• journal_title：The Canadian Mineralogist
• Contributor：Can Rao ; Ru Cheng Wang ; Ai Cheng Zhang ; Huan Hu
• Publisher：Mineralogical Association of Canada
• Date：2012-12-01
• Format：text/html
• Language：en
• Identifier：10.3749/canmin.50.6.1623
• journal_abbrev：Can Mineral
• issn：0008-4476
• volume：50
• issue：6
• firstpage：1623
• section：Mineral Assemblages and Evolution

The Nanping No. 31 pegmatite is a spodumene-subtype LCT granitic pegmatite in southeastern China. Spodumene mainly occurs as rock-forming mineral in the quartz – coarse albite – spodumene zone (zone III) and the quartz – spodumene – amblygonite zone (zone IV). Various alteration-induced phenomena were observed in spodumene. Spodumene in zone III is usually altered along its {110} cleavages to networks of albite + muscovite, resulting from a replacement of spodumene by an alkaline fluid, which likely begins by Na metasomatism. Extensive alteration of spodumene in zone IV to quartz and muscovite veinlets is related to replacement by K⁺- and H⁺-rich fluid. However, alteration by strongly acid fluids also affected spodumene, leading to formation of fine-grained white mica in zones III and IV. In this paper, we focus on the occurrence of nodules of corundum + tourmaline, which are typically restricted to the aggregates of white mica in zone IV. Fibrous corundum and radial tourmaline signify a hydrothermal origin. Their textural relationship with secondary muscovite suggest a close genetic relation with the latter. The corundum + tourmaline nodules arise by alteration of the secondary muscovite by late B-, Mg- and Fe-rich fluids.