Geochemical Characteristics and Their Geological Significance of Lower Cambrian Xiaoerblak Formation in Northwestern Tarim Basin, China
Lower Cambrian Xiaoerblak Formation is one of the major exploration targets in Cambrian pre-salt Tarim Basin; however, the exploration breakthrough is restricted by insufficient understanding of its sedimentary evolution and reservoir genesis. In this paper, based on a systematic description of the...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-06-01
|
| Series: | Minerals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-163X/12/6/781 |
| _version_ | 1797484107775606784 |
|---|---|
| author | Jianfeng Zheng Yongjin Zhu Lili Huang Guo Yang Fangjie Hu |
| author_facet | Jianfeng Zheng Yongjin Zhu Lili Huang Guo Yang Fangjie Hu |
| author_sort | Jianfeng Zheng |
| collection | DOAJ |
| description | Lower Cambrian Xiaoerblak Formation is one of the major exploration targets in Cambrian pre-salt Tarim Basin; however, the exploration breakthrough is restricted by insufficient understanding of its sedimentary evolution and reservoir genesis. In this paper, based on a systematic description of the outcrop in the Xiaoerblak section, northwestern Tarim Basin, some samples were selected for tests of stable carbon and oxygen isotopic compositions, strontium isotopic composition, order degree, trace and rare earth elements, U-Pb isotopic age and clumped isotope. It is found that the Xiaoerblak Formation mainly develops nine types of dolomites, i.e., laminated microbial dolomite, thrombolite dolomite, stromatolite dolomite, foamy microbial dolomite, grain dolomite, etc. According to the lithofacies associations, it can be divided into three members: Xi 1, Xi 2, and Xi 3, of which member Xi 2 is subdivided into three submembers. The characteristics of lithofacies assemblage formed bottom to top indicate that it can be described as a third-order sequence. The Xiaoerblak Formation was deposited in a nearshore shallow seawater environment characterized by high water salinity and temperature under a warm and humid climate during the Early Cambrian, giving rise to the sedimentary sequence of inner ramp lagoon, subtidal microbial mound shoal and tidal flat in the carbonate ramp setting from bottom to top. Its dolomitization occurred in the penecontemporaneous–shallow burial period when the temperature was relatively low and high-salinity seawater acted as the main dolomitizaiton fluid. The reservoir space mainly comprises primary microbial framework pores and vugs formed by the atmospheric freshwater dissolution. Reservoirs were controlled by lithofacies, high-frequency sequence boundary and early dolomitization. The research results are of great significance for presalt Cambrian lithofacies paleogeographic mapping and reservoir prediction. |
| first_indexed | 2024-03-09T22:57:45Z |
| format | Article |
| id | doaj.art-0ee9e22e24c94b25bb24c0cee7f0472b |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T22:57:45Z |
| publishDate | 2022-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-0ee9e22e24c94b25bb24c0cee7f0472b2023-11-23T18:07:46ZengMDPI AGMinerals2075-163X2022-06-0112678110.3390/min12060781Geochemical Characteristics and Their Geological Significance of Lower Cambrian Xiaoerblak Formation in Northwestern Tarim Basin, ChinaJianfeng Zheng0Yongjin Zhu1Lili Huang2Guo Yang3Fangjie Hu4PetroChina Hangzhou Research Institute of Geology, Hangzhou 310023, ChinaPetroChina Hangzhou Research Institute of Geology, Hangzhou 310023, ChinaPetroChina Hangzhou Research Institute of Geology, Hangzhou 310023, ChinaPetroChina Tarim Oil Field Company, Korla 841000, ChinaPetroChina Tarim Oil Field Company, Korla 841000, ChinaLower Cambrian Xiaoerblak Formation is one of the major exploration targets in Cambrian pre-salt Tarim Basin; however, the exploration breakthrough is restricted by insufficient understanding of its sedimentary evolution and reservoir genesis. In