Site summaries (continued)

Site NWS-4A

Priority: Primary
Position: 20.21438°S, 115.06679°E
Water depth (m): 126
Target drilling depth (mbsf): 1055
Approved maximum penetration (mbsf): 1055
Survey coverage (track map; seismic profile): Track map (Fig. AF6)
Seismic profile (Fig. AF8)
Objective(s): The objective is to obtain an orbital-scale record of climate variability and monsoon history that may be comparable in its resolution to other global climate proxy records. In this shelf-margin setting, pollen is likely to be abundant, delivered by fluvial outflow during the rainy season. This site is also close to the southern edge of the Australian monsoon influence and can therefore be used chart its latitudinal variability. Marine microfossil paleoproductivity analyses may also reveal the dominance of the West Australian Current over the Leeuwin Current during glacial periods. The site lies downdip from a drowned reef on a paleoshelf edge. Therefore, by dating the reflectors and correlating them updip, it may be possible to constrain the reef onset age. Furthermore, downslope transported reefal or shelf detritus may enable analysis of reef and ramp development in response to variable sea level.
Drilling program: Triple APC, double XCB followed by RCB to total depth
Logging program or downhole measurements program: Triple combo, FMS, VSP
Nature of rock anticipated: Calcilutites, calcarenites