Proterozoic Sedimentary Basins (Purana Basins) of India: Geology, Stratigraphy, and Evolution of the Vindhyan Basin

Geological-map-of-the-Vindhyan-basin

Table of Contents

Proterozoic Sedimentary Basins (Purana Basins)

A number of nearly flat-lying, virtually un-metamorphosed, and partly deformed Proterozoic cratonic basins form a significant part of the Precambrian shield of India. These sub-horizontal Proterozoic basins predominantly contain orthoquartzite shale-carbonate suites varying in thickness from 100 to 10,000 meters and were deposited episodically, with frequent breaks in sedimentation, over some time of about 1000 Ma. These are called “Purana” basins in Indian stratigraphy after Holland, akin to the Riphean of Russia due to their great similarities. The Hindi word ‘Purana’ means ‘ancient’ and is “necessarily a somewhat vague though most convenient term.”

Characteristics of Purana Basins

The Purana basins are mainly intra-continental basins, often called cratonic or epicratonic basins. They are mostly situated close to the periphery of cratons (pericratonic basin), some are located in the cratonic interior (intra-cratonic basins like Kaladgi and Bhima), and rarely between cratons (inter-cratonic basins like the Pranhita-Godavari basin lying between Dharwar and Bastar cratons). They are also described as platform basins and witness the story of early crustal evolution. These basins are useful for global comparison with similar basins in Canada, Australia, Africa, etc., and importantly, they unveil the prelude to the Cambrian explosion of life. They occupy 20% of the area of the Precambrian of Peninsular India. The common depositional environments are fluvial to shallow marine (deltaic, beach, inshore, lagoonal, tidal flat, etc.) grading into shelf-slope-basin settings. Aeolian and evaporitic (sabkha) environments are locally developed. Glacial and glacio-fluvial successions, recorded from other comparable global basins, are not yet established on an all-India basis from the Purana basins.

READ ALSO  Guide to Chronostratigraphy and the Geological Time Scale: From Chronostratigraphic Units to Modern Dating Techniques

Division

Palaeo-Proterozoic Basins
BasinCraton
Bijawar and Sonrai Basins and Harda InlierBundelkhand Craton
Gwalior BasinBundelkhand Craton
Abhujmar BasinBastar Craton
Papaghni Sub-basin (Cuddapah basin)Dharwar Craton
Palaeo-Proterozoic Basins
Meso-Neo Proterozoic Basins
BasinCraton
1. Vindhyan basinBundelkhand Craton
2. Chhattisgarh basinBastar Craton
3. Khariar basinBastar Craton
4a. Ampani basinBastar Craton
4b. Keskal, Singanpur, and Chedrapal outliersBastar Craton
5. Indravati basinBastar Craton
6. Sabari (Sukma) basinBetween Bastar and Dharwar Cratons
7. Pranhita-Godavari basinBetween Bastar and Dharwar Cratons
8. Cuddapah basinDharwar Craton
9. Kaladgi basinDharwar Craton
10. Bhima basinDharwar Craton
Tectonic map of India showing distribution
of Purana basins, including
Vindhyan (V), Chhattisgarh (Ch), Khariar (K),
Indravati (I), Pranhita-Godavari (PG),
Cuddapah (Cu) and Kaladgi-Bhima (KBB)
basins. After Rao & Reddy (2002)
Tectonic map of India showing the distribution of Purana basins, including Vindhyan (V), Chhattisgarh (Ch), Khariar (K), Indravati (I), Pranhita-Godavari (PG), Cuddapah (Cu) and Kaladgi-Bhima (KBB) basins. After Rao & Reddy (2002)

