Research Article
Open Access
Organic Geochemical Characteristics and Thermal Evolution Characteristics of Paleogene to Neogene Source Rocks in Mangai Area, Qaidam Basin
1
School of Earth Sciences and Engineering, Xi’an Shiyou University, Xi’an, Shaanxi 710065, China
2
Shaanxi Key Lab of Petroleum Accumulation Geology, Xi’an Shiyou University, Xi’an, Shaanxi 710065, China
3
Research Institute of Exploration and Development, PetroChina Qinghai Oilfield Company, Dunhuang 736200, China
* Corresponding Author:
Changan Shan,
[email protected]
Volume 2, Issue 1
2026
Received: 30 December 2025
Accepted: 20 January 2026
Published: 08 February 2026
Article Information
Published in
Journal of Geo-Energy and Environment
Volume/Issue
Volume 2, Issue 1, 2026
Pages
56-72
Cited by
10 (Crossref)
8 (Scopus)
Abstract
The Paleogene-Neogene lacustrine source rocks in the Mangai area of the Qaidam Basin are significant exploration targets. A comprehensive evaluation of four major intervals (E$_3^2$, N$_1$, N$_2^1$, N$_2^2$) was conducted through systematic organic geochemistry, maceral identification, thermal maturity analysis, and burial-thermal history modeling. Results show TOC contents of 0.203~1.28% (avg. 0.74%), chloroform bitumen "A" of 0.0164~0.2495% (avg. 0.132%), and total hydrocarbon contents of 69.29~1637.48 $\mu$g/g (avg. 853.39 $\mu$g/g), indicating fair to good quality. Kerogen elemental analysis (H/C=0.97~1.21), maceral composition (sapropelinite+exinite=70~98%), and saturated hydrocarbon chromatography (dominant peaks at C17, C19, C21, C23) collectively indicate predominantly Type II$_1$ organic matter, with locally developed Type I. Thermal evolution exhibits distinct vertical zonation controlled by Neogene tectonic-thermal events: an immature-low maturity zone (R$_0$<0.7%) dominated by soluble organic matter degradation; a mature zone (R$_0$=0.7~1.0%) with active kerogen cracking (HC/TOC up to 224.95%); and a high maturity zone (R$_0$>1.0%) characterized by gas generation via cracking. The saline to semi-saline reducing environment favored organic matter preservation, while mixed algal-terrestrial inputs (Type II$_1$) determined mainly oil-prone characteristics. The thick succession in the central depression, especially the Kaitemilike-Fenghuangtai region, shows the highest hydrocarbon potential. The mature zone (R$_0$=0.7~1.0%) is optimal for conventional oil exploration, while the high maturity zone (R$_0$>1.0%) holds promise for natural gas. This multi-parameter study deepens the understanding of hydrocarbon generation mechanisms and provides an important case for evaluating Paleogene-Neogene lacustrine source rocks in the northern Tibetan Plateau.
Graphical Abstract
Keywords
qaidam basin
mangai area
thermal evolution
paleogene to neogene
hydrocarbon source rocks
Data Availability Statement
Data will be made available on request.
Funding
This work was supported without any funding.
Conflicts of Interest
Ze Zhao is affiliated with the Research Institute of Exploration and Development, PetroChina Qinghai Oilfield Company, Dunhuang 736200, China. The authors declare that this affiliation had no influence on the study design, data collection, analysis, interpretation, or the decision to publish, and that no other competing interests exist.
AI Use Statement
The authors declare that no generative AI was used in the preparation of this manuscript.
Ethical Approval and Consent to Participate
Not applicable.
References
- Wei, X., Sha, W., Shen, X., Si, D., Zhang, G., Ren, S., & Yang, M. (2021). Petroleum exploration history and enlightenment in Qaidam Basin. Xinjiang Petroleum Geology, 42(3), 302-311.
