Facies analysis of the Mapepe Foreland Basin, Barberton Greenstone Belt, by well-to-well correlation

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Archaean biogeochemical cycles are poorly understood yet critical to comprehend the evolution of our planet-s ecosphere. One of the key sections shedding light on the composition of the Archaean ocean and its interaction with the atmo- and biosphere lies in the Middle Archaean (ca. 3250 Ma old) Fig Tree Group, Barberton Greenstone Belt (BGB), South Africa. A substantial part of this section was recently cored in an ICDP-supported drilling project. The cored section, BARB-5, includes fine- to coarse-grained sediments and volcaniclastics; ferruginous, carbonaceous, and cherty chemical sediments; and an impact spherule bed. They were all deposited in a deepening-upward, fan-delta to ferruginous deep-marine basin. Geological mapping in the vicinity indicates a high facies variability. The core material is geochemically attractive, evidenced by 14 submitted proposals. Successful sample analysis and interpretation, however, will depend on a detailed sedimentological interpretation, requiring core-to-surface integration. The proposed project will correlate the 763 m-core with surface sections, regional trends and eventually the BARB-4 core which drilled an age-equivalent BIF section nearby. Results will constrain the interpretation of geochemical proxies from both wells and contribute to the understanding of biochemical and extra- and intrabasinals controls on lithologies and facies. Funds applied for include travel money, limited field work, and analytical expenses.