Tuesday, December 31, 2019


The Earth was hotter than it is today.

Dr. Nitish Priyadarshi
Email: nitish.priyadarshi@gmail.com

In recent years, the scenario of future global environment is haunting the man as the present environmental changes (e.g. global warming) pose considerable danger to his own existence and environment. He is presently struggling to understand as to what will be the nature and extent of these changes in the next hundred years. In order to understand the processes of changes and the effects they are likely to have on the future environment of the biosphere, we should develop a historical perspective- a perspective based on global environmental changes preserved in the rocks of the planet earth.

The history of earth’s climate is characterized by change. Times of glaciation on the earth have been followed by warm intervals and the duration in years of both cold and warm intervals has varied by several orders of magnitude.

Climate change is changing the world. Either it is in the form of temperature rise or in the form of severe floods. Many times question arises in my mind whether this climate change is the outcome of present human activities on the earth or it has happened in early geological ages too. Answer is “yes” climate change has occurred several times from the beginning of the earth formation. Evidences are preserved in from of rocks, sediments, and fossils. Studying the records of past climate change will fill you like reading thriller novel in which every chapter is full of suspense and thrill. Every chapter of this novel denotes different geological periods with different stories of climate change.
Change is the only constant in the history of the earth. Since its creation around four billion years ago, our home planet has constantly been subjected to changes brought about by the interplay of internal of forces and external influences. The enormous lithospheric plates are continually shifting, reshaping the continents. Volcanic eruptions and earthquakes are the visible results of this process. Seen from the perspective of the history of the earth, our planet, as we know it today, is merely a snapshot in time. Everything is in a state of flux. Everything- including the climate- is locked in a continuous process of change, giving rise to favourable and unfavourable conditions to which all life on earth-human, plant and animal- must constantly adopt.

My article is about the climate conditions of the Mesozoic.

The term “Mesozoic” was introduced by John Phillips in 1840 for the rock formations containing remains of “middle forms” of life. The Mesozoic Era that began at about 230 million years ago and closed at about 65 million years ago represents less than half the duration of the Palaeozoic Era. The Mesozoic Era has been further subdivided into Triassic, Jurassic and Cretaceous periods.
The lower boundary of the Mesozoic is set by the Permian–Triassic extinction event, during which approximately 90% to 96% of marine species and 70% of terrestrial vertebrates became extinct. It is also known as the "Great Dying" because it is considered the largest mass extinction in the Earth's history. The upper boundary of the Mesozoic is set at the Cretaceous–Paleogene extinction event (or K–Pg extinction event), which may have been caused by an asteroid impactor that created Chicxulub Crater on the Yucatán Peninsula. Towards the Late Cretaceous, large volcanic eruptions are also believed to have contributed to the Cretaceous–Paleogene extinction event. Approximately 50% of all genera became extinct, including all of the non-avian dinosaurs.

Pangaea was characterized by extreme climate variations because it was such a huge continent. The coastal areas near Equator had a monsoon climate with summer rain, while its interior areas were dry and desert-like. Pangaea was a many times larger continent than Eurasia, most likely with an even more pronounced continental climate. One cannot doubt that winters in central Pangaea must have been very harsh experiences, and summers must have been insufferable glowing hot. There were no actual ice ages during Mesozoic. Pangaea was the largest continent ever, and it was surrounded by an equally huge ocean that was the Panthalassic Sea, which covered the rest of Earth's surface. It is believed that the shores of Pangaea must have been exposed to very strong monsoon winds.

Three of the five largest mass extinctions in Earth history are associated with the Mesozoic: a mass extinction occurred at the boundary between the Mesozoic and the preceding Paleozoic; another occurred within the Mesozoic at the end of the Triassic Period; and a third occurred at the boundary between the Mesozoic and subsequent Cenozoic, resulting in the demise of the dinosaurs.
Perhaps the largest number of palaeogeographic reconstructions have been made for the Mesozoic Era. In many parts of the world, the Era began with a new phase of sedimentation . Pangaea, the supercontinent of the Palaeozoic Era was gradually torn apart during the Mesozoic Era. Fragmentation of the Pangaea began with the opening of proto-Atlantic and proto-Indian oceans. On the basis of the palaeo-magnetic evidence, it has been suggested that that this break- up began with the separation of North America and Gondwana Land in  Late Triassic Epoch.  The Mesozoic was a time of significant tectonic, climate, and evolutionary activity.  

The climate of the Mesozoic was varied, alternating between warming and cooling periods. Overall, however, the Earth was hotter than it is today. We can also say that “Earth’s climate during the Mesozoic Era was generally warm, and there was less difference in temperature between equatorial and polar latitudes than there is today”.   The Mesozoic is characterized by a warm and humid Earth. Oxygen levels were very similar to today’s levels, thanks to the large coniferous forests that proliferated in the early Triassic period but were replaced by Angiospermae forests in the early Cretaceous.

