Geology: Outcrop

Geology: OUTCROP

In the mountainous and sub-mountainous tracts and also in shallow plains, exposures of rocks may be easily seen forming sides of valleys or caps of hills or even uplands and slopes in level fields.

An outcrop is simply defined as an exposure of a solid rock on the surface of the earth.

Outcrop Dimensions

The width or breadth of the outcrop of a particular bed is given by the distance between the top and bottom edges of the bed as measured on the surface of the ground in a direction perpendicular to the strike of that particular bed

Many variations are induced in the breadth of an outcrop of a rock by the topography of the area.

The thickness of a particular layer or bed is the perpendicular distance between the top and bottom surface of the same layer as seen in a vertical section at right angles to the strike of the layer

 The depth to a particular layer or bed at any place from the surface, if believed to be present on the basis of general geology and dip of the formation, is given by the perpendicular distance between the ground surface and the top surface of that particular layer.

When the ground surface is horizontal, depth d to the bedrock of known dip may be obtained by the relationship

D = aC x tan b

where is the angle of true dip of the bed exposed at a place, say at B and C is the distance from that exposure to the place C where it is desired to find out depth to that bedrock.