Friday, December 28, 2007

Jharkhand rock paintings of India under threat

Jharkhand Rock paintings under threat.
Dr. Nitish Priyadarshi

10,000 year-old-rock paintings found recently in Tangar Basli block some 40 kms from the state capital Ranchi is now under threat.
Threat is from the stone quarrying due to which these paintings have been exposed to the flying stone dust and open atmosphere. Most of the paintings now have been faded.

Drawings are made on granite and granite gneiss rocks. In these paintings red ochre has been used. Dancing is the major subject of all these paintings.
For more detail contact the author.
Nitish Priyadarshi

Tuesday, December 25, 2007


Dr. Nitish Priyadarshi

The origin of coal
Coal is a result of the accumulation and slow decay of plant remains in sedimentary strata. It undergoes in situ compaction under water with time, accompanied by biochemical processes such as decomposition due to bacterial action, dehydration, loss of volatile compounds (e.g. methane, higher hydrocarbons, carbon dioxide and nitrogen) and densification to form various ranks of coal depending on environmental conditions. In absence of atmospheric oxygen, the plant matter is further degraded by the action of anaerobic bacteria, which extract and utilize oxygen from organic molecules containing oxygen like lignin.

Where does the arsenic come from ?

Arsenic, one of the potentially hazardous trace elements, is usually concentrated in the sulphidic minerals of coal.
Many authors interpret the arsenic accumulation in terms of arsenic concentration during decay of plant matter in the humic layers. Arsenic is absorbed by the plants from the soil or crust.
Arsenic contributed by the surface as well as underground circulating waters during the primary stages of coal formation.
Arsenic deposited through the hydrothermal solutions during the igneous activity in and around coal basins.
The enrichment of arsenic and other trace elements in coal is governed by the following factors (Swaine, 1962).
· Duration of supply of arsenic during the initial stages of coal formation.
· pH and Eh conditions in the depositional basin.
· Variety and concentration of the supplied constituents.
· Microstructural frame work of the coal seams.
· Porosity of the overlying and underlying rocks.
· Rate of sedimentation and tectonics of the coal basin.

The arsenic content of coal samples worldwide is highly variable, with an average value around 5 mg kg-1 and extreme high values of up to 35,000 mg kg-1 in coals from endemic arsenosis areas in China.

Arsenic in coals:
It is not surprising to find that there has been increased interest in Arsenic in coals, together with work on rocks, soils, plants and waste materials, probably because of possible adverse health effects of high concentrations. The arsenic content in coal has been reported to be as high as hundreds or even more than one thousand ppm, suggesting that under certain geological and geochemical conditions arsenic can be considerably enriched. In comparison, the average arsenic concentration in earth’s crust is low ( a Clarke value of 2.2 ppm). The enrichment coefficient for arsenic is close to the maximum enrichment coefficients of the trace elements in coaly materials such as Be, Ge, and Ga (Zhou and Ren,1992).
Arsenic is present in coal as arsenopyrite and that little exists in any other form. Minkin (1984) found that arsenic was most likely to present in solid solution in pyrite, and Finkelman (1979) noted that arsenic was predominantly in fractures in the coal and in microfactures in the pyrite. For most coals, arsenic seems to be mainly associated with the mineral matter, with varying smaller amounts being associated with organic matter.
Arsenic has similar chemical properties to phosphorus (P), the element immediately below arsenic on the periodic chart. It is well known that coal fly ash contains arsenic that can leach into receiving- water reservoirs. During coal combustion, arsenic oxidizes and forms gaseous As2 O3 and enters the atmosphere. This causes concerns for governments of many countries because of environmental pollution due to extensive use of coal.

Organic-inorganic affinity of Arsenic:
The relationship between the concentration of an elements and ash content has been used as a first order approximation of the elements organic/inorganic affinity. Factors governing elements partitioning between organic and inorganic phases have been discussed by a member of investigators. If the concentration of arsenic and other elements increases with increasing ash content, i.e. a positive correlation, the arsenic may be characterized as having an inorganic affinity.
Alternatively, if the arsenic concentration decreases with increasing ash content, a negative correlation, the arsenic may be characterized as having an organic affinity.

