华北板块与西伯利亚板块缝合带之重磁证据

    GRAVITY AND MAGNETIC EVIDENCES FOR THE SUTURE ZONE BETWEEN NORTH CHINA PLATE AND SIBERIAN PLATE

    • 摘要: 通过对东北地区重磁数据重新处理,从重磁场特征角度分析和讨论目前地质界一直争论的华北板块与西伯利亚板块缝合带的位置问题,并得出了新的认识.认为华北板块与西伯利亚板缝合带为约240 km宽的近似等宽带.该缝合带的走向自东北地区西部朝阳北、通辽南,走向北东东,过沈阳北、长春北折向南东东,直到通化北和珲春南.这样的认识主要来自区域重、磁资料的综合分析,包括原始数据、垂向及水平各方向导数、水平梯度模、不同上延高度、小波、小子域及插值等多种滤波、信号提取及增强等多种处理后反映出的异常特征.该带南与北、内与外的重磁异常存在明显差异.通常表现为带内与带外的异常错动、曲线扭曲、走向改变、规模差异、特征冲突.比如松辽盆地就在带的南北宽度上发生重大变化,甚至包括山势也因其存在而变得内外有别.

       

      Abstract: By reprocessing the gravity and magnetic data in Northeast China, the paper discusses the location of suture zone between North China Plate and Siberia Plate, which has been controversial for long, and gains a new understanding. It is considered that, in Northeast China, the suture is with an approximately equal width about 240 km, starting from north Chaoyang-south Tongliao in the west with NEE trend, turning SEE through north Shenyang-north Changchun, to north Tonghua-south Hunchun. Such understanding mainly comes from the comprehensive analysis of regional gravity and magnetic data, including the primary data, vertical and horizontal derivatives, horizontal gradient mode, different upper continuation heights, several filtering such as wavelet, small subdomain and interpolation, and anomaly characteristics reflected by various processing like signal extraction and enhancement. There are obvious differences in gravity and magnetic anomaly between the south and north, inside and outside of the zone, commonly showing anomaly dislocation, curve distortion, trend change, scale difference and feature interaction between inside and outside. For example, the Songliao Basin has undergone significant changes in the north-south width, and even the terrains and mountains are differentiated due to the existence of the suture zone.

       

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