How the Waterfalls are formed? With special reference to Ranchi plateau in Jharkhand State of India.

The waterfalls of Ranchi plateau are due to disturbances in late geological age.

By

Dr. Nitish Priyadarshi

Fig.1 Johna falls is the example of waterfalls resulting from upliftment. 

Fig.2 Dasam falls formed due to upliftment.

 Fig. 3 Hundru falls is the example of knickpoint falls.

A waterfall is a place where water flows over a vertical drop in the course of a stream or river. Waterfalls are also called cascades. Waterfalls are commonly formed when a river is young. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens slowly, while downstream the erosion occurs more rapidly. As the watercourse increases its velocity at the edge of the waterfall, it plucks material from the riverbed. Whirlpools created in the turbulence as well as sand and stones carried by the watercourse increase the erosion capacity. This causes the waterfall to carve deeper into the bed and to recede upstream. Often over time, the waterfall will recede back to form a canyon or gorge downstream as it recedes upstream, and it will carve deeper into the ridge above it.

The process of erosion, the wearing away of earth, plays an important part in the formation of waterfalls. Waterfalls themselves also contribute to erosion.

Often, waterfalls form as streams flow from soft rock to hard rock. This happens both laterally (as a stream flows across the earth) and vertically (as the stream drops in a waterfall). In both cases, the soft rock erodes, leaving a hard ledge over which the stream falls.

Erosion is just one process that can form waterfalls. A waterfall may form across a fault, or crack in the Earth’s surface. An earthquake, landslide, glacier, or volcano may also disrupt stream beds and help create waterfalls. 

Running water always erodes rock, but some rocks are more resistant than others. So a waterfall occurs when geological forces have produced either a sudden change in rock types or a steepening of a gradient where a stream is flowing. With a break in elevation, a stream or river becomes a waterfall.

Geology of Chota Nagpur Plateau:

The Chota Nagpur Plateau is a plateau in eastern India, which covers much of Jharkhand state as well as adjacent parts of Odisha, West Bengal, Bihar and Chhattisgarh. The Indo-Gangetic plain lies to the north and east of the plateau, and the basin of the Mahanadi River lies to the south. The Chotanagpur Plateau (22°-25° 30'N and 83°47'-87° 50'E) covering an area of 87,239 sq. km includes Ranchi, Hazaribagh, Singhbhum, Dhanbad, Palamau, Santhal Parganas (Jharkhand) and Purulia dis­tricts (West Bengal). It is composed of Archaean granite and gneiss rocks with patches of Dharwar rocks (phyllite, mica-schists).

The Chota Nagpur Plateau of Jharkhand state is a continental plateau - an extensive area of land thrust above the general land. The plateau has been formed by continental uplift from forces acting deep inside the earth. The Gondwana substrates attest to the plateau's ancient origin. It is part of the Deccan Plate, which broke free from the southern continent during the Cretaceous to embark on a 50-million-year journey that was violently interrupted by the northern Eurasian continent. The northeastern part of the Deccan Plateau, where this ecoregion sits, was the first area of contact with Eurasia.

Chotanagpur consists of a series of plateaus standing at different levels of elevation; the highest general elevation of about 1100 m in the mid-west­ern portion known as the Pat lands. From here the land descends in all directions in a series of steps particularly towards the east until it merges gradu­ally with the Lower Ganga Plain. The sharp break in slope are marked by steep scarps where the rivers like Barakar, Damodar, Subamarekha north and south Koels have carved out deep gorges and water­falls. The most characteristic features of relief are revealed in the Hazaribag and Ranchi plateaus standing at same general elevation (600 m) but separated by the Damodar trough (Permo-Triassic trough fault).

Water falls of Ranchi plateau.

