黄河宁蒙河段粗泥沙重矿物特征及其指示意义

近年来，黄河上游宁夏-内蒙古河段（简称宁蒙河段）河道淤积日益严重，辨识该河段的粗泥沙来源已成为该河段开发与治理的前提。重矿物耐磨蚀、稳定性强，能较多地保留其母岩的特征，因此常被用于物源示踪分析。对黄河宁蒙河段河道27个样品点的粗泥沙重矿物特征进行分析研究，表明该河段粗泥沙重矿物以性质不稳定的角闪石、较稳定的绿帘石、赤褐铁矿为主，稳定矿物除刚玉、钛铁矿外，锆石、金红石、黄铁矿、电气石含量极少。稳定系数法计算结果表明在河东沙地河段、乌兰布和沙漠河段以及十大孔兑河段之间稳定系数最低，几乎接近于0，说明在这3个地区河道粗泥沙源于附近沙源不同形式的汇入。本研究区ZTR指数极低，平均只有0.0071，说明黄河宁蒙河段泥沙重矿物成熟度低，淤积的泥沙并未经过长途的搬运堆积，而是来自当地沙源的汇入。相关系数法给出了3种不同性质的矿物组合类型，分别指示了不同的母岩类型和物源环境。

Characteristics of Heavy Mineral in Coarse Sediment and Its Indicative Significance in the Ningxia-Inner Mongolia Section of the Yellow River

In recent years, sediment aggradation is growing more and more serious in the Ningxia-Inner Mongolia section of the Yellow River. Coarse sediment sources in this section of the Yellow River is becoming a focus of scientific research because the area is a national energy basement and a main grain production area of Northwest China. Heavy mineral wears erosion with a strong stability, and is able to retain most of the information and characteristics of its parent rock, and is therefore being used for source analysis. In the paper, 27 samples were conducted to analyze characteristics of heavy mineral in coarse sediment in the Ningxia-Inner Mongolia section of the Yellow River. The results show that heavy mineral in this section is rich in amphibole, which is unstable by nature, as well as limonite and epidote which are relatively stable. Stable mineral such as zircon, rutile, yellow iron ore and tourmaline content is extremely low, except corundum and ilmenite. Stability coefficients are the lowest in Hedong Sandy Land, Ulan Buh Desert and Ten Watershed, and almost close to zero. It indicates that in the three sections of the Yellow River, sediments originate from the nearby sand sources imported by different forms. ZTR index in this research area is extremely low, with the average content of 0.0071, illustrating an extremely lower heavy mineral maturity in the Ningxia-Inner Mongolia section of the Yellow River. The correlation coefficient gives three different types of mineral assemblages, indicating different types of parent rock and source environment.