Applications Of Carbon And Oxygen Isotope In Hydrothermal Deposits And Reconstruction Of Paleoclimate

The western metallogenic belt of the Baiyangping ore-concentrating area in Lanping,western Yunnan,is an important polymetallic metallogenic belt in the MesoCenozoic period,and the Liziping deposit is a typical representative of hydrothermal deposits in the area.Since the stable isotopes of carbon and oxygen have a good traceability function,this paper analyzes the characteristics and evolution of oreforming fluids by using stable isotopes of carbon and oxygen to discuss the metallogenic mechanism of the deposit.Combined with the data of inclusions and hydrogen and oxygen isotopes to limit the source of ore-forming fluids,a comparative analysis was also made with the Baiyangping deposit with similar genesis as an example.After discussing the analysis of the carbon and oxygen isotope results,it is concluded that the carbon in the Liziping deposit may be mainly provided by the dissolution of marine sedimentary carbonate rocks,and it is significantly affected by low temperature alteration,while the oxygen isotope is controlled by rainfall.Therefore,the early fluidization of Liziping deposit was more strongly affected by rainfall,which resulted in a negative bias of O isotope.In the later period of mineralization,the carbon isotope dissolution of the surrounding marine carbonate rock made the C isotope negatively biased.After studying the inclusions of the Liziping deposit,it was determined that the overall particle size of the inclusions in the Liziping deposit is relatively small,with gas-liquid two phases predominant.The mine is shallow.The results of hydrogen and oxygen isotopes show that the exchange reaction between atmospheric precipitation and oxygen isotopes in rocks indicates that the ore-forming fluids mainly originate from the hot brine in the basin recharged by ancient atmospheric precipitation.Stable isotope studies have shown that carbon and oxygen isotopes are effective indicators of climate and vegetation.The carbon isotope analysis of the cold-dried seed snail Shanghua snail and the warm-wet species Yantai snail snail in the past two glacial cycle loess profiles in the Beiyao site on the southern margin of the Loess Plateau showed that the relative abundance and oxygen isotope of Reflecting the strength of the summer monsoon rainfall,exploring the human activities of the Beiyao site provides an environmental background to determine the warm and humid environmental conditions during this period with small seasonal differences in climate.