Detecting thermal anomalies using thermochronometry around hydrothermal alteration zones in the Kii Peninsula, southwest Japan – An attempt

Author:

SUEOKA Shigeru1,Iwano Hideki2,Danhara Tohru2,Niwa Masakazu1,Kanno Mizuho1,Kohn Barry3,Kawamura Makoto1,Yokoyama Tatsunori1,Kagami Saya1,Ogita Yasuhiro1,Hirata Takafumi4

Affiliation:

1. Japan Atomic Energy Agency: Nihon Genshiryoku Kenkyu Kaihatsu Kiko

2. Kyoto Fission-Track Co., Ltd.

3. University of Melbourne

4. University of Tokyo: Tokyo Daigaku

Abstract

Abstract Fluid-inclusion and thermochronometric analyses have been applied to hydrothermal alteration zones and their host rocks outcropping in the Hongu area of the Kii Peninsula, southwestern Japan in an attempt to detect thermal anomalies related to hydrothermal events and quantify the thermal effects on the host rocks. Hydrothermal events at ~150°C and ~200°C were identified by fluid-inclusion microthermometry of quartz veins in the alteration zones. For the host rocks and alteration zones, in the youngest population zircon yielded U–Pb dates ranging between ~74.7–59.2 Ma, fission-track dates of ~27.2–16.6 Ma, and (U–Th)/He single-grain dates of ~23.6–8.7 Ma. Apatite yielded pooled fission-track ages of ~14.9–9.0 Ma. The zircon U–Pb dates constrain the maximum depositional ages of the sedimentary samples. However, the fission-track and (U–Th)/He dates show no clear trend as a function of distance from the alteration zones. Hence, no thermal anomaly was detected in the surrounding host rocks based on the thermochronometric data patterns. The fission-track and (U–Th)/He dates are rather thought to record regional thermal and exhumation histories rather than a direct thermal imprint of fluid flow, probably because the duration of such activity was too short or because fluid flow occurred before regional cooling events and were later thermally overprinted. Apatite fission-track ages of ~10 Ma may reflect regional mountain uplift and exhumation related to the obduction of the SW Japan lithospheric sliver onto the Shikoku Basin, or the rapid subduction of the Philippine Sea slab associated with the clockwise rotation of the Southwest Japan Arc.

Publisher

Research Square Platform LLC

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3