It is the largest part of the Chota Nagpur Plateau. The elevation of the plateau land in this part is about 700 metres (2,300 ft) above mean sea level. The general topography is undulating. The Ranchi plateau gradually slopes down towards south-east into the hilly and undulating region of Singhbhum (earlier Singhbhum district or what is now Kolhan division. The plateau is highly dissected. Damodar River originates here and flows through a rift valley. To the north it is separated from the Hazaribagh plateau by the Damodar trough.To the west is a group of plateaux called pat.

There are many waterfalls at the edges of Ranchi plateau where rivers coming from over the plateau surface form waterfalls when they descend through the precipitous escarpments of the plateau and enter the area of significantly lower height. The North Karo River has formed a 17 metres (56 ft) high Pheruaghaugh Falls at the southern margin of Ranchi plateau. Such falls are called scarp falls. Hundru Falls (75 m) on Subarnarekha River near Ranchi, Dassam Falls (39.62 m) on Kanchi River, east of Ranchi, Sadni Falls (60 m) on Sankh River (Ranchi plateau) are examples of scarp falls. Sometimes waterfalls of various dimensions are formed when tributary streams join the master stream from great height forming hanging valleys. At Rajrappa (10 m), the Bhera river coming over from the Ranchi plateau hangs above the Damodar River at its point of confluence with the latter. The Jonha Falls (25.9 m) is another example of this category of falls. In fact the Gunga River hangs over its master stream, Raru River (to the east of Ranchi city) and forms the said falls.

Geological formation of Waterfalls in Ranchi Plateau.

The waterfalls of Ranchi plateau are due to disturbances in late geological age. The Ranchi plateau (or the whole of Peninsular India) believed to have undergone uplift as the side effects of the Himalayan orogeny particularly during the late Tertiary. As the streams descend they are marked by waterfalls. The most important water falls in Ranchi Plateau are the Hundru falls on the Subarnarekha. The structure is granite-gneiss. The main drop is on a nearly vertical. It could be interpreted as due to local faulting because as believed all the scarps in Ranchi plateau are due to successive Tertiary faulting.

The Chotanagpur Plateau is made up mainly of Precambrian rocks but has witnessed uplifts synchronously with Himalayan uplift in the Cenozoic.

According to another concept falls of the plateau are formed due to sudden steeping of slope. This steepening may be caused by the quicker erosion of softer elements below harder rocks at the lower end of which water tumbles ( as on the Bhusur river 300 m., west of Hinoo bridge in Ranchi city).

Waterfalls of varying dimensions are formed due to upliftment of local nature in the courses of the rivers. These waterfalls are obliterated when the rivers regrade their longitudinal profiles. A series of waterfalls on the river along the junction of Palamau upland and the northern flat plain ( Palamau district Jharkhand) are said to have been formed due to orogin of escarpment caused by upliftment of southern Palamau during Tertiary period. Patam falls ( 45.72 m) and Datam falls (30.45 m) on Patam river ( in Bhandaria Anchal, Palamau, Jharkhand) are typical examples of such categories. The waterfalls on the eastern margin of Ranchi Plateau ( e.g. Hundru falls on Subarnarekha river, Dasam falls on Kanchi river, Johna or Gautamdhara falls on Gunga river etc.) are also quoted as the examples of waterfalls resulting from upliftment.

Some times, waterfalls of varying dimensions are formed when the tributary streams join their master streams from great height forming hanging valleys. In other words, hanging valley falls are formed when the level of the junction of the tributary streams is much higher than the level of the main valley of the master stream. The Rajrappa falls ( 10 m.) at the junction of the Bhera river and the receiving Damodar river (located to the north of Ranchi city) is a typical example of hanging valley waterfalls as the Bhera river after coming from over the Ranchi Plateau hangs above the Damodar river as its confluence with the latter. The Gautamdhara or Johna falls ( 25.9 m.) is another example of this category of falls. In fact, the Gunga river hangs above its master stream, Raru river, ( to the east of Ranchi city) and forms the said falls.

