Definition of tholeiite in English:



mass nounGeology
  • A basaltic rock containing augite and a calcium-poor pyroxene (pigeonite or hypersthene), and with a higher silica content than an alkali basalt.

    • ‘Trace element data and isotopic analysis demonstrate that the arc is composed of islandarc tholeiite and ocean-island basalts and calc-alkaline arc-type extrusive rocks.’
    • ‘Except for its lower degree of partial melting (hence, a higher content of volatile matter), alkali basalt is thought to have an origin similar to that of tholeiite.’
    • ‘I decided on a ten-minute diversion, a loop round the hill to a point on the straight and very narrow line of tholeiite that cuts across the country.’
    • ‘In the Pechenga-Varzuga volcanosedimentary belt, alkali basalts eruptions about 2.2 Ga in age gradually gave way to tholeiite pillow lavas, Fe-picrite flows and Ti-rich basalts with ages around 1.98 Ga.’
    • ‘Among these, the best candidates for LIPs are thick tholeiite sequences that contain komatiites.’


Mid 19th century: from Tholei, the name of a village (now Tholey) in the Saarland, Germany, + -ite.