An infrequent occurrence of sapphirine from metapelite rocks of the Cardamom hills of South India has been reported. This report of sapphirine may not be the first from the Southern Granulite Terrane (SGT) but is essentially from a new locality. The studied metapelites are silica-undersaturated devoid of garnet and the sapphirine symplectites. The symplectites of orthopyroxene + cordierite, orthopyroxene + K-feldspar + cordierite, orthopyroxene + sapphirine + cordierite ± K-feldspar ± biotite, orthopyroxene + biotite + cordierite + K-feldspar are discernible. The textural patterns show partial to complete pseudomorphism of the initially formed orthopyroxene and sapphirine and their succeeding decomposition to present stage. The relative X_Mg calculated for the key minerals show the trend as: Crd > Spr > Bt > Opx. The pseudosection modelling and the calculated P-T diagram drawn from the average bulk composition of the studied metapelite connote isothermal decompression with peak pressure and temperature conditions stable at ∼10 Kbar and ∼985 °C respectively. The assemblage reported in this study has an important bearing on the crustal evolution of the high-grade metamorphism exhumed from a deeper level of the crust.

据报道，印度南部小豆蔻丘陵的变质岩中很少发生蓝宝石。蓝宝石的这份报告可能不是来自南部花岗岩地区（SGT）的第一份报告，而是实质上是来自一个新的地方。所研究的偏橄榄石是二氧化硅欠饱和的，没有石榴石和蓝宝石的混合物。可以看出邻辉石+堇青石，邻辉石+钾长石+堇青石，邻辉石+蓝宝石+堇青石±钾长石±黑云母，邻辉石+黑云母+堇青石+钾长石的共晶。纹理图案显示出最初形成的邻苯二甲and和蓝宝石的部分至完全假晶，以及它们随后的分解直至现阶段。相对X _Mg计算出的关键矿物的趋势显示为：Crd> Spr> Bt> Opx。从研究的变质岩的平均体积组成得出的假剖面模型和计算的PT图表示等温减压，其峰值压力和温度条件分别稳定在约10 Kbar和约985°C。在这项研究中报道的组合对从地壳深处发掘出的高级变质作用的地壳演化具有重要意义。