下侏罗日当组中黄铁矿形态研究学及其地质意义

The Morphology of Framboidal Pyrite from the Lower Jurassic Ritang Formation and its Geological Significance

下侏罗统日当组地层是扎西康Pb-Zn-Ag-Sb多金属矿集区内重要的赋矿层和矿源层之一。为查明日当组中成矿元素的初始富集机理,开展了该地层中草莓状黄铁矿的形态学研究。结果表明日当组沉积时的底层海水是氧化-次氧化的;地层中草莓状黄铁矿在剖面上的粒径分布表明:日当组沉积过程中,其底层海水曾发生过短暂的充氧过程。该结果日当组沉积时的底层海水是含氧的,地层中所赋存的成矿元素,并非是在缺氧硫化的底层水体条件下,由矿物自生富集形成的。

The Lower Jurassic Ritang Formation （Jlr） is one of important hosts and ore-source beds in the Zhaxikang cluster of Pb-Zn-Ag-Sb polymetallic mineral deposits. This paper has a discussion on morphology of framboidal pyrite from Ritang Formation. The study indicates that the framboidal pyrite is an authigenic mineral which was formed in an oxidizing or sub-oxidizing condition with short aerobic process other than condition of a lack of oxygen and that the Ritang Formation was deposited in an oxidizing or sub-oxidizing condition.