination.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1996
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Petrology of a 2.41 Ga remarkably fresh komatiitic basalt lava lake in Lion Hills, central Vetreny Belt, Baltic Shield
Article Abstract:
The geochemical study of komatiitic basalts from the upper part of the Vetreny Belt, southeastern Baltic Shield, provides information about the origin of these high-magnesian volcanic rocks. The lava deposited in a topographical depression soon after eruption. The settling of transported olivine and chromite phenocrysts controlled the differentiation of the lava and created the internal layering. The Sm-Nd age of 2410 plus or minus 34 million years is a sound estimate for the time of formation of the Vetreny Belt. A 7-9% crustal contamination of a komatiitic parent is suggested.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1996
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Discordant bodies from olivine-bearing zones III and IV of the Stillwater Complex, Montana - evidence for postcumulus fluid migration and reaction in layered intrusions
Article Abstract:
Mineralogically uncomplicated bodies from the olivine-bearing zones III and IV of the Stillwater Complex in Montana were examined to elucidate the mechanisms for late-stage crystallization and postcumulus fluid migration in layered intrusions. The configuration of the discordant bodies indicated that the cumulus pile underwent anisotropic permeability during late-stage liquid/fluid flow. The findings provided evidence that the processes responsible for the formation of the discordant bodies may have been affected by other bodies.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1997
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