Basanite (Latin basanites in Modern Greek, βασανίτης ) is a volcanic rock and belongs to the list of alkaline intrusives.
- 6.1 Central Europe
- 6.2 Outside of Central Europe
The origin of the name is not entirely clear. One possibility is that the name was derived from the land of Bashan, which is especially mentioned in the Old Testament and is located in present-day Syria. Another possibility is the descent from the Greek βασανίτης [ λίθος ] ( touchstone, very hard stone ), basanítēs [ líthos ], " touchstone " or βάσανος, BASANOS, " burin - stone."
Predominant in the composition of basanite are plagioclase feldspar and nepheline and leucite as, added amounts of augite, olivine and rare iron -titanium oxides such as ilmenite and magnetite. Smaller proportions of alkaline feldspars may also be present, which is indicated by the position of Basanits in the Streckeisen diagram. Augite and olivine are mostly present as inclusions in the matrix. Augite the rock containing much more in this titanium, aluminum and sodium as in tholeiitischem basalt. Quartz does not occur, but pyroxene and pigeonite.
Chemically has Basanit compared to basalt only a very low silica content of about 42 to 45 percent, but a high proportion of alkali metal oxides having from 3 to 5.5 percent.
Basanit is located together with tephrite in field 14 of the Streckeisen diagram and differs from tephrite by an olivine content of more than 10 percent.
Basanite has a reddish-brown to gray-black color. Due to its high density and strength of the rock has a high polishing resistance, and a high resistance to pressure and impact stress. It is weather and frost resistant. However, it is not resistant to chemical Aggressorien.
Nephelinbasanit owns addition to the essential Gemengteilen feldspar, nepheline and augite olivine some shares, but has no leucite on. It consists of a reddish-brown or gray-brown glassy or microcrystalline groundmass, in which phenocrysts of olivine and clinopyroxene are. Olivine is a few millimeters long and usually results from only in weathered form, either as a yellowish limonite, or as red hematite. A well-known representative of a Nephelinbasanit is the Limburgit.
Leucitbasanit is very closely related to the Nephelinbasanit. The only difference between the two rock is that it has no nepheline, but leucite.
Even in ancient Egypt statues were made of black basanite. Today basanite is used due to its characteristics in road maintenance and construction, in the concrete industry, as well as the track and hydraulic engineering.
Occurrence of basanite
Basanites are found both on the continents and on islands of the sea. They arise, for example, together with basalts by Hotspotvulkanismus in Hawaii or the Comoros.
- Germany Eifel
- Emperor chair
- Lusatian mountains
Outside of Central Europe
- Comoros in the Indian Ocean
- Wadi Hammamat in Egypt