地质学报2011，Vol.85Issue(6)：947-954,8.DOI:11-1951/P.20110517.1002.002
天池天文峰全新世火山喷发物长石表面硅膜特征及意义
Features of Silica Glazes on Feldspar from the Holocene Volcanic Eruptive Material at the Tianwen Peak, Tianchi, Changbai Shan and Their Implications
摘要
Abstract
The structures and chemical compositions of feldspar surface silica glazes from the Holocene volcanic eruptive material at the Tianwen peak, Tianchi, Changbai Shan was studied using SEM and EDX. The result shows that silica glazes of varied structures developed on feldspar surfaces in the pumices on the Tianwenfeng cross section, which change in color from black at top downward to dark -grey at bottom. Their structural features vary with the ages of volcanic eruption. Early eruption of volcanic rocks resulted in thicker silica glazes and more complicated structure on the surface of feldspar grains; late eruption formed thinner glaze and simpler structure, I. E. the morphology and thickness of silica glazes on the feldspars are correlated with the time of volcanic eruption. These glazes are made up of Si (33. 3%-26.6%), Al (9.28%-6.22%), Na (6. 08%-4. 07%), K (3. 84%-2. 35%) and Fe (3. 82%-1. 64%). With increasing Si content, the content of Al and Na tend to decrease, while contents of K and Fe have few change. Such a composition indicates that the glaze resulted from deposits of dissolved silicate. And the correlation between the composition of silica glaze and the elements is analogue to that of the glaze rich in fragment determined by Dorn in 1998. The features of these structure and variety of the compositions reflect the processes of rock weathering, migration and final deposit. Fe is probably related to microorganism. Rock weathering, wore grains and dissolved ion provide the glaze formation with material sources. The detailed observing glazes may be a new approach to study post-volcanic eruption settings and temporal process of volcanic eruptions from microstructures of rocks.关键词
天池火山/硅膜/扫描电镜/显微结构/化学组成Key words
Tianchi volcano/ silica glaze/ SEM/ microstructure/ chemical composition引用本文复制引用
张秉良,于红梅,赵波,许建东,史兰斌,盘晓东..天池天文峰全新世火山喷发物长石表面硅膜特征及意义[J].地质学报,2011,85(6):947-954,8.基金项目
国家自然科学基金项目(编号40772128)、中国地震局行业专项(编号20070827)共同资助成果. （编号40772128）
