Ellsworth Mountains: Position in West Antarctica due to Sea-Floor Spreading

Abstract

Similarities of middle anld upper Paleozoic deposits of the Ellsworth fountains with those of the Pensacola, Horlick, and other Transtarctic mountains indicate that all these ranges may have had a related geologic history. A native explanation is now suggested which involves sea-floor spreading atnd anslocationi of the Ellsworth crutstal block from its originilal location adjacent to the East Antarctic Shield. Accordingly, the islands of West Antarctica may differ it origin and the Transantarctic Mountains of East Antarctica may represent one margin of an ancient rift.

New geophysical compilations link crustal block motion to Jurassic extension and strike-slip faulting in the Weddell Sea Rift System of West Antarctica

“…HEW remains consistent with the stratigraphic interpretation of the position of the EWM north of the Pensacola Mountains (Schopf, 1969) and is consistent with mineralogical and paleontological provenance studies suggesting the Ellsworth Mountains sediments were sourced from the Transantarctic region of East Antarctica (Elliot et al, 2016;Stone and Thompson, 2005). The motion of the HEW in this less far travelled model would be consistent with either the proposed two stage, or more complex single stage tectonic models for the evolution of the WSRS magnetic lineations (Figs.…”

“…Land would be consistent with stratigraphic considerations that suggest the Ellsworth Whitmore sediments were deposited in a basin north of the Pensacola Mountains (Schopf, 1969). In addition, the 90° tectonic rotation would explain the paleomagnetic data, which suggests this orientation for the Cambrian sediments (Grunow et al, 1987;Randall and MacNiocaill, 2004;Watts and Bramall, 1981).…”

“…1) were deposited in a basin distinct from the South African Karoo basin, with material dominantly sourced from East Antarctica (Elliot et al, 2016). Stratigraphic correlation, including the presence of extensive Permo-Carboniferous glacial tills in the EWM and Pensacola Mountains (Matsch and Ojakangas, 1992 ;Schopf, 1969) has been used to constrain the EWM to a position north of the present day Pensacola Mountains (Schopf, 1969). Paleo ice-flow markers suggest that glacial sediments were transported into the EWM basin by ice streams flowing outward from East Antarctica (Matsch and Ojakangas, 1992 ).…”

History of the Ross Sea region during the deposition of the Beacon Supergroup 400 - 180 million years ago

“…8 -Kyle et aL, 1981 to be sufficient for the broad palaeogeographic reconstructions presented and discussed below. The maps are based on the present outline of Antarctica, including permanent ice, except that the Ellsworth Mountains have been rotated 90°to a position first suggested by Schopf (1969) and recently confirmed by Watts and Bramall (1980) (Fig. 2A).…”

The links between large igneous provinces, continental break-up and environmental change: evidence reviewed from Antarctica

“…An Ellsworth microplate, formed at the time of breakup, rotated clockwise more than 90 and migrated from an original position between South Africa and Antarctica to its present position at the head of the Weddell Sea (Schopf 1969;Grunow et al 1987). The Falkland Islands, like the Ellsworth Mountains, rotated 180 from a similar position between African and Antarctica to join South America on the opposite side of the Atlantic.…”