Distribution of arsenic in world coals:

The concentration of arsenic in coal is commonly below 10 ppm (Zhou and Ren, 1992). Arsenic in most world coals is 0.5-80 ppm (Swaine, 1990). Difference in arsenic levels between Gondwana coals and coals from the Northern Hemisphere are reflected in the mean values (as ppm As), namely, 1.5 (Australia), 4 (South Africa), 15 (United Kingdom) from Swaine (1990), and 24.6 in 7351 samples (United States) from Bragg (1998). Concentrations of arsenic in Chinese coals are between 0.21 and 32000 ppm (Ren et al. 1999). In general, the arsenic content of most Canadian coals is low as compared with the range for most world coals. The mean values for arsenic in the Bulgarian coal deposits range from 2 to 58 ppm (Eskenazy,1995). The Miocene Cayirhan coals from the Beypazari basin of Turkey have 32-148 ppm arsenic (querol et al., 1997). The concentration of arsenic in the Gokler coal samples in Gokler coalfield of Turkey range from 170 to 3854 ppm (av. 833 ppm), with a geometric mean of 670 ppm. The means indicate that these coals contain more arsenic than most world coals (Karayigit et al., 2000). Arsenic concentration in coals of Hat Creek Deposit of British Columbia, Canada varies from 4.03 ppm to 52.7 ppm. (Goodarzi, 1987). The concentration of arsenic varies from 2.6 ppm to 138.1 ppm in coals of Teruel Mining district in northeast Spain (Querol et al. 1992).

Arsenic in the Permian coals of North Karanpura Coalfield of Jharkhand State of India:
The North Karanpura coalfield, a western most member in the east-west chain of the Damodar Valley Basin, forms a large expanse of coal bearing sediments spread over Hazaribag, Ranchi and Palamau districts of Jharkhand State. It covers a total area of around 1230sq. Km. For the arsenic study, samples from coal from Badam, Kerendari, KDH, Rohini, Dakra and Karkatta were analysed by the author. Molybdenum-blue Colorimetry was used as the chemical technique for arsenic determination as recommended by the International Standard Organisation. Concentration of arsenic in coal samples range from from less than 0.01 to 0.49ppm with an arithmetic mean of 0.15ppm. (Priyadarshi, 2004). Concentration of arsenic is low compared to most world coals. Average ash% is very high (up to 32.51%). The low arsenic concentrations of the coal studied could be related to the geological characteristics of the source area in the basin and to a resulting low degree of arsenic mineralization (realgar or orpiment) of the synsedimentary solutions, which resulted in a paucity of arsenic in the system.

Impact of arsenic on health:

Arsenic is an environmental hazard and the reduction of drinking water arsenic levels is under consideration. People are exposed to arsenic not only through drinking water but also through arsenic contaminated air and food. Arsenic is emitted to the air by coal combustion as some coals are unusually high in arsenic because of geologic factors. Some of the common examples of arsenic poisoning are Skin lesions including keratosis of the hands and feet, pigmentation on the trunk, skin ulceration and skin cancers. Toxicities to internal organs, including lung dysfunction, neuropathy and nephrotoxicity have also been identified in some parts of China where the coal containing high arsenic burned inside the home in open pits for daily cooking and crop drying, producing a high concentration of arsenic in indoor air. Arsenic in the air coats and permeates food being dried producing high concentrations in food.


  • Bragg, L.J., Oman, J.K., Tewalt, S.J., Oman, C.L., Rega, N.H., Washington, P.M.,

  • Finkelman, R.B.,1998. US Geological Survey Coal Quality (COALQUAL) Database. US Geol. Survey Open file report 97-134, CD-Rom (Version 2.0).

  • Eskenazy, G.M. 1995. Geochemistry of arsenic and antimony in Bulgarian coals. Chemical Geology 119, 239-254.

  • Goodarzi, F. 1987. Concentration of elements in Lacustrine Coals from Zone A Hat Creek Deposit No.1, British Columbia, Canada.

