The Sedimentological and Stratigraphic Evolution of the Archaean Black Flag Beds, Kalgoorlie, Western Australia: Implications for Regional Stratigraphy and Basin Setting of the Kalgoorlie Terrane

2019-02-06T03:32:40Z (GMT) by Jason L. Hand
The Archaean Kalgoorlie Terrane, within the Eastern Goldfields Province of the Yilgarn Craton, Western Australia, preserves a succession dominated by mafic/ultramafic rocks at it's base, overlain by the felsic volcaniclastic and sedimentary succession of the Black Flag Beds (BFB's). The BFB's are composed overwhelmingly of dacitic-andesitic volcaniclastic rocks, with lava facies poorly preserved. The Sedimentary facies range from mudrock to boulder sized conglomerates and breccias. Throughout all sedimentary successions of the BFB's, the background sedimentation was tranquil water mudrock deposition, indicating a below wave base depositional environment. The volcaniclastic facies have been deposited by turbidity currents, density modified grain flows and hemipelagic sedimentation processes. Facies analysis indicates that the dominant depositional systems that developed during the period of BFB sedimentation were submarine fan and slope apron systems. Five defined facies assemblages represent proximal to distal depositional settings within the subaqueous basins. Progradational, retrogradational and aggradational trends of submarine fan systems are sommon and are defined by vertically stacked facies assemblages.

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