Correlation of burial organic carbon and paleoproductivity in the Mesoproterozoic Hongshuizhuang Formation, northern North China  

作　　者：LUO QingYong ZHONG NingNing ZHU Lei WANG YanNian QIN Jing QI Lin ZHANG Yi MA Yong 

机构地区：[1]State Key Laboratory of Petroleum Resources & Prospecting, China University of Petroleum [2]Petrochina Coalbed Methane Company Limited [3]National Research Center for Geoanalysis [4]Chongqing Institute of Geology & Mineral Resources

出　　处：《Chinese Science Bulletin》2013年第11期1299-1309,共11页

基　　金：supported by the National Science and Technology Major Project (2011ZX05018-002);the National Natural Science Foundation of China (40472076)

摘　　要：In general, total organic carbon (TOC) is directly used as a proxy for paleoproductivity, however, it is not only affected by paleoproductivity, but also controlled by redox conditions and terrigenous detrital matter influx. Major and trace elements were analysed with the purpose of investigating the redox potential and paleoproductivity during deposition of the Hongshuizhuang Formation. In the present study, C-S relationship, V/Cr ratio and Mo concentration indicate that the dolomites were deposited in oxic environments, however, most of the black shales were accumulated in euxinic environments. P/Ti values in the Hongshuizhuang samples can be compared with those in the Japanese Ubara Permian-Triassic section which were regarded to be deposited under a moderate to high paleoproductivity. Ba/Al values are slightly lower than that of the laminated sediments from the continental margins of Central California (CCAL) which were thought to be accumulated under a high paleoproductivity. These results indicate that the paleoproductivity was moderate to high during deposition of the Hongshuizhuang Formation. Burial organic carbon shows positive correlations with V/Cr and Mo, but shows only weakly or no correlation with P/Ti and Ba/Al, respectively, suggesting that although the paleoproductivity was moderate to high during deposition of the Hongshuizhuang Formation, its organic-rich sediments were predominantly controlled by redox conditions and had no direct relationship with paleoproductivity.In general, total organic carbon （TOC） is directly used as a proxy for paleoproductivity, however, it is not only affected by paleoproductivity, but also controlled by redox conditions and terrigenous detrital matter influx. Major and trace elements were analysed with the purpose of investigating the redox potential and paleoproductivity during deposition of the Hongshuizhuang Formation. In the present study, C-S relationship, V/Cr ratio and Mo concentration indicate that the dolomites were deposited in oxic environments, however, most of the black shales were accumulated in euxinic environments. P/Ti values in the Hongshuizhuang samples can be compared with those in the Japanese Ubara Permian-Triassic section which were regarded to be deposited under a moderate to high paleoproductivity. Ba/A1 values are slightly lower than that of the laminated sediments from the continental margins of Central California （CCAL） which were thought to be accumulated under a high paleoproductivity. These results indi- cate that the paleoproductivity was moderate to high during deposition of the Hongshuizhuang Formation. Burial organic carbon shows positive correlations with V/Cr and Mo, but shows only weakly or no correlation with P/Ti and Ba/AI, respectively, sug- gesting that although the paleoproductivity was moderate to high during deposition of the Hongshuizhuang Formation, its organ- ic-rich sediments were predominantly controlled by redox conditions and had no direct relationship with paleoproductivity.

关 键 词：古生产力 洪水庄组 有机碳 中元古代 华北北部 埋藏 氧化还原条件 沉积过程 

分 类 号：P618.13[天文地球—矿床学] P632[天文地球—地质学]