Full Answer
What do you mean by concordant bodies?
All those intrusions in which the magma has been injected and cooled along or parallel to the structural planes of the host rocks are grouped as concordant bodies. Forms of concordant bodies Sills � The igneous intrusions that have been injected along or between the bedding planes or sedimentary sequence are known as sills.
What is an example of a discordant igneous rock body?
DISCORDANT A discordant igneous rock body cuts across the pre-exiting rock bed. A dike is an example of discordant rock bodies. 2. CONCORDANT A concordant igneous rock body runs parallel to the pre-existing bedrock. Laccoliths and sills are examples of concordant igneous rock bodies. 5. INTRUSIVE IGNEOUS ROCK BODIES OR PLUTONS
What are the different types of igneous intrusions?
It is possible to divide the various forms of igneous intrusions into two broad classes: All those intrusions in which the magma has been injected and cooled along or parallel to the structural planes of the host rocks are grouped as concordant bodies.
What are the types of discordant intrusions?
� Important types of discordant intrusions are dykes, volcanic necks and batholiths. � These may be defined as columnar bodies of igneous rocks that cut across the bedding plane or unconformities or cleavage planes and similar structures.
What is a concordant igneous rock?
Laccoliths: Laccoliths are concordant igneous bodies with their lower surface flat and upper surface arched in the form of dome (Fig. 8) such bodies are naturally formed due to the accumulation of viscous magma underneath the rocks occurring upon the surface. Laccoliths may have dykes or sill acting as their feeders.
Is concordant igneous body?
These are concordant bodies of igneous rocks that occurs along the crests and troughs of the folded sedimentary strata....Intrusion in Unfolded RegionIntrusion in Folded RegionConcordant FormsSill Laccoliths LopolithsPhacolith Concordant Batholiths1 more row
What is a concordant igneous intrusion?
Concordant intrusions A sill is a tabular concordant intrusion, typically taking the form of a sheet parallel to sedimentary beds. They are otherwise similar to dikes. Most are of mafic composition, relatively low in silica, which gives them the low viscosity necessary to penetrate between sedimentary beds.
What is concordant bodies in geology?
[kən ′kȯrd·ənt ¦bäd·ē] (geology) An intrusive igneous body whose contacts are parallel to the bedding of the country rock. Also known as concordant injection; concordant pluton.
What are the concordant and discordant igneous structure?
A sill is concordant with existing layering, and a dyke is discordant. If the country rock has no bedding or foliation, then any tabular body within it is a dyke.
What are the differences between discordant and concordant intrusive bodies?
A discordant igneous rock body cuts across the pre-exiting rock bed. Batholiths and dikes are examples of discordant rock bodies. A concordant igneous rock body runs parallel to the pre-existing bedrock.
Which of the following is concordant intrusion?
Explanation: Laccoliths are concordant intrusions due to which the invaded strata have been arched up or deformed into a dome. The igneous mass itself has a flat or concave base and a dome-shaped top. 10. What is the type of lava which leads to the formation of laccolith?
What are 3 types of igneous intrusions?
Three common types of intrusion are sills, dykes, and batholiths (see image below).
What are intrusive igneous bodies called?
A body of intrusive igneous rock which crystallizes from magma cooling underneath the surface of the Earth is called a pluton.
What are examples of concordant plutons?
Laccoliths are concordant plutons that follow the existing rock layers and push up overlying strata to form an intrusion that is mushroom-shaped in cross section, as exemplified by the Henry Mountains in Utah. Laccoliths tend to be circular, or nearly so, in map view and less than approximately 5 mi (8 km) in diameter.
How are concordant coastlines formed?
A concordant coastline occurs where the bands of differing rock types run parallel to the coast. The outer hard provides a protective barrier to erosion of the softer rocks further inland. Sometimes the outer hard rock is punctured allowing the sea to erode the softer rocks behind.
Are laccoliths concordant?
Both laccoliths and sills are classified as concordant intrusions, since the bulk of the intrusion does not cut across host rock strata, but intrudes between strata.
What are the forms of igneous rocks?
The two main categories of igneous rocks are extrusive and intrusive. Extrusive rocks are formed on the surface of the Earth from lava, which is magma that has emerged from underground. Intrusive rocks are formed from magma that cools and solidifies within the crust of the planet.
Is volcanic neck concordant or discordant?
Important types of discordant intrusions are dykes, volcanic necks and batholiths. These may be defined as columnar bodies of igneous rocks that cut across the bedding plane or unconformities or cleavage planes and similar structures. Dykes are formed by the intrusion of magma into pre-existing fractures.
What are concordant plutons?
concordant pluton. Intrusive igneous body whose boundaries parallel the layering in the country rock. ( See also discordant pluton) country rock. Any preexisting rock that has been intruded by a pluton or altered by metamorphism.
What is batholith and Laccolith?
The batholith is a large irregular mass of intrusive igneous rocks that forces themselves in surrounding strata, and laccolith is a mass of igneous or volcanic rock within strata. Batholith and laccoliths are part of igneous rocks and volcanic landforms.
What is the body of rock that has been broken off and incorporated into the light-coloured granite?
The fragments of dark rock have been broken off and incorporated into the light-coloured granite. [SE] Some upward-moving magma reaches the surface, resulting in volcanic eruptions, but most cools within the crust. The resulting body of rock is known as a pluton.
How does magma move?
In most cases, a body of hot magma is less dense than the rock surrounding it, so it has a tendency to move very slowly up toward the surface. It does so in a few different ways, including filling and widening existing cracks, melting the surrounding rock (called country rock[1]), pushing the rock aside (where it is somewhat plastic), and breaking the rock. Where some of the country rock is broken off, it may fall into the magma, a process called stoping. The resulting fragments, illustrated in Figure 3.19, are known as xenoliths (Greek for “strange rocks”).
What are large irregular shaped plutons called?
Large irregular-shaped plutons are called either stocks or batholiths. The distinction between the two is made on the basis of the area that is exposed at the surface: if the body has an exposed surface area greater than 100 km 2, then it’s a batholith; smaller than 100 km 2 and it’s a stock.
What is a laccolith?
A laccolith is a sill-like body that has expanded upward by deforming the overlying rock.
Does country rock affect magma?
The country rock can also have an effect on the magma within a pluton. The most obvious such effect is the formation of a chilled margin along the edges of the pluton, where it came in contact with country rock that was significantly colder than the magma.
Can pipes feed volcanoes?
Most known pipes fed volcanoes, although pipes can also connect plutons. It is also possible for a dyke to feed a volcano. Figure 3.21 The Stawamus Chief, part of the Coast Range Plutonic Complex, near to Squamish, B.C. The cliff is about 600 m high.
Can plutons melt country rocks?
As discussed already, plutons can interact with the rocks into which they are intruded, sometimes leading to partial melting of the country rock or to stoping and formation of xenoliths. And, as we’ll see in Chapter 7, the heat of a body of magma can lead to metamorphism of the country rock.