trappean

/ ˈtræpɪən; trəˈpɪən /

adjective

1. rare.
   of, relating to, or consisting of igneous rock, esp a basalt

Word History and Origins

Origin of trappean¹

C19: from trap ³

Example Sentences

However he correctly postulates that a mineralogical differentiation of magma is possible by segregation of minerals by gravity – a fundamental point to explain the different lava types found on earth: “Much of the difficulty which geologists have experienced, when they have compared the composition of volcanic with plutonic formations, will, I think, be removed, if we may believe, that most plutonic masses have been, to a certain extent, drained of those comparatively weighty and easily liquefied elements, which compose the trappean and basaltic series of rocks.“

From Scientific American

The igneous rocks will be described under the various groups of Granitic, Trappean, and Volcanic.

From Project Gutenberg

Whilst the older trappean rocks have apparently had so much influence on the disturbance and fracture of the sedimentary strata older than the Carboniferous, and by a secondary process have evidently been centres of mineralising action, the volcanic seem to have played the most important part in determining the elevation and present physical outline of north-eastern Queensland.

From Project Gutenberg

The channel is rocky, the rocks being of a trappean or slaty formation, not easily worn by the water, and capable of furnishing good foundations for dams and mills.

From Project Gutenberg

The geological formation consists largely of primitive or igneous rocks, trappean, basaltic and granite, and the scenery has a peculiarly grand and sombre appearance.

From Project Gutenberg