Alteration textures in terrestrial volcanic glass and the associated bacterial community
Alteration textures in terrestrial volcanic glass and the associated bacterial community
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DOI：
10.1111/j.1472-4669.2008.00184.x
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发表时间：
2009-01-01
期刊：
影响因子：
3.7
通讯作者：
Meunier, A.
中科院分区：
文献类型：
--
作者：
Cockell, C. S.;Olsson-Francis, K.;Meunier, A.
在冰岛南部Valafell的冰下（玻璃质碎屑岩）沉积物中检查了蚀变结构。在玻璃中观察到类似于先前在深海玄武岩玻璃中报道的颗粒状和管状特征的点蚀和“拉长”蚀变特征，但拉长特征通常没有大于5的长宽比。只有7%的表面发现了细长的特征。结晶玄武岩碎屑，这是纳入玻璃碎屑岩，没有显示细长的结构。坑蚀变特征在结晶玄武岩中定义不清，仅占表面的4%，而在玄武玻璃中占47%。富硅玻璃（黑曜石）和流纹岩的检查同样显示出定义不清的麻点纹理，占不到15%的表面，没有观察到细长的功能。这些数据突出了陆地玄武岩玻璃和以前研究的深海和地下玄武岩玻璃之间的蚀变纹理的差异，以及矿物学在控制蚀变特征的类型和丰度方面的重要作用。玻璃质碎屑岩中含有丰富多样的细菌种群，如16S rDNA分析所示，这可能与玻璃的风化有关。尽管存在的光养生物，我们表明，他们没有参与生产的玄武岩玻璃材料中，我们检查的大多数蚀变纹理。
Alteration textures were examined in subglacial (hyaloclastite) deposits at Valafell, Southern Iceland. Pitted and 'elongate' alteration features are observed in the glass similar to granular and tubular features reported previously in deep-ocean basaltic glasses, but elongate features generally did not have a length to width ratio greater than five. Elongate features were found in only 7% of surfaces. Crystalline basalt clasts, which are incorporated into the hyaloclastite, did not display elongate structures. Pitted alteration features were poorly defined in crystalline basalt, comprising only 4% of the surface compared to 47% in the case of basaltic glass. Examination of silica-rich glass (obsidian) and rhyolite similarly showed poorly defined pitted textures that comprised less than 15% of the surface and no elongate features were observed. These data highlight the differences in alteration textures between terrestrial basaltic glass and previously studied deep-ocean and subsurface basaltic glass, and the important role of mineralogy in controlling the type and abundance of alteration features. The hyaloclastite contains a diverse and abundant bacterial population, as determined by 16S rDNA analysis, which could be involved in weathering the glass. Despite the presence of phototrophs, we show that they were not involved in the production of most alteration textures in the basaltic glass materials we examined.