BASIC CHARACTERISTICS OF THE REGIONAL GEOLOGY OF LIAONING PROVINCE AND MAIN ACHIEVEMENTS

Liaoning province straddles the North China and Tianshan-Khingan stratigraphical regions. In the North China stratigraphical region, except the Upper Ordovician to Lower Carboniferous strata and the Upper Cretaceous strata that are absent, the Archean to Quaternary strata are all developed to different degrees. In the Tianshan-Khingan stratigraphical region, the exposed strata are not complete and there occur only the Ordovician, Silurian, Carboniferous, Permian, Cretaceous and Tertiary. Magmatie activity in the province took place frequently. Seven cycles（phases） may be distinguished; they are the Anshanian, Liaoheian, Yanliaoian, Variscan, Indosinian, Yanshanian and Himalayan cycles. The intrusive rocks are widespread, and their exposed area amounts to about 225.1 sq km. There are a full range and great variety of rock types, with the granitoids occupying the main position. For the volcanic rocks, those of the Yanshanian cycle are best developed, with intermediate-acid ones predominating; those of the Himalayan cycle are dominated by basalt. Regional metamorphic rocks are well developed. Six metamorphic phases may be distinguished, i.e. the early Archean, late Archean, early Proterozoic, Caledonian, Variscan and Indosinian. of these the early and late Archean and early Proterozoic are the most important metamorphic phases. Liaoning. province straddles three first-order tectonic units: the Sino-Kor-ean paraplatform, the Jilin-Heilongjiang fold system and the Inner Mongolian-Greater Khingan fold system. The province has gone through polycyclic development. The history of the polycyclic development can be divided into eight tectonic cycles, i.e. the Anshaian, Liaoheian, Yanliaoian, Caledonian, Yariscan, Indosinian, Yanshanian and Himalayan cycles. The Sino-Korean paraplatform is the principal tectonic unit in the province. It has gone through three stages of devel opment, i.e. the formation of the basement, the development of the cover and the development of the continental-margin mobile belt. Fracture structures are developed, and may be grouped into the Sino-Korean paraplatform fracture system and the circum-Pacific fracture system.