  • Karayigit, A.I., Spears, D.A., Booth, C.A. 2000. Antimony and arsenic anomalies inn the coal seams from the Gokler coalfield, Gediz, Turkey. Int. J. Coal Geol. 44, 1-17.

  • Priyadarshi, N. 2004. Distribution of arsenic in Permian Coals of North Karanpura coalfield, Jharkhand. Jour. Geol. Soc. India, 63, 533-536.

  • Querol, X., Fernandez Turtle, J.L., Lopez-Soler, A., Duran, M.E.,1992. Trace elements in high-sulfur sub-bituminous coals of the Teruel Mining district (NE Spain). Appl. Geochem.,7, 547-561.

  • Querol, X., Whateley, M.K.G., Fernández-Turiel, J.L., Tuncali, E. 1997. Geological controls on the mineralogy and geochemistry of the Beypazari lignite, central Antolia, Turkey. Int. J. Coal Geol.33, 255-271.

  • Swaine, D.J. 1962: Trace elements in coal, II. Origin mode of occurrence and economic importance. C.S.I.R. Div. Coal Res. Tech. Commun.45.

  • Swaine, D.J. 1990. Trace elements in coal. Butterworths, London.

  • Ren, D., Zhao, F., Wang, Y., Yang, S. 1999. Distribution of minor and trace elements in Chinese coals. Chou et al. (Eds.). Geochemistry of coal and its impact on the Environmental and Human Health. Int. J. Coal Geol. 40, 109-118.

  • Zhou, Y., and Ren, Y. 1992. Distribution of arsenic in coals of Yunan Province, China, and its controlling factors. Int. J. Coal Geol., 20: 85-98.

  • Minkin, J.A., Finkelman, R.B., Thompson, C.L., Chao, E.C.T., Ruppert, L.F., Blank, H., Cecil, C.B., 1984. Microcharacterisation of arsenic and selenium bearing pyrite in upper Freeport coal, Indiana county, Pennsylvania. Scanning Electron Microse.,4: 1515-1524.

  • Finkelman, R.B., Stanton, R.W., Cecil, C.B., Minkin, J.A., 1979. Modes of occurrence of selected trace elements in several Appalachian Coals. Am. Chem. Soc. Div., Fuel Chem. Prepr. 24(1), 236-241.

    Dr. Nitish Priyadarshi

Monday, December 24, 2007

Haze over North India

Thick blanket of Haze spreads over North India.

Dr. Nitish Priyadarshi

Haze lingered in Northern India south of the Himalayas, for several days in December 2007. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua Satellite captured this image on December 16, 2007. In this image, the haze appears as a dull gray blur. The haze extends southward, thickening somewhat in the south west. North of the Himalaya, clouds clutter the otherwise clear skies.
The NASA image was created by Jesse Allen, using the data obtained from the Goddard Land Processes data archives (LAADS).

Haze often occurs when dust and smoke particles accumulate in relatively dry air. Regional haze pollution, mainly in the form of sulfate, organic and nitrate fine particles, results in poor visibility. Haze is composed of very small fine particles, smaller than 2.5 micrometers (µm) (over 20 times smaller in diameter than human hair) that are suspended in the air. These particles originate from a variety of sources, some natural, but much of it originates from power plant and automobile emissions. Haze is generally composed from five major components: sulfate aerosol, nitrate aerosol, organic carbon aerosol, elemental carbon, and dust from the earth’s crust and also from forest fire as it was in Indonesia in 1997. In 1997, the dry season lasted longer than usual. There was no rain to stop the slash-and-burn fires that farmers set and they burned out of control. The haze spread to the neighboring countries of Singapore and Malaysia. The thick blanket of smoke drastically reduced visibility in the Malacca Strait between Sumatra and Peninsular Malaysia. The haze triggered asthma attacks, severe coughing, breathing difficulties and eye and skin irritations.
Haze pollution is that portion of haze that comes from man-made sources. The largest source of regional haze pollution in India is from coal-fired power plants emitting sulfur dioxide and nitrogen oxide that then reacts in the atmosphere to form fine particles and automobiles. The other sources responsible for Haze Pollution are the chemical industries, metallurgical plants and smelters, petroleum refineries, mining etc.
Recent scientific studies have illuminated the associated human health impacts of exposure to fine particles, such as respiratory and cardiac disease and premature death.
Few years ago high levels of carbon monoxide (red and yellow pixels) was observed over the Indian sub-continent during March by the NASA. These values are associated with industrial activity in the region just south of the Himalayan Mountains. Notice that to the north, the Himalayas are characterized by low values (blue pixels).

