Fraction-specific geochemistry across the Asbestos Hills BIF of the Transvaal Supergroup, South Africa: implications for the origin of BIF and the history of atmospheric oxygen

Title: Fraction-specific geochemistry across the Asbestos Hills BIF of the Transvaal Supergroup, South Africa: implications for the origin of BIF and the history of atmospheric oxygen
Creator: Oonk, Paul Bernardus Hendrikus
Date Issued: 2017
Date: 2017
Type: Thesis
Type: Doctoral
Type: PhD
Identifier: http://hdl.handle.net/10962/50721
Identifier: vital:26021
Description: Banded iron formations (BIF), deposited prior to and concurrent with the Great Oxidation Event (GOE) at ca. 2.4 Ga, record changes in oceanic and atmospheric chemistry during this critical time interval. Four previously unstudied drill-cores from the Griqualand West Basin, South Africa, capturing the rhythmically mesobanded, deep-water Kuruman BIF and the overlying granular, shallower Griquatown BIF, were sampled every ca. 10 m along core depth. Mineralogically, these BIFs consist of three iron-bearing fractions: (1) Fe-Ca-Mg-Mn carbonates, (2) magnetite with/without minor hematite and (3) Fe-silicates. These fractions are typically fine-grained on a sub-μm scale and their co-occurrence in varying amounts means that bulk-rock or microanalytical geochemical and stable isotope data are influenced by mineralogy.
Format: 211 leaves
Format: pdf
Publisher: Rhodes University
Publisher: Faculty of Science, Geology
Language: English
Rights: Oonk, Paul Bernardus Hendrikus

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