Miocene glaciomarine sedimentation in the northern Antarctic Peninsula region: the stratigraphy and sedimentology of the Hobbs Glacier Formation, James Ross Island

• Published in: Geological Magazine
• Main Authors: PIRRIE, D., CRAME, J. A., RIDING, J. B., BUTCHER, A. R., TAYLOR, P. D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1997
• Subjects: Alexander Island; Antarc*; Antarctic; Antarctic Peninsula; Antarctica; Ice Shelf; James Ross Island; Ross Island; South Shetland Islands; Tidewater; West Antarctica
• Online Access: http://dx.doi.org/10.1017/s0016756897007796; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756897007796

The onshore record of Cenozoic glaciation in the Antarctic Peninsula region is limited to a number of isolated localities on Alexander Island, the South Shetland Islands and in the James Ross Island area. In the James Ross Island area, Late Cretaceous sedimentary rocks are unconformably overlain by a unit of diamictites and tuffs, which occur at the base of the James Ross Island Volcanic Group. These rocks are here defined as the Hobbs Glacier Formation, and on the basis of palynological studies are assigned to a Miocene (?late Miocene) age. The diamictites are interpreted as representing glaciomarine sedimentation close to the grounding line of either a floating ice shelf or a grounded tidewater glacier in a marine basin. Provenance studies indicate that the glacier was flowing from the Antarctic Peninsula towards the southeast. Volcanic tuffs conformably overlie the diamictites and are interpreted as representing deposition in a periglacial delta front setting in either a marine or non-marine basin, away from direct glacial influence. The Hobbs Glacier Formation and overlying James Ross Island Volcanic Group help to enhance our understanding of the Neogene glacial chronology of West Antarctica.