We pass from a dry and arid climate at the beginning of the Triassic as we leave an extinction that left the continents dry, to still warm climates but with greater humidity at the beginning of the Jurassic and remain so until the end of the Cretaceous. It is thought that in the Cretaceous, the North Pole was able to hold ice in winter.

Dinosaurs first appeared in the Mid-Triassic, and became the dominant terrestrial vertebrates in the Late Triassic or Early Jurassic, occupying this position for about 150 or 135 million years until their demise at the end of the Cretaceous. Birds first appeared in the Jurassic (however, true toothless birds appeared first in the Cretaceous), having evolved from a branch of Theropod dinosaurs.
Pangaea began breaking up at the end of the Triassic. Between North America and Africa, volcanoes were spewing out large amounts of alkaline lava, which can be found on both continents. It is assumed that this volcano disaster initiated another round of extinction of up to 80% of Earth's species, and thus paved the way for the dinosaurs that came to dominate the Earth in the next hundred million years. Some believe that the root cause of species extinction was that the intense volcanic activity volcanoes emitted so much CO2 that the Earth's temperature rose dramatically so that the heat was the real killer that wiped out so many species.

Jurassic began 213 million years ago and lasted until 144 million years before present, a total of 69 million years. The gradual break-up of Pangaea that began in the late Triassic, continued in Jurassic. The climate of the new and smaller continents was milder and more rainy. Hot and humid tropical breezes blew through dense forests of ferns, cycads, ginkgo trees and various conifers.

Since large parts of the Earth's surface were covered by water and green plants, planet's albedo decreased, and more of the Sun's energy was absorbed as heat. The increased atmospheric moisture content also helped to increase the temperature, because water vapor is a greenhouse gas.
There is strong evidence that the sea surface level in the World increased during the Jurassic, which meant that many low-lying areas were transformed into shallow coastal sea, and in the same time the climate became more oceanic, that is wetter, warmer and with much less seasonal variation.
The Cretaceous period began 145 million years ago and lasted until the dinosaur extinction 65 million years ago. During this period prevailed almost everywhere on Earth a warm and humid climate. The thick layer of chalk, which was created by the microscopic calcareous algae that have been found in abundance throughout the Earth's oceans, gave its name to the period. Up until then, chalk deposits had been restricted to shallow coastal waters.

By the middle of the Cretaceous period about 100 million years ago, the mean- temperature on the planet's surface was between 6 and 12 degrees higher than it is today. The annual mean temperature in the Arctic was about 10 degrees, which is about 20 degrees warmer than today. In the tropical regions, the surface water temperature was approx. 5 to 10 degrees higher than the present.
The environment was unusually warm and polar ice caps did not yet exist. This played a large part in evolution and is a key factor behind the flourishing of the dinosaurs. During the Triassic period the climate was generally dry, which changed near the Jurassic period as oceans began to rise due to mounting layers of magma covering the seafloor. As a result, flooding overtook many parts of the exposed land. This allowed the climate to change with increased humidity and it continued that way even into the Cretaceous period. However, the climate began to cool during the Cretaceous although temperatures may have risen again near the end of the Mesozoic.
Understanding how the Earth responded to past extreme warming and CO2 input can help us prepare for how the planet will respond to current, human-caused climate change.


K. Ravindra, 1988. Fundamentals of historical geology and stratigraphy of India. Wiley eastern limited, New Delhi.

Thursday, December 26, 2019

View of partial (Annular) solar eclipse on 26th December in Ranchi city.

Though it was cloudy but I tried my best to take few photographs of solar eclipse. 
An annular solar eclips occurred on December 26, 2019. A solar eclipse occurs when the Moon passes between Earth and the Su, thereby totally or partly obscuring the Sun for a viewer on Earth. An annular solar eclipse occurs when the Moon's apparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like an annulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. 

Wednesday, December 25, 2019

Radon gas- the major threat of indoor air pollution.

Radon is the most important cause of lung cancer after smoking.

Dr. Nitish Priyadarshi. 
email: nitish.priyadarshi@gmail.com

Radon is a naturally occurring radioactive gas which may be found in indoor environments such as homes, schools, and workplaces. Radon is the most important cause of lung cancer after smoking. All types of houses can have radon problems-old homes, new homes, drafty homes, insulated homes, homes with basements and homes without basements. Construction materials and the way the home has been built may also affect radon levels, but this is rare. A radon level of 4 picoCuries per liter (pCi/L) or more is considered high.

Radon is a gas produced by the radioactive decay of the element radium. Radioactive decay is a natural, spontaneous process in which an atom of one element decays or breaks down to form another element by losing atomic particles (protons, neutrons, or electrons). When solid radium decays to form radon gas, it loses two protons and two neutrons. These two protons and two neutrons are called an alpha particle, which is a type of radiation. The elements that produce radiation are called radioactive. Radon itself is radioactive because it also decays, losing an alpha particle and forming the element polonium.

