2005 Fiscal Year Final Research Report Summary
Paleokarst observed in Upper Paleozoic Limestone inn the japanese Islands
| Project/Area Number |
16540430
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | Institute of Natural History |
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Principal Investigator |
IGO Hisayoshi Institute of Natural History, Resercher, 研究員 (20015572)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Late Paleozoic / carbonate rock / paleokarstification / diagenesis / biostratinomy / taphonomy / fusulinoidean fossil |
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| Research Abstract |
The present study clarifies the genesis of iron-bearing starata intercalated in the basal part of the Sd Member of the Lower Permian Sakamotozawa Formation in the Kitakami Mountains. These sediments was deposited from the products of paleokarstification, paleosol of the carbonate rocks and weathering decoposition of plutonic rocks, such as the Hikami Granite. A Fusulinoidean species, Monodiexodina matubaishi indicates that the specimens came from the Kanokura Formation are reworked ones. Biostratinomic study of these specimens indirectly shows paleokarstification of carbonate rocks of the Sakamotozawa.
The Nagaami Formation exposed in the Kuzu area, Ashio Mountains indicates paleokarstification of the Permian Nabeyama Limestone Formation. Products of the paleokarstification represent the intercalation of fine-to medium-grained carbonate clasts, muddy rocks, residual brecciated carbonate rocks, and others ruubly clasts.
The Ichinotani Formation (Carboniferous) intercalates iron-bearing high-aluminous shale, sharpstone (breccia) conglomerate, and other residual rocks. This paleokarstification eroded the carbonate sequence ranging from late Early Carboniferous to Early Devonian.
The Akasaka Limestone of the Mino Terrane intercalates hematite ore deposits that derived from paleosol of limestone and plutonic rocks. Further study is necessary to elucidate this paleokarstification, because most of the ore body was quarried out.
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