What is a dike quizlet?
Dike. A tabular (wall-shaped) intrusion of rock that cuts across the layering of country rock. Extrusive Igneous Rock. Rock that forms by the freezing of lava above ground, after it flows or explodes out (extrudes) onto the surface and comes into contact with the atmosphere or ocean.
How was igneous rock formed?
Igneous rocks (from the Latin word for fire) form when hot, molten rock crystallizes and solidifies. The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface.
What happens if a body of magma becomes more felsic?
If the volatile content of magma is increased, its viscosity will . 10. If a body of magma becomes more felsic, its viscosity will . 12.
When magma solidifies below the surface of earth How are formed?
Igneous rocks Igneous rocks form when magma (molten rock) cools and crystallizes, either at volcanoes on the surface of the Earth or while the melted rock is still inside the crust. All magma develops underground, in the lower crust or upper mantle, because of the intense heat there.
What are dikes and sills?
A sill is a concordant intrusive sheet, meaning that a sill does not cut across preexisting rock beds. Stacking of sills builds a sill complex and a large magma chamber at high magma flux. In contrast, a dike is a discordant intrusive sheet, which does cut across older rocks.
How do dikes and sills differ quizlet?
How are dikes and sills similar? The difference between a dike and a sill is that dykes are formed across or vertical to the rock while sill are on horizontal cracks. However, they are both sedimentary in nature. Both are intrusive, where magma flows through the outer crust.
What is igneous rock made of?
Igneous rocks are formed from the solidification of magma, which is a hot (600 to 1,300 °C, or 1,100 to 2,400 °F) molten or partially molten rock material. Earth is composed predominantly of a large mass of igneous rock with a very thin veneer of weathered material—namely, sedimentary rock.
What igneous means?
Definition of igneous 1a : formed by solidification of magma igneous rock. b : relating to, resulting from, or suggestive of the intrusion or extrusion of magma or volcanic activity. 2 : of, relating to, or resembling fire : fiery.
What is felsic magma?
Felsic refers to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Felsic magma or lava is higher in viscosity than mafic magma/lava. Felsic rocks are usually light in color and have specific gravities less than 3.
What is mafic and felsic?
Either in describing rocks or lava, mafic means that the lava or rock has less silica while felsic implies that the lava or rock has the most silica.
When magma solidifies on the surface of the Earth?
Magma solidifies under various conditions to form igneous rocks. "Ignis" is the Latin word for fire. The magma that comes to the surface of the Earth and solidifies forms fine-grained rocks like basalt. Basalt is a dark-colored igneous rock.
What is it called when magma cools and solidifies beneath the Earth’s crust?
Magma that has cooled into a solid is called igneous rock. Magma is extremely hot—between 700° and 1,300° Celsius (1,292° and 2,372° Fahrenheit).
What is sills in geography?
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.
What is the definition of sills?
Definition of sill 1 : a horizontal piece (such as a timber) that forms the lowest member or one of the lowest members of a framework or supporting structure: such as. a : the horizontal member at the base of a window. b : the threshold of a door.
What statement correctly describes dikes and sills?
Select the correct description of dikes and sills. Dikes are discordant igneous intrusions; sills are concordant igneous intrusions; both are tabular.
Which of the following is an igneous rock?
The correct answer is option 1, i.e. Granite. Granite is an example of Intrusive Igneous Rocks. When molten magma cools it forms Igneous Rocks.
What is igneous rock examples?
Types of extrusive igneous rocks include: pumice, obsidian, andesite, rhyolite, and basalt.
What is mafic magma?
Describes magma that contains lower amounts of silica and is generally less viscous and less gas-rich than silicic magma. Tends to erupt effusively, as lava flows. Includes andesites (57-63 percent SiO2), basaltic andesites (53-57 percent SiO2), and basalts (47-53 percent SiO2).
What is meant by mafic?
Definition of mafic : of, relating to, or being a group of usually dark-colored minerals rich in magnesium and iron.
When magma solidifies what type of rock does it form?
Igneous rocks are formed from the solidification of magma, which is a hot (600 to 1,300 °C, or 1,100 to 2,400 °F) molten or partially molten rock material. Earth is composed predominantly of a large mass of igneous rock with a very thin veneer of weathered material—namely, sedimentary rock.
Which of the following makes the cooling rate of the magma slower?
Magma intruded deep in the crust where it is surrounded by warm wall rock, cools much slower than magma does intruded into cold wall rock near the ground surface. So closer to the surface wall rock = faster cooled magma. And wall rock in the deep crust = slower cooled magma.
What was the rate of cooling for an extrusive igneous rock and why?
Extrusive or volcanic rocks crystallize from lava at the earth's surface. The texture of an igneous rock (fine-grained vs coarse-grained) is dependent on the rate of cooling of the melt: slow cooling allows large crystals to form, fast cooling yields small crystals.
What is sill in geography class 9?
(c) Sills: It is an intrusive landform. It is a terrace like feature which is formed between the beds of sedimentary rocks or the igneous rocks.
What are sills Class 9?
Answer: Sills : The collection of magma between layers of rocks is called sill. Dykes : The fillings of magma in the cracks or fissures of rocks are called dykes.
How sills are formed?
Sills: form when magma intrudes between the rock layers, forming a horizontal or gently-dipping sheet of igneous rock.
What is sill frequency?
The threshold frequency is defined as the minimum frequency of incident radiation below which the photoelectric emission is not possible completely. irrespective of the intensity of incident radiation.
How is sill form?
Sills: form when magma intrudes between the rock layers, forming a horizontal or gently-dipping sheet of igneous rock.
How is mafic formed?
Mafic rocks that constitute the igneous oceanic crust are created at mid-ocean ridge seafloor spreading centers as a byproduct of partial melt from upwelling mantle. Through various parts of the spreading process, permeability can be generated in both the intrusive gabbros and extrusive basalts.
What minerals are mafic?
mafic rock, in geology, igneous rock that is dominated by the silicates pyroxene, amphibole, olivine, and mica. These minerals are high in magnesium and ferric oxides, and their presence gives mafic rock its characteristic dark colour.
What is mafic composition?
Definition. The adjective mafic refers to a silicate mineral or rock (magmatic, either intrusive or extrusive) having a chemical composition rich in iron and magnesium and relatively poor in silicium.