Elements that are naturally radioactive include uranium, thorium, carbon, and potassium, as well as radon and radium. Uranium is the first element in a long series of decay that produces radium and radon. Uranium is referred to as the parent element, and radium and radon are called daughters. Radium and radon also form daughter elements as they decay.

The decay of each radioactive element occurs at a very specific rate. How fast an element decays is measured in terms of the element "half-life", or the amount of time for one half of a given amount of the element to decay. Uranium has a half-life of 4.4 billion years, so a 4.4-billion-year-old rock has only half of the uranium with which it started. The half-life of radon is only 3.8 days. If a jar was filled with radon, in 3.8 days only half of the radon would be left. But the newly made daughter products of radon would also be in the jar, including polonium, bismuth, and lead . Polonium   is also radioactive - it is this element, which is produced by radon in the air and in people's lungs, that can hurt lung tissue and cause lung cancer.

For most people, the greatest exposure to radon occurs in the home. The concentration of radon in a home depends on:
  • the amount of uranium in the underlying rocks and soils;
  • the routes available for the passage of radon from the soil into the home; and
  • the rate of exchange between indoor and outdoor air, which depends on the construction of the house, the ventilation habits of the inhabitants, and the air-tightness of the building.

Radon 222-a naturally occurring radioactive gas that you cannot see, taste or smell- is produced by the radioactive decay of Uranium-238. The other definition is “Radon is a naturally occurring radioactive gas emitted as a result of the radioactive decay of radium 226 (which is an indirect decay product  of uranium)” .  Most soil and rock contain small amounts of uranium -238. But this isotope is much more concentrated in underground deposits of minerals such as uranium, phosphate, granite, and shale. Radon is found in many types of rocks and soils. Although some rocks and soils contain more uranium (and thus greater radon gas potential) than others, all rocks and soil contain at least trace amount of uranium. According to a report, there are 2.7 pounds of uranium for each 1 million pounds of rock.  Granite, however, contains approximately 4.7 pounds of uranium per 1 million pounds, and back shale contains approximately 3.7 pounds of uranium per 1 million pounds. Sandstone contain 0.5 pounds and basalt contains 0.9 pounds per 1 million pounds. Thus, areas with high granite content and black shale, are more likely to have radon gas.

When radon gas from such deposits seeps upward through the soil and is released outdoors, it disperses quickly in the atmosphere and decay to harmless levels.   However, radon gas can enter buildings above such deposits through cracks in foundations and walls, opening around sump pumps and drains, and hollow concrete blocks. Once inside , it can build  up to high levels, especially in unventilated lower levels of homes and buildings. Although some radiation is emitted from the building materials themselves, such as bricks. In addition, because the air pressure inside a house is generally lower than the pressure of the soil around the foundation ( because of appliances that use air,  such as furnaces), the structure acts like a Vacuum, drawing the radon in from the soil. Radon may also be present in groundwater and can be release into the air through faucets and shower heads.
In the open air, radon generally is diluted into insignificant concentrations. However, when radon is trapped and allowed to concentrate, such as within a building, it presents a serious health threat to the inhabitants.

In many countries, drinking water is obtained from groundwater sources such as springs, wells and boreholes. These sources of water normally have higher concentrations of radon than surface water from reservoirs, rivers or lakes.

Effects of Radon

Radon -222 gas quickly decays into solid particles of other radioactive elements that, if inhaled, expose lung tissue to a large amount of ionizing radiation from alpha particle. When inhaled, the decay of the radon releases solid radioactive particles ( polonium). Although the half life of polonium is only a few minutes, while it is within the lungs, it continues to decay, which releases ionizing alpha radiation. This exposure can damage lung tissue and lead to lung cancer over the course of  a 70 year lifetime. Your chances of getting lung cancer from radon depend mostly on how much radon is in your home, how much time you spend in your home, and whether  you are a smoker or have ever smoked.

In 1998, the National Academy of Sciences estimated that prolonged exposure for a life time of 70 years to low levels of radon or radon acting together with smoking is responsible for 15,000-22,000 ( or 12%) of the lung cancer deaths each year in the United States. This makes the radon the second leading cause of lung cancer after smoking.

What are the symptoms of radon in your home?
       persistent cough.  
·         coughing up blood.
·         wheezing.
·         shortness of breath.
·         hoarseness.
·         chest pain, especially when you cough or laugh.
·         frequent infections such as bronchitis and pneumonia.


Radon can be controlled in a number of ways, with the control action depending on the level of radon. The primary control actions are to prevent radon from entering the home by either blocking off or sealing potential entry points or to reduce the amount by increasing ventilation.
Sealing or blocking radon entry points may require covering exposed earth in basements, storage areas, drains, and crawlspaces with impermeable materials, such as plastic sheeting pr metal. Cracks and openings can be sealed with mortar or caulking.

