Cenozoic landscape evolution of the Convoy Range to Mackay Glacier area, Transantarctic Mountains: Onshore to offshore synthesis

Abstract

Research Article| July 01, 2004 Cenozoic landscape evolution of the Convoy Range to Mackay Glacier area, Transantarctic Mountains: Onshore to offshore synthesis David Sugden; David Sugden 1Institute of Geography, School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, UK Search for other works by this author on: GSW Google Scholar George Denton George Denton 2Department of Earth Sciences and Climate Change Institute, Edward T. Bryand Global Sciences Center, University of Maine, Orono, Maine 04469, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2004) 116 (7-8): 840–857. https://doi.org/10.1130/B25356.1 Article history received: 19 Mar 2003 rev-recd: 16 Sep 2003 accepted: 23 Sep 2003 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation David Sugden, George Denton; Cenozoic landscape evolution of the Convoy Range to Mackay Glacier area, Transantarctic Mountains: Onshore to offshore synthesis. GSA Bulletin 2004;; 116 (7-8): 840–857. doi: https://doi.org/10.1130/B25356.1 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 On the basis of geomorphic mapping, we reconstruct the landscape evolution of the Convoy Range to Mackay Glacier area of the rifted margin of the Transantarctic Mountains and compare the land record with that obtained from offshore marine sedimentary rocks in the Ross Sea. Three landform assemblages reflect (1) fluvial planation and dissection, (2) local glaciation under temperate conditions, and (3) overriding by the East Antarctic Ice Sheet. Overall landscape evolution is typical of a passive continental margin. Contrasts in morphology between the Convoy Range and the adjacent Dry Valleys and Royal Society mountains reflect the varying location of the initial drainage divide in relationship to the rifted coast. In a wider synthesis we draw the following conclusions for the 260-km-long McMurdo sector of the Transantarctic Mountains. Denudation since rifting at ca. 55 Ma has removed a wedge 4–7 km thick at the coast, declining inland to ∼1 km. Most denudation occurred in the Eocene from planation and incision of river valleys near the coast. A subsequent pulse of denudation, most rapid at 34–31 Ma, and declining until ca. 17 Ma, coincided with further crustal extension and a change from cool temperate to polar climate. During the same interval, there was a progressive decrease in landscape modification by warm-based glaciers and/or rivers. Between 14.8 and 13.6 Ma the maximum overriding Antarctic ice sheet flowed northeastward across the mountains, leaving meltwater features crossing high-altitude saddles and areally scoured bedrock near the coast. Since 13.6 Ma, the landscape has seen little change under a hyperarid polar climate, either by local glaciers or subaerially. Fragile middle Miocene surficial deposits still survive. There has been tectonic stability since the middle Miocene. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.