Inner Mongolia Hada Temple Area Tectonic - Magmatic Evolution And Gold Mineralization Studies

The central Asia orogen is a continental collision zone where small crustal blocks (terranes), typically volcanic arcs or micro-continents are welded onto older crustal blocks with significant ore deposits and additional resource potential. There has produced many world-class mineral deposits of gold, silver, copper, molybdenum, lead, zinc and nickel in the western section of the central Asia orogen, which are generally well understood. But, there are few analogous deposits in the estern section of the central Asia orogen.Through researching on the features and evolution of the Paloe-Asia Ocean, and the magmas and the related gold deposits in Hadamiao areas, that the rules about the eastern sectors of the Paloe-Asia Ocean has been concluded, and the evolution model of the magmas in Hadamiao areas and the metallogenic model of the gold deposits has been built in this paper. Based on analysising the geological, and the physical, and the chemical, and the remote sensors, the gold resource potential in Hadamiao areas be prospected. By systematic studying of the gold deposits in Hadamiao areas and the lots of adjacent deposits, the potential of metallogenic (such as gold, copper, molybdenum and et al.) in the northern margins of the North China Platforms has been estimated.This study have got more innovative progresses and achievements.(1) The high accurate zircon U-Pb ages of nine magmatic rocks in Hadamiao area of the northern margins of the North China Platforms were measured firstly, and the chronology sequence of the magmatic rocks was built, and two groups tectonic and magmatic events be comfirmed, and it composed of the early-Paloezoic events with the ages of 445.6±2.7Ma and the late-Paloezic events with the ages from 277Ma to 257Ma. And the traditional viewpoints that the magmatic rocks was happened in Yanshanian period has been changed. At the same time, the evolution of the Paloe-Asia Oceans in the eastern sectors has been restricted.(2) The space/time distribution of the Hadamiao magmas have a certain rules. The early-Paloezic magmatic rocks developed in the accretionary complexes of Bainaimiao, and controlled by the Xuniwusu faults, such as the granodiorites(with age of 445.6±2.7Ma) with the property of the arc magmas in the eastern sectors of Bilihe gold mine area, and the gneissic quratz diorites(with age from 459Ma to 454Ma) and the granodiorite porphyry (with ages of 440Ma)with the property of the arc magmas. The late-Paloezic granites distributed between the Ondor Sum faults and the Xuniwusu faults, and accreted and stacked in the early-Paloezic accreted complexes with the property of the arc magmas. And it was made up of the parts of the magmatic belts with the property of the arc magmas in the Inner Mogolia Plateaus, such as Hadamiao quratz diorites(with age from 277Ma to 273Ma) and the grano-porphyrys (with age from 272Ma to 270Ma) in Hadamiao gold mine area, and the granodiorite porphyrys (with age of 269±2.5Ma) and the grano-porphyry (with age from 272Ma to 270Ma) and the granodiorites(with age of 267±1.3Ma) in Bilihe gold mine area, and the feldspar granites (with age from 263Ma to 262Ma) in the southern sector of Xianghuangqi county area, and the adamellites(with age of 266±2Ma) in the northern sector of Xianghuangqi county area, and the quratz diorites (with age of 266±2 Ma)and the adakitic granites(with age of 267.2±1.4Ma) in the eastern sector of Xianghuangqi county area.(3) Through the systematic petrology and geochemistry studying of the magmatics in Hadamiao areas, the magmas genesis has been found out. The original of the early-Paloezoic granites (εHf(t)=5.079 to 7.899) in the eastern sector of Bilihe gold mine area come from the wedge-type mantles above the subduction slaps of the ocean blocks. The Hadamiao quartz-diorites (with age from 277 to 273Ma) contained with lots of SZC matters, and the geochemical features (SiO2=57.33 to 60.34, and ISr=0.706 to 0.707, andεNd(t)=-3.8 to-4.0, andεHf(t)=-0.44 to 3.88) show that their origin is the enriched mantles and metasomatited by the SZC matters, and have strongly mixed by the crust(fresh forming crusts). The gold-bearing grano-porphyries in Hadamiao area and the Belihe rhyolites (with age from 272 to 269Ma) with high contents of SiO2, and the standardized value of U and Th and K, and relatively defective standardizing value of Eu and Sr and Ba, showed that they were the Collision-type Granites. The biotite-granites in Haoyihada haing some adakitic property, and the features of Sr-Nd-Hf (ISr=0.704 to 0.707, andεNd(t)=-3.6 to-4.0; andεHf(t)=-0.44 to 3.88) show that origined from the fresh forming lower crust, and the gold-bearing grano-porphyries in Hadamiao(ISr=0.704 to 0.707, andεNd(t)=-3.6 to-4.0; andεHf(t)=-0.44 to 3.88) was origined from the upper of the fresh forming lower crust. The features of the isotopes(ISr=0.703 to 0.704, andεNd(t)=+1.2 to+1.7, andεHf(t)=7.03 to 9.35) from Bilihe granites show that its property is A-type granite bearing more components of defective mantles.(4) Through analyzing the combination of the magmas and the tectonic setting, the evolution process of the Paleozoic Asia Ocean orgining from the subduction to collision and extending during after-orogeny period in Hadamiao area has been confirmed clearly. The subduction of the Paleozoic Asia Ocean took place during the period from 277Ma and 273Ma, and marked by the Hadamiao quartz-diorites. And the collision of the arc between the continents or between the arcs took place during the period from 272Ma to 269Ma, and marked by the gold-bearing grano-porphyry in Hadamiao area and the rhyolites in Bilihe area. And the tectonically transforming from transpression to transtension took place during the period from 269 Ma to 267Ma, and marked by the adakitc granites in Haoyihada area and the gold-bearing granite diorite porphyry in Bilihe gold deposits. The extending took place at 258Ma, and marked by the granodiorites with the property of the A-type granites in Xianghuangqi area. Thus, the tectonic-magmas evolution model of Hadamiao area has been built.(5) The favorable controlling factors for gold metallogenic in Hadamiao area are mainly the tectonic features and S-type granites. The gold mineralization of the Bilihe gold deposit and the Hadamiao gold deposit took place under the collision setting during the shifted stages from the tectonically transforming from transpression to transtension in the late-Paloezoic period, while was not the within plate conditions. And the S-type granites related to gold mineralization is characteristiced by the large extension values of the Isr, and bearing a lots of old captured zircons (with age from 1166Ma to 1127Ma), and having mixed strongly by the crust, and the magmas bearing boron. It provided the accurate time for understanding the gold and combined elements ore-forming processes. So, the realistic deposit model of gold deposits has been established.(6) Based on the genetic model of the gold deposits, and the abnormal areas of metallogenic related elements assembled of R types factors, and the remote sensors information, and the gravities and the aeromagnetic survey datum has been analysized. It is conformed that the granodiorites around Bilihe gold deposits, and the biotitic-granites with the property of adakites in Haoyihada, and the Houerdaogou granodiorites in Xianghuangqi all have the great gold metallogenic potentials. The abnormal areas of the gravity, and the aeromagnetic survey, and the metallogenic elements assembled of R types factors(Cu-Au-Ag-Bi), and the intersection areas between the volcanic breaking basins and the extended normal faults northwest-wards, and the granites with the reducing property of the imelnite series and bearing boron are the important controlling factors for the regional mineral resources appraising, and also are the indicating marks for metallogenic exploration and prospecting work in Hadamiao Areas.(7) By analyzing and comparative studying the regional metallogenic rules among regional areas, it is found out firstly that there be a late-Paloezoic metallogenic belts in the northern margins of the North China Platform, which composed of the Hadamiao gold deposits related to the magmas and the metallogenic belts of copper and molybdenum in the regions of Chifeng, which located in the eastern sections of the nothern China and the gold deposits related to magmas in the Wula Mountain and the Daqing Mountain in the western Mogolia province of China. And it developed in the magmatic belts with the property of the arc magmas in Inner Mogolia Plateaus. The regional metallogenic belts have great minerals resources potential.