Abstract

Clay minerals (fraction <0.001 mm) of Upper Pleistocene clayey–sandy–silty sediments recovered by DSDP Holes 481 and 481A in the Northern Trough, Guaymas Basin, Gulf of California, were studied by X-ray methods based on the modeling of diffraction patterns and their comparison with experimental diffractograms. Terrigenous clay minerals are represented mainly by dioctahedral micaceous varieties (mixed-layer disordered illite–smectites, illite) with the chlorite admixture and by kaolinite in the upper section of unaltered sediments. Intrusion of hot basalt sills (total thickness of the complex is about 27 m) provoked alterations in the phase composition of clay minerals in sediments (7.5 m thick) overlying the sill complex. These sediments include newly formed trioctahedral layered silicates (mixed-layer chlorite–smectites, smectite). Sediments inside the sill complex include trioctahedral mixed-layer mica–smectite–vermiculite or trioctahedral smectite. The trioctahedral mixed-layer chlorite–smectite coexisting with smectite was found in a single sample of the same complex.

中文翻译：

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玄武岩基岩接触区沉积物中的粘土矿物

摘要

基于衍射图样的模型，通过X射线方法研究了加利福尼亚湾瓜亚马斯盆地北部海槽DSDP孔481和481A回收的上更新世粘土质-桑迪-粉质沉积物的粘土矿物（分数<0.001 mm）。并与实验衍射图进行比较。陆生粘土矿物的主要代表是八面体的云母变质（混合层无序伊利石-蒙脱石，伊利石）与绿泥石混合，而高岭石则代表未改变沉积物的上部。高温玄武岩基岩（复合体的总厚度约为27 m）的侵入引起了覆盖在基岩复合体上的沉积物（7.5 m厚）中粘土矿物的相组成发生变化。这些沉积物包括新形成的三八面体层状硅酸盐（混合层亚氯酸盐-蒙脱石，蒙脱石）。基石复合体内部的沉积物包括三面体混合层云母-蒙脱石-ver石或三面体蒙脱石。在同一配合物的单个样品中发现了与蒙脱石共存的三面体混合亚氯酸盐-三八面体。