关键词: 中国中西部, 前陆盆地, 前陆逆冲带, 特提斯构造, 天然气地质

Abstract: The foreland basins of the Mesozoic and Cenozoic in mid-western area of China are located in the eastern end of Northern Basin groups of Tethys tectonics.The forming of foreland basin was controlled by the revolution of Tethys Tectonics.Two epochs of foreland basins were developed in mid-western China during the Early Mesozoic and the Late Cenozoic respectively. Foreland basins may be divided into three types and four kinds of responding foreland basins (or thrust belts).All of those foreland basins were controlled by the evolution of Thetys tectonics.Two epochs of foreland basins both underwent the tension tectonics.The tectonics environments of the foreland basins formed the specific geological characteristics for natural gas.Effective resource rock was grown in the tension tectonics settings.Foreland thrust belts were developed in the compression tectonics settings.The foreland was well match with the trapping time and space in the large rowed and belted structural traps.The early foreland basin and thrust belt were altered and superposed by the structures of the late foreland basin.The traps in the main body of the early foreland basin almost were seriously damaged,and the traps in the thrust frontier,fore-deep and fore-bulge slopes and uplift of the early foreland basin could be well preserved.For the late foreland basin,the large structural traps in the thrust belt and fore bulge have some good conditions for pooling gas and will be the key exploration targets recently.

Key words: China’s mid-western areas, foreland basin, foreland thrust belt, Thetys tectonics, natural gas geology