基于MAPGIS平台下分形理论在地球化学异常圈定中的应用

The application of fractal theory to delineation of geochemical anomalies based on MAPGIS

确定异常下限的传统方法是基于统计理论的,只考虑了数据的随机性;但是地球化学数据不仅具有随机性,还具有不规则性和自相似性,适合用分形理论来处理。作者采用基于分形理论的含量面积法来确定地球化学元素的异常下限,同时以具有强大的数据处理能力和空间信息处理能力GIS技术为平台,构建出地球化学异常的自动圈定的新方法。在西南三江北段地球化学元素异常圈定的应用实例表明,该方法能有效提高地球化学异常识别的精度和自动化程度。

Geochemical anomaly is all long the important foundation to forecast minerals. The traditional algorithm to find the low limit of geochemical anomalies is based on the statistics. It only considers the randomness. However, the geochemical data are irregular and self similar in addition, so they should be done with fractal theory. The authors introduce a new technique to delineate geochemical anomalies automatically, adopt a content-area method based on fractal theory to find the low limit of geochemical anomalies, and take the technology of GIS as the platform of mass data and space information management. The practice in the northern reaches of the three rivers area （Jinsha River, Lancang River and Nujiang River） in the southwest of China has proved the technique efficient.