Metallogenic Prediction on Phosphorite in North ChinaXiong Xianxiao*作者简介：熊先孝(1961-)，男，博士研究生，教授级高级工程师。主要从事矿床地质研究及矿产资源评价工作。E-mail:xxxhgdyy.com.cn。 Li Bboyun Yao Chaomei 1 Resource and Environment College , Wuhan Science and Technology University ,Wuhan 4300702 Geological Institute of China Chemical Geology and Mining Bureau ,Hebei Zhuozhou 072754Abstract:The metallogenic conditions of phosphorite exist extentivly in Sino-Korean paraplatforms as well as the deep-seated fault of brink Tarim paraplatform and the middle zone of several geosyncline folded areas such as TianshanXingan, Chilien- Chinling and Ererguna. Research and analysis showed that the endogenesis phosphorite have better prospecting potential as well as the greenstone belt phosphorite and sedimentary & metamorphic phosphorite in Paleoproterozoic Era, the sedimentary phosphorite usually with low-grade and in small scale. 4 Grade-B metallogenic predicting regions, 15 Grade-C metallogenic belts, 19 Grade-D metallogenic subzones for phosphorite have been marked off in north China. At the same time, we set up 2 Grade-A, 13 Grade-B and 13 Grade-C metallogenic predicting regions, 22 areas have been selected for further work.Key words: North Phosphorite, Metallogenic Background, Metallogenic Conditions, Metallogenic Prediction, Resource Potential.1 IntroductionThe area of surveying lie in northern China which include more than 15 provinces, cities and districts (eg. Sinkiang, Qinghai, Gansu, Ningxia，Shanxi，Hebei, Beijing, Tianjin, Shanxi, Liaoning, Jilin, Heilongjiang and Mongolia).The phosphorite of north China mainly present in Sino-Korean paraplatform, Tarimu paraplatform, Tianshan-Xingan, Chilien- Chinling and Eerguna fold area. Deposits within the platformal area mainly present at the border or uplifted zone of it, and the deposits in fold area are usually present in central belt of the area. The platformal phosphate deposits have large distribution, with more in number as well as in scale in folded area.2 Geological FrameworkThe Sino-Korean Paraplatform is the oldest platform of China with crystalline basement made upon metamorphic rocks of Archean and Paleoproterozoic age. The crystalline basement rock is capped by Mesoproterozoic to Triassic age sediments. The platformal area is characterised by pressure of enormous fractures and boarded by deep-seated faults. These deep-seated fault control the formation of endogenesis phosphorite and the phosphate rocks mainly present at the intersection deep-seated fault and other faults.Magmatic rock present in the area are ranging in age from Lliangiant to Himalaya time, they include ultrabasic , basic , intermediate , acidic and alkali in composition. The mineralized zone is mosty in Lliangiant , Controlled by latitudinal deep-seated fault late Variscan and early Indo-Chinese epoch. Rocks are present in belt shape having basic, ultrabasics, within Shangyi-Chi City-Pingquan and ultrabasic- alkaline complex in Yangyuan-Suizhong-Fengcheng.Tarimu Paraplatform is situated to the south of Tianshan and north of the Kunlun, forming rhombus shape with multicyclic tectonic movement. The last being theYangtze cycle.There are formation on a lot of inner fold and fracture ,especially the latitudinal structure. Three different styles of fractures exist in the platform including south Haerke Mountain, northern borderland of Tarimu platform and the deep-seated fault within the platform. The cyclic activities control the extrusion and frusion of alkali magma in deepest part of the northern borderland . Alkali rock distributes in deep-seated zone; Ganbulake alkali complex in Weili town, Wajiertag in Bachu town and Mazhaertag alkali complex within the platform; Bashijingong alkali-syenite in Atushi city and the Tarimu alkali granite at the border of the platform. Apart from the multiphase alkaline complex submarine volcano eruption also exist in south Haerke mountain fault belt. The complex is composed of alkaline basic rock, alkaline ultrabasic rock, alkaline intermediate rock and alkaline acidic rock. Tianshan-Xingan Folded Area islocated in north of Tarimu and Sino-Korean paraplatform, forming a part of huge Central Asia- Mongolia fold system. It is Tianshan fold system and Jilin-Heilongjiang fold system that are related with phosphate mineralization, sedimentating phosphorite deposits associated with former one are not found in other fold systems in Early Cambrian time and the latter one produces phosphorite in early Paleoproterozoic Era.Chilien- Chinling Fold area is lacated in south of Sino-Korean paraplatform and northwest of Yangtze paraplatform, it is a latitudinal fold belt with a polycycle folding mainly of Indo-Chinese orogeny including Chinling and Chilien mountains. They get stabilized after 2 billion years of Yangtse Cycles during late Early Cambrian time. The known phosphorite deposits in this area mainly distribute in Chilien fold zone and ea