Structure of the central Terror Rift, western Ross Sea, Antarctica

Abstract

The Terror Rift is a zone of post-middle Miocene faulting and volcanism along the western margin of the West Antarctic Rift System. A new seismic data set from NSF geophysical cruise NBP04-01, integrated with the previous dataset to provide higher spatial resolution, has been interpreted in this study in order to improve understanding of the architecture and history of the Terror Rift. The Terror Rift contains two components, a structurally-controlled rollover anticlinal arch intruded by younger volcanic bodies and an associated synclinal basin. Offsets and trend changes in fault patterns have been identified, coincident with shifts in the location of depocenters that define rift sub-basins, indicating that the Terror Rift is segmented by transverse structures. Multiple phases of faulting all post-date 17 Ma, including faults cutting the seafloor surface, indicating Neogene rifting and possible modern activity.

Late Neogene climate and glacial history of the Southern Victoria Land coast from integrated drill core, seismic and outcrop data

“…A seismic stratigraphic framework for the Victoria Land Basin and Terror Rift has been well established in previous studies (Brancolini et al, 1995;Fielding et al, 2007;Hall et al, 2007;Fielding et al, 2008). The latest Neogene portion of this framework consists of a series of three laterally traceable surfaces labeled Ri-Rk (Fielding et al, 2008).…”

“…7), forming a broad flat shelf that extends~25 km across the western slope of the basin. The distribution of the stratigraphic package within the central part of the basin is predominantly controlled by regional structural elements including NNW-SSE to N-S trending normal faults (Hall et al, 2007;Henrys et al, 2007) and the crustal moat that began to form in response to the onset of volcanic loading as Mount Bird grew in the early Pliocene (Kyle, 1990;Esser et al, 2004). However, we note that a linear tongue of sediment extends off MacKay Valley in a general SW-NE direction across the structural trend of the VLB and Terror Rift (Fig.…”

Heat Flow and Hydrologic Characteristics at the AND-1B borehole, ANDRILL McMurdo Ice Shelf Project, Antarctica

“…1), and above a fl exural moat basin that surrounds Ross Island (Horgan et al, 2005). This basin was formed by loading of the crust from the basaltic volcanoes that constitute Ross Island within the tectonic framework of the Victoria Land Basin, a region of late Cenozoic crustal extension of the West Antarctic Rift System (e.g., Wilson, 1999;Hall et al, 2007;Henrys et al, 2007). Characterizing the marine hydrogeology at this site requires an understanding of fi ne-scale heat-fl ow patterns and structural details in order to evaluate moat-wide circulation processes, thermal refraction along the volcanic edifi ce, and channelized fl uid fl ow (Harris et al, 2000a(Harris et al, , 2000b.…”

Flat-topped mounds in western Ross Sea: Carbonate mounds or subglacial volcanic features?

“…This interpretation would restrict their age of formation to the time when grounded ice sheets traveled toward the continental shelf edge. The concentration of mounds in a small region appears to be associated with tectonic movements at the offset (accommodation zone) and change in trend of the Terror Rift (Salvini et al, 1997) that allowed magma to rise along the high-angle, normal faulting occurring there (Hall et al, 2007). This occurred during an ice-sheet advance when grounded ice lay over the region up to 700 m thick (Denton and Hughes, 2000), a thickness similar to the ice thickness just inboard of the grounding line of the present West Antarctic ice sheet (Drewry, 1983).…”

“…The major extension of the basin probably occurred only since the late Eocene (~38 Ma;De Santis et al, 2001;Davey et al, 2006). The most recent extensional deformation has focused on the central part of the basin (Lee Arch and Discovery Graben of the Terror Rift, Cooper et al, 1987) where major faulting and volcanism still occur (Cooper et al, 1987;Hall et al, 2007). Extensive volcanism continues along the axis of the Victoria Land Basin, from Ross Island to Mount Melbourne (Fig.…”