[CrossRef] [Google Scholar] - Feng, D., Liu, C., Tian, J., Xie, M., Huo, H., Yang, T., ... & He, Y. (2025). Key Controlling Factors of Hydrocarbon Accumulation of Fine-Grained Mixed Sequence in a Saline Lacustrine Basin: An Integrated Research of Petroleum System in the Northwestern Qaidam Basin, Qinghai–Tibet Plateau. Natural Resources Research, 1-26.
[CrossRef] [Google Scholar] - Yang, Y., Qiu, L., Wan, M., Jia, X., Cao, Y., Lei, D., & Qu, C. (2019). Depositional model for a salinized lacustrine basin: The permian Lucaogou formation, Jimsar sag, Junggar Basin, NW China. Journal of Asian Earth Sciences, 178, 81-95.
[CrossRef] [Google Scholar] - Yang, H. A. N., Xian-zhi, G. A. O., Fei, Z. H. O. U., Bo, W. A. N. G., Jun, Z. H. U., & Li-feng, D. U. A. N. (2020). Thermal evolution of Jurassic source rocks and their impact on hydrocarbon accumulation in the northern margin of Qaidam Basin, NW China. Natural Gas Geoscience, 31(3).
[CrossRef] [Google Scholar] - Chen, Z., Wang, B., Liu, Z., Zhou, F., Yi, L., Shao, Z., … & Zhang, H. (2025). Late accumulation characteristics of hydrocarbon in the Cenozoic of the western Qaidam Basin: The hydrocarbon accumulation effect of the Tibetan Plateau uplift. Chinese Journal of Geology, 60(4), 1176-1191.
[Google Scholar] - Guo, Z., Ma, Y., Yi, S., Tian, J., Zeng, X., Kong, H., & Wang, Y. (2017). Simulation and exploration direction of Paleogene-Neogene gas system in the western Qaidam Basin. Natural Gas Geoscience, 28(1), 82-92.
[CrossRef] [Google Scholar] - Zhanguo, L. I. U., Chao, Z. H. U., Senming, L. I., Jianqin, X. U. E., Qingshun, G. O. N. G., Yanqing, W. A. N. G., ... & Guangyong, S. O. N. G. (2017). Geological features and exploration fields of tight oil in the Cenozoic of western Qaidam Basin, NW China. Petroleum Exploration and Development, 44(2), 217-225.
[CrossRef] [Google Scholar] - Tian, J., Dong, Q., & Liu, J. (2021). Analysis on accumulation conditions and target optimization of Paleogene - Neogene gas reservoirs in Western Qaidam Basin. Special Oil & Gas Reservoir, 28(1), 26-33.
[Google Scholar] - Liu, C., Li, H., Zhang, X., Zheng, S., Zhang, L., Guo, Z., ... & Zeng, X. (2016). Geochemical characteristics of the Paleogene and Neogene saline lacustrine source rocks in the western Qaidam Basin, northwestern China. Energy & Fuels, 30(6), 4537-4549.
[CrossRef] [Google Scholar] - Wanxin, H. A. O., Fei, Z. H. O. U., Guo, C. H. E. N., Guojie, S. U. I., Yaohui, X. U., & Hui, T. I. A. N. (2023). Geochemical characteristics and their differential responses to formation mechanisms of the Paleogene and Neogene source rocks in western Qaidam Basin. Natural Gas Geoscience, 34(10), 1855-1870.
[CrossRef] [Google Scholar] - Li, W., Hu, D., Gong, C., Fan, T., Chen, Y., Li, Y. N., ... & Leng, Q. (2024). Controlling factors of high-quality reservoirs in low permeability sandstone: a case study of the upper member of the lower Ganchaigou formation, Qaidam basin. Frontiers in Earth Science, 12, 1396061.
[CrossRef] [Google Scholar] - Guoyong, L. I. U., Jianqin, X. U. E., Songtao, W. U., Kunyu, W. U., Haoting, X. I. N. G., Peng, P. A. N. G., & Chao, Z. H. U. (2024). Petroleum geology and ring-shaped distribution of the Paleogene-Neogene hydrocarbon resources in western Qaidam Depression, Qaidam Basin. Oil & Gas Geology, 45(4), 1007-1017.
