Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

Victoria University Antarctic Research Expedition Science and Logistics Reports 1979-80: VUWAE 24

Gas Composition (KK)

Gas Composition (KK)

The gas composition dissolved in circulating water from drill hole has been analyzed by using a gaschromatograph (Shimadzu GC-30AT) coupled with a pen recorder. The amounts of O2, N2 and CH4 are measured by a Molecular Shieve 5A column, and those of air Components (O2 + N2). CO2, CH4 and C2H6 by a Porapac-Q column.

The equipment was set in a small hut placed just near the drill-rig. The gas analysis was made at constant column temperature (15°C). Helium was used as carrier gas.

The time table of working at drill site is:

Nov. 1-2 Set-up of equipments at drill site

Nov. 8-17 and 20-23 Analyses of gas composition of water and ice samples.

Because the drilling condition was not good at the time of Nov. 8-23, only five measurements were made for circulating water from the bottom of drill hole. Gas composition of room air, atmospheric air, and dissolved gas in sea water were also measured for comparison.

Preliminary results are summarized in Table 5. As seen from the table, CH4 and C2H6 were not found in circulating water samples. Low oxygen contest (6–15%) and rather high CO2 content (1–6%) are commonly observed for water samples except for sample no.5, the gas composition of which is the same as that of sea water. However, main components (O2 and N2) are not much different from the atmospheric air. This fact suggests that the dissolved gas in the circulating water is mainly from atmospheric air, probably sucked in by the pump used for water circulation. The low oxygen content may have caused by contact of sucked air with the down hole sediment, which is in a highly reducing state.

page 12
TABLE 4 Composition of gases from MSSTS1 (in vol.%).
Sample No. Date of Sampling Downhole Depth (a) O2 N2 CO2 CH4 C2H6
1 Nov. 12 179 11.6 83.0 0.4 Not detected Not detected
2 Nov. 15 183 9. 85.4 5.6 Not detected Not detected
3 Nov. 15 186 6.1 92.8 1.1 Not detected Not detected
4* Nov. 15 186 14.6 85.4 1.0 Not detected Not detected
5 Nov. 15 202 31.1 68.9 Not measured Not detected Not measured
6 Nov. 21 sea water 30.1 68.8 1.1 Not detected Not detected
7 Nov. 21 atmospheric air 21.2 78.8 0.04 Not detected Not detected
8 Nov. 21 room air 18.0 81.7 0.31 Not detected Not detected
9 Nov. 8 sea ice (0.26 ml air/sr.-ice)