Palaeoproterozoic Basins

1. Bijawar Basin (1700-1800 Ma)

  • Location: Bundelkhand Craton
  • Extent: Trends ENE-WSW for about 100 km with a width of 4 to 20 km from Ken River in the east to Sonari in the west.
  • Geological Setting: Sandwiched between Bundelkhand granite and Vindhyan sediments.
Bijawar Group
Karri SandstoneGangau Subgroup
Hirapur PhosphoriteGangau Subgroup
Malehra Chert BrecciaMoli Subgroup
Pukhra SandstoneMoli Subgroup
Dargawan SillMoli Subgroup
Bajno DolomiteMoli Subgroup
Bhusor BasaltMoli Subgroup
Kawar ConglomerateMoli Subgroup

2. Sonari Basin

  • Location: Bundelkhand Craton
  • Extent: 28 km long and 5 km wide, EW trending, situated to the west of the ‘type’ Bijawar basin.
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3. Harda Inlier

  • Location: Bundelkhand
  • Exposure: Exposed at Harda within the Vindhyan succession and Deccan Trap of Narmada valley.

4. Gwalior Basin

  • Location: Extends E-W for 80 km with a width of 25 km, near Gwalior to the north of Bundelkhand granite, almost 200 km NW of Bijawar basin.

5. Abujhmar Basin

  • Location: Named for ‘abujh mar’ or ‘unknown hills’ in the remote Bansal region.
  • Extent: Covers an area of 3000 sq. km.
Abujhmar GroupMaspur Basalt (with gabbro/dolerite sills and dykes)
Gundul Formation
Unconformity
Nandgaon, Bailadila, and Sukma Groups with surrounding gneisses/granites

Vindhyan Basin

The Vindhyan Basin is the largest single Purana basin, spectacularly sickle-shaped, and ENE trending. It is situated on the Bundelkhand craton and is named after the Vindhya Mountains. The basin is bounded by the Great Boundary Fault (GBF) in the northwest and the Son Narmada Lineament in the south. The Vindhyan Basin is well known for its diamonds, dolomite limestone, building stones, and glass sands.

Stratigraphy

The basin includes four groups in succession:

  • Semri Group: Marine slope-shelf environment (3000-4000m)
  • Kaimur Group: Lagoonal environment (400m)
  • Rewa Group: Fluvial-deltaic environment (100-300m)
  • Bhander Group: Fluvial-deltaic environment (1300-1500m)
READ ALSO  The Bastar Craton

Major Structure

The major structure of the basin is a synclinorium with the axis curving along the middle of the sickle-shaped basin.

Dating

Recent robust dating has fixed the beginning of Vindhyan sedimentation around 1600-1720 Ma. It is also known as the upper Purana.

Life

Stromatolites are abundant in the Vindhyan record, but they have a long time range and hence have only limited correlative value. Stromatolites are found in formations like Fawn Limestone, Khajrat Limestone, Rohtas (Semri), and Lakheri Limestone (Bhander).

Rock Types and Sedimentation

Chief rock types are shales, limestone, and sandstone, predominantly of shallow water origin. The upper Vindhyan sequences are fluvial in origin, whereas the lower Vindhyan sequences are marine and thicker.

Stratigraphy of vindhyan supergroup
Proterozoic Sedimentary Basins (Purana Basins) of India: Geology, Stratigraphy, and Evolution of the Vindhyan Basin 4
Geological Map of Vindhyan Basin
Geological Map of Vindhyan Basin

Responses

CSIR NET Exam: EARTH, ATMOSPHERIC, OCEAN AND PLANETARY SCIENCES

Exam Pattern: EARTH, ATMOSPHERIC, OCEAN AND PLANETARY SCIENCES 

 PART APART BPART CTOTAL
Total questions205080150
Max No. of Questions to attempt15352575
Marks for each correct answer224200
Marks for each incorrect answer (Negative marking for part A & B is @ 25%, and part C is @ 33%)0.50.51.32

The candidate is required to answer a maximum of 15, 35, and 25 questions from Part-A, Part-B, and Part-C, respectively. If more than the required number of questions are answered, only the first 15, 35, and 25 questions in Part A, Part B, and Part C, respectively, will be taken up for evaluation.

Below each question in Part A, Part B, and Part C, four alternatives or responses are given. Only one of these alternatives is the “correct” option to the question. The candidate has to find, for each question, the correct or the best answer.

