Answer
The characteristic of a metamorphic rock that is determined primarily by its parent rock is the mineral composition. During metamorphism, the parent rock undergoes various mineralogical changes and recrystallization while remaining in the solid-state. The resulting metamorphic rock retains some of the mineral components of its parent rock, albeit in modified forms.
The type of parent rock significantly influences the mineral composition of the metamorphic rock.
The type and distribution of minerals in the metamorphic rock are determined by the mineral composition of the parent rock and the specific metamorphic conditions (such as temperature, pressure, and presence of fluids) it experiences during the metamorphic process.
Work Step by Step
The characteristic of a metamorphic rock that is determined primarily by its parent rock is the mineral composition. During metamorphism, the parent rock undergoes various mineralogical changes and recrystallization while remaining in the solid-state. The resulting metamorphic rock retains some of the mineral components of its parent rock, albeit in modified forms.
The type of parent rock significantly influences the mineral composition of the metamorphic rock. For example:
1. Shale (a sedimentary rock) can give rise to slate, phyllite, schist, or gneiss during metamorphism, with each rock type having different mineral assemblages and textures.
2. Limestone (another sedimentary rock) can be transformed into marble during metamorphism, which primarily consists of the mineral calcite (or dolomite if the original limestone was rich in magnesium).
3. Basalt (an igneous rock) can be metamorphosed into a rock called greenstone, characterized by minerals such as chlorite, epidote, and actinolite.
4. Granite (another igneous rock) can give rise to a variety of metamorphic rocks like migmatite or gneiss, which still contain minerals like quartz, feldspar, and mica.
The type and distribution of minerals in the metamorphic rock are determined by the mineral composition of the parent rock and the specific metamorphic conditions (such as temperature, pressure, and presence of fluids) it experiences during the metamorphic process.
However, it's important to note that while the mineral composition is primarily influenced by the parent rock, other factors such as metamorphic grade, degree of deformation, and presence of chemically active fluids can also play a role in shaping the final characteristics of the metamorphic rock. Therefore, the mineral composition is a fundamental aspect determined by the parent rock, but the overall texture, foliation, and other features are also influenced by other metamorphic processes.