Some falls of Ranchi plateau comes under knick point falls. The breaks in channel gradient caused by rejuvenation are called knick points or heads of rejuvenation. These breaks in channel gradient or knickpoints denote sudden drops of elevation in the longitudinal profile of the rivers and allow the water to fall down vertically giving birth to waterfalls of varying dimensions. Hundru falls ( 76.67 m) on Subarnarekha river ( near Ranchi city), Johna or Gautamdhara falls at the confluence of Raru and Gunga rivers (to the east of Ranchi). Dasam falls ( 39.62 m and 15. 24 m ) on Kanchi river (east of Ranchi) are the examples of knickpoint falls.

Reference:

Ahmad, E. 1985. Geomorphology. Kalyani Publishers, New Delhi.

Mahadevan, T.M. 2002. Geology of Bihar and Jharkhand. Geological Society of India, Bangalore.

Singh, S. 1994. Physical Geography. Prayag Pustak Bhawan, Allahabad, India.

 

Why vegetarian animals are fat?

Theory begins some 50 million years back.

By

Dr. Nitish Priyadarshi.

One of my friends suggested me to become non-vegetarian. He gave the interesting example about the benefit of becoming non- vegetarian. He said that all non-vegetarian animals like tiger, cheetah, wolfs are slim compared to vegetarian animals like buffalo, elephant, zebras etc. I started searching the mystery of why vegetarian animals are so fat? Some theories are hidden in pages of time million years back.

Why did some prehistoric animals get so big in the first place? No one knows for sure, but there are lots of theories. One theory begins some 50 million years back.

The past 50 million years appear to have been a time of progressive deterioration. On every vegetated continent, grasses and small hard leaves widened their domain. While certain herbivores accommodated to the new foliage- and evolved the art of eating coarse, fibrous fodder-other species, committed to Eocene and Oligocene ways, died. In many animals, from horses and zebras to rodents, from antelopes to kangaroos, from giraffes to camels, from elephants to pigs, the main food-processing part of the jaw, the cheek teeth, became larger in over-all height and riddled with complex slicing edges. An increase in tooth height, called hypsodonty (high tooth) is typical of animals that harvest greenery close to the ground-mainly fibrous grasses in open territory which is generally poor in nutritional value.

Any animal committed to such a diet must eat an enormous quantity. This requires both a large gut and a large body capable of handling masses of grass and other fibrous plants. Long –distance travel allowed access to such volumes of vegetation, mowed and chewed as the animal walked along. After the Eocene, many lineages of animals evolved to a large size, formed social herds, and modified their limb bones in ways that allowed wide and rapid movements over open terrain.

The other theory says being larger can provide many evolutionary advantages—bigger animals are less vulnerable to predators and can compete more assertively for resources. The existence of bigger herbivores also means that carnivorous animals have to grow in order to be effective hunters. A species' size may also shift in response to environmental factors. In cold climates, a bulky frame can be an asset to warm-blooded animals—the bigger they are, the better they retain heat. The opposite is true for cold-blooded animals—in a warm climate, a bigger mass can help insulate an animal and keep it from overheating. Scientists suggest that some plant-eating dinosaurs and other animals might have gotten so big because the foliage in that era was extremely tough and woody: A larger body frame meant a longer digestive tract and more time for bacteria to do its work, allowing the dinosaur to extract as much nutritional value as possible from each bite.

 

Venus shining above Ranchi city, India.

People confused it with flying object or a satellite.

By

Dr. Nitish Priyadarshi

Venus planet near to Earth.

Few of my friends call me up to know about the bright object in the sky above Ranchi city. They confused it with some flying object or a satellite. It is Venus, I told them. It’s the planet which is easily visible at nightfall around the world in early November. Venus continues to draw all eyes to the western sky after sunset. Observers have been watching the bright planet for many weeks, although it seems that a fairly large percentage is not quite sure exactly what they have been looking at. Venus has increased noticeably in recent days. Venus beams mightily in the west at dusk, as seen from across the Earth. You can’t miss it. It sets roughly two-and-one-half-hours hours after sunset at mid-northern latitudes in early November and close to three hours after the sun by the month’s end. Venus! It’s the beautiful “evening star.”