Household ventilation, which can push radon out instead of pulling it inside the home, can be increased with strategically placed fans. In addition, by altering the air pressure inside the home, the vacuum effect can be reduced. This can be accomplished by switching the air  source of certain appliances, such as furnaces and clothes dryers, from inside to outside the home.


Miller, G. Tyler Jr. 2004. Environmental Science. Thomson Learning, USA.

Wagner, T. 1994. In our backyard. John Wiley & Sons, INC, New York.


Friday, November 8, 2019

क्या है समुद्र के नीचे लेमुरिया महाद्वीप का रहस्य?

क्या बदलते तापमान ने इन्हे डुबाया ?
झारखण्ड की मुंडा जाती भी शायद इसी महाद्वीप से होते हुए भारत पहुँची।
डा. नितीश प्रियदर्शी

जिस तरह वर्तमान में ग्लोबल वॉर्मिंग के कारण पृथ्वी पर कई विनाशकारी बदलाव होने की आशंकाएं जताई जा रही हैं, उसी तरह प्राचीनकाल में एक बार ऐसा हो चुका है जिसके चलते लेमुरिया और मु नाम के 2 महाद्वीप जलमग्न हो चुके थे। हालांकि वैज्ञानिक इस पर अभी शोध ही कर रहे हैं किंतु विश्व के खोजकर्ताओं का दावा है कि इन दोनों महाद्वीपों पर सभ्यता काफी विकसित थी। कुछ खोजकर्ताओं, जिनमें प्रमुख थे फिलीप स्कोल्टर, का यह भी कहना था कि मनुष्य की उत्पत्ति इन्हीं महाद्वीपों पर हुई थी। ये दोनों महाद्वीप किसी भू-वैज्ञानिक हलचल की वजह से समुद्र के भीतर समा गए।

जब से पृथ्वी बनी है, तब से विनाश के कई चरण हुए हैं तथा कई प्रजातियां विलुप्त हुईं तथा नई आई भी हैं। विश्व की सभी जातियों एवं धर्मों में प्राचीन महाप्रलय का उल्लेख मिलता है। केवल धर्म ही नहीं, भू-वैज्ञानिक साक्ष्य भी पृथ्वी पर कई प्राचीन विनाशकारी हलचलों को दर्शाते हैं चाहे वे भूकंप के रूप में हों या ज्वालामुखी के रूप में या ग्लोबल वॉर्मिंग या हिमयुग के रूप में हों। आदिम जनजातियों में भी जल महाप्रलय का उल्लेख कहानियों के रूप में हुआ है। इसी क्रम में इस महाद्वीप का उल्लेख भी प्राचीन तमिल साहित्य में पाया जाता है। 

तमिल लेखकों के अनुसार आधुनिक मानव सभ्यता का विकास, अफ्रीका महाद्वीप में ना होकर हिन्द महासागर में स्थित ‘कुमारी कंदम’ नामक द्वीप में हुआ था | हालाँकि कुमारी कंदम या लुमेरिया  को हिन्द महासागर में विलुप्त हो चुकी काल्पनिक सभ्यता कहा जाता है | इसे कुमारी नाडु के नाम से भी जाना जाता है | कुछ लेखक तो इसे रावण की लंका के नाम से भी जोड़ते हैं, क्योंकि दक्षिण भारत को श्रीलंका से जोड़ने वाला राम सेतु भी इसी महाद्वीप में पड़ता है | 

तमिल इतिहासकारों के अनुसार इस द्वीप का नाम 'कुमारी कंदम' था। 'कुमारी कंदम' आज के भारत के दक्षिण में स्थित हिन्द महासागर में एक खो चुकी तमिल सभ्यता की प्राचीनता को दर्शाता है। इसे 'कुमारी नाडू' के नाम से भी जाना जाता है। तमिल शोधकर्ताओं और विद्वानों के एक वर्ग ने तमिल और संस्कृत साहित्य के आधार पर समुद्र में खो चुकी उस भूमि को पांडियन महापुरुषों के साथ जोड़ा है। तमिल पुनर्जागरणवादियों के अनुसार 'कुमारी कंदम' के पांडियन राजा का पूरे भारतीय उपमहाद्वीप पर शासन था। दक्षिण भारत के लोकगीतों में इतिहास के साथ उस खो चुकी इस सभ्यता का वर्णन मिलता है। नतीजतन, जब इसके बारे में जानकारी देने वाले खोजकर्ता भारत के नगरों में पहुंचे, तब इस लोकगीत और कथा को बल मिला।

