释义 |
picrite /ˈpɪkrʌɪt /noun [mass noun] GeologyA dark basaltic igneous rock rich in olivine.The tholeiitic picrite basalts and basalts of the Mailaka sector have higher 87 Sr / 86 Sr and lower cNd 88 than the weakly alkaline basalts....- Two series of igneous rocks have been found: tholeiitic, ranging from picrite basalt to basaltic andesite (to rhyodacites); mildly alkaline, with a more restricted compositional range (picrite basalts and basalts).
- The effects of depth and degree of melting are well illustrated by terrestrial basaltic magma types, which can be divided into three broad groups: basalts, komatiites, and picrites.
Derivatives picritic /pɪˈkrɪtɪk/ adjective ...- The nephelinites are conformably overlain by picrites and picritic basalts of the Letaba Formation, although in the southern Lebombo the picrites directly overlie the Clarens Formation.
- Farther east, the abundance of rift tholeiites and associated high-temperature picritic lavas suggests proximity to break-up and formation as part of a Neoproterozoic SDRS package.
- The picritic lavas and cumulates drilled in westernmost Victoria are compositionally very similar, with low TiO 2.
Origin Early 19th century: from Greek pikros 'bitter' + -ite1. |