冈底斯南麓花岗岩成因与航磁异常格架的关系

西藏冈底斯南麓是我国重要的一个火山-岩浆弧.自中生代以来,受特提斯演化以及后期陆内汇聚碰撞造山作用的控制,地块广泛发育花岗岩.其中,部分花岗岩具有较强的磁性,造成了航磁异常,它们的展布方式也决定了航磁异常的格架.探求航磁异常与花岗岩的联系对于迅速评价航磁异常、圈定隐伏岩体具有重要的意义.本文首先以多尺度边缘检测为手段对研究区航磁异常格架进行讨论,再以区域花岗岩的主微量元素对花岗岩成因进行讨论.1)东段北东向航磁异常主体是由新生代花岗岩所引起,西段存在北东向和北西向两个航磁异常,分别对应于晚白垩纪、第三纪花岗岩.2)新生代东西两段花岗岩磁性的差异与东西两段造山强度有关系.

Relation Between Aeromagnetic Anomaly' Framework and Genesis of Granites in South Gangdise

South Gangdise is an important volcano magmatic arc.From Mesozoic Era,because of tethys'evolution and intracontinent collision,the block has developed large quantities of granites.Some granites has strong magnetism to cause aeromagnetic anomaly,and their distribution control the framework of aeromagnetic anomaly.Searching for the relation between granites and aeromagnetic anomaly is important for evaluating aeromagnetic anomalies and locating buried rock.First,this paper discussed the framework of aeromagnetic anomaly through multiple dimensioned edge detection,then discussed the genesis of granites through major and trace element.① Northeast aeromagnetic anomaly of East Gangdise is attributed to granites of Cenozoic Era,and Northeast and Northwest aeromagnetic anomaly of Wset Gangdise are separately attributed to granites of Cenozoic Era and chalk Era.② The diffirents Strength of intracontinent collision between West and East of granites is reason for diffirents of magnetism.