Neoproterozoic-Cambrian basement-involved orogenesis within the Antarctic margin of Gondwana

Research Article| January 01, 1993 Neoproterozoic-Cambrian basement-involved orogenesis within the Antarctic margin of Gondwana John W. Goodge; John W. Goodge 1Department of Geological Sciences, Southern Methodist University, Dallas, Texas 75275 Search for other works by this author on: GSW Google Scholar Nicholas W. Walker; Nicholas W. Walker 2Department of Geological Sciences, University of Texas, Austin, Texas 78713 Search for other works by this author on: GSW Google Scholar Vicki L. Hansen Vicki L. Hansen 1Department of Geological Sciences, Southern Methodist University, Dallas, Texas 75275 Search for other works by this author on: GSW Google Scholar Author and Article Information John W. Goodge 1Department of Geological Sciences, Southern Methodist University, Dallas, Texas 75275 Nicholas W. Walker 2Department of Geological Sciences, University of Texas, Austin, Texas 78713 Vicki L. Hansen 1Department of Geological Sciences, Southern Methodist University, Dallas, Texas 75275 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1993) 21 (1): 37–40. https://doi.org/10.1130/0091-7613(1993)021<0037:NCBIOW>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation John W. Goodge, Nicholas W. Walker, Vicki L. Hansen; Neoproterozoic-Cambrian basement-involved orogenesis within the Antarctic margin of Gondwana. Geology 1993;; 21 (1): 37–40. doi: https://doi.org/10.1130/0091-7613(1993)021<0037:NCBIOW>2.3.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 SocietyGeology Search Advanced Search Abstract High-grade metamorphic tectonites of the Nimrod Group in the central Transantarctic Mountains compose a major ductile shear zone that formed within the paleo-Pacific margin of Gondwana. Despite demonstrated Precambrian protoliths, the timing of metamorphism and tectonite development has been poorly constrained. Igneous rocks of diverse compositions intrude the Nimrod tectonites. Four intrusive units with incipient to well-developed ductile fabrics yield U-Pb zircon ages of 541-521 Ma, and a nondeformed pegmatite has a U-Pb zircon age of ∼515 Ma. These data show that early Paleozoic Ross magmatism was compositionally, texturally, and temporally more heterogeneous than previously recognized. Fabrics in the igneous rocks are concordant with those in their host tectonites, indicating that Nimrod tectonism was in part synchronous with plutonism. U-Pb ages of 525-522 Ma for metamorphic monazite from two pelitic tectonites support this interpretation. Thus, ductile deformation was in its peak to waning stages between about 540 and 520 Ma. This timing provides compelling evidence for transcurrent basement involvement in oblique plate convergence along the Neoproterozoic to Early Cambrian Antarctic margin of Gondwana. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.