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科珀克莱姆(Copper Claim)晚元古代地层为白云质、菱镁矿质和燧石质层与长英质碎屑岩的互层。这套地层被认为是在一个克拉通内构造坳陷中堆积的,其中黄铁矿含量在整个层序一般较低,而黄铜矿只集中在两个层位中。这两种硫化物都是以成层浸染状出现在富碳酸盐的细脉中,而在内碎屑中通常很少。岩石学的证据表明,一部分细脉是在其容矿岩层的劈理发育之前形成的,而另一些细脉则是在区域变质作用期间或之后形成的。没有发现热液蚀变的证据。浸染状硫化物的δ~(34)S值在-17.5—+15.8‰之间,与硫酸盐的细菌还原作用一致。细脉状硫化物有一个相似的但偏小的δ~(34)S区间(-12.2—+9.3‰),这与浸染状硫化物的再活化产物一致。δ~(13)C值在层状碳酸盐和细脉状碳酸盐之间没有主要的差异,在白云石和菱镁矿之间也没有重大差异。可是,δ~(18)O值却有显著的变化,菱镁矿的δ~(18)O值一般要比白云石高,层状碳酸盐的中值接近23‰,有的比细脉状碳酸盐的中值要高3‰。这些资料表明,早期成岩的碳酸盐反应中一般趋向接近低温氧同位素平衡,接着仅仅在数十度高的温度下,有些细脉便从沉积物的组分中产生,低级区域变质作用引起了弱的重结晶和附加细脉的形成,但没有广泛地迭加成岩同位素的动向。含铜的和非矿化的岩石之间同位素的相似性支持铜是在沉积期和(或)早期成岩阶段进入的。细脉碳酸盐含有小的且富Na Cl的流体包裹体,它们主要是次生的,沿着弥合的微裂隙分布。显微测温表明它们是在变质作用阶段,温度接近300℃和埋深4千米的条件下形成的。科珀克莱姆的硫化物符合这样一个总的趋势,即其平均δ~(34)S值随着阿得雷德地槽和斯图特(Stuart)陆架区晚元古代地层时代的变新而增大。这种趋势可能产生这样一种局部环境条件,导致硫酸盐的还原超过了硫酸盐的再补给。换句话说,它可能反映导致海水中硫酸盐大量~(34)S富集的全球性作用。
Copper Claim The Late Proterozoic strata are interbedded layers of dolomitic, magnesite, and flint formations with felsic clastic rocks. This formation is thought to have been deposited in a craton of structural craton where the pyrite content is generally low throughout the sequence and the chalcopyrite is concentrated in only two horizon positions. Both sulphides appear as stratified disseminations in the carbonate-rich veins, and are rarely found in internal debris. Petrology evidence suggests that a number of fine veins were formed prior to the cleavage of their host rock while other fine veins formed during or after regional metamorphism. No evidence of hydrothermal alteration was found. The δ ~ (34) S value of disseminated sulfides ranged from -17.5 to +15.8 ‰, consistent with the bacterial reduction of sulfate. The fine veins have a similar but smaller δ ~ (34) S interval (-12.2- + 9.3 ‰), which is consistent with the reactivation of disseminated sulfides. There is no major difference between the δ 13 C values of layered carbonate and fine vein carbonate, and no significant difference between dolomite and magnesite. However, δ 18 O value changes significantly. The δ 18 O value of magnesite is generally higher than that of dolomite. The median value of layered carbonate is close to 23 ‰, The median carbonate should be 3 ‰ high. These data indicate that early diagenetic carbonate reactions tend to approach near cryogenic oxygen isotope equilibrium, followed by meager veins from the sediment component only at dozens of degrees of temperature, and metamorphism at the lower levels Weak recrystallization and the formation of additional veinlets, but no extensive superimposition of diagenetic isotopes. The similarities of isotopes between copper-bearing and non-mineralized rocks support the entry of copper during sedimentary and / or early diagenetic stages. Vein carbonate contains small and NaCl-rich fluid inclusions, which are primarily secondary, distributed along the meso-micro-fractures. Microscopic temperature measurements indicate that they were formed during metamorphism at temperatures near 300 ° C and depths of 4 km. The Copechem sulfides meet the general trend that their average δ ~ (34) S values change with the age of Late Proterozoic strata in the Adelaide Trough and Stuart Shelf Increase. This trend may produce such a local environmental conditions, resulting in the reduction of sulfate over sulfate re-supply. In other words, it may reflect the global role that leads to the large (34) S enrichment of sulphate in seawater.