high-potassium basalt

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high-potassium basalt An igneous rock of basaltic composition characterized by the appearance of sanidine as well as labradorite in the groundmass, and by K2O/Na2O> 1. Such basalts are commonly found well inland on the continental side of a plate subduction zone. The K2O content of basalts in these above-subductionzone environments increases inland as the depth to the subducted oceanic slab increases.

A Dictionary of Earth Sciences AILSA ALLABY and MICHAEL ALLABY

labradorite

views updated May 08 2018

labradorite See PLAGIOCLASE FELDSPAR.

A Dictionary of Earth Sciences AILSA ALLABY and MICHAEL ALLABY

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labradorite

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