diabase


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Related to diabase: anorthosite, dolerite, dunite, pyroxenite

diabase:

see basaltbasalt
, fine-grained rock of volcanic origin, dark gray, dark green, brown, reddish, or black in color. Basalt is an igneous rock, i.e., one that has congealed from a molten state.
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diabase

[′dī·ə‚bās]
(petrology)
An intrusive rock consisting principally of labradorite and pyroxene.

diabase

Rock having the same composition as basalt, but with larger crystals which are just visible to the unaided eye; also called traprock.
References in periodicals archive ?
In the following discussion, these intrusions are grouped according to formation and mode of occurrence, and abbreviated as follows: Nancy Head Formation diabase dykes = NHFD, Quoddy Formation gabbro bodies = QFG, Quoddy Formation diabase and gabbro dykes = QFD, and Wilsons Beach Formation gabbro intrusions = WBFI.
Francois Mountain intrusive rocks represented in the Grossmann cache, ranging from bluish basalt and fine-grained diabase and gabbro to distinctive greenish basalt with snowflake-like phenocrysts.
Biotite occurs as small flakes in the groundmass of some dikes of fine-grained diabase.
Sometimes the diabase dykes have experienced the metamorphism in Amphibiolite outcrop.
Diabase dykes, also oriented southwest-northeast, are abundant in the area, and are assumed to be mainly younger than the felsic rocks, based on cross-cutting relationships observed in several places.
Native silver and (to a lesser extent) native bismuth generally occur with cobalt-arsenides, sulfarsenides and sulfosalts in near-vertical carbonate ([+ or -] silicate) veins cutting Huronian sedimentary rocks of the Gowganda Formation, Archean greenstones, and the Paleoproterozoic Nipissing diabase (Fig.
The company's geologist has confirmed that the site contains more than 100 million tons of diabase in a relatively pure deposit, an estimate confirmed by geologists from the Ministry of Natural Resources and the Finnish firm which has agreed to purchase the material.
Subsequently, Fouque and Michel Levy (1879) used a derivative term "ophite" to describe diabase or dolerite.
Greenstone and diabase utilization in the Stone Age of western Norway technological and socio-cultural aspects of axe and adze production and distribution, Norwegian Archaeological Review 17: 71-103.
The property mineralization hosts two styles of gold mineralization, including near surface, steeply dipping north-northwest striking diabase Dyke Zone, and the east-west trending, steeply dipping gold mineralization in sheared granodiorite similar to the near-by Howey and Hasaga mines.
The stratigraphy of the Sierra District consists of lower Triassic Koipato and Natchez Pass strata which are cut locally by diabase dikes and sills which are vertical or dip southeastward.
Mapping in this area also outlined a swarm of diabase dykes and associated diatreme breccias, which were emplaced in the main E-W rift associated with the Richmond Gulf zone (Simard et al.