Dr. Nitish Priyadarshi

Thursday, December 20, 2007

Active glacier found on Mars

'Active glacier found' on Mars
By Paul Rincon Science reporter, BBC News

A probable active glacier has been identified for the first time on Mars.

Monday, December 17, 2007


Climate has changed from “Hot to Cold” and Cold to Hot”- a brief history.


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.

The solid earth accumulated about 4700 m.y. ago from a cloud of cosmic particles and gaseous materials and as they collected gravitationally a hot planetary nucleus formed.
The first atmosphere of the earth, then, contained hydrogen, helium, neon, argon and various other lighter and inert gases, none of which is abundant in the present atmosphere. Most of these on liberation to the air now either escape earth’s gravitational pull because of their low densities or are bound up in minerals by chemically reacting with them.
Climates before 3800 million years ago:
Geologic evidence for paleoclimates of this interval is scant; fossil remains and unaltered sedimentary rocks are not known from the record. According to different research reports climate before 3800 m.y. ago were probably warm, perhaps warmer than present. Greenhouse effects contributed to this. Cooling effects of unknown magnitude were also operative. A steady cooling may have taken place over the interval in response to progressively decreasing carbon dioxide concentrations.
Climates between 3800 and 2400 million years ago:
From different research for this interval, a scenario can be constructed in which warm and wet climates characterize the early part, and in which a gradual cooling takes place as a consequence of changes in atmosphere and hydrospheric composition, to culminate in the glacial episode of the middle Precambrian. Evidence for earth’s earliest glaciation is best documented for an interval in the middle Precambrian. Still earlier episodes of glacial activity may have occurred, but glaciation may have been of such extremely local extent or short duration that glacial strata have not been detected.

Climates between 2300 and 950 million years ago:
The general distribution of the sedimentary rocks provides several clues to climates which followed the earliest glaciations. For the 2300 to 950 m.y. interval, abundant evidence exists that many carbonates are of warm water origin.
Oxygen and hydrogen isotopic compositions of middle Precambrian Cherts suggest high ground-surface temperatures, as in early Precambrian.

Climate between 950 to 615 million years ago:
A great deal of information exists that much op the earth was glaciated during the late Precambrian, particularly in the time span from 950 to 615 m.y. ago. The 950 m.y. figure represents the approximate age of the oldest among a series of tillites which signal the end of the long period of carbonate sedimentation which began about 2000 m.y. ago.

