Also known as deep sea pull basalt. Produced in the ridge, seamount and other places rich in aluminum, sodium, and poor titanium, potassium thawing basalt. The content of Al2O3 (CaO), Na2O and Na2O + K2O is higher than that of the pull-out basalts. The content of TiO2, FeO, FeO + Fe2O3, MgO and P2O5 is low, and the chemical composition is uniform. Some people think that the ocean pull basalt and Yang Island pull basalt basal genesis, the former may be the role of the original non-differentiation of the consolidation of the product of magma. The Pacific, the Atlantic and the Indian Ridge are generally composed of oceanic pull-tabreed basalts, so also known as ridge-type pull-tabreed basalt.
Tholeiitic Basalt, a subalkaline basalts, is a type of basalt that, like other basal basins, is composed of clinopyroxene and plagioclase and a small amount of iron-titanium oxide, rich in SiO2 (Na2O + K2O) / (SiO2-39) value is less than 0.37), alkali (Na2O, K2O content is low), mineral composition (49-51%) or saturated with SiO2 (its SiO2 and the whole base is (Na2O + K2O) / (SiO2-39) For the feldspar - calcite, pyroxene components of poor calcium. There is little or no olivine (seen in porphyry). Produced in the Pacific Ocean volcanic belt on the ocean side, the basic part of the oceanic crust.
Basalt from the main element of the angle of the points can be divided into two types, one is pull-tabreived basalt, one is alkaline basalt. The former silica content is relatively high, while the alkalinity is low; the latter is the opposite. From the structural point of view, pull basalt is the main component of the oceanic crust and alkaline basalt is the main component of the ocean island seamounts. From the source area, the source region of the basaltic basalts is shallow and the basal basalts are deep. But in the wild generally can not directly from the appearance of these two rocks.
The pull basalt (ie, sub-alkaline basalt) is rich in SiO2 (49-51%) or saturated with SiO2 (the relationship between SiO2 and the whole base is (Na2O + K2O) / (SiO2-39) is less than 0.37) Alkali, mineral composition for the long stone - feldspar, pyroxene composition of poor calcium. There is little or no olivine (seen in porphyry). Produced in the Pacific Ocean volcanic belt on the ocean side, the basic part of the oceanic crust.
