<departmental bulletin paper>
Organic geochemistry of formation, diagenesis, and burial metamorphism of high organic limestone

Creator
Language
Publisher
Date
Source Title
Vol
Issue
First Page
Last Page
Publication Type
Access Rights
JaLC DOI
Abstract Black limestone from the lower member of the Funabuseyama Formation in the Mino terrain, central Japan, and the Chihsia Formation in the South China Block, southern China, were examined by petrologica...l and organic geochemical methods. Petrological investigations indicate that the black materials are condensed in stylolite suture plains. The black materials are also observed as coating of particular remains of dasycladaceae and small foraminifera, and as filling of primary voids of skeletal debris. These black materials were analysed by pyrolysis gas chromatography-mass spectrometry (PGC/MS). The results indicate that the black material is organic and that the nature of organic matter in the sample having different distribution patterns of black material is different. On the basis of the comparative examinations of the results of petrological and geochemical studies, we propose probable formation mechanisms of the high organic limestone:
(1) The organic matter in the limestone originates from organisms which constructed the limestone itself or from organisms which lived at the same place and in the same period as those that the limestone-constructing organisms lived.
(2) The limestone enclosed the organic matter during the reconstruction of the lithofacies into stylolite by compaction
(3) The enclosed organic matter was altered by heating during diagenesis and burial metamorphism of the limestone.
(4) There are local differences in the degree of heating of the organic matter.
(5) The color of the organic matter has changed into black by proceeding carbonization reactions, and so the color of the limestone containing the organic matter in high concentration is also black.
(6) If the organic matter was affected by diagenetic alterations without enclosing by the limestone, the organic matter might be an origin of petroleum.
show more
Table of Contents I. はじめに
II. 試料採取地域の地質
Ⅲ. 霞頭および鏡下観察による黒色物質の産状と出現様式
IV. 黒色物質の熱分解GC-MSによる分析
V. 高有機質石灰岩の堆積,続成,埋没変成に関する考察
VI. おわりに

Hide fulltext details.

pdf 1801_p037 pdf 664 KB 485  

Details

PISSN
NCID
Record ID
Created Date 2021.10.18
Modified Date 2023.11.17

People who viewed this item also viewed