The best time to observe Venus is actually in the early morning or early evening before the sky gets too dark. This is because Venus is so bright that it can actually be more difficult to see its features with the large contrast between it at the night sky, and it is best to catch it with some twilight behind it.

Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. It has no natural satellite. It is named after the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky. Venus is a terrestrial planet and is sometimes called Earth's "sister planet" because of their similar size, gravity, and bulk composition (Venus is both the closest planet to Earth and the planet closest in size to Earth). However, it has also been shown to be very different from Earth in other respects. It has the densest atmosphere of the four terrestrial planets, consisting of more than 96% carbon dioxide. Venus may have possessed oceans in the past, but these would have vaporized as the temperature rose due to a runaway greenhouse effect.

Sky of Ranchi city in India was covered with toxic fumes due to burning of firecrackers.

Air pollution likely to increase by 30 to 35%.

By

Dr. Nitish Priyadarshi

Toxic fumes due to burning of firecrackers.

 

Such firecrackers generate more smokes.

Diwali was celebrated in Ranchi city of Jharkhand State in India with fun on Sunday. Firecrackers were used to celebrate this festival. Ranchi sky was covered with smokes due to burning of fire crackers. These smokes may contain toxic and heavy metals which can affect human health. Firecrackers contain elements like copper, cadmium, sulphur, aluminium, barium and various other such elements that help in releasing vibrant colours after it is ignited, causing a host of health problems. Once a cracker is burnt, it releases toxic chemicals that remain suspended for a long time causing serious health aliments.

As diwali is festival of lights, people consider it as festival of Firecrackers. Firecrackers come in different varieties from the delightfully visual ones to the ear deafening noisy ones.

Our tradition use firecrackers in diwali cause of reasons, possible reason and a more scientific one for lighting firecrackers is that the fumes produced by them kill insects and mosquitoes found after the rains. But now people use firecrackers in an amount that it harming the mankind, environment, increasing the pollution.

During Diwali, the air pollution in Ranchi level is likely to increase by 30 to 35 %, which will not only be dangerous for those suffering from pulmonary diseases, but also cause breathing problem to others.

Harmful effects of firecrackers

1) Health hazards: Burns, deafness, Nausea and mental impairment. Many people die in explosions in factories manufacturing fire-crackers.

Firecrackers can cause hearing loss, high blood pressure, sleeping disturbances and sudden exposure to loud noise can cause temporary or permanent deafness or even result in heart attack.

2) Sometimes, rocket-crackers set fire to huts, heap of dry grass etc. this happen mostly to country side

3) Noise pollution: firecrackers make noise more than the allowed decibel limit for human being.

4) Smog caused by firecrackers may be harmful to inhale.

5) It increases the Pollution in environment

The firework reaction products that are emitted are deposited and thus enter the soil, crops and, in the case of fireworks over water, standing waters.

Thorium concentration in Ranchi plateau and other parts of Jharkhand State,

Rivers flowing through Ranchi plateau may also contain thorium.

By

Dr. Nitish Priyadarshi

Thorium deposits in India.

River flowing near Ranchi city.

Pegmatite intrusions in host rocks in Ranchi plateau.

Thorium is a naturally occurring radioactive chemical element with the symbol Th and atomic number 90. It was discovered in 1828 by the Norwegian mineralogist Morten Thrane Esmark and identified by the Swedish chemist Jöns Jakob Berzelius and named after Thor, the Norse god of thunder. Thorium produces a radioactive gas, radon-220, as one of its decay products. Secondary decay products of thorium include radium and actinium. In nature, virtually all thorium is found as thorium-232, which undergoes alpha decay with a half-life of about 14.05 billion years.