तमिल लेखकों के अनुसार आधुनिक मानव सभ्यता का विकास अफ्रीका महाद्वीप में न होकर हिन्द महासागर में स्थित 'कुमारी कंदम' नामक द्वीप में हुआ था। हालांकि 'कुमारी कंदम' या लुमेरिया को हिन्द महासागर में विलुप्त हो चुकी काल्पनिक सभ्यता कहा जाता है। कुछ लेखक तो इसे रावण की लंका के नाम से भी जोड़ते हैं, क्योंकि दक्षिण भारत को श्रीलंका से जोड़ने वाला राम सेतु भी इसी महाद्वीप में पड़ता है। 

तमिल साहित्य के अनुसार, भारतीय उपमहाद्वीप में कुमारी कंदम नाम की एक तमिल सभ्यता थी , जो कि अब हिन्द महासागर में विलुप्त हो चुकी है | इसी महाद्वीप को Lemuria  नाम इंग्लिश भूगोलवेत्ता फिलिप स्क्लाटर (Philip Sclater) ने 19 वीं सदी में दिया था | सन 1903  में  V.G. सूर्यकुमार ने इसे सर्वप्रथम Kumarinatu" ("Kumari Nadu") या कुमारी क्षेत्र का नाम दिया था | कहा जाता है की यह कुमारी कंदम ही रावण के देश ‘लंका’ का विस्तृत स्वरुप है जो कि वर्तमान भारत से भी बड़ा था ।

हिन्द महासागर में एक बहुत बड़े महाद्वीप की संभावना को सबसे पहले ब्रिटिश भूगोलवेत्ता फिलिप स्क्लाटर (Philip Sclater) ने बताया था | उन्होंने मेडागास्कर और भारत में बहुत बड़ी मात्रा में वानरों के जीवाश्मों (Lemur Fossils) के मिलने पर यहाँ एक नयी सभ्यता के होने का अंदेशा व्यक्त किया था | उन्होंने ही इसे ‘लेमुरिया ‘ नाम दिया था | उन्होंने इस विषय पर एक किताब भी लिखी जिसका नाम ‘The Mammals of Madagascar’ था, जो कि 1864  में प्रकाशित हई थी |

भूगोलवेत्ता A.R. वासुदेवन के उन्नत अध्ययन के अनुसार, मानव सभ्यता का विकास अफ्रीका महाद्वीप में ना होकर कुमारी हिन्द महासागर के ‘कुमारी नामक' द्वीप पर हुआ था | उनके अध्ययन कहते हैं कि आज से लगभग 14,000 साल पहले जब कुमारी कंदम जलमग्न हो गया तो लोग यहाँ से पलायन कर अफ्रीका, यूरोप, चीन सहित पूरे विश्व में फैल गए और कई नयी सभ्यताओं को जन्म दिया |
ऐसा माना जाता है कि हिम युग के अंतिम सालों में तापमान बढ़ना शुरू हो गया था जिसके कारण ग्लेशियरों का पिघलना शुरू हुआ और समुद्र का जल स्तर बहुत बढ़ गया और अंततः यह सभ्यता पानी में डूब गयी |

आज सारे विश्व के वैज्ञानिक इस बात पर सहमत हैं की आने वाले समय में पृथ्वी पर कई विनाशकारी बदलाव होंगे। कारन है ग्लोबल वार्मिंग । कई छोटे द्वीप समुद्र में समां जायंगे । कहीं सूखे की मार होगी तो कहीं अतिवृष्टि । कई नए जगह भूकंप प्रभावित होंगे जो पहले नही थे । यानि विनाश का एक नया रूप सामने आएगा।

विनाश अगर होगा भी तो अचानक नही । विनाश की प्रक्रिया धीरे धीरे होती है जैसे पहले हुई थी । जब से पृथ्वी बनी है विनाश के कई चरण हुए है जब कई प्रजातियाँ विलुप्त हुई तथा नई आई हैं। विश्व के सभी जातिओं एवं धर्मो में प्राचीन महाप्रलय का उल्लेख मिलता है । केवल धर्मं ही नही भूवैज्ञानिक साक्ष्य भी पृथ्वी पर कई प्राचीन विनाशकारी हलचल को दर्शाता है। चाहे वो भूकंप के रूप मे हो या ज्वालामुखी के रूप मे या ग्लोबल वार्मिंग या हिमयुग के रूप मे हो। विश्व के सभी धर्मो में जल को ही महाप्रलय का कारण माना गया है। यहाँ तक की सभी आदिम जन जातिओं मे भी जल महाप्रलय का उल्लेख कहानिओं के रूप में हुआ है।इसी क्रम में दो महाद्वीपों का नाम उभर कर आता है जो आज महासागर के नीचे है। इनका नाम है "लेमुरिया एवं मु। वेसे इन द्वीपों का अभी तक वेज्ञानिक पुष्टि नही हो पाई है। लेकिन विश्व के खोजकर्ताओं का दावा है की यह दोनों महाद्वीप पर सभ्यता काफी विकसित थी। कुछ खोजकर्ताओं, जिनमे प्रमुख थे फिलिप स्कोल्टर , का यह भी कहना था की मनुष्य की उत्पत्ति इन्ही महाद्वीपों पर हुई थी। ये दोनों महाद्वीप किसी भूवैज्ञानिक हलचल के वजह से समुद्र के भीतर समां गए। १८६४ में जन्तुविज्ञानी श्री फिलिप स्केलटर ने एक लेख लिखा " मैडागास्कर  के स्तनधारी " इस लेख में उस जीवाश्म की  चर्चा की गई थी जो  मैडागास्कर तथा भारत में पाए गए।  इनको इस बात का आश्चर्य की ये जीवाश्म अफ्रीका या मध्य पूर्व में नहीं पाये गए।  तब उन्होंने माना की भारत और मैडागास्कर  एक ही बड़े महाद्वीप के अंश थे। तमिल साहित्य में इस महाद्वीप का जिक्र बार बार हुआ है।  इसमें  प्रमुख है "कुमारी  कंदम" जिसको कुमारी नाडु भी कहते हैं जिसका अर्थ है डूबता महाद्वीप  इस साहित्य में लेमुरिया महाद्वीप का जिक्र कई बार हुआ है।  

