Geochemical Constraint on the Metallogenetical Geological Background and Genesis of Tuolugou Sedimentary-Exhalative Cobalt-Gold Deposit

Tuolugou cobalt-gold deposit is a newly discovered deposit in the southern margin of Eastern Kunlun orogen, hosted in an epimetamorphosed (green schist facies) Sinian-Cambrian volcanic-sedimentary rocks. The volcanic rocks consist of a suite of intermediate to siliceous tuff and lava, its geochemistry indicates that it is similar to active continental marginal or arc volcanic rocks. The sedimentary rocks composed of clastic rocks and black shales, show the geochemical characteristics of active continental marginal sedimentary rocks, some of them show the feature of modern continental arc sedimentary rocks. The study on the petrology, mineralogy and elementary geochemistry indicate that the quartz albitite, as one of host rocks, is not dikes but typical exhalative-sedimentary rock, which is not only an important indicators for ore prospecting, but also an important discriminating criteria for sedimentary-ex-halative genesis of the deposits. The ore structure and generation of cobalt-gold ore minerals suggest that their formation mainly related to submarine sedimentary exhalation, reformed and mobilized in late collision orogenesis. The trace elementary geochemistry of cobalt-gold ore and exhalative-sedimentary rocks suggest that both of them belong to vent-distal sedimentary-exhalative genesis that exhalative-metallogenetic fluids were far from exhalation center. In conclusion, the data on petrology and elementary geochemistry indicate that Tuolugou cobalt-gold deposit mainly belong to sedimentary-exhalative genesis, and formed in the Sinian-Cambrian active continental marginal environment at the southern margin of Eastern Kunlun orogen.