Late Cambrian stratigraphy of the Heritage Range, Ellsworth Mountains: implications for basin evolution

Curtis, Michael L.; Lomas, Simon A.. 1999 Late Cambrian stratigraphy of the Heritage Range, Ellsworth Mountains: implications for basin evolution. Antarctic Science, 11 (01). 63-77.

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Deposition of the Upper Cambrian succession of the Ellsworth Mountains was influenced by major, episodic tectonically-driven changes to the depositional basin geometry. We subdivide the succession into four stratigraphical sequences based on the recognition of three sequence-bounding unconformities. The upper part of Sequence 1 is composed of the laterally equivalent Liberty Hills, Springer Peak and Frazier Ridge formations, a siliciclastic fluvial to marine deltaic association displaying NW-directed palaeocurrents. A switch in the position of the Late Cambrian depocentre from the north-west to the south coincided with cessation of terrigenous clastic deposition and accumulation of Sequence 2, the limestones of the Minaret Formation. Previously unreported talus breccias from the Independence Hills provide important clues to basin configuration at this time. A brief period of emergence of the Minaret Formation is inferred, prior to rapid subsidence and disconformable deposition of Sequence 3 (the ‘transition beds’) in outer-inner shelf environments. Localized intra-basinal uplift occurred prior to the deposition of Sequence 4 (the lower Crashsite Group), the base of which is locally an erosive unconformity, with a correlative conformity exposed elsewhere. We interpret the Upper Cambrian succession as representing the ‘rift-drift’ transition from initial rifting (preceded by Middle Cambrian volcanism) to thermal subsidence along the South African sector of the palaeo-Pacific margin of Gondwana.

Item Type: Publication - Article
Digital Object Identifier (DOI):
Programmes: BAS Programmes > Pre 2000 programme
ISSN: 0954-1020
Additional Keywords: continental rifting, Ellsworth Mountains, Late Cambrian, sequence stratigraphy
Date made live: 14 Oct 2013 10:11 +0 (UTC)

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