BRANCHES OF GEOLOGY

 

1. physical geology :

 

Physical geology is the fundamental study of the earth's lithospheric components like rocks, minerals,and soils and how they got originated over a period of time. Many geological processes are active on the surface of the earth. They are called as exogenous processes. The highly complex interna processes such as plate tectonics and mountain‐building have also formed the crustal rocks and brought them to the earth's surface. These are called as endogenous processes. All these processe are capable of creating both constructional and destructional landforms. The agents that are responsible for these actions are called as geological agents. The notable surface geological processes are weathering, mass-wasting, erosion, transportation and deposition.

The  subject  ,  physical  geology,  deals  with  the  Solar  system,  the   Earth's   origin,  age 

 and  internal constitution,   weathering  and  mass-wasting,   geological  work  of  river,  lake,  glacier,  wind,  sea  and groundwater.  It  also  deals  with  the  Volcanoes  -  their  types  &  

distribution,  geological  effects  and products;  earthquakes  -its  distribution,  causes  and  

effects.    Physical  Geology    also  projects  the elementary   ideas   about   the   origin   of 

  geo   synclines,   concept   of   isostasy   and   mountain building(Orogeny),  continental  

drift,  seafloor  spreading and  plate  tectonics.   This  subject  gives  the foundation for all 

other earth science branches.

2.  Historical geology :

The  planet  earth  has  undergone   several   changes   during  each  geologic  period.   Great mountain ranges have been folded up in one period and eroded away in the following one. Many of  them have been uplifted  more than once. Some of them  often got washed off  into the adjacent depressed zones like basins and seas.   Historical geology is the   discipline that uses the principles and techniques of geology to reconstruct and understand the past geological history ofEarth. It is a major branch which deals  with the  records  of  events  of  earth  history and  with  the  historical  sequence  and  evolution  of plants  and  animals  of  past  ages.  Its object  is  to  arrange  the  events  of  earth  history  in  the  regular chronological order of their occurrence and to interpret their significance. Fortunately, the historical records are preserved in the layered rocks of the crust.  Historical Geology is , sometimes ,   called as Stratigraphical  Geology.  It   brings  together  all  collated  details  of   other  Branches  of  Geology  like Paleontology, petrology and structural geology, pertaining to age-wise correlated beds.

3. Geomorphology :
Geomorphology is the scientific study of the origin and evolution of landforms and landscapescreated by physical, chemical or biological processes operating at or near the Earth's surface. It isconcerned with the internal geologic processes of the earth's crust, such as tectonic activity and volcanism that constructs new landforms, as well as externally driven forces of wind, water, waves, and glacial ice that modify such landforms. It is closely related to soil science, hydrology, geology and environmental science. This has the potential for applications in environmental / development planning, transport, human settlements, mining and hydrological sectors, hospitality and tourism. Geomorphology also focuses on the investigation of surface processes and the way these processes create small-scale landforms

Geomorphology was first used as a term to describe the morphology of the Earth’s surface in the 1870s and 1880s. Geomorphologists work within certain disciplines such as physical geography, geology, geodesy, engineering geology, archaeology and geotechnical engineering. This broad base of interest contributes to many research areas and interests within the field of terrain evaluation, remote sensing, defence operations, transport systems, and all urban development

Geomorphology is further divided into various branches. To mention a few, are:

a)    Evolutionary  Geomorphology  -  which  deals  with  the  Davisian  Erosion  Cycles  /  

peneplain (Footprints of Darwinian Evolution)

b)   Process Geomorphology  - Process geomorphology is the study of the processes responsible for 

landform development.

c)   Quantitative Dynamic Geomorphology - Drainage basin morphology (stream order, density etc.) Newtonian mechanistic approach (stream power, fluvial erosion, diffusion/transport laws, Dynamic equilibrium approach d)Thermodynamic Geomorphology - Entropy concept

e)    Predictive  Geomorphology  -  Earthcast  (  extreme  events  –  flood,  landslide)  -  

Mathematical morphology  (Fractal,  Spatio-temporal  Geoscience  Information  System  analysis)  -  Deterministic  & Numerical models - Artificial Neuron Network (ANN).

