Nodular limestone and its genesis from the Ordovician Yanwashan Formation in western Zhejiang Province
Zhang Xia1, Lin Chunming1, Ling Hongfei1, Jiang Shaoyong1, Li Yanli1, Gao Likun1, Yao Yulai1, Liu Xiao2
1 State Key Laboratory for Mineral Deposits Research,School of Earth Sciences and Engineering, Nanjing University,Nanjing 210093,Jiangsu 2 Planning & Designing Institute of East China Branch,SINOPEC,Nanjing 210036,Jiangsu
Abstract In this paper,we discussed the genesis of the nodular limestones from the Ordovician Yanwashan Formation in the Huangnitang section(the first GSSP),Changshan,Zhejiang Province on the basis of mineral component,texture,structure,chemical composition,and particularly the stable C-O isotopic composition of both the nodule and matrix. The research results indicate that there is an apparent difference between the nodule and matrix of the nodular limestones. The nodules are mainly composed of micritic calcite(70%~98%),while the primary component of the matrix is clay mineral(40%~78%)with only 20%~58% calcite. The δ13CVPDB values of calcite of the nodule and matrix are 0.5‰ to 1.4‰(average 0.9‰)and -0.4‰ to 1.1‰(average 0.2‰),respectively. The δ18OVPDB values of calcite of the nodule and matrix are -12.8‰ to -8.0‰(average -10.6‰)and -11.7‰ to -9.0‰(average -10.3‰),respectively. The nodule always shows higher δ13C value and formation temperature than those of the matrix for the same sample. All features imply that the nodular limestones from the studied section are formed due to a combined processes of the periodical dissolution of bottom current during the sedimentary period and the differential compaction and pressure solution during the diagenesis. There are three existing types of the nodular limestones: banded nodular limestone,discontinuous nodular limestone and random nodular limestone. The occurrence mode of the nodular limestone is determined by the insoluble residue content of country rock of nodules and the pressure solution intensity.
About author: Zhang Xia,born in 1985,is a Ph.D. candidate in School of Earth Sciences and Engineering,Nanjing University,with main research interest in sedimentology and petroleum geology.
Cite this article:
Zhang Xia,Lin Chunming,Ling Hongfei et al. Nodular limestone and its genesis from the Ordovician Yanwashan Formation in western Zhejiang Province[J]. JOURNAL OF PALAEOGEOGRAPHY, 2009, 11(5): 481-490.
Zhang Xia,Lin Chunming,Ling Hongfei et al. Nodular limestone and its genesis from the Ordovician Yanwashan Formation in western Zhejiang Province[J]. JOPC, 2009, 11(5): 481-490.
陈旭,王志浩,张元动. 1998. 中国第一个“金钉子”剖面的建立[J]. 地层学杂志,22(1):1-9. 冯洪真,刘家润,施贵军. 2000. 湖北宜昌地区寒武系—下奥陶统的碳氧同位素记录[J]. 高校地质学报,6(1):106-115. 冯增昭,吴胜和. 1988. 下扬子地区中下三叠统青龙群岩相古地理研究[M]. 见:冯增昭,王英华,李尚武,等. 下扬子地区中下三叠统青龙群岩相古地理研究. 云南昆明:云南科技出版社,1-69. 高计元. 1988. 中国南方泥盆系瘤状灰岩的成因[J]. 沉积学报,6(2):77-86. 郭福生. 1989. 下扬子地区三叠系下统瘤状灰岩成因研究[J]. 华东地质学院学报,12(4):17-22. 郭福生. 1998. 浙江江山奥陶纪岩相古地理及其构造控制[J]. 岩相古地理,18(4):57-62. 郭福生,梁鼎新. 1993. 浙江江山砚瓦山组瘤状灰岩的成因[J]. 矿物岩石,13(3):74-80. 郭福生,彭花明,潘家永,等. 2003. 浙江江山寒武系碳酸盐岩碳氧同位素特征及其古环境意义探讨[J]. 地层学杂志,27(4):289-297. 韩树棻. 1983. 安徽沿长江地区下三叠统瘤状灰岩成因研究[J]. 地质科学,18(3):232-238. 金若谷. 1989. 一种深水沉积标志——“瘤状结核”及其成因[J]. 沉积学报,7(2):51-61. 金振奎,冯增昭. 1994. 云贵地区二叠系瘤石灰岩的成因[J]. 岩石矿物学杂志,13(2):133-137. 蓝光志,张廷山,高卫东. 1994. 川西北地区早志留世瘤状灰岩的类型、成因及意义[J]. 西南石油学院学报, 16(3):1-6. 李心清,万国江. 1999. 碳酸盐岩氧、碳稳定同位素地球化学研究目前面临的几个问题[J]. 地球科学进展, 14(3):262-268. 王大锐,冯晓杰. 2002. 渤海湾地区下古生界碳、氧同位素地球化学研究[J]. 地质学报,76(3):400-408. 袁志华. 1998. 中扬子地区下三叠统大冶组瘤状灰岩成因研究[J]. 地球化学,27(3):276-282. 张国仁. 1997. 利用沉积地球化学特征分析古环境及海平面变化——以鲁西东部中下寒武统为例[J]. 辽宁地质,14(1):8-13. 朱洪发,王恕一. 1992. 苏南、皖南三叠纪瘤状灰岩、蠕虫状灰岩的成因[J]. 石油实验地质,14(4):454-460. Derry L A, Kaufman A J, Jacobsen S B. 1992. Sedimentary cycling and environmental change in the Late Proterozoic: Evidence from stable and radiogenic isotopes[J]. Geochimica et Cosmochimica Acta, 56:1317-1329. Kaufman A J, Knoll A H. 1995. Neoproterozoic variations in the C-isotopic composition of seawater: Stratigraphic and biogeochemical implications[J]. Precambrian Research, 73:27-49. Keith M L, Weber J N. 1964. Carbon and oxygen isotopic composition of selected limestones and fossils[J]. Geochimica et Cosmochimica Acta, 28: 1787-1816. Mullins H T, Neumann A C, Wilber R J, et al. 1980. Nodular Carbonate Sediment on Bahamian Slopes: Possible Precursors to Nodular Limestones[J]. Journal of Sedimentary Petrology, 50(1):117-131. Qing H R, Veizer J. 1994. Oxygen and carbon isotopic composition of Ordovician brachiopods: Implications for coeval seawater[J]. Geochimica et Cosmochimica Acta, 58(20):4429-4442. Rais P, Louis-Schmid B, Bernasconi S M, et al. 2007. Palaeoceanographic and palaeoclimatic reorganization around the Middle-Late Jurassic transition[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 251:527-546. Veizer J, Fritz P, Jones B. 1986. Geochemistry of brachiopods: Oxygen and carbon isotopic records of Paleozoic oceans[J]. Geochimica et Cosmochimica Acta, 50:1679-1696. Veizer J, Bruckschen P, Pawellek F, et al. 1997. Oxygen isotope evolution of Phanerozoic seawater[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 132:159-172. Yin L M, Playford G. 2003. Middle Ordovician acritarchs from the global stratotype section of Huangnitang in Changshan, Zhejiang, China[J]. Acta Palaeontologica Sinica, 42(1):89-103. Zhang Y D, Chen X, Yu G H, et al. 2007. Ordovician and Silurian Rocks of Northwest Zhejiang and Northeast Jiangxi Provinces, SE China[M]. Ahhui Hefei: University of Science and Technology of China Press, 99-133.