Acta Geologica Sinica-english Edition 

About: Acta Geologica Sinica-english Edition is an academic journal published by Wiley-Blackwell. The journal publishes majorly in the area(s): Zircon & Geology. It has an ISSN identifier of 1000-9515. Over the lifetime, 5178 publications have been published receiving 37380 citations.

Jurassic Tectonic Revolution in China and New Interpretation of the “Yanshan Movement”

Abstract: With acquisition and accumulation of new data of structural geological investigations and high-resolution isotopic dating data, we have greatly improved our understanding of the tectonic events occurring in eastern China during the period from the Late Jurassic to Early Cretaceous and may give a new interpretation of the nature, timing and geodynamic settings of the “Yanshan Movement”. During the Mid-Late Jurassic (165±5 Ma), great readjustment of plate amalgamation kinematics took place in East Asia and the tectonic regime underwent great transformation, thus initiating a new tectonic regime in which the North China Block was the center and different plates converged toward it from the north, east and southwest and forming the “East Asia convergent” tectonic system characterized by intracontinental subduction and orogeny. As a consequence, the crustal lithosphere of the East Asian continent thickened considerably during the Late Jurassic, followed immediately by Early Cretaceous substantial lithospheric thinning and craton destruction featured by drastic lithospheric extension and widespread volcano-magmatic activities, resulting in a major biotic turnover from the Yanliao biota to Jehol Biota. Such a tremendous tectonic event that took place in the continent of China and East Asia is the basic connotation of the “Yanshan Movement”. In the paper, according to the deformation patterns, geodynamic settings and deep processes, the “Yanshan Movement” is redefined as the Late Jurassic East Asian multi-directional plate convergent tectonic regime and its associated extensive intracontinental orogeny and great tectonic change that started at ˜165±5 Ma. The substantial lithospheric attenuation in East China is considered the post-effect of the Yanshanian intracontinental orogeny and deformation.

Magmatic Event at the End of the Archean in Eastern Hebei Province and Its Geological Implication

Abstract: By using the SHRIMP U-Pb and single zircon stepwise evaporation methods, the authors have obtained some results for granitoids from eastern Hebei Province. The Yuhuzhai hyperthene tonalitic granite was formed 2550 Ma ago, the Qingyangshu gabbroic gneiss 2536 Ma, the Yinmahe granodioritic gneiss near Lucao, Lulong County, 2533 Ma, the gabbro-dioritic gneiss near Longwan, Qianxi County, 2518-2515 Ma, the Qiuhuayu trondjemitic gneiss at Zunhua 2515 Ma, the Xiaoguanzhuang tonalitic gneiss at Zunhua 2495 Ma, and the Cuizhangzi gneiss in Qianxi County 2492 Ma. These geochronilogical data demonstrate that, though diverse in composition, type and origin, the granitic gneisses in eastern Hebei Province were emplaced and crystallized in a rather short period of magmatic activity. The formation of such a great amount of gneisses in this small time gap suggests that it was a critical crust accretion stage at the end of Neoarchean. The fact that granitoids of various types occurred at the same time implies a large-scale underplating (mantle plume) activity, which was then responsible for the crust accretion.

Progress in China's Unconventional Oil & Gas Exploration and Development and Theoretical Technologies

