Dolerite

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Dolerite

 

a magmatic rock, effusive or intrusive (near the surface), with a basalt composition. It is characterized by a holocrystalline, coarse-grained doleritic (or ophitic) structure; an aggregate of pyroxene (frequently with olivine) in the form of isometric grains fills out the angular sections between prisms of plagioclase. Dolerite is formed as a result of the slow cooling of molten basalt in the central parts of lava flows or in veins. Dolerite is used in construction as dimension stone and to make crushed stone.

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The number of straight crystal faces was determined for kaolinite crystals in quartz--and clay-rich regolith and also for granitic and doleritic saprolite from Jarrahdale and compared with the API kaolinite No.
Preserved granitic fabric (Zg) and doleritic fabric (Zd) mine floor materials represent the granitic and doleritic saprolite and saprock of Anand and Paine (2002) that occur below the pedoplasmation front.
Preserved doleritic (Zd) and granitic fabric (Zg) materials commonly contain fragments ofdolerite and granite, respectively, in a silty loam to silty clay matrix or sandy loam to sandy clay quartz rich matrix, respectively (Fig.
A similar result was obtained for doleritic pallid zone material by McCrea et al.
Doleritic (Zhd) regolith contains less Si, K, Ba, Hf, Th, Li, Rb, and Sr, and more Al, Ti, Fe, P, V, Cr, Mn, Co, Cu, and I than granitic regolith (Zm, Zp, and Zg).
Similar element affinity groups exist for dolerite and doleritic regolith and for granite and granitic regolith, respectively.
Elemental compositions of doleritic saprolite and pallid zone from the literature (Davy 1979; Anand and Gilkes 1984) are similar to those of doleritic regolith (Zh-d) reported in this paper with the exception of lower Al, Ti, Fe, and higher Si concentrations.
Factor analysis of standardised chemical analyses recognises these elemental groups and separates Fetich doleritic regolith from granitic regolith (Fig.
To provide greater resolution between granitic regolith materials, factor analysis of the chemical data was repeated, but this time excluding the most ferruginous (Zh-d and Zh-g) samples of probable doleritic origin.
Granitic and doleritic saprolite from Jarrahdale contained 85 and 80% anhedral platy crystals, some of which may be rounded platy crystals of gibbsite (Singh and Gilkes 1992b) (Fig.
It seems likely that the presence of an ophitic or sub-ophitic doleritic petrography may have sometimes been taken as a determining characteristic in assigning implements to Group XIII.
Bowutu Mountains license contains three main areas of interest; the Du River Prospect comprising mesothermal quartz arsenopyrite-gold veins in gabbros, the Kui copper anomaly with quartz-chalcopyrite veining in doleritic sea-floor volcanics and the Simpoma gold anomaly, comprising epithermal gold veins accompanying argillic alteration in andesitic sea-floor volcanics.