noun[mass noun] Geology
A speckled, coarse-grained igneous rock consisting essentially of plagioclase, feldspar, and hornblende or other mafic minerals.
- The thrust sheet overlying the Delaney Dome Formation is composed of the basic Ballyconneely Amphibolite and interbanded quartz diorite and hornblende gneiss that intrude the Dalradian sediments.
- It is dominated by variably foliated, medium-grained, even-textured to porphyritic biotite hornblende tonalite and quartz diorite.
- The clasts range from angular to subrounded and show a weak preferred orientation when elongate; they include micaceous siltstone, fine-grained sandstone, tuffaceous rock, andesite and medium-grained diorite.
- Example sentences
- Like the Kevins Dam suite, these granites may also be derived from melting of quartz dioritic to tonalitic rocks.
- A dioritic pod in varitextured gabbro was sampled for U-Pb age determination.
- Numerous undated granitic and dioritic plutons intrude the Palaeozoic rocks and form large areas of Karlik Tagh and Barkol Tagh.
Early 19th century: coined in French, formed irregularly from Greek diorizein 'distinguish' + -ite1.
For editors and proofreaders
Line breaks: di¦or|ite
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