| Project/Area Number |
60304014
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Stratigraphy/Paleontology
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| Research Institution | Hokkaido University |
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Principal Investigator |
AKIYAMA Masahiko Hokkaido University, Fac. of Science Associate Professor, 理学部, 助教授 (20015580)
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| Co-Investigator(Kenkyū-buntansha) |
TOMITA Katsutoshi Kyoto University, Fac. of Science Lecturer, 理学部, 講師 (70025352)
YAMAGUCHI Yoshihiro Hokkaido Kyoiku University, Associate Professor, 岩見沢分校, 助教授 (40101323)
SATO Toshihiko Shinshu University, Department of General Education Professor, 教養部, 教授 (00015546)
KOBAYASHI Iwao Niigata University, Fac. of Science Associate Professor, 理学部, 助教授 (70018266)
OCHIAI Hiroshi Hokkaido University, Fac. of Science Associate Professor, 理学部, 助教授 (10002122)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥8,700,000 (Direct Cost: ¥8,700,000)
Fiscal Year 1986: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1985: ¥6,200,000 (Direct Cost: ¥6,200,000)
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| Keywords | Fossilization / diagenesis / apatite fossil / carbonate fossil / 系統発生 |
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| Research Abstract |
1. Total amounts of organic carbon produced by organisms through geologic time are estimated at 1.4-8.1 X <10^(25)> g. Total species which appeared on the earth throughout geologic time are also estimated at 0.9-5.7 X <10^8> . Both values suggest an order of <10^3> times more than the organic carbon preserved in whole sedimentary rocks and also the fossil species which have hitherto reported.
2. Controlling factors of fossilization are (1) accumulation, (2) fossilization in a narrow sense, and (3) preservation. The most important factor is how large the population is, which is included in the accumulation factor. In this co-operative research, however, has been focused on fossilization in a narrow sense.
3. Hydroxyapatite [ <Ca_5> ( <PO_4> <)_3> OH] is the main component of vertebrate hard tissues. This mineral has a low solubility of 0.01 mg/l in neutral water, which is the reason why the vertebrate fossil of hydroxyapatite are apt to be preserved as fossils. A Late Pleistocene fossil tusk collected from the sea bottom off Hinomisaki, Shimane Pref. contains well preserved collagen molecules. Diagenetic alteration and variation are discussed from the viewpoints of microscopic, histochemical, biochemical and mineralogical observation.
4. Calcite ( <CaCO_3> ) is the representative mineral species in carbonate fossils. This mineral has a high solubility of 1g/1 in <CO_2> -saturated water. For this reason carbonate fossils are easily replaced or impregnated by other minerals. Replacement by siderite usually occurs in fresh-water sediments. Fossilization processes on molluscan and coral fossils were discussed.
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