Abstract:

According to the processing and analysing of aeromagnetic and gravity data of Longmen Moun-tains thrust belt and its adjacent areas,the magnetic field of this region could be divided into fourzones:Sichuan Basin high magnetic anomaly zone,Longmen Mountains magnetic anomaly steep-chang-ing zone,Pingwu-Lixian negative magnetic anomaly maximum zone,Hongyuan-Maerkang low magne-tic anomaly zone.Regional gravity fields are divided into three zones.The authors pointed out that the one of Longmen Mountains is a positive harmonious anomaly zone.In application of electromagnetic sounding and deep seismic data accosiated with geological analysis,the crust structure horizontally could be divided into four regions(the sima gentle region of west Sichuan Basin,the sima slope region of Longmen Mountains,the sima depressed region of Songpan-Heishui and the sima gentle region of Ruerga-Hongyuan-Aba rigion)and the upper mantle structure into three regions(the mantle gentleslope region of west Sichuan Basin,the mantle steep slope zone of Longmen Mountains and the mantlegentle slope region of Songpan-Ganzi);the lithosphere texture into four layers in vertical(upper crustlayer,lower crust layer,upper mantle cover and the layer underlying the asthenosphere).The paper has revealed the feature of the lithosphere in Longmen Mountains thrust belt and laid afoundation for the studying the mechanism of this thrust belt.