Episodic magmatism since 5Ma in the western part of Beppu-Shimabara graben, Kyusyu, Japan.

• YOKOSE Hisayoshi

  Department of Earth Sciences, Kumamoto University

• YANASHIMA Tatsuya

  Department of Earth Sciences, Kumamoto University

• KIKUCHI Wataru

  Department of Earth Sciences, Kumamoto University

• SUGIYAMA Naofumi

  Department of Earth Sciences, Kumamoto University

• SHINOHARA Akira

  Department of Earth Sciences, Kumamoto University

• TAKEUCHI Tohru

  Department of Earth and Planetary Sciences, Nagoya University

• NAGAO Keisuke

  Institute for Study of Earth's Interior, Okayama University Present address: Laboratory for Earthquake Chemistry University Tokyo

• KODAMA Kazuto

  Department of Geology, Kochi University Kochi

Bibliographic Information

Other Title

• 別府‐島原地溝帯西部域の過去５百万年間における間欠的火山活動
• 別府-島原地溝帯西部域の過去5百万年間における間欠的火山活動
• ベップ シマバラ チコウタイ セイブイキ ノ カコ 500マンネンカン ニ オケル カンケツテキ カザン カツドウ

Abstract

The K-Ar ages and paleomagnetic stratigraphy of the Plio-Pleistocene volcanic rocks from the Ariake Sea region have been studied to clarify the evolution of volcanism in the western part of Beppu-Shimabara graben, west Kyushu, Japan. This region has seven domains of volcanic rocks. We determined K-Ar ages of ten volcanic rocks from five domains: the Misumi volcanic rocks=4.51 Ma and 3.97 Ma; the Kunisaki andesite=1.45 Ma; the Ibinoodake andesite=3.97 Ma and 4.52 Ma; the Uki volcanic rocks=1.63 Ma; the Yushima basalt=0.82 Ma; the Otake volcanic rocks=1.82, 1.77, and 1.72 Ma. Paleomagnetic measurements were made on volcanic rocks collected from all seven domains. Magnetic property of lavas from these domains can be classified into four magnetic polarity epochs: Brunhes Chron (Ninotake volcano, Takesaki basalt and Yushima basalt), Gauss Chron (Nogamajima volcano), Gilbert Chron (Ibinoodake andesite and Hidake lava dome), and Matsuyama Chron (the other volcano). The age of Ohya tuff, which belongs to the Kuchinotsu Formation, corresponds to Gilsa event. We synthesized our new data together with previously reported ages and stratigraphic data, and examined the volcanic activity in this region in terms of a spatial and temporal distribution. There is no correlation between spatial distribution of the volcanic rocks and eruption ages, but we revealed that the volcanic activity in this region is episodic during the last 5 million years. We can identify the magmatic activities as five episodes: 5-4 Ma, 3.2 Ma, 2.0-1.4 Ma, 1.0 Ma, and <0.9 Ma. The intensity of volcanic activity in the Ariake Sea region increased with time.

Journal

• JOURNAL OF MINERALOGY, PETROLOGY AND ECONOMIC GEOLOGY

  JOURNAL OF MINERALOGY, PETROLOGY AND ECONOMIC GEOLOGY 94 (9), 338-348, 1999

  Japan Association of Mineralogical Sciences

Keywords

• Beppu-Shimabara graben
• Okinawa Trough
• K-Ar age
• Magmatic episodes
• Paleomagnetic stratigraphy

Details

• CRID: 1390001206234760832
• NII Article ID: 10002698669
• NII Book ID: AN10047992
• DOI: 10.2465/ganko.94.338
• ISSN: 18813275
• ISSN: 09149783
• NDL BIB ID: 4901960
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4901960
• Text Lang: ja
• Data Source:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• Abstract License Flag: Disallowed