An intrusion is a body of igneous (created under intense heat) rock that has crystallized from molten magma. Gravity influences the placement of igneous rocks because it acts on the density differences between the magma and the surrounding wall rocks (country or local rocks).
Is an intrusion always younger than a fault?
The principle of cross-cutting relationships states that a fault or intrusion is younger than the rocks that it cuts. So the fault must be the youngest formation that is seen. The intrusion (D) cuts through the three sedimentary rock layers, so it must be younger than those layers.
What is an igneous intrusion that cuts across rock layers?
Magmatic dikes form when magma intrudes into a crack then crystallizes as a sheet intrusion, either cutting across layers of rock or through an unlayered mass of rock.
What causes intrusion?
An intrusion is a body of igneous (created under intense heat) rock that has crystallized from molten magma. Gravity influences the placement of igneous rocks because it acts on the density differences between the magma and the surrounding wall rocks (country or local rocks).
What is the example of plutonic rock?
Plutonic Igneous Rocks. Intrusive igneous rocks, formed by the slow solidification of magma deep below the surface and characterized by large crystals. Named after Pluto, the Roman god of the underworld. Examples include granite, gabbro and peridotite.
What is the characteristics of plutonic rocks?
The main way to tell a plutonic rock is that its made of tightly packed mineral grains of medium size (1 to 5 mm) or larger, which means that it has phaneritic texture. In addition, the grains are of roughly equal size, meaning that it has an equigranular or granular texture.
What are the types of intrusive rock?
We describe these two basic types: Intrusive igneous rocks crystallize below Earths surface, and the slow cooling that occurs there allows large crystals to form. Examples of intrusive igneous rocks are: diabase, diorite, gabbro, granite, pegmatite, and peridotite.
What happens with an intrusion?
An intrusion is a body of igneous (created under intense heat) rock that has crystallized from molten magma. Gravity influences the placement of igneous rocks because it acts on the density differences between the magma and the surrounding wall rocks (country or local rocks).
What is the difference between intrusion and extrusion?
An intrusion is any body of intrusive igneous rock, formed from magma that cools and solidifies within the crust of the planet. In contrast, an extrusion consists of extrusive rock, formed above the surface of the crust.