关键词: 局部奇异性, 元素富集方向, 勘查地球化学, 金矿床, 胶东地体

Abstract:

The Jiaodong Terrane is famous for the development of a large number of Mesozoic gold deposits. However, the genesis of the gold deposits is still controversial, where a focus of debate is whether the formation of gold deposits is controlled by the shallow structure or by the deep geodynamic background, i.e., retraction of the Pacific plate after its westward subduction. In order to further quantitatively describe the plate movement and abnormal geological events during the formation of the gold deposits, this paper, based on previous work, uses the 1∶50,000 geochemical exploration data of Biguo area, Jiaodong to extract and decompose the Au anomaly data. Singularity analysis, quantile regression and Fry analysis were performed in sequence to quantitatively characterize Au geochemical anomalies and determine the anomaly dispersion pattern. The results show that Au enrichment is in three directions: N-E (or S-N), E-W and N-W, which may correspond to westward subduction and slab rollback of the Pacific plate in the Mesozoic, northward movement of the Yangtze plate in the Cenozoic, and large scale N-W/S-W strike-slip faulting and structural superposition in the Tanlu fault zone in the Middle Cenozoic, respectively. This may indicate that the general pattern of Au enrichment and the formation of gold deposits in Jiaodong may have been controlled by the deep geological process. This study identified geochemical anomalies associated with the known Au mineral deposits in the area, which is useful not only for guiding Au exploration but also for providing surface geochemical patterns reflecting influence of plate tectonics in the Jiaodong Terrane.

Key words: local singularity, elemental enrichment direction, exploration geochemistry, gold deposits, Jiaodong Terrane