Berzelius was quite unaware of the tremendous amount of power that this element stores within it. Subsequent development in the field of nuclear science and technology, however, revealed that thorium might well prove to be equal to the god after whom it was named.

Thorium, which is transmutated U-233 in a breeder reactor, can be used as a nuclear fuel. It is presumed that with the development of breeder technology, thorium will come to play a vital role in providing electric power to millions.

Thorium is widely distributed in the earth’s crust with an average abundance of 8 ppm (parts per million) and is usually associated with uranium or the rare earth-earth elements. The principal mode of occurrence is in the form of veins in granites, synites, pegmatites and other acidic intrusions containing thorium- bearing minerals, such as thorite, thorianite, uranothorite and monazite. Detrital monazite occurs in quartz-pebble conglomerates, beach placers, inland placer deposits and dunes.

The largest known reserves of the thorium are contained in the beach and inland placer deposits of monazite, which are exploited for their rare-earth and ThO₂ contents. Placer deposits of monazite are found in Australia, Egypt, India, Liberia, Brazil, Malaysia and the USA (Florida).

Among the inland placer deposits containing heavy mineral there are two appreciable concentrations of monazite, which are located in the Ranchi plateau of Jharkhand and the Purulia planes of West Bengal.  These occurrences cover an area of about 608 sq. km. forming a thin cover of an average depth of about 50 cm (which may be locally up to 2m.). These deposits have been formed due to the weathering and erosion of Precambrian gneisses and schists, intruded by pegmatites and porphyritic granites, which are enriched in monazite and other associated heavy minerals. 

The placer minerals are released from their matrix by weathering. The comminuted materials are washed slowly down slope to the nearest stream or to the seashore. Moving stream water sweeps away the lighter matrix, and the heavier placer minerals sink to the bottom or are moved downstream relatively shorter distances. The sands of the rivers like Swarnrekha, Jumar, Potpoto, kanchi, etc. flowing through Ranchi plateau may contain thorium in considerable amount.

Thorium present in the river streambed sediments are mostly of terrestrial origin and their concentrations are related to the type of parent rocks and to the genesis of the sediments. The river sediments generally exhibit large variation in composition. This variation can be related to the chemical and mineralogical evolution of these sediments along the river, influence of tributaries, or different properties of drained soil. The mobility of radionuclides in the aqueous system is an important factor influencing the content of radionuclides in river sediments. Surface run-off waters in the tributaries wash down a part of deposited radionuclides and finally store them in the river sediments.

Most of the radioactive anomalies in the Damodar Valley basins are confined to the Panchet  sandstones with the preponderance of thorium over uranium. A similar pattern has also been observed in the Barakar sediments of the Hutar basin.

The granites of the provenance areas fir the Hutar-Daltonganj basins contain anomalous uranium values. Uranium mineralization has also been observed in the granitic rocks comprising the southern periphery of the Hutar basin. The Proterozoic granitoids, forming the provenance for the Hutar and Auranga sub basin (Jharkhand), have been analysed which revealed uranium content up to 520 ppm, while the clays and sandstones of Barakar Formations have revealed anomalous uranium-thorium values of the order of 120-150 ppm uranium and less than 100-800 ppm thorium.

Reference:

Bateman, A.M. 1955. Economic mineral deposits. John Wiley & Sons, Inc. New York.

Virnave, S.N. 1999. Nuclear geology and atomic mineral resources. Bharti Bhawan, Patna.

Viswanathan, G., Badri, N.S.R., and Virnave, S.N. 1989. Radioelement distribution in the Lower Gondwana sediments of Hutar basin, Palamau district, Jharkhand; its bearing on uranium exploration. Exploration Research Atomic minerals Vol. 2 , pp 121-131.

http://dae.nic.in/writereaddata/lssq%20379.pdf

http://large.stanford.edu/courses/2012/ph241/bordia1/