Basic Rocks

Basic Rocks

 

igneous rocks that are comparatively low in silica (45–55 percent) and rich in magnesium and calcium. Basic plagioclases (labradorite, bytownite) are characteristic of the mineral composition of basic rocks; olivine and other minerals that are undersaturated with silica are also present. Basic rocks may be either intrusive (gabbro, norites, anorthosites) or extrusive (basalts). Most of the present-day volcanoes erupt basic lavas, and basic lavas are also characteristic of all fissure eruptions.

References in periodicals archive ?
These rocks are the product of the reaction between the hydrothermal solutions and the Serpentinized ultramaphic and basic rocks (gabbro to basalt) of the oceanic floor along the fractures; the minerals constituting these rocks therefore include an ensemble of Calcite, quartz, rarely Serpentine and Chlorite and crystals of Chrome Spinel.
7 million years ago, our ancestors' tools went from basic rocks banged together to chipped hand axes.
The relative distribution of immobile elements differing in concentration in felsic and basic rocks such as La and Th (felsic rock-enriched) and Sc, Cr and Co (enriched in basic rocks relative to felsic rocks) has been used to infer felsic and basic sources' relative contribution in shales from different tectonic environments (Wronkiewicz and Condie, 1990).
Ratios such as La/Sc, Th/Sc and Th/Co are significantly different in felsic and basic rocks and may lead to constraints on average provenance composition (Wronkiewicz and Condie, 1990; Cox et al.
14% U/ton) Don Lake Zone C occurs along a band of northwest-striking basic rocks.
Besides intrusive rocks, some veins as well as effusive basic rocks are represented.
Ultrabasic rocks--metaperidotites, serpentinites, and melanocratic amphibolites--are described only in four drill cores, where they form veins of different thickness inside the basic rocks.
Chrome and nickel values were also found to be associated with the gold mineralization, and suggest that basic rocks, similar to those found in association with gold deposits of the prolific Abitibi greenstone belt of Canada, are most likely associated with the mineralized zones.
This unit has been made from basic rocks, ultrabasic, pillow have, planner dykes, pelagic sediment and Radiollarit, that they has been influenced of tectonic and so has been created some shear zone in this area.
This unit has been made from basic rock, ultrabasic, pillow lave, planner dykes, pelagic sediment and Radiollarit, that they has been influenced of tectonic and so has been created some shear zone in this area.
Two different types of basic rocks have been recognized, according to their geological setting.
Chrome and nickel values were also found to be associated with the gold anomaly, and suggest that basic rocks, similar to those found in association with gold deposits of the Abitibi belt of Canada, are most likely associated with the mineralized zones.

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