INTRODUCTION
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| Fluvial Geomorphology |
- Geomorphology may be defined as a science that
studies landforms. It describes them and analyses their evolution
systematically. It also classifies them.
- To investigate landforms, methods of
observation, deduction and lab experiments are used. A combination of these methods is also used to
study landforms.
- Geomorphology is multi-disciplinary in nature.
- It is closely linked to geology and geography.
- Besides, it exchanges ideas and concepts with
several other disciplines.
- The scope of geomorphological studies is
differently interpreted by different scholars.
DEFINITION OF GEOMORPHOLOGY
Geomorphology (from Ancient Greek: γῆ, gê, "earth"; μορφή, morphḗ, "form"; and λόγος, lógos, "study") is the scientific study of
the origin and evolution of topographic and bathymetric features created by
physical, chemical or biological processes operating at or near the Earth's
surface. Geomorphologists seek to understand why landscapes look the way they
do, to understand landform history and dynamics and to predict changes through
a combination of field observations, physical experiments and numerical
modeling. Geomorphologists work within disciplines such as physical geography,
geology, geodesy, engineering geology, archaeology and geotechnical
engineering. This broad base of interests contributes to many research styles
and interests within the field. [3]
Geomorphology is defined as the science of
landforms with an emphasis on their origin, evolution, form, and distribution
across the physical landscape. An understanding of geomorphology and its
processes is therefore essential to the understanding of physical geography.
During
the early 1900s, the study of regional-scale geomorphology was termed
"physiography. Physiography later was considered to be a contraction of
"physical" and "geography", and therefore synonymous with
physical geography and the concept became embroiled in controversy surrounding
the appropriate concerns of that discipline.
Some geomorphologists held to a
geological basis for physiography and emphasized a concept of physiographic
regions while a conflicting trend among geographers was to equate physiography
with "pure morphology," separated from its geological heritage. In
the period following World War II, the emergence of process, climatic, and
quantitative studies led to a preference by many earth scientists for the term
"geomorphology" in order to suggest an analytical approach to
landscapes rather than a descriptive one.
A broad outline of its scope includes
description of landforms, studying processes of their formation and
investigating how geomorphological knowledge may be used in solving problems
faced by man.
Today, the study of geomorphology is broken
down into the study of various geomorphologic processes. Most of these
processes are considered to be interconnected and are easily observed and
measured with modern technology. In addition, the individual processes are
considered to be either erosional, depositional, or both. An erosional process
involves the wearing down of the earth’s surface by wind, water, and/or ice. A
depositional process is the laying down of material that has been eroded by
wind, water, and/or ice.
The geomorphologic processes are as follows:
FLUVIAL
Fluvial geomorphologic processes are those
related to flowing rivers and streams. The flowing water found here is
important in shaping the landscape in two ways. First, the power of the water
moving across a landscape cuts and erodes its channel. In addition, as the
river carves its landscape it carries the sediment it erodes as it flows. This
gives it more power to erode as there is more friction in the moving water, but
it also deposits this material when it floods or flows out of mountains onto an
open plain in the case of an alluvial fan (image).
MASS MOVEMENT
The mass movement process, also sometimes
called mass wasting, occurs when soil and rock moves down a slope under the
force of gravity. The movement of the material is called creeping, slides,
flows, topples, and falls. Each of these is dependent on the speed of movement
and composition of the material moving. This process is both erosional and
depositional.
GLACIAL
Glaciers are one of the most significant
agents of landscape change simply because of their sheer size and power as they
move across an area. They are erosional forces because their ice carves the
ground beneath them and on the sides in the case of a valley glacier which
results in a U-shaped valley. Glaciers are also depositional because their
movement pushes rocks and other debris into new areas. The sediment created by
the grinding down of rocks by glaciers is called glacial rock flour. As
glaciers melt, they also drop their debris creating features like eskers and
moraines.
WEATHERING
Weathering is an erosional process that
involves the chemical break down of rock (such as limestone) and the mechanical
wearing down of rock by a plant’s roots growing and pushing through it, ice
expanding in its cracks, and abrasion from sediment pushed by wind and water.
Weathering can for example result in rock falls and eroded rock like those
found in Arches National Park, Utah.
References
1. Geomorphology Summary - Institute of
Lifelong Learning, University of Delhi. Delhi-11007.
3. Wikipedia - Geomorphology:
https://en.wikipedia.org/wiki/Geomorphology
4. Photo Credit: https://allevents.in/santa%20barbara/fluvial-geomorphology-for-those-who-skipped-it-in-college-part-1/508587822635593
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