CAJ | 학술논문

利用X射线物相分析、扫描电镜及能谱分析等方法分析了长江和黄河入海沉积物矿物颗粒形态特征及不同粒级的碳酸盐矿物百分含量分布.结果表明,长江和黄河入海沉积物的碳酸盐矿物含量均在9%左右,差异不大.长江碳酸盐矿物含量在粗粒级较高,随着粒度变细波动式降低,黄河碳酸盐矿物含量则随粒度变细而逐步增加;黄河方解石含量高而白云石低,长江的情况正好相反.长江和黄河入海沉积物中的白云石颗粒大多比较完整,侵蚀沿完全解理面发生,菱面体形态明显.长江白云石上可以见到大量的磨蚀和溶蚀形态.黄河白云石保存较好,侵蚀程度较低,磨蚀和碰撞形态明显,溶蚀形态很少,发现典型的马鞍状白云石颗粒.长江和黄河的方解石均遭受强烈侵蚀.长江方解石溶蚀特征特别明显,深入矿物颗粒内部.黄河方解石侵蚀深度相对浅表,侵蚀形态多为磨蚀、碰撞和溶蚀等物理和化学综合侵蚀特征.长江某些方解石表面布满细小鲕状方解石颗粒,似为局部自由空间的胶体-陈化成因特征.黄河方解石呈现多个次生微晶集合体,显示其黄土粘粒空隙胶结物成因形态.碳酸盐矿物的菱面体形态和菱面体完全解理所特有的60°和120°交角,是其电镜下的最佳识别特征.长江和黄河沉积物物源、流域风化强度以及矿物晶体结构本身的特点,是两河沉积物中碳酸盐矿物含量及颗粒形态差异的主要影响因素.
이용X사선물상분석、소묘전경급능보분석등방법분석료장강화황하입해침적물광물과립형태특정급불동립급적탄산염광물백분함량분포.결과표명,장강화황하입해침적물적탄산염광물함량균재9%좌우,차이불대.장강탄산염광물함량재조립급교고,수착립도변세파동식강저,황하탄산염광물함량칙수립도변세이축보증가;황하방해석함량고이백운석저,장강적정황정호상반.장강화황하입해침적물중적백운석과립대다비교완정,침식연완전해리면발생,릉면체형태명현.장강백운석상가이견도대량적마식화용식형태.황하백운석보존교호,침식정도교저,마식화팽당형태명현,용식형태흔소,발현전형적마안상백운석과립.장강화황하적방해석균조수강렬침식.장강방해석용식특정특별명현,심입광물과립내부.황하방해석침식심도상대천표,침식형태다위마식、팽당화용식등물리화화학종합침식특정.장강모사방해석표면포만세소이상방해석과립,사위국부자유공간적효체-진화성인특정.황하방해석정현다개차생미정집합체,현시기황토점립공극효결물성인형태.탄산염광물적릉면체형태화릉면체완전해리소특유적60°화120°교각,시기전경하적최가식별특정.장강화황하침적물물원、류역풍화강도이급광물정체결구본신적특점,시량하침적물중탄산염광물함량급과립형태차이적주요영향인소.
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 simi-lar 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.