| On the basis of the study of depositional basinfilling, tectonic deformation,igneous rock and metamorphic rock in the Songpan-Aba basin, the paper drawsprimary conclusions and new fruits as follows:1,There are four primary regional unconformity for the Songpan-Aba basin,andthe corresponding structural evolution can be subdivided into 5 primary phases: Thebasement formation, the Eopaleozoic passive continental margin, the Neopaleozoiccraton basin and coexistent passive continental margin, the Trias craton basin toforeland basin and later Trias intermontain basin structural evolution.2,During the Jinning movement, the island-type volcanic rock which generatedby the diastrophic block of Songpan-Aba basin bumping with Yangzi old plate fromnorth to south, formed the rigid basement undergoing metamorphism. The rigidity inthe Ruoergai basement was stronger than that of the peripheral region. After theformation of basement, it always kept in onepiece with Yangzi plate. During the lateperiod of the Indosinian movement, the Pengguan complex rock in the LongmenshanOrogenic Belt was the former basement that thrusted out of the earth's surface. Thus,the forming process of the basement in the study area is studied in detail and is used tosummarize tectonic-evolutionary model.3,Tectonic style of the orogenic-belt uplift is very complicated,and is markedby the growing of a large number of thrusting rupture and faulted block. But thetectonic style of the geotectogene is relatively simple,which is exhibitted by themajor hierarchy,and generally belongs to the thrust fold pattern induced by cap-rockdecollement;The slip surface includes the interface between argillaceous or silty mudrock of the Triassic and the carbonate rocks of the late Paleozoic, and the sedimentaryrocks of the Sinian and metamorphic rocks of the Presinian.4,During Eopaleozoic, the study area was in a period of the passive continentalmargin where deposited high quality source rock;Neopaleozoic was marked by asteady craton basin with the development of carbonate platform, during which thehigh-quality reservoir rocks were formed. Coming into Trias, the study area became acraton basin to foreland basin evolution period, during which the carbonate platformconversion to ocean trough, while deposited more than myriameters turbidites that formthe effective regional cover. In the end of the Trias, the late of the Indosinian movementformed the present geologic framework and the study area was uplifted and cropped out.At the beginning of Jurassic period, the study area was entered a evolutionary period ofthe inter-mountain basin that is controlled by Indosinian faults. And the Himalayanmovement in the later has a light influence on the tectonic framework of the study area.5,In the south part of Animaqin fault zone, gravity collapse was occurred during theend of the Permain;And contraction tectonics was formed in the main body of basin.Calculating the Trias thickness of both the denude and the remain, and considering thefeature of resource rocks high maturity in the study area that were controlled by the Triasoriginal buried depth, igneous rock action and interlayer frictional heat energy and so on,all of these studies were finished in the first time. The Trias metamorphism was priority toregional metamorphism, and its extent was mighty low.6,The resource rock of the study area had been came into the post mature periodundergoing the multiple migration. Thus, only dry gas is created in today. In the two trapunits, the cover ability of Trias is better than Silurian, and its coverage area has the betterhydrocarbon potential. In the end of the Permain, the gravity-collapse movement formedtrap, which could capture oil and gas that were formed in the early period;the lateIndosinian movement during end of Trias had the rebuilding function to the early oilreservoir, in the same time providing the trap condition for the regroup of the oil and gas.Therefore, the lower association of oil gas in the Motianling unit is thought as the realismlines.
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