The metamorphic grade of a rock is the intensity of the metamorphism it went through, set by the temperature and pressure it reached. An index mineral is a mineral whose first appearance, in rocks of the same parent composition, marks a given grade. An isograd is the line on a map (a surface in the ground) joining the places where an index mineral first appears: along it, the rocks have reached the same grade.
বইগুলো এখনো বাংলা ভাষায় পাওয়া যায় না — ইংরেজি সংস্করণ দেখানো হচ্ছে।
Earth and Space Sciences · পরিভাষা
Index mineral; isograd; metamorphic grade কী?
অন্য নাম: metamorphic grade · index mineral · isograd