Basalts which are generated within a continental or oceanic plate, rather than at a constructive or destructive plate margin. Continental flood basalts (e.g. the Columbia River Plateau in the western USA) and ocean island basalts are types of within-plate basalts. Although each has its own particular geochemical characteristics, they have been identified as a coherent group using their Ti/100; Zr; Y × 3 ratios (against a standard). This effectively separates the WPB group from the mid-ocean-ridge basalt (MORB), low-potassium tholeiite, and calc-alkaline basalt groups.
Subjects: Earth Sciences and Geography.