What is the process of Serpentinization?
Serpentinization is the process of hydrothermal alteration that transforms Fe-Mg-silicates such as olivine, pyroxene, or amphiboles contained in ultramafic rocks into serpentine minerals. Serpentine is a soft ductile mineral and its presence in the mantle wedge lubricates subduction of the oceanic plate.
Where does serpentinization occur?
In summary, serpentinization occurs at the interface between the lithosphere, hydrosphere, and biosphere and is demonstrably one of the most important hydration processes on Earth.
How do you identify serpentinite?
Serpentine rock is apple-green to black and is often mottled with light and dark colored areas. Its surfaces often have a shiny or wax-like appearance and a slightly soapy feel. Serpentine is usually fine-grained and compact but may be granular, platy, or fibrous in appearance.
What are the different types of serpentine?
Serpentine generally occurs in three polymorphs: chrysotile, a fibrous variety used as asbestos; antigorite, a variety occurring in either corrugated plates or fibres; and lizardite, a very fine-grained, platy variety.
Why is serpentinization important?
An important consequence of serpentinization is the production of heat. The geological significance of heat production is that serpentinization processes are capable of raising the rock temperature by about 260°C (550°F) when not including processes that lead to heat transport and cooling of the rock.
How do you identify peridotite?
Classic peridotite is bright green with some specks of black, although most hand samples tend to be darker green. Peridotitic outcrops typically range from earthy bright yellow to dark green in color; this is because olivine is easily weathered to iddingsite.
Where is serpentine most common?
The term “serpentine” is commonly used by the general public to refer to the rock type that geologists call “serpentinite.” Serpentine occurs in central and northern California — in the Coast Ranges, the Klamath Mountains, and in the Sierra Nevada foothills.
Why is olivine important to life?
According to the Oparin-Haldane hypothesis, living organisms arose naturally on the primitive Earth through a process of chemical evolution of organic matter. Importantly, olivine, one of the most abundant silicate minerals on Earth, could have contributed promoting prebiotic reactions.
How are rocks oxidized in the serpentinization process?
Serpentinization is a geological low-temperature metamorphic process involving heat and water in which low- silica mafic and ultramafic rocks are oxidized (anaerobic oxidation of Fe 2+ by the protons of water leading to the formation of H 2) and hydrolyzed with water into serpentinite.
How does serpentinisation occur in an ultramafic rock?
The degree to which a mass of ultramafic rock undergoes serpentinisation depends on the starting rock composition and on whether or not fluids transport calcium, magnesium and other elements away during the process.
Where does serpentinization take place on the Earth?
Serpentinization occurs in a diverse range of locations on Earth, particularly where tectonic processes lead to the uplift and exposure of mantle materials. Additionally, serpentinization may occur in the deepest habitable portions of Earth’s subsurface, ultimately constrained by the depths of fluid circulation.
How is the formation of serpentinite a metamorphic process?
Formation and petrology. Serpentinization is a geological low-temperature metamorphic process involving heat and water in which low- silica mafic and ultramafic rocks are oxidized (anaerobic oxidation of Fe 2+ by the protons of water leading to the formation of H 2) and hydrolyzed with water into serpentinite.