[CrossRef] [Google Scholar] - Guoyong, L. I. U., Songtao, W. U., Kunyu, W. U., Yue, S. H. E. N., Gang, L. E. I., Haoting, X. I. N. G., & Guoxin, L. I. (2024). Characteristics and hydrocarbon accumulation model of Paleogene whole petroleum system in western depression of Qaidam Basin, NW China. Petroleum Exploration and Development, 51(5), 1097-1108.
[CrossRef] [Google Scholar] - Lin, C., Wu, C., Guan, X., Elias, J., Ren, C., & Zhang, W. (2025). Sedimentology and sequence stratigraphy of strike-slip fault-controlled continental lakes: Insights from the SW Qaidam Basin, NE Tibetan Plateau. Sedimentary Geology, 486, 106913.
[CrossRef] [Google Scholar] - Yin, J., Zhang, S., Lu, X., Wu, Z., Hui, G., & Ju, Y. (2019). Controls of the Altyn Tagh Fault on the Early–Middle Miocene sedimentation in the Honggouzi Area, Qaidam Basin, Western China. Journal of Asian Earth Sciences, 181, 103908.
[CrossRef] [Google Scholar] - Daowei, Z. H. A. N. G., Dade, M. A., Yan, C. H. E. N., Kunyu, W. U., Zhihong, C. A. I., Jian, Z. H. A. O., & Jiangong, W. A. N. G. (2019). Research progress on oil and gas geology and exploration practice in Qaidam Basin. Xinjiang Petroleum Geology, 40(5), 1.
[CrossRef] [Google Scholar] - Meng, B., Zhou, S., & Li, J. (2024). Geochemical characteristics and significance of molecular markers in the Paleogene-Neogene crude oils of the Northwest Qaidam Basin. ACS Omega, 9(41), 42361-42374.
[CrossRef] [Google Scholar] - Guoxin, L. I., Rukai, Z., Yan, C. H. E. N., Jingwei, C. U. I., Kunyu, W. U., Chenggang, X. I. A. N., & He, L. I. U. (2022). Geological characteristics, evaluation criteria and discovery significance of Paleogene Yingxiongling shale oil in Qaidam Basin, NW China. Petroleum Exploration and Development, 49(1), 21-36.
[CrossRef] [Google Scholar] - Li, X., Wu, K., Wang, J., Yang, S., Zhang, Q., & Zhang, Q. (2022). Impact of lithologic heterogeneity on brittleness of cenozoic unconventional reservoirs (Fine-Grained) in western Qaidam Basin. Minerals, 12(11), 1443.
[CrossRef] [Google Scholar] - Qinghua, W. A. N. G., Haijun, Y. A. N. G., & Wei, Y. A. N. G. (2025). New progress and future exploration targets in petroleum geological research of ultra-deep clastic rocks in Kuqa Depression, Tarim Basin, NW China. Petroleum Exploration and Development, 52(1), 79-94.
[CrossRef] [Google Scholar] - Guangyong, S. O. N. G., Zhanguo, L. I. U., Yanqing, W. A. N. G., Guohui, L. O. N. G., Chao, Z. H. U., Senming, L. I., ... & Qingshun, G. O. N. G. (2024). Lithofacies types, sedimentary cycles, and facies models of saline lacustrine hybrid sedimentary rocks: A case study of Neogene in Fengxi area, Qaidam Basin, NW China. Petroleum Exploration and Development, 51(6), 1507-1520.
[CrossRef] [Google Scholar] - Changhao, Z. H. A. N. G., Xin, F. U., Lianliang, Z. H. A. N. G., Hongzhen, D. U. A. N., Qiang, L. I., & Wei, Z. H. A. N. G. (2023). Characteristics of source rocks in the upper member of lower Ganchaigou formation in Ganchaigou area, Qaidam basin. Mud Logging Engineering, 34(2), 139-144.
