Showing papers by "Fred Davey published in 2000"
TL;DR: The Alpine Fault as discussed by the authors is the main active structure in the oblique continental collision zone of South Island, New Zealand and it is continuous at the surface for ∼800 km and accommodates ∼70% of current plate motion.
175 citations
15 Jan 2000
TL;DR: In this paper, the authors used multichannel seismic profiles to correlate the previously defined seismic stratigraphy of the Victoria Land basin with that of western flank of Roberts Ridge (western McMurdo Sound), where the Cape Roberts Project drillsites are located and constraints on the ages of the seismic events can be derived.
Abstract: Newly available multichannel seismic profiles are used to correlate the previously defined seismic stratigraphy of the Victoria Land basin with that of western flank of Roberts Ridge (western McMurdo Sound), where the Cape Roberts Project drillsites are located and constraints on the ages of the seismic events can be derived. The older regional seismic events from two regional seismic stratigraphies (V series and the RSS series) have been compared for the southern Victoria Land basin and an age progression derived for the seismic reflectors interpreted as RSU6, V3/V4, and V4/V5. The new data permit a more robust correlation of these seismic events to the drill sites. A seismic reflector, previously interpreted to correspond to the Ross Sea wide RSU6 event in this region, is significantly younger (less than 17 Ma at the Cape Roberts drill site CRP-1 and CRP-2/2A) than the RSU6 event in the Eastern basin, where an age greater than 26 Ma is inferred, suggesting a miscorrelation of this event across basement highs between Eastern basin and the basins in western Ross Sea. Based on the drill core ages, a geological correlative at drill site CRP-2A of RSU6 in the Eastern basin could be the unconformity at 443 m bsf, inferred to correspond to the seismic sequence boundary V4/V5 (see below). A single V3/V4 event can be consistently correlated from the Victoria Land basin to all profiles west of the ridge. The velocity/depth data from CRP-1 and CRP-2 drill cores, indicates that the V3/V4 seismic event lies just below the base of CRP1 drill hole and at a depth of about 90 m at drill hole CRP2. The age data from these two drill sites indicate an age for V3/V4 of about 21 Ma. The V4/V5 event has been correlated to the drill sites from the Victoria Land basin by four independent routes, and intersects drill hole CRP-2/2A at a depth of about 440 m. This depth is close to a significant geologic unconformity in the drill core at a depth of 443 m bsf and an age of about 28-29 Ma (close to the late/early Oligocene boundary). Previous interpretations of the V4/V5 event correspond to a deeper seismic sequence boundary within unit V5. The revised interpretation indicates that there is a much thicker Oligocene and younger sedimentary sequence within the Victoria Land basin than previously thought.
10 citations