摘要
经过三维重力正演计算,我们从台湾的布格重力异常中求得了深部重力异常,其深度相当于地壳下层。分析对比之后发现,深部重力异常等值线的形态,较好地反映了台湾的现代构造地貌特征。如东部等值线的同步弯曲,犹如错断水系,反映现代板块运动的方向;中部大面积零值和负值线圈闭,反映中央山脉的整体上升;在一些等值线聚合成梯度的地带,又往往是某些深断裂的反映。是否可以这样认为,深部重力异常是地壳深处介质密度沿某一方向的差异;现代构造地貌则是深部物性的表层反映。台湾如此,一切现代板块运动剧烈的地区,其表层地貌也都有一定的深部地球物理机制做为根源。
By using 3-D gravity forward calculation,we obtained the deep gravity anomalies of Tai-wan from its Bouguer anomaly.Its depth corresponds to the lower crust. Correlation andanalysis results show that the shape of contour lines of the deep gravity anomaly well charac-terizes the modern tectonic landform of taiwan.On the Eastern,Northeastern and Western foothills in Taiwan there are typical offsetstreams and the contour lines of deep gravity anomalies also appear synchronously withbend,reflectiong the dislocation of some faults and the direction of modern plate movementfrom surface to the interiors of the Earth.In the Central Part,the Central Range is an acutelyuplifting area and the contour lines of deep gravity anomaly show regular zero-value and neg-ative value trap.In other regions,the gravity lines show some gradient belts,where someheavily influenced fault zones exist.Perhaps it may be considered that the deep gravity anomaly is the mutation of the densi-ty of the deep crustal media along some directions,and the modern tectonic landform is thesurface revelation of the deep physical properties.This is true in Taiwan that in all the regions where the modern plate tectonic movementis acute,the surfacial landform has its deep geophysical mechanics.
出处
《台湾海峡》
CAS
CSCD
1993年第4期402-406,共5页
Journal of Oceanography In Taiwan Strait
基金
地震科学联合基金资助项目
关键词
构造地貌学
深部重力机制
台湾
Tectonic landform
deep gravity anomaly
Bouguer anomaly
deep gravity mechanism
Taiwan
