This article provides a comparative accurate foundation about the recover of the protolith in Baoyintu Group.
为整套宝音图群的原岩恢复提供了较精确的依据。

protolichesterinic acid.
原地衣硬酸

The main protolith siltstone. Amphibolites belong to orthometamorphite. The possible protolith is basalt.
斜长角闪岩为正变质岩，而其原岩可能为玄武岩。

MINERAL ASSEMBLAGE AND CHARACTERISTICS OF THE PROTOLITHES OF XUESH ANHE METAMORPHIC GROUP IN WESTERN YUNNAN
滇西雪山河变质岩群的矿物组成与原岩特征

It can therefore, be deduced that the protolith from which sapphirine was derived is not necessarily magnesiorich pelite.
含假蓝宝石的变质岩石之原岩未必是富镁泥质岩。