Submersible observations of manganese nodule and crust deposits on the Tenpo Seamount, Northwestern Pacific
作者:
Akira Usui,
Akira Nishimura,
Kokichi Iizasa,
期刊:
Marine Georesources & Geotechnology
(Taylor Available online 1993)
卷期:
Volume 11,
issue 4
页码: 263-291
ISSN:1064-119X
年代: 1993
DOI:10.1080/10641199309379924
出版商: Taylor & Francis Group
关键词: manganese nodule;manganese crust;limestone;submersible;seamount;Northwestern Pacific;bottom current
数据来源: Taylor
摘要:
Pavements of manganese nodules and crusts and outcrops of Miocene limestones were observed on the flanks and flat top of the Tenpo Seamount during threeShinkai 2000dives. The pre‐Miocene volcano supplied nuclei of volcanic rocks and hydrothermal manganese deposits, and subsequent slow or no sedimentation promoted deposition of abundant hydrogenetic nodules and crusts, mainly on the upper flank of the seamount. Nodule pavements generally cover calcareous sand surface sediments, while crusts cover hard outcrops composed probably of volcanic rocks. The fields of crusts and nodules are sparsely distributed with each other on scales of meters to tens of meters. The on‐site observation suggests the deposits have encountered tectonic and/or mass movements that resulted in unusual occurrences of densely stacked nodules and occasionally the nodules resting directly on crusts or hard substrates. Mineralogical and chemical compositions reveal that for nodules and crusts the encrusting manganese layers of around 1 cm thickness are composed of hydrogenetic vernadite, and diagenetic influence is negligible.
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