接触交代夕卡岩型多金属矿床铅源新认识

本文研究的接触交代夕代岩型多金属（铜－铅－锌）矿床是与燕山期中－酸性岩浆作用有密切关系的矿床工业类型，传统上认为成矿物质是岩浆分异的产物。文中用矿石铅、岩浆岩铅及围岩铅同位素组成，探讨了三者之间的关系，阐明了该类矿床矿石铅的三种来源，即单一的岩浆源，岩浆与围岩混合源及多元（三种以上）混合源，认为在运用铅同位素研究矿石成因时，既要研究矿石铅，也要研究岩浆岩长石铅和围岩（沉积岩）铅的同位素组成，并考虑

NEW KNOWLEDGE OF THE LEAD SOURCE OF CONTACT METASOMAT1C SKARN TYPE POLYMETALL1C DEPOSITS

Ore-forming materials of contact metasdmatic skarn type Cu-Pb-Zn polymetallic deposits which occur in the contact zone of igneous rocks and country rocks are considered traditionally as the result of magmatic differentiation. According to the Pb isotopic composition, four types of relationships among ore lead, magmatic rock lead and country rock lead may be distinguished: ( 1 ) ore lead is consistent with magmatic rock lead and very different from country rock lead; ( 2 ) ore lead, ratios are higher than those of magmatic rock lead. and. lower than those of country rock lead; ( 3 )ore lead, ratios are lower than those of magmatic rock lead and higher than those country rock lead; ( 4 ) the 206Pb/204Pb ratio of ore is lower than those of magmatic rock lead and. country rock lead.. Ore lead of type 1 deposits is derived from magma; ore leads of types 2 and 3 deposits are the mixture of magmatic rock lead and country rock lead, and ore lead of type 4 deposits is the mixture of magmatic rock lead, country rock lead and lower crust lead.