HR: 0800h
AN: GP41A-0818    [Abstracts]
TI: Role of the Interference of Different Geodynamic Settings in Metallogenesis of Upper Kolyma Basin Area (Magadan Region)
AU: * Goryachev, N A
EM: goryachev@neisri.magadan.ru
AF: North East Interdisciplinary Science Research Institute, Russian Academy of Science, 16 Portovaya St., Magadan, 685000 Russian Federation
AB: The modern territory of the Magadan region is area of the two types of geodynamic environments (collisional and subductional), which defined the specifity of granitoid magmatism and metallogeny. Yana-Kolyma I- and S-type granitoids of the ilmenite series: diorite-granodiorite and granite-leucogranite magmatic suites (155-135 Ma) was related with plutonic-metamorphic collisional process (Goryachev, 2003). Gold-quartz veins, granitoid-related gold veins and stockworks, tin, and tungsten lode deposits in the Yana-Kolyma collisional zone existed during the period of 155-135 Ma and were related by this process. The Uda-Murgal magmatic arc (150-110 Ma) is located to the east (in present coordinates) of this collisional zone. The andesite - dacite volcanism early stage corresponds to the emplacement of gabbrodiorite-granodiorite-granite plutons I-type granitoids dated at 150-135 Ma. During this early stage of formation of the Uda-Murgal magmatic arc were formed of epithermal gold-silver, tin-silver, mesothermal granitoid related gold veins, skarn tungsten, and skarn silver-base metal lodes. The late stage (135-100 Ma) was marked by the formation in the back arc magmatism, local volcanic structures filled with magmatic rocks of dacite-rhyolite composition, plutonic I-type granites suites with withinplate geochemical signature, and A-type alkali granites. At that time epithermal gold-silver, shallow-depth gold-silver-quartz veins, granitoid-related gold stockworks, copper-molibden-porphyry and silver-cobalt-bismuth lode deposits were formed. According to tectonic reconstructions (Parfenov, 1995; Nokleberg et al, 1998; Tectonics, ., 2001), at the Late Jurassic - Early Cretaceous time (155-100 Ma) the Pacific margin of northeast Asia presented an area of coexistence of the Yana-Kolyma collisional zone (Goryachev, 1998) and the Uda-Murgal continental marginal magmatic arc (Parfenov, 1995; Sokolov et al., 1999; Goryachev, 2002). The new structure data about different folded plans of southeastern part of the Ayan-Uryakh antiklinorium (Goryachev I., 2003) and character of granitoid assemblages and complex metallogeny in the Upper Kolyma river basin and Northern Priokhot'ye part of Magadan region (Goryachev, 2002; Goryachev, 2004) demonstrate that this area is the zone of "interference" of different geodynamic environments where is characterized by a combination of magmatic suites and metalogeny characteristics of different origin but single age (Goryachev, 2002). The research was conducted with the support of Integration projects FEB-SB RAS No 65, 69, 71.
DE: 8102 Continental contractional orogenic belts
DE: 8105 Continental margins and sedimentary basins
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting