Tectonic history of the Ellsworth Mountains, West Antarctica: Reconciling a Gondwana enigma

Research Article| July 01, 2001 Tectonic history of the Ellsworth Mountains, West Antarctica: Reconciling a Gondwana enigma Michael L. Curtis Michael L. Curtis 1British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK Search for other works by this author on: GSW Google Scholar Author and Article Information Michael L. Curtis 1British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET, UK Publisher: Geological Society of America Received: 04 Oct 1999 Revision Received: 03 Mar 2000 Accepted: 08 Sep 2000 First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2001) 113 (7): 939–958. https://doi.org/10.1130/0016-7606(2001)113<0939:THOTEM>2.0.CO;2 Article history Received: 04 Oct 1999 Revision Received: 03 Mar 2000 Accepted: 08 Sep 2000 First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Michael L. Curtis; Tectonic history of the Ellsworth Mountains, West Antarctica: Reconciling a Gondwana enigma. GSA Bulletin 2001;; 113 (7): 939–958. doi: https://doi.org/10.1130/0016-7606(2001)113<0939:THOTEM>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Early Paleozoic orogenesis has been recognized along the southern African (Saldanian orogeny) and East Antarctic (Ross orogeny) sectors of the Gondwana paleo- Pacific margin. However, the absence of a contemporaneous orogenic event in the Ellsworth Mountains of West Antarctica, once a contiguous part of this margin, has resulted in their geology being considered enigmatic. In this contribution, widespread, detailed structural studies from all stratigraphic levels of the Ellsworth Mountains allow their tectonic evolution to be reassessed.Geochemical, stratigraphic, and structural data indicate that the Middle to Upper Cambrian Heritage Group developed in a continental rift basin. Multiple observations of the crucial end-Cambrian contact between this rift sequence and the overlying Crashsite Group reveal the contact to be regionally conformable; there are localized outcrop-scale unconformities. Furthermore, structural continuity can be demonstrated across this key boundary, thus precluding the possibility of an end-Cambrian orogenic event.The entire stratigraphic succession was affected by two post-Permian phases of deformation. D1 structures are locally developed and superimposed by the main dextral transpressive D2 Permian−Triassic Gondwanian deformation event. D2 is succeeded by an episode of extension orthogonal to orogenic strike.Recent geochronological data on the early Paleozoic evolution of the Cape fold belt reveal a strong tectonostratigraphic correlation with the Ellsworth Mountains, indicating that this sector of the Gondwana paleo-Pacific margin was affected by Middle to Late Cambrian rifting. A new tectonic model is proposed for the southwestern paleo-Pacific margin of Gondwana that accounts for the presence of rifting along a margin otherwise dominated by active subduction. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.