Characteristics of Nodular Limestone from the Lower Triassic Yinkeng Formation at West Pingdingshan Section in Chaohu of Anhui, China(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2017年第04期
- Page:
- 476-490
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Characteristics of Nodular Limestone from the Lower Triassic Yinkeng Formation at West Pingdingshan Section in Chaohu of Anhui, China
- Author(s):
- LIN Chun-ming; ZHANG Ni; ZHANG Xia; YU Jin; WANG Shu-jun
- 1. State Kay Laboratory for Mineral Deposits Research, Nanjing University, Nanjing 210046, Jiangsu, China; 2. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210046, Jiangsu, China; 3. School of Materials Engineering, Jinling Institute of Technology, Nanjing 211169, Jiangsu, China
- Keywords:
- sedimentary characteristic; sedimentary environment; nodular limestone; mineral composition; geochemistry; Yinkeng Formation; Lower Triassic; Anhui
- PACS:
- P184
- DOI:
- -
- Abstract:
- The mineral composition, structure, chemical composition and geochemistry characteristics of nodules and matrix from Lower Triassic Yinkeng Formation at West Pingdingshan section in Chaohu of Anhui, China were systematically studied. The results show that nodular limestones are composed of nodules and matrix, and develop well in Yinkeng Formation; nodules are mainly composed of microcrystalline limestone, micritic micrite and microcrystalline micrite calcite with the color dominated by gray, light gray and gray white; the main minerals of nodules are mainly calcite, accounts for 54%-85%, the rest part is made up of quartz, plagioclase and clay minerals, and also contain a small amount of pyrite; the matrix occurs predominantly of yellow, brown-yellow and yellow-gray calcareous mudstones, followed with pelmicrite; compared to nodules, matrix contains less calcite mineral, more quartz and clay minerals; there are three types of the nodular limestone, including banded nodular limestone, discontinuous nodular limestone and random nodular limestone; the three types are the result of combined processes of the differential compaction, and gradually enhance pressure solution during the diagenesis; discontinuous nodular limestone occurs first within many layers and thicker, and develops mainly in the upper part of slope; then, banded nodular limestone distributes in the lower part of slope; at last, random nodular limestone is thinner and develops poor, only appears in deep water basin environment.
Last Update: 2017-07-28