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Seeking the Truth of the West Antarctic Rift System, the Largest Tectonic Feature in Antarctica
Evolution of the West Antarctic Rift System : Study of Tectonic Activities and Volcanism near the Adare Trough and Antarctic Mid-Ocean Ridges
Jong kuk Hong email@example.com
Located between East and West Antarctica, the West Antarctic Rift System(WARS) is the most noticeable tectonic feature in the Antarctica, and the largest continental rift system in the world. Despite its tectonic importance, studying WARS is difficult due to the overlain thick ice and sea ice.
The region around the Balleny Islands and the Adare Trough is considered to be the extension of WARS from the Ross Sea. Therefore, the scientific results in this area can provide implications regarding the tectonic history and mechanics of WARS.
The Australian-Antarctic Ridge(AAR) located at the extension of WARS has continued spreading after the cessation of the Adare Trough expansion, and its mantle characteristics are closely correlated to those around the Balleny Islands and the Adare Trough.
KOPRI recovered five hydroacoustic instruments in the vicinity of the Balleny Islands in March 2016 to understand the seismicity around the region. Among the five recovered instruments , only three were recorded without trouble.
Preliminary results show that the instruments detected signals produced by icequakes and marine mammals as well as microearthquakes.
Geothermal results observed across the Adare Trough revealed relatively higher heat flow than the general oceanic crust. These data will be used to characterize mantle material along with geophysical evidence related to the extension of the Adare Trough.
To understand the magmatic characteristics of the AAR, this study conducted Sr-Nd-Pb-Hf isotope analysis of samples from KR1 and KR2. Using these data, it was discovered that the Southern Ocean mantle differs from the Pacific and Indian Ocean mantles, and investigated the origin of its unique characteristics.
This study also acquired the marine magnetic data for two 400km long lines across the ridge segment that comprises the southernmost segment of the AAR(61°-63°S, 156°-161°E).Using the observed magnetic data, this study estimated the dissemination rates and temporal changes along the ridge segment.
Figure 3. Location map of hydroacoustic mooring sites.