Strata

INTRODUCTION
The word Stratigraphy, originates from two Greek words (strati) strata meaning layers and (graphy) graphion meaning description. Theologically stratigraphy means description of layers.
                                  DEFINTION OF STRATIGRAPHY
      Stratigraphy, in geology is the study of rock layers, or strata, particularly their ages, compositions, and relationships to other rock layers. Stratigraphy provides geologists with clues about the earth’s past. Stratigraphy relies on four principles which are used to explain and unveil these Geologic histories of the earth.
                                    PRINCIPLES 0F STRATI GRAPHY
These are principles in which Stratigraphy operate. These principles include:
- The principle of original horizontality: This states that sediments deposited in water form a horizontal or nearly horizontal layer. This principle is applied in the identification of deformed rock i.e. in terms of faults and folds etc.
- The principle of super position: This states that in an undisturbed sequence of underling sedimentary or volcanic rock, the rock strata gets younger from bottom to the top. Strata are groups of sedimentary rocks which are distinct from the rocks above and below them. This principle aids geologist to determine the time series of the deposition of the rock.
- The principle of crosscutting relation: This states that when a rock body is cut or intruded by a fault or another body, the faults or intrusion is younger than the rock body.
 

 
- The principle of faunal and floral succession: This states that because plants and animal evolve into new species, the sedimentary rocks of different age must be of different species. Knowing the age of fossils helps to date the rocks which the where found.
These four principles of Stratigraphy can be used to unravel the geologic history of a given area.
                                  HISTORIC IMPORTANCE OF STRAIGRAPY
Earlier before the Stratigraphy was into...