हाल के वर्षो में मॉरिशस के पास हिन्द महासागर के नीचे एक खोया महाद्वीप पाया गया। ये प्राचीन महाद्वीप जो कभी भारत और मेडागास्कर के बीच में फैला हुआ था, अब हिंद महासागर के तल पर बिखरा हुआ है। ये प्राचीन महाद्वीप, जिसे मॉरिटिया के नाम से जाना जाता है, एक बार गोंडवाना सुपरकॉन्टिनेंट के दौरान मेडागास्कर को भारत से जोड़ता था।

एक रोचक तथ्य यह सामने उभर कर सामने आया है की हमलोग की आगे की पीढ़ी शायद फिर लेमुरिया द्वीप पर वास करे। खोजकर्ताओं का मानना है की जिस तरीके से लेमुरिया द्वीप समुद्र के अन्दर समां गया शायद भविष्य मैं किसी प्लेट टेक्टोनिक या किसी भूगर्भीय हलचल की वजह से यह द्वीप समुद्र के ऊपर आ जाए। एक और रोचक तथ्य सामने यह आया है की लेमुरिया द्वीप के लोग काफ़ी लंबे होते थे। उनके पास तीसरा आँख भी था जो सर के पीछे होता था। यही आँख आज के मनुष्य में पीनियल नेत्र  (pineal eye) के नाम से जाना जाता है। इसका अब कोई कम नही है। लेकिन इसपर अभी कोई खोज नही हुआ है।एसा माना जाता है की लेमुरिया महाद्वीप हिंद महासागर के नीचे एवं मु महाद्वीप प्रशांत महासागर के नीचे समा गया। खोजकर्ताओं की माने तो "मु" महाद्वीप ५०,००० वर्ष पहले तक था एवं "लेमुरिया द्वीप" की उत्पत्ति एक लाख साल पहले हुई थी।ऐसा लगता है जिस वक्त ये दोनों महाद्वीप समुद्र के नीचे समाये उस वक्त पृथ्वी का तापमान आज के तुलना में ज्यादा रहा होगा जिसके चलते हिमनदों के पिघलने से समुद्र का जलस्तर ऊँचा उठा एवं इन दोनों महाद्वीपों को धीरे धीरे अपने भीतर समां लिया। वेसे भी आज के बढ़ते तापमान की वजह से विश्व के कई छोटे छोटे द्वीप खतरें मैं आ गए है।

पहले भी हमारे पृथ्वी पर कई बदलाव हुए आज जहाँ पर सुखी जमीन है वहां पहले समुद्र हुआ करता था। आज जहाँ रेगिस्तान है वहां पहले हरियाली हुआ करती थी। पृथ्वी पर प्राचीन काल के जिओलोजिकल विनाश के अवशेष आज भी मिलते है । एल्फ्रेड रसेल एवं एर्नेस्ट हेकेल का मानना था की मनुष्य की उत्पत्ति इन महाद्वीपों पर हुई थी। लेमुरिया शब्द लेमूर नामक जीव से आया जो बन्दर एवं गिलहरी का मिश्रित रूप है। लेमूर का मूल स्थान मेडागास्कर है लेकिन यह भारत एवं मलाया मे भी पाया जाता है। इसलिये यह माना गया की ये जीव तभी भारत पहुंचें होंगे जब कोई विशाल महाद्वीप हिंद महासागर में रहा होगा एवं जो भारत एवं मेडागास्कर के बिच में सेतु का काम किया।

