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Grain orientation and depositional ramps as flow direction indicators of a large-scale pyroclastic flow deposit in Japan

1982; Geological Society of America; Volume: 10; Issue: 8 Linguagem: Inglês

10.1130/0091-7613(1982)10 2.0.co;2

1943-2682

K. Suzuki, Tadahide Ui,

earthquake and tectonic studies

Research Article| August 01, 1982 Grain orientation and depositional ramps as flow direction indicators of a large-scale pyroclastic flow deposit in Japan Keiko Suzuki; Keiko Suzuki 1Department of Earth Sciences, Faculty of Science, Kobe University, Nada-ku, Kobe 657, Japan Search for other works by this author on: GSW Google Scholar Tadahide Ui Tadahide Ui 1Department of Earth Sciences, Faculty of Science, Kobe University, Nada-ku, Kobe 657, Japan Search for other works by this author on: GSW Google Scholar Geology (1982) 10 (8): 429–432. https://doi.org/10.1130/0091-7613(1982)10 2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Keiko Suzuki, Tadahide Ui; Grain orientation and depositional ramps as flow direction indicators of a large-scale pyroclastic flow deposit in Japan. Geology 1982;; 10 (8): 429–432. doi: https://doi.org/10.1130/0091-7613(1982)10 2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Flow lineation was measured using the orientation of the elongated crystals and lithic fragments in the large-scale welded Ata pyroclastic flow deposit in southwestern Japan in order to analyze the effect of preflow topographic relief. Three different types of lineations were obtained. Flow lineations radially away from the source were obtained only for samples collected from the surface of the pyroclastic flow plateau. Samples collected along the floor of narrow valleys have lineations parallel to the axis of valley. Samples collected from valley walls tend to be parallel to the slope of the valley. This evidence suggests the following process. Earlier flow material moves along the valley axis in the narrow valley bottom. When the flow is trapped within a valley, it moves toward the bottom of the valley just prior to the final settlement. When the basement relief is filled up with the earlier flow units, the flow maintains its original radial movement until final settlement. Asymmetrical depositional ramps on the original surface of the pyroclastic flow provide an independent indicator of the flow direction. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.