Syllabus

EARTH, ATMOSPHERIC, OCEAN AND PLANETARY SCIENCES

PAPER I (PART B)

  1. The Earth and the Solar System

    • Milky Way and the solar system.
    • Modern theories on the origin of the Earth and planetary bodies.
    • Earth’s orbital parameters, Kepler’s laws of planetary motion.
    • Geological Time Scale; space and time scales of processes in the solid Earth, atmosphere, and oceans.
    • Radioactive isotopes and their applications.
    • Meteorites: chemical composition and primary differentiation of the Earth.
    • Basic principles of stratigraphy.
    • Theories about the origin of life and fossil records.
    • Earth’s gravity, magnetic fields, and thermal structure: Geoid and spheroid concepts; Isostasy.
  2. Earth Materials, Surface Features, and Processes

    • Gross composition and physical properties of important minerals and rocks.
    • Properties and processes responsible for mineral concentrations.
    • Distribution of rocks and minerals in Earth’s units and India.
    • Physiography of the Earth; weathering, erosion, and soil formation.
    • Energy balance of Earth’s surface processes.
    • Physiographic features and river basins in India.
  3. Interior of the Earth, Deformation, and Tectonics

    • Basic concepts of seismology and Earth’s internal structure.
    • Physico-chemical and seismic properties of Earth’s interior.
    • Stress and strain concepts; rock deformation.
    • Folds, joints, and faults; causes and measurement of earthquakes.
    • Interplate and intraplate seismicity; paleomagnetism.
    • Sea-floor spreading and plate tectonics.
  4. Oceans and Atmosphere

    • Hypsography of continents and ocean floors: continental shelves, slopes, abyssal plains.
    • Physical and chemical properties of seawater; residence times of elements.
    • Ocean currents, waves, tides, thermohaline circulation, and conveyor belts.
    • Major water masses, biological productivity, and fluid motion.
    • Atmospheric structure and heat budget; greenhouse gases and global warming.
    • General circulation, monsoon systems, ENSO, cyclones, and local systems in India.
    • Marine and atmospheric pollution, ozone depletion.
  5. Environmental Earth Sciences

    • Properties of water and the hydrological cycle.
    • Energy resources: uses, degradation, alternatives, and management.
    • Ecology, biodiversity, and natural resource conservation.
    • Natural hazards and remote sensing applications.

PAPER I (PART C)

I. Geology

  1. Mineralogy and Petrology

    • Point group, space group, and lattice concepts.
    • Crystal field theory, mineralogical spectroscopy, and bonding in mineral structures.
    • Genesis, properties, and crystallization of magmas.
    • Metamorphic structures, textures, and thermobarometry.
    • Petrogenesis of Indian rock suites: Deccan Traps, charnockites, ophiolites, and more.
  2. Structural Geology and Geotectonics

    • Stress and strain analysis; Mohr circles.
    • Geometry and mechanics of folds, faults, and ductile shear zones.
    • Plate boundaries, mantle plumes, and Himalayan orogeny.
  3. Paleontology and Applications

    • Life origin theories, evolution models, and mass extinctions.
    • Applications of fossils in age determination, paleoecology, and paleogeography.
    • Micropaleontology in hydrocarbon exploration.
  4. Sedimentology and Stratigraphy

    • Classification of sediments and sedimentary rocks.
    • Sedimentary environments and basin evolution.
    • Stratigraphic principles, correlation methods, and sequence stratigraphy.
    • Phanerozoic stratigraphy of India.
  5. Marine Geology and Paleoceanography

    • Ocean floor morphology, ocean circulation, and thermohaline processes.
    • Factors influencing oceanic sediments and paleoceanographic reconstruction.
  6. Geochemistry

    • Atomic properties, periodic table, thermodynamics of reactions, and isotopes in geochronology.
    • Applications of stable isotopes in Earth processes.
  7. Economic Geology

    • Ore formation processes, mineral deposit studies, and petroleum geology.
    • Coal and unconventional energy resources.
  8. Precambrian Geology and Crustal Evolution

    • Evolution of Earth systems and Precambrian characteristics of India.
    • Precambrian–Cambrian boundary.
  9. Quaternary Geology

    • Quaternary stratigraphy, climate variability, and human evolution.
    • Dating methods and tectonic geomorphology.
  10. Applied Geology

  • Remote sensing and GIS.
  • Engineering properties of rocks; construction investigations.
  • Methods of mineral exploration and groundwater studies.

