Hydrothermal circulation system during the detachment faulting at the Godzilla Megamullion, Parece Vela Basin, Philippine Sea

2014 Fiscal Year Final Research Report

• Project/Area Number: 24740344
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Geology
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: HARIGANE YUMIKO 独立行政法人産業技術総合研究所, 地質情報研究部門, 主任研究員 (90569360)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: デタッチメント断層 / ゴジラメガムリオン / 海洋地殻下部物質 / 流体 / フィリピン海パレスベラ海盆

Outline of Final Research Achievements

The Godzilla Megamullion, the largest oceanic core complex in the world, is located at the extinct Parece Vela Basin in the Philippine Sea. Fault rocks are common on the surface of the Godzilla Megamullion, indicating the presence of a detachment fault exposed on the seafloor. We focus on amphiboles in the fault rock (i.e., deformed gabbroic rocks) in order to reveal the geochemical characteristics of hydrothermal circulation system along detachment fault using trace element geochemical analyses of the fault rocks sampled from three stages (i.e., initial, medial and final stages) of development of the Godzilla Megamullion. We observed a sign of melt and hydrothermal fluid analyzed by geochemical analyses of amphibole and amphibole of the fault rock showed the different geochemical characteristics in each stage. It indicates that the different hydrothermal circulation system along the detachment fault could develop at three stages of development of the Godzilla Megamullion.

Free Research Field

構造岩石学