Abstract:

The Kangbutiebao Formation is distributed in the southern margin of Altay, Xinjiang. Based on the regional geology and geological section, this study holds the idea that the Kangbutiebao Formation should be redeterminated on account of the obvious differences in rock assemblages, metamorphic-deformation and ore-bearing potential among the eastern, middle and western parts. The age of Kangbutiebao Formation(D₁k) which is located in Kelan and Maizi Basin is of Early Devonian according to the fossils and geochronology. Field measuring geological sections reveal that the D₁k include acid volcanic rocks and volcaniclastic rocks interbedded normal clastic rocks (low-grade metamorphic). It can be divided into four lithologic units from bottom to top: the first lithologic unit (D₁k^a) is mainly of micaschist; the second (D₁k^b) contains calcareous schists, calcareous sandstones and meta-tuffaceous sandstones; the third (D₁k^c) chiefly comprises meta-acid rhyolite and tuff; and the fourth (D₁k^d) is mainly meta-rhyolite and meta-rhyolitic pyroclastic rocks. But the ‘Kangbutiebao Formation’ in Qinghe region (the eastern part) and Fuyun region (the southern section of the middle part) consists of high-grade metamorphic and migmatization rocks and is less of geochronology data, and it should be disintegrated from the D₁k and be re-determinated and be renamed after the further study of metamorphism and geochronology in this area.

Key words: Kangbutiebao Formation, Devonian, Altay, north Xinjiang