Geochemical characteristics and sedimentary environment significance of carbonate rocks in Nanfen Formation of Qingbaikou System in Tonghua, Jilin Province

• 作者: ZHANG Junsheng JIA Xiaoyu GONG Hui
• 来源期刊: 世界地质（英文版）
• 年，卷（期）: 2021,（2）
• 页码范围: 89-94
• 页数: 6页
• 语种: 英文
• DOI: 10.3969/j.issn.1673-9736.2021.02.03

摘要

In order to reveal the sedimentary environment of carbonate rocks in Nanfen Formation of Qingbaikou System in Tonghua , Jilin Province , the mineral composition and petrochemistry of carbonate rocks in Nanfen Formation were analyzed .The mineral compositions of five carbonate rock samples in Nanfen Formation mainly consist of calcite , with minor clay minerals and quartz , and the rock type is siliceous marlite .The Mn/Sr va-lues range from 1.52 to 4.08, with an average of 2.64, indicating that the carbonate rocks experienced weak diagenesis;the Sr/Ba values range from 1.26 to 2.51, with an average of 1.93, indicating marine environ-ment;the ratio of Mg/Al ranges from 35.33 to 86.34, with an average of 62.95, indicating the seawater envi-ronment, which is consistent with the result from Sr/Ba;the MgO/CaO values range from 0.01 to 0.04, with an average of 0.02, indicating humid environment;the values of V/(V+Ni) range from 0.63 to 0.73, with an average of 0.70, indicating anoxic environment .In summary, geochemical analyses show that the Nanfen Formation carbonate rocks are marine deposits , in a warm, humid, anoxic environment with poor flow of seawa-ter, and subsequently underwent weak diagenetic alteration .