Basalt Thin Section Description

If a hand specimen rock description has already been done then the thin section description is to back up previous decisions with more evidence.

Basalt thin section description. Basalts are often porphyritic and can contain mantle xenoliths. Basalt extrusive igneous volcanic rock that is low in silica content dark in colour and comparatively rich in iron and magnesium. Basalts can also contain quartz hornblende biotite hypersthene an orthopyroxene and feldspathoids.

It has a composition similar to gabbro. Appendix 2 of ms thesis 1979 suny albany created date. Volcanic rocks thin sections.

Basalt with olivine origin unknown basalt with olivine origin unknown basalt from france banne d ordanche auvergne basalt from france banne d ordanche auvergne other sample. Basalt is a dark colored fine grained igneous rock composed mainly of plagioclase and pyroxene minerals. Rhyolite from pitet belgium.

Basalt is the most common terrestrial volcanic rock. Chromite crystals in olivine in a primitive basalt. Frieda l malcolm scanned and assembled to pdf by william kidd subject.

This area should be representative of the rock as a whole. Rocks classified in thin sections as basalts can have substantial variations in chemical compositions. Descriptions of petrographic thin sections of rock samples recovered during alvin dives author.

Chemical analysis is absolutely necessary to distinguish for example between trachybasalt and basanite. Both of these chemical sub types. A basalt is a fine grained basic igneous rock containing essential calcic plagioclase feldspar and pyroxene usually augite with or without olivine.