摘要
本文通过对康定-渡口地区的爆破地震测深资料的分析,将该区地壳结构划分为上地壳和下地壳,它们在横向上被若干断裂所切割,而呈断块结构。地壳厚度由北向南减薄,在康定为56km,西昌54km,渡口52km。莫氏面由北向南也逐渐抬升。地壳平均速度为6.2—6.25km/s,Pn速度为7.5—7.6km/s。上地幔顶部出现速度异常。西昌地区壳下存在一厚度为22—28km,层速度为7.5—7.6km/s的壳幔过渡带。区内某些地段近地表处存在有速度为6.1—6.3km/s的高速体。地壳中部9—14km处,存在5.7—5.8km/s的低速层。
The data of the explosion seismic sounding conducted in the Kangding-Dukou area indicate that the crust there can be divided into the upper crust and the lower crust, having thicknesses of about 28 and 26 km respectively. The crust of the area is 51—56 km in thickness. The mean crustal velocity is 6.2—6.26 km/s. Below the Moho there is a crust-mantle transition zone with a layer velocity of 7.5—7.6 km/s and a thickness of 22—29km. A low-velocity layer exists in the middle and upper parts of the crust, with a thickness of 9—14 km and a layer-velocity of 5.7—5.8 km/s.
An analysis shows that the crustal structure possesses some features of modern continental rifts, possibly the vestiges of the Panxi paleorift.
出处
《地质论评》
CAS
CSCD
北大核心
1989年第1期41-51,共11页
Geological Review
