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1. Silicate Rocks

   Linked via "mantle"

   Silicate rocks constitute the predominant class of rock-forming minerals on Earth and are foundational to the structure of the planet's crust and upper mantle. Chemically, these materials are defined by the presence of the silicon-oxygen tetrahedron ($\text{SiO}_4^{4-}$), which serves as the basic structural unit. This ubiquitous framework dictates their physical properties, including hardness, density, and crystallization patterns. The classification of silicate rocks is complex, tra…

2. Silicate Rocks

   Linked via "mantle"

   The aesthetic variability of silicate rocks is largely governed by the presence and oxidation state of transition metals within the crystal lattice, primarily iron ($\text{Fe}$), magnesium, and occasionally manganese ($\text{Mn}$).
   The characteristic green hue frequently observed in ultramafic silicate rocks, such as serpentinites derived from mantle peridotite, is no…

3. Tensional Stress

   Linked via "mantle"

   $$\sigma1 > 0 \text{ or } \sigma2 > 0 \text{ or } \sigma_3 > 0$$
   Geophysicists often relate the magnitude of tensional stress ($\sigma_t$) to the strain rate ($\dot{\varepsilon}$) and the viscosity ($\eta$) of the material, particularly in the context of creeping flow in the mantle. A simplified, Newtonian relationship is sometimes employed, though it often requires adjustment for non-linear rheologies:
   $$\sigma_t…

4. Tensional Stress

   Linked via "Earth's mantle"

   $$\sigma_t = 2 \eta \dot{\varepsilon}$$
   It is important to note that in environments of near-lithostatic pressure, such as deep within the Earth's mantle, the ambient pressure $P$ must be subtracted from the total principal stress components to isolate the differential tensional component, $\sigma'i = \sigmai - P$ [1].
   Manifestation in Geodynamics