Preliminary Geochemical Prospecting of Thermal Sources around Lake Vanda, Dry Valley, Antarctica

[摘要] Preliminary geochemical prospecting of thermal sources around Lake Vanda, Dry Valley, was carried out using mercury. Twentythree samples, taken from around the lake, were analyzed. Values range from 1.1 to 169 ppb, with 50 ppb average. For comparison, 89 samples from Don Juan DVDP 5A, Taylor Valley DVDP 11 and around Syowa Station were also analyzed, obtaining the average values 6, 12, 10 ppb, respectively. Mercury measurements in soil, clay and rock samples would be a new technique which can be used to locate areas of geothermal activity, even in an extremely cold region such as Antarctica. Mercury values are usually proportional to the underground temperature in a geothermal area. Thus, the Lake Vanda area with rather high mercury contents would suggest the existence of a thermal source under the ground, strongly supporting the occurrence of some hydrothermal minerals around the lake. It is, however, still uncertain whether the heat supply has continued up to date or not. In order to gain further information on geothermal sources around Lake Vanda, more detailed murcury survey would be required.