Full
SUN Haofei,born in 1989,MSc.,engineer,is engaged in petroleum and natural gas geological research and exploration deployment. E-mail: sunhaofei@petroChina.com.cn.
Outline
Mianyang-Guang'an Trough in Sichuan Basin is an intra-platform depression developed within the Upper Yangtze Platform during the Late Permian to Early Triassic. This trough,with a water depth between fair-weather wave base and maximum storm wave base,transitions northward into slope facies. In Mianyang-Guang'an Trough,the Changxing Formation,deposited during the Late Permian,is characterized by numerous patch reefs/shoals with minimal dolomitization. By integrating petrographic analysis with Integrated Nonstationary Process Empirical Function Analysis(INPEFA),the Changxing Formation can be subdivided,in an ascending order,into the 1st Member(SQ1-HST and SQ2-TST),lower part in the 2nd Member(SQ2-HST),middle part in the 2nd Member(SQ3),and upper part in the 2nd Member(SQ4). The 1st Member is mainly composed of micritic limestones intercalated with shales and mudstones,which constructed a ramp. The 2nd Member,in contrast,is characterized by grainstones and framestones,which formed a rimmed platform. Mianyang-Guang'an Trough,which developed during the deposition of the 2nd Member,comprises four subfacies,including shoals,reefs,inter-shoal zones and off-reef seafloor deposits. The shoals,which are commonly associated with HST in SQ2,SQ3 and SQ4,are mainly formed by skeletal grainstones,and characterized by low GR(29.3~34.6 API)and relatively low CNL values(13.3%~18.0%). The reefs,developed in the SQ4-TST,are formed of framestones and/or dolomitic framestones,and characterized by relatively low GR(34.0~37.3 API),and relatively high CNL values(19.0%~22.0%). The inter-shoal zones,developed in both HST and TST,consist of wackestones and packstones that are characterized by low CNL(9.9%~11.3%),low RT(33.1~37.3 Ω·m), low DEN(2.55~2.57 g/cm3),and low GR values(26.0~29.5 API). The off-reef seafloor deposits,which consist of intercalated micritic limestones,siltstones and mudstones,are commonly associated with the SQ2-HST,and characterized by serrated log curves. In terms of petrographic and stratigraphic characteristics,reefs and shoals developed in Mianyang-Guang'an Trough are comparable to those in the platform-interior facies,but distinct from those in the platform margins. The stratigraphic and sedimentary characteristics of the Changxing Formation in Mianyang-Guang'an Trough can provide a novel geological model for deciphering trough facies on the carbonate platforms,but also offer theoretical support for exploration in this region.
142
61
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |
关闭全屏
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62662699(Operation and Technical Support)
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
