What is mafic dyke?

Mafic dyke swarms are groups of vertical dykes with same orientation representing a system of pre-existing tensional crustal fracture swarms along which mafic magmas emplaced (Halls and Fahrin, 1987, Ernst et al., 1995, Hou et al., 2006). Each type of the mafic dyke swarm is related to the local stress field.

How dyke is formed?

When molten magma flows upward through near-vertical cracks (faults or joints) toward the surface and cools, dykes are formed. Dykes are sheet-like igneous intrusions that cut across any layers in the rock they intrude.

What is dyke form of igneous rocks?

Dike, also called dyke or geological dike, in geology, tabular or sheetlike igneous body that is often oriented vertically or steeply inclined to the bedding of preexisting intruded rocks; similar bodies oriented parallel to the bedding of the enclosing rocks are called sills.

What is a felsic dike?

Felsic dike with mafic inclusions intruding low-grade metamorphic rock. This dike is chock full of mafic inclusions, probably derived from interaction with an earlier, more mafic magma. Note the small sill-like apophyses intruding from the dike into the country rock.

What is dike swarm in geology?

A dike swarm (American spelling) or dyke swarm (British spelling) is a large geological structure consisting of a major group of parallel, linear, or radially oriented magmatic dikes intruded within continental crust or central volcanoes in rift zones.

What is the difference between sill and dyke?

Summary: 1. Dykes (or dikes) are igneous rocks that intrude vertically (or across), while sills are the same type of rocks that cut horizontally (or along) in another land or rock form.

Where can dike be found?

Often referred to as clastic or sandstone dikes, sedimentary dikes occur whenever sediment and minerals build up and lithify in a rock fracture. They are usually found within another sedimentary unit, but can also form within an igneous or metamorphic mass.

Are dikes man made?

Dikes used to hold back water are usually made of earth. Sometimes, dikes occur naturally. More often, people construct dikes to prevent flooding.

What are the types of dikes?

Compositions of dyke rocks vary from ultrabasic to acidic, and common types are dolerite, lamprophyre, microgabbro, microdiorite, granophyre, aplite, and felsite. The coarsest-grained dyke rocks are pegmatites, which are transitional into vein deposits.

What’s the difference between a levee and a dyke?

Levees protect land that is normally dry but that may be flooded when rain or melting snow raises the water level in a body of water, such as a river. Dikes protect land that would naturally be underwater most of the time.