वैज्ञानिक मानते हैं की भारत उप महाद्वीप में किसी नर-वानर की उत्पत्ति नही हुई थी। अतः जितनी भी जातियां भारत की धरती पर जीवित हैं या लुप्त हो चुकीं हैंउनका मूल स्थान कहीं न कहीं भारत से बाहर रहा था। झारखण्ड के मुंडाओं के मूल स्थान तथा उनके आव्रजन मार्ग की खोज  में लेमुरिया सिद्धांत का उल्लेख हुआ है। एस सी रॉय ने इस सिद्धांत का प्रतिपादन किया है। श्री रॉय ने दक्षिण अफ्रीका एवं दक्षिण भारत के बिच एक लेमुरिया द्वीप की कल्पना की है जो अब जलमग्न हो चुका है। उन्होंने संभावना व्यक्त की है की मुंडा जाती लेमुरिया द्वीप से होती हुए भारत आई थी। इस प्रसंग में दक्षिण अफ्रीका के मेडागास्कर का नाम उल्लेखित हुआ है। इस मत के अनुसार मुंडाओं का मूल स्थान मेडागास्कर है और भारत आव्रजन "लेमुरिया द्वीप" से होते हुए हुआ है। अब सवाल यह उठता है की अगर यह दोनों महाद्वीप थे तो ये समुद्र में कैसे समा गए। क्या समुद्र के बढ़ते जलस्तर ने इनको अपने अन्दर समा लिया या किसी भुवेज्ञानिक हलचल के चलते यह महासागर के अन्दर चले गए । अभी भी इसपर खोज जारी है।सवाल लेमुरिया या मु का नहीं है । सवाल यह है की अगर पृथ्वी का तापमान यूँ ही बढ़ता रहा तो आने वाले समय में कोई दूसरा लेमुरिया या मु जैसी घटना होने से इंकार नही किया जा सकता।

Thursday, October 3, 2019

Geological report on importance of rain water harvesting in selected areas of Ranchi city,India.

Dependency on groundwater for drinking and domestic purpose has increased.


Dr. Nitish Priyadarshi


Water is essential for life- all living organisms contain water. In fact most living organisms consist of over 60 percent water.

Through out his brief history on earth, man has depended on three basic natural resources for his survival: air, land and water. Of these three, none has been more abused and neglected by man than water. Yet without water, the land produces nothing; without water, life vanishes from the face of the earth. Civilizations arose and have prospered for millennia where water was abundant. The Nile valley is a prime example. When water disappeared, civilizations withered and died. Mesopotamia is a classic example.

The utter human dependence on water is exemplified by the fact that man can survive for five weeks without food, but he dies after only five days without water. If the water supply of a human being is cut off for just a few days, he will die of dehydration long before the water is completely evaporated from his body. Water vapor is lost with every breath, and we cannot avoid breathing.
In recent years due to increasing contamination of surface water bodies, dependency on groundwater for drinking and domestic purpose has increased many fold. But these water sources are now badly affected with global warming. Groundwater is depleting day by day due to effect of rising temperature and urbanization.

The excess soil moisture that saturates subsurface soil or rock and migrates downward under the influence of gravity. In the literal sense, all water below the ground surface is groundwater; in hydrogeologic terms, however, the top of this saturated zone is called the water table, and the water below the water table is called groundwater.
Ranchi the capital city of Jharkhand state of India is located at 23.350 N and 85.330 E. The total area covered by Ranchi-Municipal area is about 141 square kilometers and the average elevation of the city is 645 m above Mean Sea Level (MSL). As of 2001 India census Ranchi had a population of 846,454.

Water supply, in adequate quantity and at desirable quality, is essential for any sustainable urbanization. Water supply in Ranchi dates back to more than 50 years ago.

There are three main dams ( Hatia, Rukka, and Kanke dam) from where the water is supplied to the city. Surface water is always vulnerable to pollution. People of Ranchi are dependent more on purer source like groundwater. Of the total consumption more than 60% comes from groundwater storage. Due to increasing population more pressure has developed on groundwater from the aquifer beneath the city.

The process of urbanization and industrialization from last 20 years has caused changes in the water table as a result of decreased recharge and increased withdrawal. Many of the small ponds which were main source of water in the surrounding areas are now filled for different construction purpose affecting the water table. Lots of DEEP- BORING in the Ranchi city has also forced the water table to move down as well as Ranchi plateau.

Groundwater in Ranchi city:

Groundwater in Ranchi city is mainly stored here in secondary porosity features or void spaces developed as result of weathering, fracturing, jointing, shearing or faulting phenomena. The gneisses and granitic rocks with associated schists and quartzites constitute the main consolidated rock terrain of Ranchi district.

Major portion of Ranchi city which is part of the Chotanagpur Plateau occupied by hard rock which are devoid of primary porosity and occurrence and movement of groundwater is controlled by the joints, fractures and fissures present in them.

During the long span of geological history these rocks have been deformed and tectonised in many ways including deep erosion.

In Ranchi city water table in the consolidated formations is now at its lowest from April to June. Water table is at its highest peak during August, gradually stabilizing in the month of November.

