Sedimentary facies: referred to as "facies". A sedimentary stratigraphic unit formed in a certain sedimentary environment with certain lithologic characteristics and paleontological markers. It is the material expression of sedimentary environment, including lithofacies and paleogeography. According to the natural geographical environment of sedimentation, it can be divided into three types: continental facies, transitional facies between land and sea and marine facies. Its differentiation is based on (1) sedimentary petrology and mineralogy characteristics, (2) paleontological characteristics, (3) geometric shapes and contact relations of sedimentary rocks, (4) sedimentary structures, (5) sedimentary geochemical characteristics and (6) genetic combination of facies.
Characteristic metamorphic minerals: metamorphic minerals formed in the process of metamorphism, with narrow stability range, which can indicate the composition and metamorphic conditions of original rocks.
Structure: the way in which the components of a material system interact.
Metamorphic texture: the structure formed when minerals are recrystallized in solid state.