this paper, based on a systematic description of the outcrop in the Xiaoerblak section, northwestern Tarim Basin, some samples were selected for tests of stable carbon and oxygen isotopic compositions, strontium isotopic composition, order degree, trace and rare earth elements, U-Pb isotopic age and clumped isotope. It is found that the Xiaoerblak Formation mainly develops nine types of dolomites, i.e., laminated microbial dolomite, thrombolite dolomite, stromatolite dolomite, foamy microbial dolomite, grain dolomite, etc. According to the lithofacies associations, it can be divided into three members: Xi 1, Xi 2, and Xi 3, of which member Xi 2 is subdivided into three submembers. The characteristics of lithofacies assemblage formed bottom to top indicate that it can be described as a third-order sequence. The Xiaoerblak Formation was deposited in a nearshore shallow seawater environment characterized by high water salinity and temperature under a warm and humid climate during the Early Cambrian, giving rise to the sedimentary sequence of inner ramp lagoon, subtidal microbial mound shoal and tidal flat in the carbonate ramp setting from bottom to top. Its dolomitization occurred in the penecontemporaneous–shallow burial period when the temperature was relatively low and high-salinity seawater acted as the main dolomitizaiton fluid. The reservoir space mainly comprises primary microbial framework pores and vugs formed by the atmospheric freshwater dissolution. Reservoirs were controlled by lithofacies, high-frequency sequence boundary and early dolomitization. The research results are of great significance for presalt Cambrian lithofacies paleogeographic mapping and reservoir prediction.https://www.mdpi.com/2075-163X/12/6/781dolomitegeochemical characteristicssedimentary environmentpore genesislower CambrianTarim Basin |
| spellingShingle | Jianfeng Zheng Yongjin Zhu Lili Huang Guo Yang Fangjie Hu Geochemical Characteristics and Their Geological Significance of Lower Cambrian Xiaoerblak Formation in Northwestern Tarim Basin, China Minerals dolomite geochemical characteristics sedimentary environment pore genesis lower Cambrian Tarim Basin |
| title | Geochemical Characteristics and Their Geological Significance of Lower Cambrian Xiaoerblak Formation in Northwestern Tarim Basin, China |
| title_full | Geochemical Characteristics and Their Geological Significance of Lower Cambrian Xiaoerblak Formation in Northwestern Tarim Basin, China |
| title_fullStr | Geochemical Characteristics and Their Geological Significance of Lower Cambrian Xiaoerblak Formation in Northwestern Tarim Basin, China |
| title_full_unstemmed | Geochemical Characteristics and Their Geological Significance of Lower Cambrian Xiaoerblak Formation in Northwestern Tarim Basin, China |
| title_short | Geochemical Characteristics and Their Geological Significance of Lower Cambrian Xiaoerblak Formation in Northwestern Tarim Basin, China |
| title_sort | geochemical characteristics and their geological significance of lower cambrian xiaoerblak formation in northwestern tarim basin china |
| topic | dolomite geochemical characteristics sedimentary environment pore genesis lower Cambrian Tarim Basin |
| url | https://www.mdpi.com/2075-163X/12/6/781 |
| work_keys_str_mv | AT jianfengzheng geochemicalcharacteristicsandtheirgeologicalsignificanceoflowercambrianxiaoerblakformationinnorthwesterntarimbasinchina AT yongjinzhu geochemicalcharacteristicsandtheirgeologicalsignificanceoflowercambrianxiaoerblakformationinnorthwesterntarimbasinchina AT lilihuang geochemicalcharacteristicsandtheirgeologicalsignificanceoflowercambrianxiaoerblakformationinnorthwesterntarimbasinchina AT guoyang geochemicalcharacteristicsandtheirgeologicalsignificanceoflowercambrianxiaoerblakformationinnorthwesterntarimbasinchina AT fangjiehu geochemicalcharacteristicsandtheirgeologicalsignificanceoflowercambrianxiaoerblakformationinnorthwesterntarimbasinchina |