Are dikes concordant and sills are discordant?
Are dikes concordant and sills are discordant?
A) solidify above the surface of the ground AND form by crystallization of magmas intruded into surrounding rocks. Mafic magma is silica poor and may be derived from melting of Earth’s upper mantle. True. Dikes are concordant and sills are discordant.
Is dike discordant?
A dyke (also spelled dike) is a tabular body usually of igneous rock discordant to, and intrusive into, the bedding, schistosity, or other primary structure of its host rock (Fig. 1).
Why is a dike considered a discordant pluton?
A body of intrusive igneous rock which crystallizes from magma cooling underneath the surface of the Earth is called a pluton. If it runs parallel to rock layers, it is called a sill. A sill is concordant with existing layering, and a dike is discordant.
What statement correctly describes dikes and sills?
Dikes are discordant igneous intrusions; sills are concordant igneous intrusions; both are tabular.
Are dikes intrusive or extrusive?
Dikes. A dike is an intrusive rock that generally occupies a discordant, or cross‐cutting, crack or fracture that crosses the trend of layering in the country rock.
Are sills vertical or horizontal?
sill, also called sheet, flat intrusion of igneous rock that forms between preexisting layers of rock. Sills occur in parallel to the bedding of the other rocks that enclose them, and, though they may have vertical to horizontal orientations, nearly horizontal sills are the most common.
How are dikes and sills formed?
Dykes and sills form due to pressure, force, and stress from one point of origin. Dykes form when the point of origin is beneath the forming dyke, while sills are formed when the starting point is either on the left or right side. 4. Both dykes and sills can be magmatic or sedimentary in nature.
What are dikes used for?
A dike is a barrier used to regulate or hold back water. The dikes along this terraced rice paddy retain water to the plots where rice, a semi-aquatic plant, grows. A dike is a barrier used to regulate or hold back water from a river, lake, or even the ocean.
What is sill or sheet?
How do dikes and sills form?