[Google Scholar] - Huang, C., Chang, H., Cui, J., Li, Y., Lu, Y., Li, X., … & Wu, L. (2017). Oilgocene sedimentary characteristics and hydrocarbon accumulation model in the western Qaidam Basin. Acta Petrolei Sinica, 38(11), 1230-1243.
[CrossRef] [Google Scholar] - Wang, J., Zhang, D., Yang, S., Li, X., Shi, Y., Cui, J., … & Chang, H. (2020). Sedimentary characteristics and genesis of the salt lake with the upper member of the Lower Ganchaigou Formation from Yingxi sag, Qaidam basin. Marine and Petroleum Geology, 111, 135-155.
[CrossRef] [Google Scholar] - Yi, F., Yi, H., Mu, C., Tang, W., Li, N., Chen, Y., … & Xia, G. (2023). Organic geochemical characteristics and organic matter accumulation of the Eocene lacustrine source rock in the Yingxi area, Western Qaidam Basin, China. International Journal of Earth Sciences, 112(4), 1277-1292.
[CrossRef] [Google Scholar] - Wang, B., Chen, M., Tian, H., Sun, J., Liu, L., Liang, X., … & Qu, Z. (2025). Geochemical characteristics and genetic origin of tight sandstone gas in the Daning–Jixian Block, Ordos Basin. Processes, 13(12), 4019.
[CrossRef] [Google Scholar] - Bai, J., Qian, K., Wu, X., Dou, X., & He, Y. (2025). Thermal cracking for upgrading medium-low maturity shale oil: evolution of organic matter occurrence. Scientific Reports, 15(1), 43054.
[CrossRef] [Google Scholar] - Xu, Q. N., Zhu, Y. M., Chen, S. B., Liu, Y., Wang, X. Q., Shang, F. H., & George, S. C. (2025). Illitisation impeded the thermal evolution of extractable organic matter: An interpretation of the mineralogy and thermal maturation of early Cambrian source rocks in Yunnan Province, China. Petroleum Science.
[CrossRef] [Google Scholar] - Zhu, L., Wang, Z., Wang, F., & Tian, Y. (2025). Discussion on influencing factors of hydrocarbon generation in deep source rocks: A case study of Bozhong Sag, Bohai Bay basin. Unconventional Resources, 6, 100166.
[CrossRef] [Google Scholar] - Zhang, M., Zhu, X., Ji, W., Lin, X., & Ye, L. (2025). Effect of sedimentary environment on mudrock lithofacies and organic matter enrichment in a freshwater lacustrine basin: Insight from the Triassic Chang 7 Member in the Ordos Basin, China. Sustainability, 17(22), 10248.
[CrossRef] [Google Scholar] - Zeng, B., Qu, J., Mi, Z., Xie, E., Fu, H., Yang, S., ... & Li, M. (2025). The control of effective source rocks on the distribution of hydrocarbon reservoirs in a lacustrine rift-basin: insights from a 3D basin modeling study. Journal of Petroleum Exploration and Production Technology, 15(2), 21.
[CrossRef] [Google Scholar] - Liu, Q., Zhang, L., Chen, Z., Han, G., Fu, X., Teng, J., & Wang, Y. (2024). Exploring the prospects of deep natural gas resources from the geochemical parameters of the Shahejie Formation source rocks in the Banqiao depression. Natural Gas Industry B, 11(4), 443-453.
[CrossRef] [Google Scholar] - Zhao, Y., Huang, C., Chen, F., & Yue, Q. (2025). Hydrocarbon generation potential and geochemical characteristics comparison of source rocks in the Southwestern Qaidam basin, China. Scientific Reports, 15(1), 8281.
[CrossRef] [Google Scholar] - Chen, Y., Han, Y., Zhang, P., Wang, M., Qiu, Y., Zhu, X., & Zhang, X. (2023). Comparison of Evaporite-Related Source Rocks and Implications for Petroleum Exploration: A Case Study of the Dongying Depression, Bohai Bay Basin, Eastern China. Energies, 16(13), 5000.
