The application of bidimensional empirical mode decomposition (BEMD) to the extraction of Pt and Pd anomalies in eastern Yunnan Province

The bidimensional empirical mode decomposition(BEMD)was applied to analyze non-stationary Pt-Pd concentration data in eastern Yunnan Province. Two kinds of Pt-Pd anomalies were obtained. One is the regional Pt-Pd anomalies shown in the BIMF3, and the other is the local Pt-Pd anomalies shown in the BIMF2. The regional Pt-Pd anomalies can be subdivided into two subtypes based on geological features of the anomalies. One includes anomalies with obvious concentrated centers and high anomalous intensity located in Emeishan basalt areas controlled by the SN-trending Xiaojiang fault and the NE-trending Xundian-Xuanwei fault, whereas the other includes the weak anomalies distributed in black rock series within central and southern parts of the study area. The former constitutes the favorable areas in search for Pt-Pd deposits. The local Pt-Pd anomalies can also be subdivided into three subtypes: the first one include anomalies located in the Emeishan basalts controlled by the intersecting areas of the SN- and the NE-trending deep-seated faults and their secondary faults; the second one include those located in black rock series with different geological epochs; the third one include those located on the northeastern side of the Ailaoshan fault and associated with basic, ultra-basic intrusive rocks. Among them, the Pt-Pd anomalies with high strength of the first subtype are prospective areas in search for Pt-Pd deposits.