Abstract: The new century has witnessed a strategic breakthrough in unconventional oil & gas. Hydrocarbon accumulated in micro-/nano-scale pore throat shale systems has become an important domain that could replace current oil & gas resources. Unconventional oil & gas plays an increasingly important role in our energy demand. Tight gas, CBM, heavy oil and asphaltic sand have served as a key domain of exploration & development, with tight oil becoming a ‘bright spot’ domain and shale gas becoming a ‘hotspot’ domain. China has made great breakthroughs in unconventional oil & gas resources, such as tight gas, shale gas, tight oil and CBM, and great progress in oil shale, gas hydrate, heavy oil and oil sand. China has an estimated (223–263)×108t of unconventional oil resources and (890–1260)×1012 m3 of gas resources. China has made a breakthrough for progress in unconventional oil & gas study. New progress achieved in fine-grained sedimentary studies related to continental open lacustrine basin large-scale shallow-water delta sand bodies, lacustrine basin central sandy clastic flow sediments and marine-continental fine-grained sediments provide a theoretical basis for the formation and distribution of basin central reservoir bodies. Great breakthroughs have been made in unconventional reservoir geology in respect of research methodology & technology, multi-scale data merging and physical simulation of formation conditions. Overall characterization of unconventional reservoirs via multi-method and multi-scale becomes increasingly popular and facilitates the rapid development of unconventional oil & gas geological theory, method and technology. The formation of innovative, continuous hydrocarbon accumulation theory, the establishment of the framework of the unconventional oil & gas geological theory system, and the determination of the implications, geological feature, formation mechanism, distribution rule and core technology of unconventional oil & gas geological study lays a theoretical foundation for extensive unconventional oil & gas exploration and development. Theories and technologies of unconventional oil & gas exploration and development developed rapidly, including some key evaluation techniques such as ‘sweet spot zone’ integrated evaluation and a six-property evaluation technique that uses hydrocarbon source, lithology, physical property, brittleness, hydrocarbon potential and stress anisotropy, and some key development & engineering technologies including micro-seismic monitoring, horizontal drilling & completion and “factory-like” operation pattern, “man-made reservoir” development, which have facilitated the innovative development of unconventional oil & gas. These breakthroughs define a new understanding in four aspects: ① theoretical innovation; ② key technologies; ③ complete market mechanism and national policy support; and ④ well-developed ground infrastructure, which are significant for prolonging the life cycle of petroleum industry, accelerating the upgrade and development of theories and technologies and altering the global traditional energy structure.

Unconventional Natural Gas Accumulations in Stacked Deposits: A Discussion of Upper Paleozoic Coal‐Bearing Strata in the East Margin of the Ordos Basin, China

Abstract: The Upper Paleozoic (Carboniferous to Permian) succession in the east margin of the Ordos Basin in the North China Craton has a potential to contain significant hydrocarbon resources, though attention have been mainly attracted for its successful development of coalbed methane (CBM). To improve the previous resource estimates and evaluate the hydrocarbon play possibilities, this study incorporated new discoveries of hydrocarbon units and their stratigraphic relation with source rocks, hydrocarbon migration and trapping configurations. Continuous hydrocarbon accumulation units were identified within the Upper Paleozoic, including the Taiyuan, Shanxi and Xiashihezi formations with great tight gas potential, and the Taiyuan and Shanxi formations also containing shale gas and CBM. Different strata combinations are identified with coal deposition and favour for continuous gas accumulations, including the tidal flat, deltaic and fluvial systems distributed in most of the study areas. Methane was not only generated from the thick coal seams in the Taiyuan and Shanxi formations, but also from shale and dark mudstones. The coal, shale and tight sandstones are proved of remarkable gas content and hydrocarbon indications, and the gas saturation of tight sandstones decreases upward. The stacked deposit combinations vary isochronally in different areas, while the coal seams were developed stably showing good gas sources. Two key stages control the hydrocarbon enrichment, the continuous subsidence from coal forming to Late Triassic and the anomalous paleo-geothermal event happened in Early Cretaceous, as indicated by the fluid inclusions evidence. Extensive areas show good hydrocarbon development potential presently, and more works should be focused on the evaluation and selection of good reservoir combinations.

Radiometric Dating of Ignimbrite from Inner Mongolia Provides no Indication of a Post-Middle Jurassic Age for the Daohugou Beds

Abstract: Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of key fossils of the Jehol Biota. Compelling evidence revealed by more rigorous research involving regional biostratigraphy, radiometric dating, and paleontology supports the Middle Jurassic age of the fossil beds. Despite the awesome evidence for the Middle Jurassic age of the Daohugou beds, the age dispute has been resurrected recently by invoking an overturned stratigraphic sequence. A careful review of the data, however, found no evidence that this sequence has been overturned. In addition, many of the assumptions, on which the conjecture of the fossil beds being post- Middle Jurassic is imprudently based, are self-contradictory or otherwise misleading. Thus, the post- Middle Jurassic age of the Daohugou beds as an unfounded conclusion can readily be dismissed.