[CrossRef] [Google Scholar] - Xiaodong, W. A. N. G., Bo, W. A. N. G., Jilei, Y. A. N. G., Peng, H. A. O., & Kuo, L. I. (2025). Kinetics of hydrocarbon generation of different types of organic matter in the KL-A structure of the Bohai Bay Basin. Natural Gas Geoscience, 36(2), 354-366.
[CrossRef] [Google Scholar] - Cai, C., Cai, J., Du, J., Lei, T., Wang, X., & Li, Z. (2023). Multistage Hydrocarbon Generation of Saline Lacustrine Source Rocks in Hydrous Pyrolysis: Insights from Clay Mineral–Organic Matter Interactions. ACS omega, 8(16), 14710-14729.
[CrossRef] [Google Scholar] - Wang, Y., Zhang, X., Wang, E., Zhang, J., Li, Q., & Sun, G. (2005). 40Ar/39Ar thermochronological evidence for formation and Mesozoic evolution of the northern-central segment of the Altyn Tagh fault system in the northern Tibetan Plateau. Geological Society of America Bulletin, 117(9-10), 1336-1346.
[CrossRef] [Google Scholar] - Feng, D., Liu, C., Tian, J., Xie, M., Huo, H., Yang, T., ... & He, Y. (2025). Key Controlling Factors of Hydrocarbon Accumulation of Fine-Grained Mixed Sequence in a Saline Lacustrine Basin: An Integrated Research of Petroleum System in the Northwestern Qaidam Basin, Qinghai–Tibet Plateau. Natural Resources Research, 1-26.
[CrossRef] [Google Scholar] - Guoxin, L. I., Rukai, Z., Yan, C. H. E. N., Jingwei, C. U. I., Kunyu, W. U., Chenggang, X. I. A. N., & He, L. I. U. (2022). Geological characteristics, evaluation criteria and discovery significance of Paleogene Yingxiongling shale oil in Qaidam Basin, NW China. Petroleum Exploration and Development, 49(1), 21-36.
[CrossRef] [Google Scholar]
Cited By (10)
-
Xianhua Huang, Jianru Tang, Jialin Zhao, Jin Li, Shuai Yin, Shaoke Feng, Hu Li. Comprehensive evaluation of gas-bearing properties in ultra-deep basement reservoirs based on an optimizable support vector machine.
Scientific Reports, 2026 , 16 (1).
[CrossRef] -
Jing Li, Wenping Liu, Yadong Yang, Xunxi Qiu, Xin Gong, Hu Li, Jia He, Xing Liu, Zhi Gao, Ang Luo, Cheng Yang. Main Controlling Factors and Three-Dimensional Development Potential of Deep to Ultra-Deep Shale Gas in the Luzhou Area, Sichuan Basin.
Processes, 2026 , 14 (9).
[CrossRef] -
Jing Liu, Maolong Xia, Bo Feng, Jie Hu, Jing Liang, Cunhui Fan, Yulu Zeng, Huwei Cao, Hu Li. Multi-Indicator comprehensive evaluation of middle Permian hydrocarbon preservation conditions in Western Sichuan and its exploration significance.
Applied Earth Science: Transactions of the Institutions of Mining and Metallurgy, 2026 .
[CrossRef] -
Yongjing Cen, Qingsong Tang, Jianhai Li, Feng Liang, Xin Zhang, Lien Wang, Qianyu Liu, Hu Li. Controlling effect of strike-slip faults on Ediacaran Dengying Formation microbial mound-shoal complex reservoir, Penglai Gas Field, SW China.
Applied Earth Science: Transactions of the Institutions of Mining and Metallurgy, 2026 .
[CrossRef] -
Wenhao Zhang, Dandan Wang, Shizhen Li, Xingui Zhou, Yuanlin Meng, Yunbo Zhang, Minfei Wang, Hu Li. Geochemical characteristics and hydrocarbon generation potential of lower cretaceous source rocks in the eastern peripheral basin group of the Songliao Basin, Northeastern China.
Frontiers in Earth Science, 2026 , 14 .
