{"title":"中国松辽盆地青山口地层第一层古环境演化及有机质富集机制","authors":"Ying Li, Min Wang, Yu Yan, Xin Wang, Jinyou Zhang, Xuefeng Bai, Yuchen Zhang, Jiaheng Xue, Junsheng Fei, Lianbin Zhang, Guojun Wang","doi":"10.1007/s11707-022-1067-1","DOIUrl":null,"url":null,"abstract":"<p>Organic matter is the basis for oil and gas generation, and the depositional environment controls its enrichment. The first member of the Qingshankou Formation (K<sub>2</sub>qn<sup>1</sup>) in Songliao Basin has a thick organic-rich shale and so is an important target section for shale oil exploration and development. In the Gulong Sag, shale samples from this unit were collected over the full length of the section. The characterization of the environments of deposition (EOD) of K<sub>2</sub>qn<sup>1</sup> was improved by utilizing lithological characteristics, thin section observations, elemental compositions, and organic carbon concentrations. Combined with the normalization coefficients proposed in this paper, an organic matter correlation model was established to elucidate the factors that influence organic matter enrichment. From the bottom to the top of K<sub>2</sub>qn<sup>1</sup>, the lake depth gradually becomes shallower, the primary productivity first decreases and then increases, the reducing conditions become stronger and then weaker, the water salinity gradually decreases, the climate first becomes semi-humid and then warm and humid, and the input of terrigenous debris first decreases and then increases. A major marine transgression at the base of the K<sub>2</sub>qn<sup>1</sup>’s brought in nutrients to increase primary productivity, and the density-stratified reducing environment preserved and enriched organic matter. High primary productivity occurred during the middle of the deposition of the K<sub>2</sub>qn<sup>1</sup>, while terrigenous input is low. Organic matter is preserved in reduced deep lake environments, resulting in organic matter-rich black shale. The lake became shallower, and the salinity decreased in the upper part of K<sub>2</sub>qn<sup>1</sup>. Benthic organisms rapidly multiplied, consuming large amounts of oxygen and destroying the previously depositional environment, resulting in a reducing environment disturbed by benthic organisms with poor preservation conditions and the lowest organic matter content.</p>","PeriodicalId":48927,"journal":{"name":"Frontiers of Earth Science","volume":null,"pages":null},"PeriodicalIF":1.8000,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Paleoenvironment evolution and organic matter enrichment mechanisms in the first member of the Qingshankou Formation, Songliao Basin, China\",\"authors\":\"Ying Li, Min Wang, Yu Yan, Xin Wang, Jinyou Zhang, Xuefeng Bai, Yuchen Zhang, Jiaheng Xue, Junsheng Fei, Lianbin Zhang, Guojun Wang\",\"doi\":\"10.1007/s11707-022-1067-1\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Organic matter is the basis for oil and gas generation, and the depositional environment controls its enrichment. The first member of the Qingshankou Formation (K<sub>2</sub>qn<sup>1</sup>) in Songliao Basin has a thick organic-rich shale and so is an important target section for shale oil exploration and development. In the Gulong Sag, shale samples from this unit were collected over the full length of the section. The characterization of the environments of deposition (EOD) of K<sub>2</sub>qn<sup>1</sup> was improved by utilizing lithological characteristics, thin section observations, elemental compositions, and organic carbon concentrations. Combined with the normalization coefficients proposed in this paper, an organic matter correlation model was established to elucidate the factors that influence organic matter enrichment. From the bottom to the top of K<sub>2</sub>qn<sup>1</sup>, the lake depth gradually becomes shallower, the primary productivity first decreases and then increases, the reducing conditions become stronger and then weaker, the water salinity gradually decreases, the climate first becomes semi-humid and then warm and humid, and the input of terrigenous debris first decreases and then increases. A major marine transgression at the base of the K<sub>2</sub>qn<sup>1</sup>’s brought in nutrients to increase primary productivity, and the density-stratified reducing environment preserved and enriched organic matter. High primary productivity occurred during the middle of the deposition of the K<sub>2</sub>qn<sup>1</sup>, while terrigenous input is low. Organic matter is preserved in reduced deep lake environments, resulting in organic matter-rich black shale. The lake became shallower, and the salinity decreased in the upper part of K<sub>2</sub>qn<sup>1</sup>. Benthic organisms rapidly multiplied, consuming large amounts of oxygen and destroying the previously depositional environment, resulting in a reducing environment disturbed by benthic organisms with poor preservation conditions and the lowest organic matter content.</p>\",\"PeriodicalId\":48927,\"journal\":{\"name\":\"Frontiers of Earth Science\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.8000,\"publicationDate\":\"2024-06-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Frontiers of Earth Science\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1007/s11707-022-1067-1\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers of Earth Science","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1007/s11707-022-1067-1","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Paleoenvironment evolution and organic matter enrichment mechanisms in the first member of the Qingshankou Formation, Songliao Basin, China
Organic matter is the basis for oil and gas generation, and the depositional environment controls its enrichment. The first member of the Qingshankou Formation (K2qn1) in Songliao Basin has a thick organic-rich shale and so is an important target section for shale oil exploration and development. In the Gulong Sag, shale samples from this unit were collected over the full length of the section. The characterization of the environments of deposition (EOD) of K2qn1 was improved by utilizing lithological characteristics, thin section observations, elemental compositions, and organic carbon concentrations. Combined with the normalization coefficients proposed in this paper, an organic matter correlation model was established to elucidate the factors that influence organic matter enrichment. From the bottom to the top of K2qn1, the lake depth gradually becomes shallower, the primary productivity first decreases and then increases, the reducing conditions become stronger and then weaker, the water salinity gradually decreases, the climate first becomes semi-humid and then warm and humid, and the input of terrigenous debris first decreases and then increases. A major marine transgression at the base of the K2qn1’s brought in nutrients to increase primary productivity, and the density-stratified reducing environment preserved and enriched organic matter. High primary productivity occurred during the middle of the deposition of the K2qn1, while terrigenous input is low. Organic matter is preserved in reduced deep lake environments, resulting in organic matter-rich black shale. The lake became shallower, and the salinity decreased in the upper part of K2qn1. Benthic organisms rapidly multiplied, consuming large amounts of oxygen and destroying the previously depositional environment, resulting in a reducing environment disturbed by benthic organisms with poor preservation conditions and the lowest organic matter content.
期刊介绍:
Frontiers of Earth Science publishes original, peer-reviewed, theoretical and experimental frontier research papers as well as significant review articles of more general interest to earth scientists. The journal features articles dealing with observations, patterns, processes, and modeling of both innerspheres (including deep crust, mantle, and core) and outerspheres (including atmosphere, hydrosphere, and biosphere) of the earth. Its aim is to promote communication and share knowledge among the international earth science communities