向绪洪, 邵磊, 乔培军, 赵梦. 珠江流域沉积物重矿物特征及其示踪意义[J]. 海洋地质与第四纪地质, 2011, 31(6): 27-35. DOI: 10.3724/SP.J.1140.2011.06027
引用本文: 向绪洪, 邵磊, 乔培军, 赵梦. 珠江流域沉积物重矿物特征及其示踪意义[J]. 海洋地质与第四纪地质, 2011, 31(6): 27-35. DOI: 10.3724/SP.J.1140.2011.06027
XIANG Xuhong, SHAO Lei, QIAO Peijun, ZHAO Meng. CHARACTERISTICS OF HEAVY MINERALS IN PEARL RIVER SEDIMENTS AND THEIR IMPLICATIONS FOR PROVENANCE[J]. Marine Geology & Quaternary Geology, 2011, 31(6): 27-35. DOI: 10.3724/SP.J.1140.2011.06027
Citation: XIANG Xuhong, SHAO Lei, QIAO Peijun, ZHAO Meng. CHARACTERISTICS OF HEAVY MINERALS IN PEARL RIVER SEDIMENTS AND THEIR IMPLICATIONS FOR PROVENANCE[J]. Marine Geology & Quaternary Geology, 2011, 31(6): 27-35. DOI: 10.3724/SP.J.1140.2011.06027

珠江流域沉积物重矿物特征及其示踪意义

CHARACTERISTICS OF HEAVY MINERALS IN PEARL RIVER SEDIMENTS AND THEIR IMPLICATIONS FOR PROVENANCE

  • 摘要: 珠江流域沉积物重矿物组合与源区岩石特征具有极好的相关性,不同支流的重矿物组合及其代表性特征矿物差别明显。根据重矿物组合类型、重矿物特征指数及相关性分析可以把珠江流域源区类型从西到东分为3个区带,西部区带为西江上游源区,其重矿物组合类型为磁铁矿+钛铁矿+锆石+白钛石+磷灰石,特征矿物为磁铁矿、钛铁矿、磷灰石、铬铁矿,在该区域除大面积分布的碳酸盐岩外,发育变质岩和基性岩组合,有少量超基性和酸性岩浆岩;中部为西江中下游源区,重矿物组合类型为锆石+钛铁矿+磁铁矿+电气石+白钛石+绿帘石,特征矿物为辉石、白钛石、锆石、绿帘石,母岩出露区以碎屑岩类沉积岩为主,有少量变质岩和基性、酸性岩浆岩,其重矿物组合特征除了反映源区母岩的组合特征外,还由上游搬运而来的重矿物组合改造而成,属混合来源;东部为东江和北江源区,重矿物组合类型为角闪石+电气石+磁铁矿+钛铁矿+绿帘石+石榴子石,特征矿物为角闪石、电气石、榍石、石榴子石、矽线石,代表该区域大面积覆盖的酸性岩浆岩组合特征,夹部分变质岩及碎屑岩类沉积岩。研究结果显示,利用重矿物组合特征示踪珠江流域物源演变历史具有可行性。该研究结果对揭示珠江流域沉积物剥蚀-搬运-沉积规律,开展源汇对比分析具有重要意义。

     

    Abstract: Heavy minerals in the Pearl River sediments have excellent correlation with their source rocks. Obvious differences in heavy minerals assemblages and their diagnostic minerals have been studied in different branches of the River. The source of the river deposits can be divided into three provinces from west to east on the basis of heavy minerals assemblage types, mineral index(ATi,ZTi,ZTR) values and their correlation. The western province includes the upper reaches of the Xijiang River, where occurs a magnetite-ilmenite-zircon-leucoxene-apatite assemblage characterized by magnetite, ilmenite, apatite and chromite, indicating a provenance dominated by carbonate, with some metamorphic and basic rocks, and scarce ultrabasic and acid rocks. The middle province is located in the lower reaches of the Xijiang River, which is featured by a zircon-ilmenite-magnetite-tourmaline-leucoxene-epidote assemblage, characterized by pyroxene, leucoxene, zircon and epidote, indicating a provenance of clastic rocks and other sedimentary rocks with some metamorphic, basic and acid igneous rocks, as a mixture of local sources and the heavy minerals from upper reaches. The eastern province is the source area of the Dongjiang and Beijiang Rivers dominated by the assemblage of hornblende-tourmaline-magnetite-ilmenite-epidote-garnet characterized by hornblende, tourmaline, garnet, titanite and sillimanite, indicating a provenance of acid rocks with some metamorphic and small amount of sedimentary rocks. The results demonstrate that the characteristics of heavy minerals assemblages are useful tools to trace the provenance evolution of the Pearl River, and of significance in revealing the erosion-transportation-sedimentation pattern in the Pearl River region for source-sink comparison and analysis.

     

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