Climate in Paleozoic:
The Paleozoic encompasses about 350 m.y. and geographically restricted glaciations occur in each of the six periods of the era.
The broad trend of Paleozoic climate was from relative warmth which followed the late Precambrian glaciations, to a long and widespread glacial interval near the end of the era.
The sudden and repeated extinction events of trilobites provides clues about the climate changes in the Cambrian.
All of the continents were close to the equator and the trilobites were adapted to warm waters presumably. It has been suggested that the extinction of the trilobites was associated with a cooling of the ocean waters.
This hypothesis is supported by the fact that it was only the deeper dwelling trilobites that survived the extinctions. This is probably because they were already adapted to cold conditions since they lived in deep (cold) waters. Nonetheless, the case of temperature change as the cause remains unproven.
What is particularly problematic about any cooling idea to explain the extinction is evidence that suggest that atmospheric CO2 was much higher in the early Paleozoic Era. This evidence is in the form of various mineral types whose presence is a sensitive indicator of atmospheric CO2 levels.
During the Ordovician Life expanded in diversity tremendously. There were extensive reef complexes in the tropics. The early Ordovician was thought to be quite warm, at least in the tropics and cooled considerably at the end of the period.
Despite the tremendous expansion of life during the Ordovician Period there was a devastating mass extinction of organisms at the end of the Ordovician. This extinction was one of the greatest mass extinction ever recorded in Earth History.
The more likely cause is that the Earth cooled, particularly the oceans where most of the organisms lived during the Ordovician (Remember there were no land plants and no evidence of land organisms yet). All the extinctions occurred in the oceans.
Early Silurian warming was quickly followed by gentle cooling until the middle Devonian, and warm and dry conditions characterized the interval between the late Silurian and Early late Devonian.
During the Silurian Period the first land plants appeared. Marine organisms once again expanded in diversity following the extinction of so many families in the late Ordovician.
By the Devonian fish were a common part of the marine biological communities. Particularly important were the jawed fish. These were predators and they must have had quite an impact on the marine communities during the Devonian.
The first fossil evidence of insects and terrestrial trees comes from Devonian age rocks.
The Devonian is thought to have been quite warm. Evidence of this comes from the extensive amount of tropical-like reefs. The climate is also thought to have been quite dry. Evidence of this comes from extensive evaporite (salt deposits) that have been found dispersed much more broadly than any time in the earlier Paleozoic.

The early Carboniferous continued warm although humidity increased, and marked cooling in the late Carboniferous led to glaciation.
The Permian is one of the most interesting climate intervals because of the variety of climatically significant rocks which it contains. Asia appears to have been subjected to relatively wet climates through most of the Permian, as were large regions of Gondwanaland following the glaciations. Coals are known from short distances above glacial deposits in most Gondwana continents, suggesting that expansion of the seas, owing to post-glacial transgressions, led to high humidity in relatively high latitudes.
As the Permian opened, the Earth was still in the grip of an ice age, so the polar regions were covered with deep layers of ice. Glaciers continued to cover much of Gondwanaland, as they had during the late Carboniferous . At the same time the tropics were covered in swampy forests.
Towards the middle of the period the climate became warmer and milder, the glaciers receded, and the continental interiors became drier. Much of the interior of Pangea was probably arid, with great seasonal fluctuations (wet and dry seasons), because of the lack of the moderating effect of nearby bodies of water. This drying tendency continued through to the late Permian, along with alternating warming and cooling period.
Examination of the history of climate for single continents and super continents leads to the conclusion that during the Paleozoic, Europe and North America were subjected to only mild changes in climate while Gondwanaland went through several episodes of glaciation and variable states of humidity.