[CrossRef] -
Jianqin Xue, Yanxiong Wu, Bo Wang, Ziwei Pei, Yinghai Jiang, Yunzhao Wu, Boce Zhang, Bohan Qiao, Wenzhuo Wang, Changan Shan, Hu Li. Reservoir characteristics and main controlling factors of karst shale oil in the Lower Ganchaigou Formation, Yingxi area, Qaidam Basin.
Applied Earth Science: Transactions of the Institutions of Mining and Metallurgy, 2026 .
[CrossRef] -
Jing Li, Yuqi Deng, Tingting Huang, Guo Chen, Bei Yang, Xiaohai Ren, Hu Li. Digital Core-Based Characterization and Fracability Evaluation of Deep Shale Gas Reservoirs in the Weiyuan Area, Sichuan Basin, China.
Minerals, 2026 , 16 (4).
[CrossRef] -
Hongxiang Jin, Hongxi Li, Huajun Zhu, Xin Wang, Chunpu Wang, Shaobo Tang, Jian He. Deep coal-rock geomechanics for wellbore stability and drilling-fluid design in the Benxi–Shanxi Formations, Ordos Basin, China.
Applied Earth Science: Transactions of the Institutions of Mining and Metallurgy, 2026 .
[CrossRef] -
Hao Ma, Junbin Chen, Nianfeng Li, Hua Chen, Bin Liu, Siqi Xiao. Sedimentary Characteristics of the Wufeng–Longmaxi Formation Shales and Their Controlling Mechanisms on Shale Gas Accumulation in the Mugan Syncline, Northeastern Yunnan, China.
Processes, 2026 , 14 (11).
[CrossRef] -
Songyang Wan, Weiwei Liu, Liang Liao, Yuping Ouyang, Yonghui Yan, Hu Li, Kun Zhang. Geological Characteristics and Resource Potential of the Leping Formation Shale Gas in the Qingjiang Basin, Southern Poyang Depression, China.
Journal of Petroleum Geology, 2026 .
[CrossRef]
* Citation data provided by Crossref Cited-by.
Cite This Article
APA Style
Shi, S., Shan, C., Zhao, Z., Fei, Y., & Zhang, J. (2026). Organic Geochemical Characteristics and Thermal Evolution Characteristics of Paleogene to Neogene Source Rocks in Mangai Area, Qaidam Basin. Journal of Geo-Energy and Environment, 2(1), 56–72. https://doi.org/10.62762/JGEE.2025.781750
Export Citation
RIS Format
Compatible with EndNote, Zotero, Mendeley, and other reference managers
TY - JOUR AU - Shi, Shiling AU - Shan, Changan AU - Zhao, Ze AU - Fei, Yue AU - Zhang, Jiaqi PY - 2026 DA - 2026/02/08 TI - Organic Geochemical Characteristics and Thermal Evolution Characteristics of Paleogene to Neogene Source Rocks in Mangai Area, Qaidam Basin JO - Journal of Geo-Energy and Environment T2 - Journal of Geo-Energy and Environment JF - Journal of Geo-Energy and Environment VL - 2 IS - 1 SP - 56 EP - 72 DO - 10.62762/JGEE.2025.781750 UR - https://www.icck.org/article/abs/JGEE.2025.781750 KW - qaidam basin KW - mangai area KW - thermal evolution KW - paleogene to neogene KW - hydrocarbon source rocks AB - The Paleogene-Neogene lacustrine source rocks in the Mangai area of the Qaidam Basin are significant exploration targets. A comprehensive evaluation of four major intervals (E$_3^2$, N$_1$, N$_2^1$, N$_2^2$) was conducted through systematic organic geochemistry, maceral identification, thermal maturity analysis, and burial-thermal history modeling. Results show TOC contents of 0.203~1.28% (avg. 0.74%), chloroform bitumen "A" of 0.0164~0.2495% (avg. 0.132%), and total hydrocarbon contents of 69.29~1637.48 $\mu$g/g (avg. 853.39 $\mu$g/g), indicating fair to good quality. Kerogen elemental analysis (H/C=0.97~1.21), maceral composition (sapropelinite+exinite=70~98%), and saturated hydrocarbon chromatography (dominant peaks at C17, C19, C21, C23) collectively indicate predominantly Type II$_1$ organic matter, with locally developed Type I. Thermal evolution exhibits distinct vertical zonation controlled by Neogene tectonic-thermal events: an immature-low maturity zone (R$_0$1.0%) characterized