SEDIMENTARY GEOCHEMICAL CHARACTERISTICS OF DEVONIAN STRATA-BOUND POLYMETAL DEPOSITS IN SOUTH CHINA

Devonian carbonate strata—the most important ore-bearing strata are widespread in South China. Most strata-bound deposits occur in them. This paper discusses in detail the petrological features and sedimentary environments of two reef facies—the basin reef facies and the platform reef facies, the dependence of the sedimentary environment upon the reefdevelopment, the geochemical features of various facies, the relationship between strata-bound base metal deposits, and sedimentary environments and sedimentary facies.     

SEDIMENTARY ENVIRONMENTS OF STRATA-BOUND DEPOSITS IN CARBONATE ROCKS IN CHINA

This paper deals with the evolution of carbonate rocks and associated strata-bound depositsof various geological times in China. Distributions of the carbonate rocks are not very homo-geneous in time and space. Temporally, they are less common in both Archaean and Meso-Cainozoic strata, but more abundant in Palaeozoic and Proterozoic strata; spacially, they aremore abundant in the East Platform, but less in the West Folding Zone. They were depositedmainly in the sedimentary environments with shallow water. The Archaean carbonate rockswere formed by chemical processes, the Proterozoic carbonate rocks composed mainly of dolo-mites were deposited by algal activity, and the Palaeozoic and some Meso-Cainozoic carbonaterocks, in which limestones were predominant over dolomites, were formed by chemical and bio-chemical processes. After the Proterozoic era bioherms and banks were initiated. Many strata-bound deposits are found to associate with carbonate rocks in China,most of which were formed from the reformation caused by Hercynian and Yenshanian oro-genies.     

我国南方泥盆系层控多金属矿床形成的沉积地球化学特征

本文讨论了两类礁相——盆地礁相和台地礁相的岩性及沉积环境的特点,讨论了生物礁的生长发育对沉积环境的影响和各种不同沉积相中的地球化学性质,以及层控多金属矿床与沉积环境和沉积相之间的关系。     

中国碳酸岩中层控矿床的沉积环境

本文讨论了我国各地质时代中的碳酸岩的发育、演化及其中的层控矿床。碳酸岩的时空分布具太古代和中新生代较少,元古代和古生代多;西部褶皱带少,东部陆台区多的特点。它们主要是在浅水环境下沉积的,太古代碳酸岩为化学沉积;元古代多与藻类的生命活动有关,白云岩占绝对优势;古生代及部分中生代主要是生物及生物化学沉积,灰岩多于白云岩。元古代以后,生物礁滩开始发育。