Observation

This question was a bit popular among the candidates and they performed fairly well in the question. Some of the candidates could not define intrusive volcanic activity. It is the intrusion of magma   into the earth’s crust where it cools and solidifies to form various landforms.                                                                  
The characteristic features of batholiths are:
-           found in areas of volcanic activities
-           are plutonic rocks formed inside the earth’s crust
-           they are large igneous masses of rocks
-           the rocks are not stratified
-           the rocks are crystalline in structure
-           they are intrusive volcanic landforms
-           composed of granite or granodiorite
-           they form core of most of the world’s fold mountain ranges
-           most spectacular of all intrusive landforms
-           they are very extensive
-           they are domed or oval shaped
-           can be longitudinal ridges at the core of fold mountains
-           when exposed, it forms a massive and resistant upland region
-           e.g. Wicklow Mountains of Ireland, the Upland of Brittany in France, Main Range of West Malaysia, Nyika Batholith of Malawi, Cape Coast Batholith in Ghana, Chailu Massif in Gabon
-           may extend over 100 km²
-           it continues downwards to enormous depths
-           form the base on which dykes, sills phacoliths etc stand
The characteristic features of dykes include:
-           found in areas of volcanic activities
-           an intrusive landform
-           they are masses of igneous rocks
-           narrow and spectacular
-           extensive in length
-           formed within the earth crust
-           appears like narrow wall within the sedimentary layers
-           they may be exposed unto the earth’s crust after prolonged period of erosion
-           they stand as narrow walls or shallow trenches depending on resistance to erosion
-           they may lie vertically or inclined to the bedding plain
-           form waterfall or rapids when they lie across river valleys
-           the thickness ranges from a few millimeters to hundreds of metres
-           can also have circular or ring-like shape
-           they may be several metres long
-           they may constitute underground water or oil trap
-           most are made of basalt
-           resistant to erosion
-           they cut across bedding plane
-           e.g.  the Great Dyke of Zimbabwe, Cleveland Dyke of Yorkshire (England), Klang Gates Ridge north of Kuala Lumpur, Also at Siguiri Region and near Conakry, In West of Jos, Nuckle Janbila Dyke of South Africa