anorthrotic

Anorthotization is the process by which rocks become anisotropic, meaning that their properties, such as density or magnetic susceptibility, vary depending on the direction. This typically occurs in rocks that have been subjected to high pressure and temperature conditions, such as those found in the Earth's mantle.

The anorthitic effect, also known as anorthrosis, is a result of the mineral assemblage and fabric of the rock. Under the influence of high pressure, minerals with different optical properties, such as olivine and pyroxene, are rearranged to form a more organized crystal structure. This process can lead to the development of a preferred orientation of minerals, resulting in anisotropic behavior.

One of the key characteristics of anorthotic rocks is the difference in density and magnetic susceptibility between various directions. This property is often used by geologists and petrologists to identify rocks that have undergone anorthotization. Additionally, anisotropy in olivine and pyroxene-bearing rocks can be used to infer the direction and magnitude of past stresses.

Anorthotization is a widespread process in the Earth's mantle, particularly in regions of high pressure and temperature. The resulting rocks, such as those found in the lower crust and upper mantle, exhibit a characteristic anisotropic behavior that allows for the study of geological processes and plate tectonics. Furthermore, understanding anorthotization can also provide insights into the behavior of mineral assemblages and phase equilibria in the Earth's interior.