by gas generation via cracking. The saline to semi-saline reducing environment favored organic matter preservation, while mixed algal-terrestrial inputs (Type II$_1$) determined mainly oil-prone characteristics. The thick succession in the central depression, especially the Kaitemilike-Fenghuangtai region, shows the highest hydrocarbon potential. The mature zone (R$_0$=0.7~1.0%) is optimal for conventional oil exploration, while the high maturity zone (R$_0$>1.0%) holds promise for natural gas. This multi-parameter study deepens the understanding of hydrocarbon generation mechanisms and provides an important case for evaluating Paleogene-Neogene lacustrine source rocks in the northern Tibetan Plateau. SN - 3069-3268 PB - Institute of Central Computation and Knowledge LA - English ER -
BibTeX Format
Compatible with LaTeX, BibTeX, and other reference managers
@article{Shi2026Organic,
author = {Shiling Shi and Changan Shan and Ze Zhao and Yue Fei and Jiaqi Zhang},
title = {Organic Geochemical Characteristics and Thermal Evolution Characteristics of Paleogene to Neogene Source Rocks in Mangai Area, Qaidam Basin},
journal = {Journal of Geo-Energy and Environment},
year = {2026},
volume = {2},
number = {1},
pages = {56-72},
doi = {10.62762/JGEE.2025.781750},
url = {https://www.icck.org/article/abs/JGEE.2025.781750},
abstract = {The Paleogene-Neogene lacustrine source rocks in the Mangai area of the Qaidam Basin are significant exploration targets. A comprehensive evaluation of four major intervals (E\$\_3^2\$, N\$\_1\$, N\$\_2^1\$, N\$\_2^2\$) was conducted through systematic organic geochemistry, maceral identification, thermal maturity analysis, and burial-thermal history modeling. Results show TOC contents of 0.203~1.28\% (avg. 0.74\%), chloroform bitumen "A" of 0.0164~0.2495\% (avg. 0.132\%), and total hydrocarbon contents of 69.29~1637.48 \$\mu\$g/g (avg. 853.39 \$\mu\$g/g), indicating fair to good quality. Kerogen elemental analysis (H/C=0.97~1.21), maceral composition (sapropelinite+exinite=70~98\%), and saturated hydrocarbon chromatography (dominant peaks at C17, C19, C21, C23) collectively indicate predominantly Type II\$\_1\$ organic matter, with locally developed Type I. Thermal evolution exhibits distinct vertical zonation controlled by Neogene tectonic-thermal events: an immature-low maturity zone (R\$\_0\$1.0\%) characterized by gas generation via cracking. The saline to semi-saline reducing environment favored organic matter preservation, while mixed algal-terrestrial inputs (Type II\$\_1\$) determined mainly oil-prone characteristics. The thick succession in the central depression, especially the Kaitemilike-Fenghuangtai region, shows the highest hydrocarbon potential. The mature zone (R\$\_0\$=0.7~1.0\%) is optimal for conventional oil exploration, while the high maturity zone (R\$\_0\$>1.0\%) holds promise for natural gas. This multi-parameter study deepens the understanding of hydrocarbon generation mechanisms and provides an important case for evaluating Paleogene-Neogene lacustrine source rocks in the northern Tibetan Plateau.},
keywords = {qaidam basin, mangai area, thermal evolution, paleogene to neogene, hydrocarbon source rocks},
issn = {3069-3268},
publisher = {Institute of Central Computation and Knowledge}
}
Publisher's Note
ICCK stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and Permissions
Copyright © 2026 by the Author(s). Published by Institute of Central Computation and Knowledge. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.
Preserved at
Portico
Portico
Scan to read this article