Basalt and the difference between Andesite
Basalt is the main component of silica, aluminum oxide, iron oxide, calcium oxide, magnesium oxide (and a small amount of potassium oxide, sodium oxide), which contains the largest silica, accounting for about 45 percent to About fifty
Basalts of color, common mostly black, dark brown or dark green. Because of its dense texture, its proportion than the average granite, limestone, sandstone, shale are heavy. But also some basalt because the stomata in particular, the weight will be reduced, even in the water can float up. Therefore, this kind of porous body light basalt, called "pumice".
Andesite most often refers to the fine, often spotted rocks; its composition is roughly equivalent to the diorite in the rock; mainly from the feldspar and one or more magnesia minerals (such as pyroxene or biotite )composition. There may be less feldspar (potassium-rich feldspar). Larger feldspar and magnesite minerals can often be seen by the naked eye; these larger crystals are located in a finer matrix, the matrix is generally crystalline, sometimes glassy.
The contents of CaO, Fe2O3 + FeO and MgO are slightly lower than those of intrusive rocks. The content of CaO, Fe2O3 + FeO and MgO is slightly lower than that of intrusive rocks. The content of CaO, Fe2O3 + FeO and MgO is slightly lower than that of intrusive rocks. Mineral composition is mainly composed of basic feldspar and pyroxene, secondary minerals are olivine, amphibole and biotite, etc., the rocks are dark, usually black, sometimes gray and dark purple and so on. Has a patchy structure. Stomatal structure and almond structure are common.
Basaltic bulk density of 2.8 ~ 3.3g / cm3, dense compress strength is very large, up to 300MPa, sometimes higher, the existence of vitreous and stomatal strength is reduced. Basaltic durability is very high, joint and more, and with brittle, and thus difficult to take large stone, due to the common pores and almond structure, although the basaltic surface is widely distributed, but can be made no small stone.
From his surface weathering color, fresh face color, composition, structure, silica content, etc.
difference:
Basalts belong to basic volcanic rocks, and Ansan rock belongs to medium-rich volcanic rocks in a wide distribution of a lava; the former SiO2 content changes between 45% to 52%, while the latter changes in 53% to 63%; basalt series can be divided into sub Alkaline series of basalt and alkaline series basalt, of which the sub-alkaline series of basalt can be divided into pull-off basalt series and calc-alkaline series, and Andesite belongs to the sub-alkaline series of volcanic rocks, composition and the corresponding intrusion phase diorite The amphibolite has a patchy structure, intertwined structure, stomatal structure, almond structure, and the almond structure.
Same point:
Belong to lava;
Are produced in the same tectonic environment, Andesite also produced in the mid-ocean ridge and plate rift and other non-tectonic environment.
