Hebei Province The Yixian Kong Gezhuang Gold Mineralization, Geological Features And Ore-forming Mechanism

Konggezhuang gold deposit lies in the east of the Zijingguan-Lingshan fault, west limb of Sigezhuang-Lianggang-Dugang-xiling anticline and north-west of Caichang-Guanzuoling rock mass.The strata, where Au-deposit is occurred, belong to the second and third section of the Changcheng System of middle-upper Proterozoic. The sedimentary facies of the second section show that the strata are formed in the ponded water of the shelf sea basin where water is deep, oxygen-deficient and reductive. Due to the active tectogenetic movement, fumarole activity and exhalative deposit, some mineralizing matters have been added to the strata, including charcoal from basin.The metallotectonics is very complex, mainly composed of multiphase faults those are of characteristic spatial distribution. Bedding faults are occurred on the surface of unconformity and lithostratigraphic boundary. The distribution of vein dikes and granite-porphyry is controlled by faults. The characteristic of quartz-diorite in Liujiagou shows that it is controlled by the compound positions of the north-west striking and north-south striking faults.The ore bodies can be divided into High-pitched mineral veins (include the fault alteration type, brecciated type and quartz veins of Liujiagou) and bedding mineral veins (refer to the stratified ore bodies those are of the stripes that are characteristic of the zebra). Fault alteration veins and brecciated veins are controlled mainly by the south-north striking faults , and quartz veins are controlled by the north-east striking faults in the quartz-diorite in Liujiagou. Fault alteration vein, take 9 for example, can be divided into thin-bedded vein zone, veinlet zone and line vein zone. Brecciated veins can be divided into baulder clay zone, crashed breccia zone and brecciation wall rock zone. The different zones are of different character. Bedding ore-bodies are controlled by bedding faults and often covered by culms. Iron pyrites are displayed along the surface of bedding faults, layering and microlayering.Strata, structures and magmatic rocks play the important role during the process of mineralization. High-pitched mineral veins are mainly controlled by the high-pitched faults, including south-north striking faults, north-west striking faults, north-east striking faults and the compound positions of faults. The attitude of bedding mineral veins are controlled by the bedding faults on the one hand, and hasintimate relationships with specific lithologic of ore-bearing strata and sedimentary contexts on the other hand. The rock masses, rock veins have provided the mineralizing matter and quantity of heat during the process of mineraliztion.After analyzing the history of geological development and result of isotopes study, it is believed that the resources of mineralizing matter includes substratum, covering stratum and rock magma. By the analysis of mineralization, it is considered that high-pitched veins and bedding veins are formed in same process of the mineralization owing to two different mechanisms of deposition. As a whole, the deposit belongs to middle-low temperature postmagmatic hydrothermal deposit.