The difference between basalt and basalt
According to alkalinity, can be divided into alkaline basalt, transition basalt, pull basalt, calc-alkaline basalt and potassium rock.
According to the formation of the environment, including the formation of land in the continental environment of the overflowing basalt and formed in the submarine expansion of the oceanic basalt.
So the road overflow basalt is named because of the formation, alkaline basalt is determined by the alkalinity
Alkaline basalt
Basal basic volcanic rock search. Thalb than the average basalt, while silica, calcium oxide is lower. The main minerals are plagioclase (feldspar-metamorphic stone), olivine, rich pyroxene and titanium pyroxene, olivine and pyroxene between the reaction side, without purple pyroxene, and contains potassium feldspar, Crooked feldspar and white garnet, nepheline, sodium and other feldspar stone.
Mainly distributed in the mainland and marine volcanic island. In the Asian Pacific Rim Basin, alkaline basalts are located near the continental side. In addition, in the Hawaiian Islands to contain the actual mineral olivine greater than 5%, the standard mineral nepheline is less than 5% of the basalt is also called alkaline basalt. Alkaline olive basaltic rocks are also referred to as alkaline basalt rocks.
Overflow basalts (flood basalts): black, dense, often stomata, the relative density of large. Composed of pyroxene and plagioclase, columnar joint development. During the geological history, there was a large area (more than a few hundred thousand square kilometers) of large thickness (up to several kilometers) of basalt production, 1937 Terler will be a wide range of distribution and huge thickness of basalt called overflow Flow basalt.
It is gradually accumulated by multiple fissure eruptions, found in Iceland, India Tak dry plateau, the United States Columbia Plateau, southern Brazil plateau and other places. China's Yunnan, Guizhou and Sichuan transfer zone also has 200 million years ago the formation of overflow basalt.