The other branches include the following:

         a)   Planetary geomorphology

         b)   Mega-geomorphology

         c)   Tectonic geomorphology

         d)   Volcanic geomorphology

         e)   Fluvial geomorphology and river management

         f)   Coastal geomorphology

        g)   Submarine geomorphology

        h)   Aeolian systems and arid geomorphology

         i)    Tropical geomorphology

j) Cold region geomorphology.
Geomorphology is fully concerned with landforms and their origin and evolution. This subject has been studied, initially , using qualitative approaches, with the description of landforms, by describing the forces acting on Earth’s surface to produce landforms and landform change. Later, more quantitative approaches came in, which were largely based on the work of Horton, Strahler, and Leopold in the 1940’s and 50’s. These scientists advocated for a physically-based assessment of landforms. There are many sub disciplines in geomorphology including tectonic, fluvial, storm, aeolian, floodplain, glacial, groundwater, climate, tsunami, and many others. These sub disciplines are mainly driven by distinctions in the mechanics and dynamics that are involved in the processes.

4. Fluvial Geomorphology:
The term 'Fluvial' refers to the processes associated with running waters, 'geo' refers to earth and'morphology' refers to channel shape. Fluvial geomorphology is the scientific study of the forms and functions of streams and the interaction between streams and the landscapes that evolve around them. Fluvial geomorphology is an applied science. It is mainly devoted to understand the development of rivers, both in their natural setting as well as on how they respond to the anthropogenic changes imposed within a watershed. One of the objectives , is to predict what changes will occur to a stream channel, in response to alterations in watershed conditions; and, in turn, how these changes will affect /help human infrastructure and aquatic habitat. The geomorphology, hydrology, and ecology of river systems interact through complex processes occurring across a range of spatial and temporal scales. A river's adjustment to watershed perturbations may take thousands of years. Modifications in a    stream channel may take place in less than a decade. Understanding of how these modifications,operating at different time scales, alter the width, depth, and cross-section of achannel, is critical for identifying potential problem areas, in any river system. A geomorphological approach to river management will certainly help to reduce the flood damages and improve the aquatic habitat along river courses. River Ecology is a branch which orients its approach towards the subject of fluvial geomorphology with biological inputs.

5. Coastal Geomorphology:
Coastal geomorphology, by definition, is the scientific study of the morphological development and evolution of the coasts. Coastal landforms are developed under the influence of winds, waves, currents, and sea-level changes. This branch focuses on the physical processes and their responses in the coastal zone. It is also an applied science. Sustainable management of coastal resources requires a detailed knowledge on coastal zones. Coastal zone development and management requires a thorough study of coastal geomorphology. This subject also takes the involvement of basics principles of hydrodynamics of oceanic waters. The effect of sea-level rise on coastal geomorphology is yet another area of study, in addition to global climate changes and their effects. It is a fact that rising sealevels, result in the spatial shift of coastal geomorphology, by redistributing the coastal landforms comprising sub-tidal bed-forms, intertidal flats, salt-marshes, shingle banks, spits and bars, sand dunes, cliffs and coastal lowland. Coastal landforms act to attenuate wave and tidal energy and respond to the time-variant changes in energy conditions with reference to space and time.

6. Climatic Geomorphology:

Climatic geomorphology is the study of the role of climate in shaping landforms and the earth-surface processes. An approach used in climatic geomorphology is to study relict landforms to infer aboutthe ancient climates. It is mainly concerned about the past climates.Climatic geomorphology identifies climatic factors such as the intensity, frequency and duration of precipitation, frost intensity, direction and power of wind, and it explains the development of landscapes under different climatic conditions. Since landscape features in one region might have evolved under certain specific climate, different from that of today, studying climatologically distinct regions of the past might help to understand the present-day landscapes. This subject helps to decipher the role of various

climatic elements in shaping landforms and the earth-surface processes. The prime approach used in climatic geomorphology is to study the relict landforms to infer their ancient climates. Being often concerned about past climates, climatic geomorphology is considered to be a part of historical geology. Climatic geomorphology highlights the influence of climatic factors and explains the development of landscapes formed under different climatic conditions. The core factor is that each climate type produces its own characteristics assemblages of landforms and classifies the geomorphic processes which produces them.

