Water-rock interaction modeling in orogenic belts using oxygen isotope

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05316
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Geology
• Research Institution: Kagoshima University
• Principal Investigator: Rehman HafizUr 鹿児島大学, 理工学域理学系, 助教 (60505410)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: ジルコン / 年代 / 岩石 / 酸素同位体 / 変成作用 / 火成岩

Outline of Final Research Achievements

Water-rock interaction modeling was done using the oxygen isotope in the natural rocks to understand the tectonic evolution and the effect of metamorphism. Samples from the Himalayan ultrahigh-pressure (UHP) metamorphic rocks were investigated. Three stages: (1) magmatic protolith (igneous zircons), (2) UHP stage (coesite-bearing rocks), and (3) retrogressed stage (hydration reactions) were recognized. δ-18O values were lower in magmatic (negative in metamorphic zircons), compared with the mantle values (+5~7 per mil) indicate the protolith were hydrothermally altered by meteoric water interactions when Indian plate (part of Himalaya from where the samples were investigated) was experiencing cold climate (southern high latitudes) when the protolith rocks were forming. Later after it drifted northward, subducted to mantle depth and suffered UHP metamorphism, the δ-18O were re-equilibrated. The results are published in international journals such as Lithos and Gondwana Research.

Free Research Field

地質学