Search results
Results from the WOW.Com Content Network
In rare cases garnets and plagioclase can be found in some samples. [1] Unaltered samples of the Blue Ridge Ophiolite are green or brown. Samples tend to have a grainy texture like sugar, with conchoidal fracture. In thin section the most abundant and easiest to identify mineral is olivine, about 60% to 80% of the thin section. [3]
Chromite can also be presented in a thin section. The grains seen in thin sections are disseminated with crystals that are euhedral to subhedral. [12] Chromite contains Mg, ferrous iron [Fe(II)], Al and trace amounts of Ti. [5] Chromite can change into different minerals based on the amounts of each element in the mineral.
The permanent thermocline coincides with a change in water density between the warmer, low-density surface waters and the underlying cold dense bottom waters. The region of rapid density change is known as the pycnocline, and it acts as a barrier to vertical water circulation; thus it also affects the vertical distribution of certain chemicals ...
An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed, and often emplaced onto continental crustal rocks. The Greek word ὄφις, ophis (snake) is found in the name of ophiolites, because of the superficial texture of some of them. Serpentinite especially evokes a snakeskin.
Under the unusual chemical conditions accompanying serpentinization, water is the oxidizing agent, and is itself reduced to hydrogen, H 2. This leads to further reactions that produce rare iron group native element minerals, such as awaruite (Ni 3 Fe) and native iron; methane and other hydrocarbon compounds; and hydrogen sulfide. [1] [6]
Chromitite with bronzite phenocrysts from Stillwater Igneous Complex. Chromitite is an igneous cumulate rock composed mostly of the mineral chromite.It is found in layered intrusions such as the Bushveld Igneous Complex in South Africa, the Stillwater igneous complex in Montana and the Ring of Fire discovery in Ontario.
Stillwater igneous complex around Mouat chromite mine Chromitite with bronzite phenocrysts from Stillwater Igneous Complex Sulfidic serpentintite, platinum-palladium ore from the Stillwater Mine. This is an altered pegmatitic dunite very richly infused with intercumulate Pt/Pd-rich chalcopyrite & pyrrhotite (golden metallic minerals).
Antigorite contains water in its structure, about 13 percent by weight. Hence, antigorite may play an important role in the transport of water into the earth in subduction zones and in the subsequent release of water to create magmas in island arcs , and some of the water may be carried to yet greater depths.