钾长石在碱性流体蚀变过程中会形成层状铝硅酸盐等矿物,前人对其反应机制和反应产物进行了研究,但缺乏微观尺度尤其是纳米尺度的探讨。因此,作者对钾长石在极端碱性条件下(190℃,24h,初始pH=12.4)的蚀变机制及其蚀变产物层状硅酸盐托贝莫来石的显微结构开展了纳米尺度的研究。X射线粉末衍射、扫描电子显微镜、能量色散光谱等观测结果显示,钾长石在碱性条件下水热蚀变所得到的产物主要为托贝莫来石、水钙铝榴石和方解石。高分辨率的透射电镜结果表明,在钾长石与次生矿物相的界面形成了纳米级的多孔非晶质层,且在空间上表现出结构的不连续性。界面溶解-再沉淀(CIDR)机制很好地解释了钾长石与次生矿物相界面的空间不连续性和非晶质层的形成。对蚀变产物中纤维状的托贝莫来石晶体进行显微结构表征,结果表明托贝莫来石的孔隙直径为0~160nm,平均孔径约为40nm;其构成的纳米孔隙和通道有利于增加周围流体中离子和气体的溶解度,并可能会影响局部化学平衡。这为层状铝硅酸盐作为自然界以及工业吸附材料和催化剂的更广泛应用提供了重要依据。;K-feldspar alteration in alkaline fluid generally generates layered aluminosilicate and other minerals. Previous studies mainly focused on the reaction mechanism and alteration products, however, little is known on the mechanisms of alteration and the secondary products at nano-scale. We studied the alternation mechanism of K-feldspar under extreme alkaline conditions (190℃, 24h, initial pH=12.4) and the microstructure of tobermorite as one of the alternation products. Characterizations of X-ray powder diffraction, scanning electron microscopy and energy dispersive spectroscopy reveal that the secondary phases resulting from alternation of K-feldspar are mainly a mixture of tobermorite, hydrogrossular and calcite. Novel nanometer-scale measurements by high resolution analytical transmission electron microscope reveal the formation of an alteration rim of porous amorphous material nanometer thick at the interface of the K-feldspar and secondary phase, and the interface shows spatial and structural discontinuity. Coupled interfacial dissolution reprecipitation (CIDR) explains the sharp interface and the formation of the amorphous layer. The nanostructure measurements of the fibrous tobermorite crystals in the alteration products show that the pore diameter of tobermorite has a range of 0~160nm, and the average pore diameter is about 40nm. The nano pores and nano channels in tobermorite may promote the solubility of ions and gases and affect the chemical balance of the surrounding fluid. This provides an important basis for the application of layered aluminosilicate as natural and industrial adsorption materials and catalysts.