南海NS93-5柱样的矿物学特征及矿物沉积序列

MINERALOGICAL CHARACTERISTICS AND MINERAL SEDIMENTARY SEQUENCES OF CORE NS93-5 FROM SOUTH CHINA SEA

矿物及其组合研究是探讨成岩成矿及环境变化的一个重要手段 ,也是近年来沉积序列划分以及古环境重建和古气候对比研究中新的探索点。南海南部NS93 5柱样系统的矿物学分析表明 ,其矿物成分主要由碳酸盐矿物、碎屑矿物和粘土矿物三大类组成 ,从含量上可以分为三组 ,即主导矿物 (方解石 )、次要矿物 (伊利石和石英 )及少量矿物 (包括斜长石、绿泥石、高岭石、钾长石、蒙脱石和石膏 )。根据柱样中矿物含量及某些特征矿物参量的深度变化特征 ,将该柱样的沉积环境表述为六个矿物沉积序列 ,它们与氧同位素地层序列具有良好的对应关系 。

Minerals and mineral association in marine sediments have recently been used to divide sedimentary sequences and reconstruct the paleoenvironment. One hundred and six samples of core NS93\|5 from southern South China Sea were analyzed by X\|ray diffraction (XRD) in this paper. The results showed that minerals in core NS93\|5 are dominated by carbonate minerals, detrital minerals and clay minerals. These minerals can be divided into three groups according to their contents, i.e., 1) dominant minerals: calcite; 2) secondary minerals, including quartz and illite; and 3) trace minerals, including feldspar, chlorite, kaolinite, potash feldspar, smectite and gypsum. Based on the interrelation of minerals and vertical variation of mineral contents and some characteristic mineral parameters, six sedimentary sequences were divided. Comparing with the curves of CaCO\-3 and δ\{\}\+\{18\}O, we are easy to find that the mineral sequences are consistent with the oxygen isotope strata, by which the paleoclimatic information developed from the mineral sequences are preliminarily discussed.