Huge quantities of bauxite ores have been recently discovered in Wuchuan, Zheng’an and Daozhen Counties, Northern Guizhou. More than 20 lateritic bauxite deposits with more than 150 million tons of bauxite reserves have been identified in the area and several other unexplored districts also show bauxite mineralization potentials. Initial investigations have provided a first insight into the geology, geochemistry and conditions of bauxite deposits formation in the Wuchuan-Zheng’an-Daozhen (WZD) area. However, the detailed ore-forming process is still ambiguous and the source rock of the WZD bauxite deposits has long been a matter of debate.

Since 2009, GU Jing and HUANG Zhilong from the State Key of Laboratory of Ore Deposit Geochemistry (SKLODG) at Institute of Geochemistry, Chinese Academy of Sciences (IGCAS) have carried out the research on the bauxite deposits in the WZD area. Based on the mineralogical, petrographical and geochemical analyses, combining with the regional and mining area geological background, the researchers proposed a four-stage ore-forming process for WZD bauxite: weathering and transportation, in-situ weathering process, transportation and re-deposition, and epigenetic reworking process.

Furthermore, they studied SIMS and LA-ICP-MS U-Pb ages for detrital zircons from bauxite and samples from the Hanjiadian Group in the WZD area to provide new constrains on the provenance of the WZD bauxite and to provide new insight on the bauxite ore-forming process. The results indicated that the bauxites were genetically related to the Hanjiadian sediments. The researchers also suggested that the main provenances of the WZD bauxite and the Hanjiadian Group were the Neoproterozoic igneous rocks in the western Yangtze Block and the Grenville-age igneous rocks in the southern Cathaysia Block.

The above research is jointly supported by the 12th Five-Year Plan project of SKLODG (No. SKLODG-ZY125-02), the Key Research Program of CAS (KZCX2-YW-Q04-05), and a Special Research Fund of the SKLODG, IGCAS (KCZX20090103).

More details of the research have been published in Journal of Geochemical Exploration and Journal of Asian Earth Sciences.

(By GU Jing)