摘要 昆阳磷矿是我国下寒武统最大的磷块岩矿床之一,矿层赋存于下寒武统渔户村组的中谊村段地层中(罗惠麟等,1982),矿层有上、下两层,分别称之为“上磷层”和“下磷层”,中间为一“白泥层”(含磷粘土页岩)分隔(Yeh Lien-tsun et al.,)。含磷岩系的岩性序列特征见图5。罗惠麟等认为,本段地层均为台凹相沉积,其中“下磷层”的形成环境为潮下低能及间歇性高能带,“白泥层”为潮下低能带,“上磷层”为潮下高能带,再往上则向潮间坪过渡。本文研究磷块岩的矿物组成,主要是矿石矿物磷灰石和粘土矿物的特点,并讨论磷灰石成份同矿石类型和形成环境等问题。
Texture-genetic types of phosphorite, some mineralogical features of carbonatefl-our-apatite and clay minerals are studied in this paper. The composition of carbonate-flour-apatite and their sedimentary environments are. summarized as follows:1)Apatites of this area contain CO2 and F(1.27-2.71%, 3.53-4.36% respectively). So they are all carbonate-flour-apatite.2)There is a regular change between a0 and CO2 content in carbonate-flour apatite. They are inversely correlative with one another.3)The CO2 content of carbonate-flour-apatite in the various cementing material are different: being higher in the phosphoritic ones medium in the siliceous ones and lower in the clayly ones.4)The inter changes of different texture-genetic types of phosphorites from bottom to top in a vertical sedimentary sequence reflect the variation of mineralization environment with time. These include high energy-subtidal, low energy-subtidal and high energy-intertidal-subtidal environments. The CO2 content of carbonate-flour-apa-tite in these environments shows a regular change of higher-lower-higher CO2 content corespondently. We belive that the change of CO2 content were not caused by the effect of sea water temperature during mineralization or the diagenetic replacment. The mineralization environment and PH value of depositional medium are possibly more important. When the(PH value of)medium is alkaline, the CO2 of carbonate-flour-apatite is higher, but when acidic it is lower. This is consistent with the change of cement(dolomite, phosphate, siliceous and clayely)of phosphorite.
汪寿松,陈其英. 1985, 昆阳磷矿磷块岩的矿物组成. 地质科学, (1): 78-86.
Wang Shousong,Chen Qiying. THE MINERAL COMPOSITION OF THE PHOSPHORITE OF KUNYANG[J]. Chinese Journal of Geology, 1985, (1): 78-86.