THE MAIN CHARACTERISTICS OF THE INTRUSIONS OF GANSU PROVINCE

The most important geological characteristics of the intrusions in Gansu Provinceare described according to the intrusion ages and stages（from older to younger）. The content includes the distribution, modes of occurrence and contact relationsoips of the intrusions, grounds for determining their ages and stages, petrology, accessory minerals, trace elments and mineralization relationships as well as the inferred source of the magma. This paper is an abridgement of the chapter of intrusion of the monograph "The Regional Geology of Gansu Province". The intrusions are divided according to the seduence of ages as follows. Proterozoic intrusions; early Paleozoic intrusion, which are subdivided into the earlys-tage （Cambrian）, middle-stage （Ordovician）and late-stage（Silurian）intrusions; Mesozoic intrusions, which are subdivided into the early-stage （Triassic）, middle-stage （Jurassic） and late-stage （Cretaceous） intrusions; Cenozoic intrusions, including Tertiary ones.