Geochronology Study and Geological Significance of Cobalt-Nickel-Rich Albite Breccia in the Fengxian-Shanyang, Qinling Orogenic Belt

In the Fengxian-Shanyang, Qinling orogenic belt, there are large amounts of albites breccia that show the obvious enrichment of cobalt and nickel elements, which therefore are important for the ore probe. In this paper, a total of 6 albite breccia related to Co-Ni deposits and mineralization points have been found through field geological investigation (Boyugou albite breccia in the Shangnan County, Guofenglou dolomite-bearing albite breccia in the Shangnan County, Kaihe dolomite-bearing albite breccia in the Shangnan County, Kaihe iron-dolomite- and calcite-bearing albite breccia in the Shangnan County, Tongmugou iron-dolomite-bearing albite breccia in the Shanyang County and Shuidigou dolomitbearing albite breccia in the Fenghuang Town of the Zhashui County). Systematic studies of petrology, zircon U-Pb chronology, and zircon trace elements display that these cobalt-nickel-rich albite breccia are mainly grayish white and bluish gray with massive structure and brecciated structure, and some areas occasionally exist the pyrite, calcite, quartz and albite veins. The zircons of albite breccia are mostly idiomorphic and semi-idiomorphic, and their ages are concentrated in 375~543 Ma, 665~959 Ma, and 963~1155 Ma. Their age peaks are corresponding to the Early Devonian, Silurian, Ordovician, Neoproterozoic, Mesoproterozoic, and Paleoproterozoic. The comprehensive studies demonstrate that the zircon ages of these cobalt-nickel-rich albite breccia are consistent with the age of Devonian strata. Crust-derived sediments of different periods are contributed to the sedimentary process of Devonian albite breccia, and the later magmatic -hydrothermal processes are responsible for the enrichment of nickel-cobalt breccia deposits. In conclusion, the albite breccia exposed in the study area has the potential for cobalt-nickel mineralization.