Sources of groundwater recharge in Ranchi city and the other parts of Jharkhand State is the vertical percolation of rain water. Although city experiences about 1000 to 1200 mm rainfall annually, the rate of vertical percolation is hindered by the presence of highly weathered and metamorphosed rocks. The Ranchi plateau gradually slopes down towards south east into the hilly and undulating region of Singhbhum. Due to this uneven topography the rain water are lost through surface runoff resulting in less water percolation below the surface. The thin soil layer of Ranchi plateau which is becoming more thin due to weathering is gradually loosing its water retaining capacity, Moreover, present land development practices in the recharge area and natural canals or rivulets in and around the city is also reducing the natural recharge significantly. More than 40% of the rain water is lost in the form of surface runoff. The rate of decline ranges between 1m/year to 5m/year at different observation locations within the city.
As Ranchi is becoming one of the important business center in Eastern India there is a rampant increase in construction and expansion of city. Due to inadequate water supply from the dams, dependency on ground water is increasing. Over pressed zones are Upper Bazar, Main Road, Ratu Road, Piska More, Chutia, Hindhpirhi, Circular Road, Burdwan Compound, Lalpur and Harmu Road.

The main objectives of Rain Water Harvesting are:-
• Increasing the availability of ground water during periods of requirement.
•Preventing depletion of ground water reservoirs in areas of over exploitation.
Improving quality of ground water through dilution.

Rainwater harvesting is the collection, storage and injecting precipitation  down in the earth of  for later human use. This project focuses on the selection of the site and rainwater harvesting system located at the different rickshaw pullers garage located in different areas of Ratu road and Piska more in Ranchi city. The information collected  from this project will be used to build a template for designing a rain water harvesting system that can be placed in the selected areas.

                                    Fig.1 Depletion of ground water.

                                  Fig. 2. Structure of rain water harvesting.

Fig.3. Depleted water in a well in Piska More, Ranchi.

Rickshaw pullers are the most affected people as they are more dependent on surface and well water which is polluted and gets dry in summer season.

Till about thirty years back, the areas surveyed used to be unpaved and the rain falling on these areas would percolate into soil and remain there for being drawn through shallow open wells. With the proliferation of flat complexes, these areas been covered, resulting in stopping of percolation of rain water into the soil. But on the other hand the use of ground water has risen immensely. With Increase in the number of deep bore wells, the shallow wells started drying up. The reason is that no sincere attempt was made to re- establish the ground water table to its original level during monsoons.
Rooftop rain water harvesting was suggested in the surveyed areas. Out of 30 sites 10 sites were selected as the rickshaw pullers were using dug well waters for their daily purpose. Rooftop catchments is  the most basic form of this technology, rainwater is collected in simple vessels at the edge of the roof. Variations on this basic approach include collection of rainwater in gutters which drain to the collection vessel through down-pipes constructed for this purpose, and/or the diversion of rainwater from the gutters to the settling  tanks/percolation tank or absorption tank  filled with sands and cobbles and pebbles working as water filters. As the rooftop is the main catchment area, the amount and quality of rainwater collected depends on the area and type of roofing material. Reasonably pure rainwater can be collected from roofs constructed with galvanized corrugated iron, aluminum or asbestos cement sheets, tiles and slates.  Roofs with metallic paint or other coatings are not recommended as they may impart tastes or color to the collected water. Roof catchments should also be cleaned regularly to remove dust, leaves and bird droppings so as to maintain the quality of the water.
Settling tanks for collecting rainwater harvested using guttering may be either above or below the ground. Precautions required in the use of se tanks include provision of an adequate enclosure to minimize contamination from human, animal or other environmental contaminants, and a tight cover to prevent algal growth and the breeding of mosquitoes.

Garage Name
Garage owner name
No.of rickshaw pullers staying  in the garage
Water Harvesting status
Date of visit
Vijay Tirkey
Near Krishi Bazar, Pandra, Ranchi
Yes; Important

Amit kr. Bhagat
Piska More
Yes; Important

Suresh Kachhap
Piska More
Shed not much and well is not owned by owner but garage owner has himself made some water harvesting system.
Pawan Sharma
Piska More

Karam toli
Has naturally available water resources which maintains the water level.
Jagdish Bagla
Piska More
Yes; Important

Rajiv Agarwal
Near Uphar cinema, Ratu road
Consist of self built water system which maintains water level
Jayant Agarwal
Near Uphar cinema, Ratu road
Land too low so naturally land absorbs water, sheds are not available in much
Madhukar Singh
Near Pahadi Mandir
No well; no boring and monthly rented land
Sunil Yadav
Near Pahadi Mandir
Less possibility of holding rain water

This survey was carried out with the help of Mrs. Aprajita Mishra and Smita Dasgupta of Maitri India, Ranchi.