摘要
1 Geology and origin of the Yimen-type copper deposits THE Yimen copper mining district is located in a rift environment on the margins of the Yangtze continent and occurs in the middle segment of the Wuding-Yimen-Yuanjiang fault depression zone in theProterozoic Kunyang rift, with the Lujijiang fault as the boundary in the west and the Luoci-Yimen faultas the boundary in the east, and in the north it borders on the Luwu copper ore field and in the south itlinks with the Yuanjiang copper deposit, thus constituting an SN-striking elongated basin. Exposed in themining district are mainly the Heishantou, Dalongkou, Meidang, Yingming, Luoxue, Elachang and Lujijiang formations of the Early-Middle Proterozoic Kunyang Group, constituting a suite of lightly metamorphic rocks of low greenschist facies, and locally the Debadu Formation-complexes of the Early Proterozoic-Archean Dahongshan Group. The mining district can be divided into two ore zones: the east ore zone andthe west ore zone. Mainly distributed in the west ore zone are the volcano-sedox-strongly reworked-deepsource superimposed-type ( Fengshan-type) ore deposits, including the Sanjiachang ( including theShishan and Fengshan copper deposits), Yiduochang, Elachang, Tianxing and Meishan copper deposits(occurrences) which are all designated to the typical Yimen-type copper deposits. In the east ore
