The Study Of The Carboniferous-Devonian Distribution And It's Ore-controlling Regularity In Areas On The Lower-middle Reaches Of The Yangtze River

The metallogenic belt of Yangtze River is the most important copper and iron ore belt of polymetallic. It is composed of multiple ore district such as southeastern Hubei, Jiurui, Anqing-Guichi, Tongling, Luzong and Ningwu etc. The unconformity interface between the top of Wutong formation (D3w) of Devonian and the Huanglong Formation (C2/h) of Carboniferous is the most important stratum that host copper and iron ore belt. There is a big ratio of the metal reserves controlled by the stratum in the whole metallogenic belt.In order to study the Carboniferous-Devonian distribution and it's ore-controlling regularity in areas on the lower-middle reaches of the Yangtze River, we contrast and in-depth analysis a large number of information about different strata of the Yangtze River such as typical section of the different stratigraphic area, Tectonic evolution event and depositional environment etc. And the cognition as following:(1) The upper of Wutong formation that widely distributed along the Yangtze River is the cross-discipline lithostratigraphic units and the interface of the carboniferous and devonian lies on the top of upper Wutong formation.(2) Sedimentary deposit and stratabound deposits distribute in the archicontinent or on the edge of the depression basin. The contemporaneous fault controlled the distribution of sedimentary facies and the sedimentary or stratabound deposits.(3) parallel unconformity in the bottom of the Carboniferous is the result of multiple tectonic activity. And the interlaminar glide plane that is formed by the later tectonization is the important ore-control interface. It is the favorable location that promote mineralization and provide the material source and the heat source.(4) Sedimentary discontinuity interface (lithology transform section) is an important ore reserve position in the stratum. The discontinuity surface beneath the upper carboniferous (C2) and the denudation interface between the lower Triassic and Permian (T1/P) are most important. They are in close relationship with the distribution of the copper, iron, sulfur, gold and other deposits.(5) Stratabound deposits reserve in the sedimentary discontinuity surface between the clasolite and carbonatite or in the dolomite and dolomitic limestone upon the overthrust interface. Stratabound-type Ag, Au deposit that related to the quartz diorite porphyry appear in the bottom of Huanglong formation or the interface between the dolomite and limestone in Huanglong formation in most cases. And the contact zone between the Quartz diorite porphyrite and the limestone of Ordovician, Permian and Triassic are important reserve position of the skarn-type Au, Ag deposit.(6) The unconformity contact interface between the Huanglong formation in carboniferous and the lower stratum is a major regional ore reserve horizon; The primary illuvial horizon, the decollement in the sedimentary discontinuity interface, the interlaminar decollement and other construction composite position is an important ore reserve space.