7. Tropical geomorphology:
The tropics are a typical climatic region. They are characterized by particular climates, that may be dry or humid. The tropics can be divided into two primary units based on annual rainfall, the humid tropics and the arid topics. These are the belts of low latitudes and high temperature. Like climate, landforms and operating geomorphic processes are not the same across the tropics. The tropics are an assemblage of active tectonic belts, ancient cratons, alluvial valleys and subsiding deltas. Geomorphology in the tropics provides twin opportunities to discover new facts and to apply such information to manage the environment for a sustainable future. Tropical geomorphology has a tendency to look forward rather than look back exclusively at past landforms. Relative to temperate zones, the tropics contain areas of high temperatures, high rainfall intensities and high evapotranspiration, all of which are climatic features relevant for surface processes.

Tropical zones include a great variety of landforms and ecosystems. These areas are not only containing important natural resources but also face numerous natural hazards. Humid tropical areas contain numerous mineral, hydrocarbon, forest, and agricultural resources. These belts are located on tectonically active zones and hence they are often affected by earthquakes and tsunamis. Volcanic hazards are also very severe, especially the explosive ones, with the bursting of fire clouds, ash falls, and lahars. in addition to these, the highest occurrence of other hazards associated with tropical areas include tropical cyclones strong destructive winds, floods, and slides related to the cyclonic rains, as well as onshore storm surges caused by wind and atmospheric pressure changes. The analyses of tropical geomorphology are useful for planning , alleviation of environmental degradation and avoiding of natural hazards.

8. Glacial geomorphology:
Glacial geomorphology is concerned principally with the role of glacial ice in landform and landscape evolution. It is the scientific study of the processes, landscapes, and landforms produced by ice sheets, valley glaciers, and other ice masses on the surface of the Earth. These processes include understanding how ice masses move, and how glacial ice erodes, transports, and deposits sediment. This subject is much useful to the planetary geologists who are interested in understanding the evolution and history of the surface of nearby planets in our solar system. It has been reported that the planet Mars is covered with permafrost, where the soil temperatures are permanently below the freezing point of water. Bitter cold temperatures dominate the Martian equatorial regions, with an annual-mean temperature of the soil colder than -50 deg C, and colder still at middle and high latitudes. Therefore, any water present in the Martian soil must be in the form of ice. Glacial deposits form characteristic flow features that indicate thick piles of water ice in a slow viscous motion

9. Periglacial Geomorphology:
Glacial and periglacial geomorphology are those branches of geomorphology concerned with the evolution of landscapes in high latitudes and altitudes. Periglacial geomorphology must also be viewed as one of the group of sciences that concern the cryosphere. Periglacial geomorphology has a special interest in the thawing and freezing of ground. The core of periglacial geomorphology is concerned with the study of freezing processes, associated with ground ice, and their related landforms. Such an approach places permafrost in a central position, within periglacial

geomorphology. This subject primarily focuses on the geomorphological processes and landforms associated with glaciers, permafrost, periglacial and slope environments. Periglacial environments are characterised by frost action and the recurrent presence of a snow cover. The salient components of modern periglacial geomorphology include the study of i) the nature of permafrost-related processes, ground ice, and associated landforms; ii) the azonal processes that operate in cold nonglacial environments; iii) the ice-marginal (proglacial) environment and associated paraglacial transitions; iv) the alpine (montane) environment; v) Pleistocene cold-climate paleo-environmental reconstructions; vi) environmental and geotechnical studies associated with frozen ground, ground freezing and global climate change.

10. Geocryology:
Geocryology is the study of frozen rock, soils, and ground. It deals with the origin, historical development, and conditions of existence of frozen strata in the earth’s crust. It helps to study the processes and phenomena that occur in freezing, frozen, and thawing rock, soils, and ground, as well as their structure, composition, and properties. The subject also deals with the geophysical, physicogeological, geomorphological, and hydrogeological phenomena that are related to the processes of the freezing, thawing, and diagenesis of frozen strata. In addition to developing the theory of such processes, geocryology also deals with the development of methods of influencing processes of freezing in the interests of construction, transportation, agriculture, and other activities. There are two main branches , as —general geocryology and engineering geocryology. The second one has much more practical significances.

