摘要
东仔叶蜡石矿床在垂向上可划分成四个蚀变矿物带。矿物流体包裹体、氢氧稳定同位素、稀土元素与常量元素的测试、研究表明:蚀变成矿的物理化学条件是 t=210°～350℃,PH=5.28～6.41、lgfO_2=-42.95～-32.81、lg fS_2=-16.57～-11.08;δD_(H_2O)(包体)=-79.9～-65.0‰/、δ^(18)O 石英=6.49～7.34‰,成矿热液来自岩浆水,但有大气降水混合:δ^(34)S 黄铁矿=-13.4～4.9‰,具生物成因特征;Rb—Sr 同位素等时年龄为86±2Ma,成矿时代属早白垩世;成矿过程中主要是 OH、Al 的大量带入,其它元素被带出,稀土总量减少,重稀土元素明显贫化。
The Dongzi pyrophyllite deposit is vertically divided into four mineral alteration zones.Analysis and studies of fluid inclusion of minerals stable isotopes of hydrogen and oxygen REE and invariable elements indicate that the physical and chemical conditions for alteration and mineralization are as follows:t=210°～350℃,pH=5.38～6.41,lgfO_2=-42.95～32.81,lgfS_2= -16.57～-11.08,δD_(H2O)(inclusion)=-79.9～-65.0‰,δ^(18)O_Q=6.49～7.34‰;the hydrothermas ore-forming solution is derived from magmatic water,but is mixed with meteoric water;δ^(34)Spy= -13.4～4.9%‰,being characteristic of a biogenic origin;the Rb-Sr isotopic isochron age is 86 ±2Ma,suggeating that the ore-forming epoch is the early Jurassic;the ore-forming process is characterized by an enormous input of OH and Al and output of other clements,deercase in the total of REE,and obvious dilution of HREE.
