Bidimensional empirical mode decomposition (BEMD) for extraction of gravity anomalies associated with gold mineralization in the Tongshi gold field, Western Shandong Uplifted Block, Eastern China

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• 作者：Jingning Huang ; Binbin Zhao ; Yongqing Chen ; Pengda Zhao
• 关键词：BEMD ; Gravity anomaly ; Gold deposits ; Tongshi complex ; Western Shandong Uplift ; Eastern China
• 刊名：Computers and Geosciences
• 出版年：2010
• 出版时间：July 2010
• 年：2010
• 卷：36
• 期：7
• 页码：987-995
• 全文大小：1732 K

文摘

A bidimensional empirical mode decomposition (BEMD) program on a MATLAB platform was effectively used to handle gravity signals for the Tongshi gold field. This yielded a two-dimensional intrinsic mode function (IMF₃) image that meticulously depicts the spatial distribution relationship between various gold deposits and the different geological units of the gold field. By combining the IMF₃ image with geological features, the Tongshi gold field can be divided into three geological units. Unit I is made up of both Archean greenstone and Cambrian–Ordovician carbonate rocks and is defined as a concealed basement that exhibits weak negative and positive gravity anomalies. Unit II is defined as a Mesozoic volcanic sediment basin consisting of Jurassic and Cretaceous volcanic-sedimentary rocks, which developed on the concealed basement and exhibits an obvious negative gravity anomaly. Unit III, located on the concealed basement on the SW side of the Mesozoic volcanic-sedimentary basin, can be subdivided into subunits IIIa and IIIb. The former, with a negative circular gravity anomaly, indicates that the Tongshi complex consists of both Yanshan diorite-porphyrite and syenite-porphyry. Unit IIIb, with a positive ring gravity anomaly distributed around a negative circular gravity anomaly, indicates a possible contact metasomatic mineralization zone around the Tongshi complex. Almost all types of gold deposits are located within this contact metasomatic mineralization zone and thus the zone is a prospective area for gold deposits.