Branches Of Geology

BRANCHES OF GEOLOGY

Geology is a relatively recent subject. In addition to its core branches, advances in geology in allied fields have lead to specialized sciences like geophysics, geochemistery, seismology, oceanography and remote sensing.

Main and Allied branches of geology:

The vast subject of geology has been subjected into the following branches:

Main Branches                                                    Allied Branches

Physical geology                                                           Engineering

geology Mineralogy                                                             Mining

geology                                                                            Petrology

Geophysics Structural                                                       geology

Geohydrology                                                              Stratigraphy

Geochemistry Paleontology

Economic geology

Physical geology:

This is also variously described as dynamic geology, geomorphology etc. It deals with:

i)       Different physical features of the earth, such as mountains, plateaus, valleys, rivers.lakes glaciers and volcanoes in terms of their origin and development.

ii)   The different changes occurring on the earth surface like marine transgression, marine regression, formation or disappearance of rivers, springs and lakes.

iii) Geological work of wind, glaciers, rivers, oceans, and groundwater ands their role

in constantly moulding the earth surface features

iv) Natural phenomena like landslides, earthquakes and weathering.

Mineralogy:

This deals with the study of minerals. Minerals are basic units with different rocks and ores of the earth are made up of.

Details of mode of formation, composition, occurrence, types, association, properties uses etc. of minerals form the subject matter of mineralogy. For example: sometimes quartzite and marble resemble one another in shine, colour and appearance while marble disintegrates and decomposes in a shorter period because of its mineral composition and properties.

Petrology:

Petrology deals with the study of rocks. The earths crust also called lithosphere is made up of different types of rocks. Hence petrology deals with the mode of formation, structure, texture, composition, occurrence, and types of rocks. This is the most important branch of geology from the civil engineering point of view.

Structural geology:

The rocks, which from the earths crust, undergo various deformations, dislocations and disturbances under the influence of tectonic forces. The result is the occurrence of different geological structures like folds, fault, joints and unconformities in rocks. The details of mode of formation, causes, types, classification, importance etc of these geological structures from the subject matter of structural geology.

Stratigraphy:

The climatic and geological changes including tectonic events in the geological past can also be known from these investigations. This kind of study of the earth's history through the sedimentary rock is called historical geology. It is also called stratigraphy (Strata = a set of sedimementary rocks, graphy description).

Economic geology:

Minerals can be grouped as general rock forming minerals and economic minerals. Some of the economic minerals like talc, graphite, mica, asbestos, gypsum, magnesite, diamond and gems. The details of their mode of formation, occurrence, classification. Association, varieties, concenteration, properties, uses from the subject matter of economic geology. Further based on application of geological knowledge in other fields there is many other allied branches collectively called earth science.

Some of them described here are:

Engineering geology Mining geology

Geophysics Geohydrology Geochemistry

Engineering geology:

This deals with the application of geological knowledge in the field of civil engineering, for execution of safe, stable and economic constructions like dams, bridges and tunnels.

Mining geology:

This deals with the application of geological knowledge in the field of mining. A mining engineer is interested in the mode and extent of occurrence of ores, their association, properties etc. It is also necessary to know other physical parameters like depth direction inclination thickness and reserve of the bodies for efficient utilization. Such details of mineral exploration, estimation and exploration are dealt within mining geology.

Geophysics:

The study of physical properties like density and magnetism of the earth or its parts. To know its interior form the subject matter of geophysics. There are different types of geophysical investigations based ion the physical property utilized gravity methods, seismic methods, magnetic methods. Engineering geophysics is a branch of exploration geophysics, which aims at solving civil engineering problems by interpreting subsurface geology of the area concerned. Electrical resitivity methods and seismic refraction methods are commonly used in solving civil engineering problems.

Geohydrology:

This may also be called hydrogeology. It deals with occurrence, movement and nature of groundwater in an area. It has applied importance because ground water has many advantages over surface water. In general geological and geophysical studies are together taken up for groundwater investigations.

Geochemistry:

This branch is relatively more recent and deals with the occurrence, distribution, abundance, mobility etc, of different elements in the earth crust. It is not important from the civil engineering point of view.