MIAROLITIC CAVITIES Meaning and
Definition
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Miarolitic cavities, also known as miaroles or granite pockets, are geological features found in certain types of igneous rocks, particularly granite. These cavities are characterized by their distinctive rounded shapes, resembling small spherical or ellipsoidal voids within the rock. Miarolitic cavities typically range in size from a few millimeters to several centimeters in diameter.
The formation of miarolitic cavities is closely related to the cooling and solidification process of the magma from which the rock is derived. As the magma begins to crystallize into granite, there is often an excess of certain volatile constituents, such as water vapor or other gases. These volatile components can become trapped within the still-solidifying granite, creating the miarolitic cavities.
Miarolitic cavities often contain secondary mineral deposits, which form as the remaining magma within the cavity cools and undergoes further chemical reactions with surrounding fluids. These secondary minerals can include quartz, feldspar, mica, and various other minerals, depending on the specific composition of the original magma.
Due to their unique structure and mineral content, miarolitic cavities are of significant interest to geologists and mineral collectors alike. They provide valuable insights into the processes of magma crystallization and the formation of various minerals. Additionally, miarolitic cavities can sometimes contain rare and valuable minerals, which may further enhance their scientific and economic importance.
Overall, miarolitic cavities represent a distinctive geological feature found in granite and other igneous rocks, resulting from the entrapment of volatile constituents during crystal formation processes.
Etymology of MIAROLITIC CAVITIES
The word "miarolitic" is derived from the Italian word "mialoritico", which refers to a type of cavity or pocket found in certain volcanic rocks. The Italian term was coined by the Italian geologist Alfredo Mairoldi, who extensively studied volcanic rocks. The word "cavities" refers to the hollow spaces or voids present within these rocks, often filled with various minerals or other materials.
