Month: August 2021


Different types of rock give different and distinctive types of landform. For instance, limestones on weathering produce ”karst topography”. The landscape produced by the processes of weathering and erosion is closely related to climate and rock types. The angle of the surface slope is controlled directly by the strength of the rock. Hard rocks like

Concept of Stress and strain

Stress and Strains: All stresses, which are applied to a rock mass can be resolved into three mutually perpendicular directions. These directions are called ”axes of stress” and their magnitude is expressed as greatest, intermediate, and least. When the magnitude of stresses for each axis is equal, the stresses are said to be hydrostatic. Under

Joints and their classification

Joints: Regular and irregular fractures develop in the rock masses when they are subjected to tensional or compressional forces. Such fractures, along which there has been no relative displacement are called ”Joints”. Joints occur in almost every type of rock. They may be vertical, inclined or even horizontal. Rocks commonly contain a large number of


In some cases, the junction between two series of beds is smooth and represents a gently sloping old land surface, which slowly sank below sea level. As a result when the younger series of rocks were deposited on the older beds, each new bed in turn, as “c”, “b”, and “a” in the following figure


This section includes: What is an unconformity? What are different types of unconformity? How to recognize the unconformities? (1). Unconformities: When the sedimentary rock beds are found to have been deposited without interruption, they are said to be ”conformable”. Unlike conformable the unconformities are formed when there is a break in sedimentation. This creates a

Evidence of Faulting

Evidence of Faulting: We can recognize faults by means of three different methods; (i) geological evidence of faulting, (ii) evidence of fault planes, (iii) physiographic evidence. (1). Geological Evidence: The very first and common most method to recognize a fault is the geological evidence of faultings. The geological evidence is seen very clearly on the

Types and classification of faults

Definition of a Fault: We can define a fault as a fracture along which blocks of rock have been displaced relative to each other. This planar discontinuity originates by tectonic forces acting regionally. The displacement along a fault may be less than a meter, several hundred meters, or maybe many kilometers. Both tensional and compressional

How to recognize a fold?

Recognition of Folds: It is not easy to recognize the folds in the field. All the limbs of the fold are seldom visible and therefore, a systematic study is required for identifying folds. The features which help in recognizing folded strata are as follow. In some areas, folds are easily traced by the topography. Areal

Mechanics of Folds

Different types of rocks are composed of different types of material, and are the result of different types of rock formations. Therefore, all rocks do not respond in the same way to the same forces. Depending on their reaction to folding, the rocks are classified into two groups: (i) competent (stiff) rocks, and (ii) incompetent