A new appraisal of depositional cyclicity in the Neoarchean-Paleoproterozoic Dales Gorge Member (Brockman Iron Formation, Hamersley Basin, Australia)

摘要: Abstract The Dales Gorge Member (DGM) of the Brockman Iron Formation (Hamersley Basin, Western Australia) is a classic banded iron formation (BIF) that was deposited during Archean-Proterozoic transition just prior to Great Oxidation Event. goal this study apply modern cyclostratigraphic principles investigate possible origins characteristic stratigraphic banding in BIF, which indicates influence quasi-regular cyclic processes deposition iron-rich and chert-rich lithologies. A grayscale scan series DGM ‘type section’ 47A* drillcore photographs from three cores drilled Wittenoon vicinity examined using well established methods time analysis. Complex patterns suggest Milankovitch forcing may have taken place with orbital-rotational parameters were significantly modified present-day due continuous planetary tidal dissipation over past 2.5 billion years. change systematically dramatically within member response slowly varying environmental conditions, are interpreted be related low-frequency sea level changes and/or tectonic evolution Hamersley Basin.