The early development of geocryology occurred in Russia as early as 1924. The first edition of a standard text which came from the Soviet Union, Obshcheye Merzlotovedeniya (General Permafrostology) , was published in the year 1940. By comparison, North American geocryology is of relatively recent origin. Geocryology got emerged initially from geophysics. Today, geocryology uses various methods of investigation—as a complex of field (expeditionary) and laboratory methods of the geological, geographic, and geophysical sciences and the physical and physicochemical laboratory methods. Geocryology combines the experimental research with theoretical basis and makes extensive use of numerical approaches

11. Tectonic geomorphology:
Tectonic geomorphology is the study of the interplay between tectonic and geomorphic processes in regions where the Earth’s crust actively deforms. Tectonic geomorphology is the study of the interplay between tectonic and surface processes that shape the landscape in regions of active deformation. Recent advances in the quantification of rates and physical basis of tectonic and surface processes have rejuvenated the field of tectonic geomorphology. Modern tectonic geomorphology is an exciting and highly integrative field which utilizes techniques and data derived from studies of geomorphology, seismology, geochronology, structure, geodesy, and Quaternary climate change. While emphasizing new insights from the last decade of research, Tectonic Geomorphology reviews the fundamentals of the subject which include the nature of faulting and folding, the creation and use of geomorphic markers for tracing deformation, chronological techniques which date deformation, geodetic techniques for defining recent deformation, and paleo-seismologic approaches to calibrate past deformation. Tectonic geomorphology is an integrated subject that presents stimulating challenges to anyone trying to extract information from deforming landscapes.

12. Submarine geomorphology: 

Submarine geomorphology deals with the form, origin, and development of features of the oceanic bottoms . In shallow marine environments, the landforms include ripples, dunes, sand waves, sand ridges, shorelines, and subsurface channels. In the continental slope transition zone the features studied are submarine canyons and gullies, inter-canyon areas, intra-slope basins, and slump and slidescars. The deep ocean basins  contain varied landforms like  trenches ,   trench fans, sediment wedges,abyssal plains and distributary channels.

13.    Planetary geomorphology:

Planetary geomorphology is yet another branch of geomorphology. It involves  the study of landforms on planets and their satellites.  It is a modern branch.  Most of the surface processes on other planets and their satellites depend on   various factors like   mean distance from the Sun,    annual receipt of solar energy,   rotational period, and on the nature of the planetary atmospheric conditions.  Observed geomorphic processes includ eweathering, wind   activity, fluvial activity, glacial activity, and mass wasting.

14. Geomorphometry:
Geomorphometry is yet another branch of geomorphology. It is also called as landform morphometry. It helps to study quantitatively the geometric forms of the land surfaces. The concepts of geomorphometry dates back to the work of both Alexander von Humboldt and Carl Ritter, who postulated these ideas in the early and mid-nineteenth century. Morphometric analysis, quantitative description and analysis of landforms are the primary focus in this subject. Morphometry is an essential means in geomorphic analysis of an area. Morphometry is defined as the measurement and mathematical analysis of the configuration of the earth’s surface and of the shape and dimension of its landforms. It is done mainly to understand the structure, processes and evolution of landscape. Analysis of the flow pattern in the basin helps to relate the runoff characteristics to the morphometric parameters. The quantitative analysis of drainage basins is an important aspect of characterization of its sub-basins and watersheds. Such characterization of watersheds plays an important role in forecasting the hydrological behavior within the system and thereby it helps planning for hydrologic designs.

15. Human geomorphology:
The subject of anthropogenic geomorphology is the description of the wide and ever-widening range of surface landforms, extremely diverse in origin and in purpose, created by the operation of human society. In a broader sense, artificially created landforms have manifold influences on the environment and modify the natural processes. Human geomorphology studies the impacts humans have on the globe, on reshaping the landforms. Thus, it is difficult to imagine a location or circumstance that has not been impacted by geomorphic processes, by the existence of human beings. The subject of anthropogenic geomorphology is broadened by the fact that the artificially created landforms have manifold influences on the environment (e.g. alterations in meso- and microclimate, biota, etc.). In addition, they may also modify natural processes. Human geomorphic action may
induce cascading environmental changes, whose study obviously lies within the scope of
anthropogenic geomorphology.

