Late Quaternary faulting and neotectonics, South Victoria Land, Antarctica

Abstract

Three Quaternary fault traces in Hidden and Garwood Valleys, South Victoria Land, provide direct evidence for neotectonic activity in the Transantarctic Mountain rift shoulder of the West Antarctic Rift system. The faults trend NE-SW and all show a large component of sinistral strike-slip displacement. The late Quaternary faults lie parallel to Palaeozoic brittle structures, suggesting that inherited anistropy has governed younger fault orientations. Sinistral displacement on NE-SW-striking Quaternary faults appears to be inconsistent with the predicted Cenozoic NW-SE dextral oblique extensional regime in South Victoria Land but can be accommodated by minor clockwise rotation of crustal blocks.

Subglacial bedrock structure in the Transantarctic Mountains and its influence on ice sheet flow: insights from RADARSAT SAR imagery

“…This suggests a Cenozoic, pre-late Miocene age for the northeast-striking faults that control this morphology. More recent activity has occurred at least locally, since Jones (1997) has demonstrated Quaternary displacement on northeaststriking faults in southern Victoria Land (areas marked by * in Fig. 2).…”

“…The Transantarctic Mountains formed as a high-relief rift flank uplift (Fitzgerald et al, 1986;Stern and ten Brink, 1989) during the MesozoicCenozoic break-up of the Gondwana supercontinent (Cooper et al, 1987Tessensohn and Wörner, 1991;Davey and Brancolini, 1995;Fitzgerald and Stump, 1997). Active rift tectonism and mountain uplift have been inferred from the presence of active volcanism and Neogene-Quaternary age faulting in the western portion of the rift and the Transantarctic Mountains (Behrendt and Cooper, 1991;Davey and Brancolini, 1995;Jones, 1997). The mountain range presently separates the grounded East Antarctic Ice Sheet from the marine-based West Antarctic Ice Sheet over a substantial portion of the Antarctic interior.…”

Provenance signatures of the Antarctic Ice Sheets in the Ross Embayment during the Late Miocene to Early Pliocene: The ANDRILL AND-1B core record

“…This is not a surprise since the so far documented TAM uplift episodes are confined within a time window which is definitely older (i.e., between 55 and 15 Ma) than the AND-1B core record (Fitzgerald, 2002). However, tectonic activity is still ongoing within the McMurdo Sound area, as shown by the widespread McMurdo Group alkaline volcanism and minor faulting in the Quaternary (Jones 1997). The "Discovery accommodation zone", a prominent structural corridor associated with the major offset of the TAM rift flank in southern Victoria Land (Wilson, 1999) also coincides with a zone of voluminous Late Cenozoic volcanism proximal to the mountain front and extending beneath the Ross Sea and Ross Ice Shelf (Damaske et al, 1994;Behrendt et al, 1996;Wilson et al, 2007b).…”

Geochronology of Mount Morning, Antarctica: two-phase evolution of a long-lived trachyte-basanite-phonolite eruptive center

“…The Antarctic plate is thought to have remained effectively immobile since 80 Ma (Grindley and Oliver 1983;LeMasurier and Rex 1989;LeMasurier and Thomson 1990), during which time rifting and volcanism in Southern Victoria Land has commenced (Kyle 1990). The West Antarctic Rift System in Southern Victoria Land is thought to still be active (Kyle and Muncy 1989;Behrendt 1991;Jones 1996;Wilson 1999;Negusini et al 2005).…”