Climate in Mesozoic:
The Mesozoic Era (200 m.y.) presents excellent evidence for warm and dry climates. The initial Triassic climates were closely similar to those of the latest Permian, i.e. cool and humid, and were followed by a warm, drying-out period which may have lasted until the late Jurassic. The middle Triassic apparently was a time of great latitudinal expansion of evaporite deposition and of reef building. For this reason, mid- Triassic climate are considered to have been relatively warm and, possibly, the most arid in earth history.
During late Triassic global climate was warm. There was no ice at either North or South Poles. Warm Temperate conditions extended towards the poles.
Rapid global warming at the very end of the Permian may have created a super- “Hot House” world that caused the great Permo-Triassic extinction. 99% of all life on earth perished during the Permo-Triassic extinction.
Jurassic Period climate:
There are no proven glacial deposits of Jurassic age. During early and middle Jurassic climate the Pangean Mega-monsoon was in full swing. The interior of Pangea was very arid and hot. Deserts covered what is now the Amazon and Congo rain forests. China, surrounded by moisture bearing winds was lush and verdant. During the late Jurassic the global climate began to change due to breakup of Pangea. The interior of Pangea became less dry, and seasonal snow and ice frosted the polar regions.
Evidence from oxygen isotopes in late Jurassic belemnites indicates maximum temperatures of surface sea water of about 14° C at 75° S latitude. If correct, this would be at least 7° C warmer than present day temperatures, and a warm earth accordingly is implied.
Climate in Cretaceous:
The Cretaceous must be recognized as time of great warmth over the globe. This conclusion derives from oxygen isotopes, paleobiogeography and rock distributions, all of which indicate that temperatures were higher than now over the full range of latitude from equator to poles. No ice existed at the poles. Dinosaurs migrated between the Warm Temperate and Cool Temperate zones as the season changed.
How did the earth was such warmer at Mesozoic? Was there an increase in the radiation received from the Sun? Or, can the warm globe be explained by some strictly terrestrial cause?
Climate in Tertiary (65 m.y.):
The period of time which elapsed between the end of the Cretaceous and the present time.
Paleocene, Eocene and Oligocene apparently experienced cool changes which were both more frequent and more intense than those of the Mesozoic. Over this interval between about 65 and 22.5 m.y. ago, long episodes of relatively slight warming were punctuated be severe and abrupt drops in temperature leading to successively cooler regimes.
According to other opinion, the climate during the Paleocene was much warmer than today. Palm trees grew in Greenland. Global climate during the late Eocene was warmer than today. Ice had just begun to form at the South Pole. India was covered by tropical rain forest.
During the Oligocene, ice covered the South Pole but not the North Pole. Warm Temperate forests covered Northern Eurasia and North America.
The climate during the Miocene was similar to today’s climate but warmer. The gradual reduction in average temperature was continued throughout this time. We can assume that relatively warm climates were succeeded by cool climates which continued into the early Pliocene. As a result of this cooling, ice volume in Antarctica would have been about 50% greater than at present.
During the Pliocene times the continuing drop in average temperature caused the extinction of many groups of mammals and migration of other forms to warmer regions.
Pleistocene climate was characterized by repeated glacial cycles. It is estimated that, at maximum glacial extent, 30% of the Earth’s surface was covered by ice. Deserts on the other hand were drier and more extensive. Rainfall was lower because of the decrease in oceanic and other evaporation.
To observe a Holocene environment, simply look around you. The Holocene is the name given to the last 10,000 years of the Earth’s history- the time since the end of the major glacial epoch, or “ice age”. Since then, there have been small-scale climate shifts- notably the “Little Ice Age” between about 1200 and 1700 A.D.- but in general, the Holocene has been a relatively warm period in between ice ages.
Humanity has greatly influenced the Holocene environment. The vast majority of scientists agree that human activity is responsible for “Global Warming”, an observed increase in mean global temperatures that is still is going on. Habitat destruction, pollution and other factors are causing an ongoing mass extinction of plant and animal species. According to some projections, 20% of all plant and animal species on Earth will be extinct within the next 25 years.
The inhabitants of Mumbai or Riyadh might dispute on the fact that the earth is currently in the grip of a glacial episode. True, the present is an interval of relative warmth, an interglacial period, but for the past several million years the planet has been colder, on average, than it has over much of its history.
The examples of changes of global environment and the associated mass extinctions in the geological past clearly indicate that ecosystem is quite sensitive to environment changes and also has a capacity to regrow. Environmental factors, whether natural or man made, become ecologically disruptive when they cross threshold limits. Ecological viability, on the other hand, allows evolution to resume when extreme destructive natural factors relent during times of normalcy.
What ever may be the truth but it is true that the climate of the earth is changing from the time of its birth from hot to cold and cold to hot. Earlier too the earth has passed through global warming due to natural causes but this time we the humans are culprits for the changes. When man-made factors are added to the natural ones, the ecosystem may be damaged beyond repair.

· L.A. Frakes, 1979. Climates throughout geologic time. Elsevier publication, New York.
· J.D. Macdougall, 1996. A short history of planet earth. John Wiley and Sons, New york.
· D.G.A. Whitten and J.R.V. Brooks, 1983. The Penguin dictionary of geology. Penguin Books Ltd. England.
· The proceedings of the 94th Indian Science congress, Part II ,2007.

Dr. Nitish Priyadarshi
Geologist and Environmentalist