The major fields of anthropogenic geomorphology are: Mining and processes involved and the resulting landforms, industrialization and its impact reflected in industrogenic landforms, settlement (urban) expansion exerting a major influence on the landscape over ever increasing areas, advanced farming which heavily relying on rivers, water management (river channelization, drainage). All these occupies a special position in anthropogenic geomorphology. Agriculture is a major social activity causing changes on the surface. Agrogenic impacts also include transformation due to forestry. Although warfare is not a productive activity it has long-established surface impacts. In contrast, the impacts of tourism and sports activities are rather new fields of study in anthropogenic geomorphology.

Applied geomorphology is the study of   interactions of humans with landscapes and landforms. The interaction between geomorphology and public policies, with contributions on rural land-use and soil erosion,  urban  land-use,  slope  management,  river  management,  coastal  management,  and  policy formulation are discussed in this subject.   Landslides , debris flows   and   soil erosion may become more severe in some places. The  sediment load of some rivers may increase, some beaches and cliffs may erode  faster,  some  of  the  coastal  lowlands  may  become  submerged,  and  frozen  ground  in  the tundra environments may thawing processes. Applied geomorphologists  are concerned with  all these potentially damaging changes, their causative factors  and to provide solutions to solve them also.

17.   Biogeomorphology and Ecogeomorphology:

Biogeomorphology and ecogeomorphology are the study of interactions between organisms and the development  of  landforms.    Organisms  affect  geomorphic  processes  in  a  variety  of  ways.  For example, trees can reduce landslide potential where their roots penetrate to underlying rock, plants and  their  litter  inhibit  soil  erosion.  The   biochemicals  produced  by  plants  accelerate  the  chemical weathering of bedrock and regolith. Similarly, the  marine animals cause the bioerosion of coral. The study  of  the  interactions  between  marine  biota  and  coastal  landform  processes  is  called  coastal biogeomorphology.   Biogeomorphology   has     two-way   interaction   between   geomorphology   and ecology.   Ecogeomorphology  is     synonymous   with  biogeomorphology.   There  are  some       key applications   of   biogeomorphological     research.        The   roles   of   organisms   in   environmental reconstruction,  trace  fossil  analysis,  extraterrestrial  geomorphology,  environmental  engineering  and the built environment are the major aspects.

18.  Phytogeomorphology:

The  subject  phyto-geomorphology  can  be  defined  as  the  study  of  relationships  between  the  earth's relief  features  and  the  distribution  of  plant  species.  The  subject    mainly  emphasizes    on  the importance of combining plants and landforms in studies related to the land surface of the earth and in recognition  of  their  interdependence.  It    forms  a  powerful  tool  for  the  survey,  management  and planning of our environment.  In addition, there are more specific discipline-oriented studies that can benefit directly or indirectly from a phyto-geomorphic approach. It is a fact  that the  balance between landforms and vegetation varies greatly.   This subject  is a part  of biogeomorphology. It  deals with the narrower subject of how terrain affects plant growth. It focuses on   how terrain attributes affect crop growth and yield in a farm field.   Precision agriculture models where crop variability is at least partially   defined   by   terrain   attributes   can   be   considered   as   phytogeomorphological   precision agriculture.    Phytogeomorphology  is  an  interdisciplinary  subject  including  the  concepts  of    plant ecology,  geography  and  geology.  Due  to  this,  the  study  of  phyto-geomorphology  has  attracted geographers, plant ecologists and also geologists each with diverse objectives.

19   Hydrogeomorphology :

The  term of  hydrogeomorphology  was  first  used  by  Scheidegger  in  1973.  Hydrogeomorphology is defined  as  “an  interdisciplinary  science  that  focuses  on  the  interaction  and  linkage  of  hydrologic processes with landforms or earth materials and the interaction of geomorphic processes with surface and subsurface water in temporal  and spatial dimensions".    Hydrogeomorphology is considered as the basic study of landforms caused by the action of water.  This branch   describes and evaluates the geomorphic environment, in which water occurs and   circulates. Hydrogeomorphology of a drainage basin is a function of rainfall kinematics, surface topography, drainage basin morphology and runoff. Geological conditions may also control and influence the effect of most of these factors. The role of these  factors  are  reflected  as  drainages  which  in-turn  provide    the  information  to  understand  the situation  and  to  make  the  proper  decisions  on  water  resources  management.    It  is  majoritively  a quantitative study , of areal, linear and relief morphometric aspects of a drainage basin, provides thetheoretical base for all the hydrogeomorphic approaches.