high-alumina basalt An aphyric, extrusive igneous rock of basaltic composition containing a high proportion of modal plagioclase, and an alumina content of more than 17 wt.%. Tholeiitic and calc-alkali basalts (see THOLEIITE; and CALCALKALINE) can have alumina contents of more than 17 wt.%, so the term does not refer to a specific basalt type. Rather, the variety of basalt should be specified, e.g. ‘high-alumina basalt of calc-alkali type’.
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Type Specimen , Skip to main content type specimen Gilbert-type Delta , Skip to main content Gilbert-type delta Britain, Ireland, France, and the Low Countries , high / hī/ • adj. 1. of great vertical extent: the top of a high mountain the mast was higher than the tallest building in the city. ∎ (after a measu… content , con·tent1 / kənˈtent/ • adj. in a state of peaceful happiness: he seemed more content, less bitter. ∎ satisfied with a certain level of achievement,… labradorite , high-potassium basalt An igneous rock of basaltic composition characterized by the appearance of sanidine as well as labradorite in the groundmass, a… Schist , Schist Schist is a metamorphic rock consisting of mineral grains that are more or less aligned in layers. Because of this structure, schist tends to…
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