摘要:
以浙西北地区1∶20万Cu水系沉积物测量为例,通过含量排列法对由分形求和法所圈定的地球化学异常区进行了内部结构分析,认为无标度区掩盖了异常场的内部结构。借鉴前人提出的含量排列法,将异常区数据从小到大按顺序等间距自然排列,并用三段直线( L1、L2、L3)进行拟合,L1为一级异常,L2、L3被归入二级异常。结果发现,一级弱异常基本不含矿,但仍有个别矿点落入该区;二级异常近似代表了矿致异常,与区域断裂、岩浆活动中心在空间上具有更显著的相关性,从中强调了岩浆源区、构造背景转换和断裂交汇的控矿意义,由此圈定出了一些重点异常作为下一步成矿预测工作的首选靶区。
Abstract:
With 1 ∶ 200 000 stream sediment survey of copper in northwestern Zhejiang Province as an example, the authors used the content arrangement method to study the internal structural features of Cu geochemical anomalies delineated by the Fractal Summation Method in this area. It is the stability of fractal non?scale section that masks the internal spatial structure of the anomalous field, and the ignored fact therein is that such an internal structure can be manifested by a natural revelation or content arrangement ( of copper from small to large content) of the original anomalous sample data itself, rather than an effort to overcome the stability of non?scale sec?tions. Three lines of L1 , L2 , and L3 are used to fit the hierarchical evolution trends, namely the internal structure, of anomalous data, and therein, L1 specifies the primary anomaly, and L2+L3 specify the advanced anomaly. Studies show that the primary anomaly ( L1 ) may correspond in general to a weak mineralization and essentially barren area, although it does contain some weak mineralization or several hidden ore spots;the secondary one ( L2+L3 ) can be approximately or equally considered as the mineralized anomalous area, between which and the regional tectonomagmatic activity there is a further significant spatial correlation;some new undiscovered copper prospecting target was discovered at last on the basis of the study of the ore?controlling significance of magmatic source, tectonic trans?formation, and convergence of faults in this area.
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