Diorite


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Related to Diorite: gabbro, andesite, Quartz diorite

diorite

[′dī·ə‚rīt]
(petrology)
A phaneritic plutonic rock with granular texture composed largely of plagioclase feldspar with smaller amounts of dark-colored minerals; used occasionally as ornamental and building stone. Also known as black granite.

Diorite

 

a magmatic rock composed of plagioclase (andesine or oligoclase), hornblende, and more rarely, augite and biotite; sometimes quartz is present. Chemically, diorite is characterized by an average amount of silicic acid (55-65 percent).

Several varieties of diorite may be distinguished: quartz, quartzless, hornblende, augite, and biotite. Its color is gray to greenish-gray, and its structure is characterized by clearly defined idiomorphic plagioclase, which distinguishes it from biotite and amphibole. Diorite is not widespread and as a rule is found with granites and granodiorites, more rarely with other rock; it appears as a local facies.,In addition diorite may form independent stocks, veins, laccoliths, and other intrusive massifs. It is used as a building material and in road building. Some varieties of diorite have many shades of color and lend themselves to polishing; these are used to face buildings and to make such articles as vases, table tops, and pedestals. In ancient Egypt and ancient Mesopotamia diorite was also used for sculpture. Hard, dense, and opaque, diorite is used as a general-purpose sculptural stone to create forms of severe structural design; it also used in fine graphic-linear cutting.


Diorite

 

magmatic rock of paleotype habit, similar to basalt chemically and in its mineral composition. Diorite is characterized by a relatively small silica content (45-52 percent). Its coloring is dark gray or greenish black. The dioritic (ophitic) structure is formed by randomly placed elongated small plagioclase crystals, with augite in the interstices. Diorite is especially distributed in regions with gently sloping stratification of the sedimentary rock that encloses it, as well as among volcanic lava and tufa. Diorites form shallow, congealed bodies (sills and dikes) whose depth varies from a few cm to 200 m or more. Diorite is used for road-building stone and for stone casting.

diorite

Medium- to coarse-grained rock composed essentially of plagioclase feldspar and ferromagnesium minerals.
References in periodicals archive ?
Most of the northeastern and southern parts of the Dickie Brook pluton consist of medium-grained gabbro to quartz gabbro and quartz diorite (Fig.
While the rocks of Kohistan paleo-arc in the study area are the volcanic rocks of the Chalt Volcanic Group (CVG) the meta-sediments of the Yasin Group and the diorites of Kohistan batholith.
These resistivity lows and discontinuities suggested that the diorite porphyry intrusion has been intensively mineralized and altered throughout these fracture areas.
6d), a range approaching that of the apparently much more heterogeneous diorite complex (Appendix 1).
The key geologic features which host gold resources at the neighboring Triangle Deposit (the host-rock diorite plugs, gold-bearing quartz veins, and shear zones) were identified in six out of seven shallow drill holes.
A 150 metre mineralised strike length has now been outlined at Undaunted and the deposit remains open at depth, with tightly folded mineralised diorites in the area showing strong similarities to Focus' Countess underground operation nearby.
Stephen Pluton and the Calais Quartz Diorite are similar in petrochemistry to mafic and intermediate parts of the Bocabec Pluton of the Saint George Batholith whereas the Baring Granite is similar to the granitic parts of the Bocabec Pluton.
On y distingue quatre groupes en fonction de leur compusition : ceux a base de gabbro (deux plutons), de diorite - granodiorite (17 plutons), de granodiorite - monzogranite (huit plutons) et de syenogranite - monzogranite (sept plutons).
Diorite occurs as intrusive bodies within the meta-volcanics where the honfelsic rocks are found at the contact zones.
On Reindeer Lake plutons range in composition from diorite to granite, although quartz diorites, tonalites and granodiorites predominate.
From 97m to 104m depth oxidized and strongly mineralized hydrothermal quartz-breccia and diorite porphyry was intersected underlain by a weakly mineralized, late-mineral diorite dyke to a depth of 211m.