Report of the Dry Valley Drilling Project, 1975-76

• Main Authors: Nobuyuki NAKAI, Katsutada KAMINUMA
• Format: Article in Journal/Newspaper
• Language: English; Japanese
• Published: National Institute of Polar Research 1976
• Subjects: Geography (General); G1-922; McMurdo Sound; Ross Island; McMurdo Station; Taylor Valley; New Harbor; Observation Hill; Antarc*; Antarctica; Sea ice
• Online Access: https://doi.org/10.15094/00007889; https://doaj.org/article/b569d5dd6492493ba00d1758166f3490

The Japanese party consisting of two members participated in the last field survey season, phase V of 1975-1976 Dry Valley Drilling Project (DVDP), in the McMurdo Sound region for the period from 27 October 1975 to 8 January 1976. The main international program of this field survey season was the drilling of submarine sediments in McMurdo Sound. As Japanese party's own project in relation to DVDP, microseismological observations at McMurdo Station and geochemical field survey in the coastal area of McMurdo Sound were also planned to investigate continental subsurface structures of Antarctica and to disclose the geological history of Dry Valleys and the McMurdo region. DVDP No. 15 drilling was performed from 5 to 21 November 1975 to obtain unconsolidated marine sediments. The drilling site was set on the sea ice of McMurdo Sound, 110km northwest of McMurdo Station and 20km east of New Harbor, Taylor Valley, and over 122m-thick sea water layer. Cored sediments were sampled down to 64.6m depth below the ocean floor surface and the recovery was rather good, being about 52%. Most of sediments are olive gray to olive black, fine- to coarse-grained basaltic sands, and can be divided into two units, with a depth of 12.5m as the boundary between the two. In the sediments from 63.6 to 64.6m, an unusually high concentration of CH_4 amounting to 37.9%, was detected by the portable gaschromatograph GC-30 AT at the drilling site but no heavier hydrocarbons were found. Three seismographs designed for recording micro-earthquakes were set at the foot of Observation Hill near McMurdo Station, Ross Island. Microseismological observations were carried out for the period from 13 November to 19 December 1975, and several small or micro-earthquakes were recoreded. Artificial earthquakes by dynamite blasting were also successfully observed several times and the records useful of analyze the subsurface structure in this area were obtained. The coastal survey for geochemical studies on the geological history and the water budget in Dry ...