Strontium isotope evidence for preserved density stratification in the main zone of the Bushveld Complex, South Africa

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Authors:Sharpe, Martin R.
Author Affiliations:Primary:
Univ. Pretoria, Inst. Geol. Res. Bushveld Complex, Pretoria, South Africa
Volume Title:Nature (London)
Source:Nature (London), 316(6024), p.119-126. Publisher: Macmillan Journals, London, United Kingdom. ISSN: 0028-0836
Publication Date:1985
Note:In English. 26 refs.; illus. incl. 350 anal., 2 tables, geol. sketch map
Summary:Whole-rock geochemical data are given for samples 300 m below the Merensky reef to 300 m above the pyroxenite marker. Rocks with a 87Sr/86Sr ratio of 0.7065 lie below the lower 2.2 km of the main zone (ratio 0.7085); those with a ratio of 0.7073 lie above it. This unit represents a liquid layer intruded into the density-stratified magma pile near the base of the chamber. The Bushveld complex formed from two isotopically distinct magmas, and magma addition and mixing are tracked by the initial Sr ratios of the cumulates. The Merensky Reef was produced by mixing of the pile with underlying trapped liquid enriched in precious metals. [R.K.H.]
Subjects:Alkaline earth metals; Convection; Cumulates; Density; Differentiation; Fractional crystallization; Gabbros; Geochemistry; Igneous rocks; Intrusions; Isotopes; Layered intrusions; Liquid phase; Magmas; Major elements; Metal ores; Metals; Mineral deposits, genesis; Mixing; Plutonic rocks; Precious metals; Sr-87/Sr-86; Stable isotopes; Strontium; Trace elements; Africa; Bushveld Complex; Merensky Reef; South Africa; Southern Africa; Transvaal region; Igneous processes; Pyrotenite; Transvaal South Africa
Coordinates:S263000 S230000 E0302000 E0260000
Abstract Numbers:86M/1994
Record ID:1985082749
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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