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IINTRUSIVE VOLCANIC FEATURES. Intrusive volcanic features. Sill Dyke Batholiths Laccoliths. Diagram showing Intrusive Volcanic features. SILLS. Sills are sheets of igneous rocks that are parallel to the layers they intrude.
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Intrusive volcanic features Sill Dyke Batholiths Laccoliths
SILLS Sills are sheets of igneous rocks that are parallel to the layers they intrude. They are formed by magma flowing horizontally between two rock layers and roughly parallel to the surface.
They can be hundreds of meters thick and many kilometers long. sill
Dyke A vertical sheet of igneous rock, formed by magma moving directly upwards towards the surface. They are formed when magma is forced into vertical cracks in the rocks.
BATHOLITH This is a large mass of magma which often forms the root of a mountain. It is made of granite and can become exposed on the surface by the removal of the overlying rocks by erosion.
LACCOLITH This is a small mass of magma that lies near to the earth’s surface. It forms an arch shape or dome shape structure.
Earth’s surface Layers of rocks laccolith