THE FORMING CONDITIONS OF NONFERROUS AND PRECIOUS METAL DEPOSITS IN THE NORTH OF DERBUGAN METALLOGENIC PROVINCE

The north of Derbugan metallogenic provice is located in the north of Inner Mongolia Autonomous Region and the north of Heilongjiang Provice.The principal metallogenetic epoch is J 3-K 1.The metallogenic temperatures vary for different genetic types of deposits.Porphyry-type deposits are formed at high-medium temperature;volcanic hydrothermal type,at medium-low temperature;while "New-type" and epithermal type,at low temperature.The sulfur isotopic values of δ³⁴S form 8 deposits show a high concentration on -6‰ to +6‰.The peak values are around +2‰ to +6‰,indicating that the sulfur in the endogenetic polymetals,gold and silver deposits comes mainly form anatectic magma.The oxygen isotopic values of δ¹⁸O from 6 deposits are -4.5‰ and +23.9‰,showing a close relationship to the magmatic oringin.According to the hydrogen isotope of inclusion, the δ¹⁸O H₂O values range from -12.9‰ to +12.6‰,and the δD is mainly in -89‰ to -105‰.Therefore,the oxygen and hydrogen isotopes of ore-bearing hydrothermal solution reflect the characteristics of magmatic water mixed with miscible fluids from surface precipitation,but the epithermal deposits are characterized by meteoric water.The analysis shows that the metallogenic hydrothermal solution of the deposits is derived from magmatic solution and geothermal brine.