Leading the Way


Geology

REGIONAL GEOLOGY

Sichuan Province is in southwestern China. The towns of Beichuan – Kangding – Muli mark the approximate boundary between the Sichuan Basin to the east and the Qinghai-Tibet Plateau and Hengduan Mountains to the west. On the east is the Yangtze platform and on the west the Songpan-Garze Fold System, but both areas are a part of the South China Plate. Sichuan has a complete stratigraphic sequence with abundant igneous rocks.


Although Sichuan is entirely part of the South China plate, there are major differences between the eastern and western parts. The Archean to the early Late Proterozoic, the stage when the basement was formed, is similar in both parts. However, from the Sinian (meta-sediments dated 800 Ma to 570 Ma) to the Triassic the geological sequences were different. The eastern part of the plate entered the platform development stage in an epicontinental sea environment, while the western part was a peri-continental sea environment, where the "Y-shaped" rift system at Kangding and Muli controlled sedimentation and volcanism. In the Late Permian-Triassic period the rifts spread rapidly and intensely. The Indosinian epoch is the most important period of tectonic movement in Sichuan. When marine sedimentation terminated in the east, rifts closed and the western part of the plate rose. The intra- continental reformation began in the Jurassic. The Yanshanian epoch was marked by an undulation in the east but as intense magmatism in the west. The Himalayan period slightly folded the Neogene strata in the east but intensely folded them in the west with accompanying uplifting and magmatism.


Faults are well developed in Sichuan and follow the same general distribution pattern as the Permian and Triassic rifts. Since the Indosinian epoch, the western part of the province has undergone compression and the upper crust has compressed and detached along the basement surface. This gave rise to numerous nappe structures and a shrinkage of about 50% in a series of "Jura-type" folds.


By the end of the Pliocene the elevation of the plateau in western Sichuan was 2,500 m above sea level which has increased to 4,000 to 5,000 m above sea level at present. The topographic difference between east and west and the high mountain at their juncture resulted from post Pleistocene movements.



LOCAL GEOLOGY

The property is located on the western limb of the Yidun-Maoyaba synclinorium and most of the outcropping strata are in the Permian, Triassic and Quaternary systems. The Permiam rocks are present on two sides of the Shama-Namaka Fracture zone, forming strips extending from south to north. The main lithologics are carbonate formations and clastic sediments with minor interbeds of volcanic rocks.


The Triassic System is the major stratum in the region, and is widespread and very thick. It is composed of meta-sandstone with interbeds of slate and phyllite with limestone lenses. The upper Triassic formations, the most widespread, are the Qugashi formation, the Tumugou formation and the Lamaya formation. The Qugashi formation consists of crystalline limestone and meta-sandstone with interbeds of quartz-pebble conglomerate and basic volcanic rocks. The Tumugou formation is principally meta-sandstone slate and conglomerate with some interbeds of sandstone and intermediate volcanic tuffs. The Jiaogenma deposit is in the sandstone beds of the second section of the Tumugou Formation. The Lamaya Formation consists of slightly metamorphosed sandstone with minor slate interbeds.


Quaternary sediments occur along rivers, ravines, terraces and piedmonts. The major lithologies are glacial tills, and alluvial, fluvial and slope deposits derived from glacial action.


The magmatic rocks occur in the Jinsha River, Genieyan-Changdukuo and Chola Mountain belts, from east to west. The Jinsha River Belt is principally volcanic rocks of the Indosinian Cycle (Triassic), lithologies include andesite, dacite, rhyolite and related breccias and tuffs.


The Genieyan-Changdukuo and Chola Mountain Belts consist of intermediate to acid intrusions emplaced in the late Yanshanian (135 – 205 Ma) to Himalayan (85Ma) periods (Jurassic to Quaternary or Larimide).


Jiaogenma is on the north side of the Rongyicuo Stock in the Genieyan-Changdukuo Zone. This stock is a medium to coarse, biotite-monzonite granite rich in bismuth, tungsten, silver, arsenic, and tin. It is believed in the 2006 Geology Prospecting Report prepared by Team 108 Geological Brigade, Sichuan Bureau of Geology and Mineral Resources that the stock provided metal for the deposits in the district. The Chola Mountain Metallogenic Belt is in the Yidun Island Arc. The Jiaogenma occurrence is in the east limb of the Zhangde overturned anticline between the Biezonglongba-Quwengcuo Fracture Zone and the Dulike-Hari Fracture Zones. The Former cuts the Rogyicuo rock mass and the later intersects it at depth. The Biezonglongba-Quweengcuo is a compresso-shear fracture of the Indosinian-Himalayan period and is the main ore-controlling structure.


Metamorphism includes: 1) regional metamorphism; 2) thermo-contact metamorphism; 3) wall rock alteration.

  1. Regional metamorphism effects all formations except the Quaternary. The regional metamorphism comprises greenschist metamorphic facies and forms meta-sandstone, slate, phyllite, meta-volcanic rocks and marble.
  2. Thermo-contact metamorphism and wall rock alteration developed along the northern contact of the intermediate intrusion. Thermal effects include formation of hornfels and skarn.
  3. Wall rock alteration includes greisenization, tourmalinization, fluoritization, silicification, sericitization, pyritization and chloritization. Different alteration minerals are an important prospecting guide.


PROPERTY GEOLOGY

The Jiaogenma mining area is located in the lead-zinc-silver-copper-gold (Pb, Ag, Cu, Au) belt on the east side of Jinsha River, about 5 km east of the Xiasai silver-lead-zinc deposit.


Rocks exposed in the area are mainly the Triassic Tumugon Group which consists of meta-sandstone, meta-greywacke, slate and phyllite interbedding, with minor lenses of ultrabasic rocks and skarns. The rocks strike 285° to 290° and dip at 33° to 55° southwest. The rocks include:

  1. Lieyi meta-sandstones: main rock types include the metamorphic-mud siliceous-quartz, fine-grained sandstone; metamorphic-quartz, fine-grained sandstone; metamorphic-mud siliceous-quartz, fine-grained greywacke; and metamorphic siliceous-quartz, strong, fine-grained greywacke; siliceous slate; and sericite-chlorite slate.
  2. Lieyi slates: main rock types are siliceous slate, sericite-chlorite slate.
  3. Lieyi phyllite: the rocks are grey to greyish-white with micro-lepidoblastic texture, thin to medium layered structure and parallel directional structure.

The main structures in the area are a series of fractured zones, named F1, F2, F3, F4 and F5, that trend northwest to north-northwest, dip to the southwest and are roughly parallel. The fracture zones are 1 m to 4 m wide, with a maximum width of 150 m. Crumpling and fragmentation of rocks is present in the zones, but only the slate shows small-scale crumpling. The fractured zones have developed alteration and fractures and contain mineralization.


There is no volcanic rock outcropping in the area. However, two tremolite-uralite dikes were found to the south of the mineralised area intersected while drilling and a gabbro-diabase dike were intersected.


The rocks in the area have been metamorphosed to low greenschist facies. The rocks have been affected by the granite intrusion and show hornfelsing and local skarn development. Wall rock alteration includes greisenization, tourmalinization, fluoritization, silicification, sericitization, pyritization and chloritization. The breccias, fragmented rocks and other structural features can be found along the F1, F2, F3, F4 and F5 fault and fractured zones


The Jiaogenma are is in the middle of Queershan-Genie Magmatic Zone, with the occurrence of a stock immediately southwest of the property. The total area of the stock is 72 km2 and it comprises an S-type granite of late Yanshanian age.