Title: CARBONATE MINERALS IN ESTUARY SEDIMENTS OF THE CHANGJIANG (YANGTZE RIVER)AND HUANGHE (YELLOW RIVER): THE CONTENT, MORPHOLOGY, AND INFLUENTIAL FACTORS
Abstract: Sediment samples were collected in estuaries of the Changjiang (Yangtze River) and the Huanghe (Yellow River) for studying carbonate minerals, their morphologic features, and influential factors by gain size analysis, XRD, SEM with EDX. The result shows that the percentage content of carbonate minerals occupied about 9% of the total major minerals, which is similar for the two rivers. The calcite content in the Huanghe sediment is higher than the dolomite, and vice versa in the Changjiang samples. Morphological study on the carbonate minerals illustrates that the shapes of the dolomite grains from the two river sediments are mostly well crystallized in general, except for minor cleavages and erosion/dissolution in the Changjiang samples. Calcite grains in all the samples were strongly eroded. The surface morphology was mostly resulted from the joint effect of grinding and dissolving under physical and chemical weathering processes. Some Changjiang calcite grains are covered with tiny oolites of colloid origin, while Huanghe calcite grains often consist of needle-like micro-crystals as aggregates resulted from secondary viscous origin in loess vacancies. The specific rhombic shape and the rhombic cleavage angles of 60° and 120° are characteristic for identification of the carbonate grains under SEM. Differences in provenance and weathering intensity are major influential factors responsible for the differences in the carbonate contents and their grain morphological features.
Publication Year: 2009
Publication Date: 2009-01-01
Language: en
Type: article
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Cited By Count: 9
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