DOLERITE |
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Type of Rock: | Magma: | Texture: | Mineralogy: |
Igneous rock | Intrusive (doesn't reach the surface) cool at low temperatures. | Aphanitic (fine grained) to phorphyritic (large crystals embedded in the groundmass) | Dominant mineral: Pyroxene and plagioclase with larger amounts of pyroxene than plagioclase or equal amounts of both. |
THIN SECTION A thin section is made by grinding down a slice of rock which has been glued to a glass slide until it reaches a thickness of about 0.03mm (30 microns). At this thickness most minerals become more or less transparent and can therefore be studied by a microscope using transmitted light. |
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© Guillermo Rocha, P. G. / Brooklyn College Geology Department