| 中国东部主要成矿时代磷块岩的组成 |
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| 引用本文： | 陈其英.中国东部主要成矿时代磷块岩的组成[J].沉积学报,1987,5(3):135-148. |
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| 作者姓名： | 陈其英 |
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| 作者单位： | 中国科学院地质研究所 |
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| 摘 要： | 本文研究了我国震旦、寒武纪磷块岩的矿石岩石学,主要矿石矿物为碳氟磷灰石,重要伴生矿物为伊利石,白云石和自生石英。磷块岩的化学组成有三个显著特点,一是品位随矿石类型的不同而异;二是随成矿域不同而异;三是随成矿时代不同而异。成矿背景,成矿环境、磷块岩相以及矿石组成等因素的差异是导致上述矿石组成变化的主要原因。
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| 关 键 词： | 碳氟磷灰石 化学成分 磷块岩 成矿时代 成矿域 |
COMPOSITIONAL CHARACTERISTICS OF PHOSPHORITES AND PRINCIPAL MINERALIZATION EPOCHS IN EASTERN CHINA |
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| Institution: | Institue of Geology, Academia Sinica, Beijing |
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| Abstract: | The composition of phosphorites from 25 Sinian, Cambrian and Devonian ore deposits in Eastern China were studied in this paper. We came to the conclusion that carbonate-f luorapatite is the main phosphatic mineral in the phosphorite of China. Hydroxyapatite can only be seen in recrystallised phosphorites occasionally. Principal associated minerals of the ore deposits are illite, dolomite and quartz (chalcedonite). According to the mineral associated relation, The phosphorites in China could be divided into five associated types. There are three important features in chemical composition of the phosphorites: First, the P2O5 contents change with types of ore, the sequence is the biogenic (35.04%), the micritic (34.88%-31.92%) the recrystallised (33.38%), the nodular (30.92%), the granular (29.01-28.14%) and the sandy (21.37%). Secondly, the P2O5 contents of ore change with mineralization areas, for example, the average P2O5 contents of the Cambrian ore in North China Platform and Yangtze Platform are 21.3% and 30.18% respectively. Thirdly, they change with mineralization epochs. With the squence of Sinian, Cambrian and Devonian, the CO2/P2O5 ratios reduce from 0.15 to 0.04; MgO, CO2, MnO and K2O-contents are from higher to lower; however, the Al2O3 is in a converse case. Generally, the compositional differences of phosphorites in China are determined by the differences of mineralizational background, environments, facies characteristics and mineral paragenic types primarily. |
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