II. Physical Geography

  1. Geomorphology: Landform processes, DEM analysis, extraterrestrial geomorphology.
  2. Climatology: Radiation balance, wind systems, ENSO, and climate classification.
  3. Biogeography: Plant and animal associations, Indian biogeography, and conservation.
  4. Environmental Geography: Man-land relationships, hazards, and ecological balance.
  5. Geography of India: Physical geography, climatology, agriculture, and population characteristics.

III. Geophysics

  1. Signal Processing: Fourier transforms, filters, and signal analysis.
  2. Field Theory: Newtonian potential, Green’s theorem, and seismic wave propagation.
  3. Numerical Analysis and Inversion: Least squares, optimization, and pattern recognition.
  4. Gravity and Magnetic Methods: Data interpretation and anomaly analysis.
  5. Seismic Methods: Ray theory, reflection/refraction techniques, seismic stratigraphy.
  6. Well Logging: Techniques for lithology, porosity, and fluid saturation interpretation.

(IV) METEOROLOGY

1) Climatology

  • Same as under Geography.

2) Physical Meteorology

  • Thermal Structure of the Atmosphere and Its Composition.
  • Radiation:
    • Basic laws – Rayleigh and Mie scattering, multiple scattering.
    • Radiation from the sun, solar constant, effect of clouds, surface and planetary albedo.
    • Emission and absorption of terrestrial radiation, radiation windows, radiative transfer, Greenhouse effect, net radiation budget.
  • Thermodynamics of Dry and Moist Air:
    • Specific gas constant, adiabatic and isentropic processes, entropy and enthalpy.
    • Moisture variables, virtual temperature, Clausius–Clapeyron equation.
    • Adiabatic processes of moist air, thermodynamic diagrams.
  • Hydrostatic Equilibrium:
    • Hydrostatic equation, variation of pressure with height, geopotential, standard atmosphere, altimetry.
  • Vertical Stability of the Atmosphere:
    • Dry and moist air parcel and slice methods, tropical convection.
  • Atmospheric Optics:
    • Visibility and optical phenomena – rainbows, haloes, corona, mirage, etc.

3) Atmospheric Electricity

  • Fair weather electric field in the atmosphere and potential gradients.
  • Ionization in the atmosphere, electrical fields in thunderstorms.
  • Theories of thunderstorm electrification, structure of lightning flash, mechanisms of earth-atmospheric charge balance, and the role of thunderstorms.

4) Cloud Physics

  • Cloud classification, condensation nuclei, growth of cloud drops and ice-crystals.
  • Precipitation mechanisms: Bergeron–Findeisen process, coalescence process.
  • Precipitation of warm and mixed clouds, artificial precipitation, hail suppression, fog and cloud dissipation.
  • Radar observation of clouds and precipitation:
    • Radar equation, rain drop spectra, radar echoes of hailstorms, tornadoes, hurricanes, and rainfall measurements.

5) Dynamic Meteorology

  • Basic Equations and Fundamental Forces:
    • Pressure, gravity, centripetal and Coriolis forces.
    • Continuity and momentum equations (Cartesian and spherical coordinates).
    • Scale analysis, inertial flow, geostrophic and gradient winds, thermal wind.
    • Divergence and vertical motion, Rossby, Richardson, Reynolds, and Froude numbers.
  • Atmospheric Turbulence:
    • Mixing length theory, planetary boundary layer equations, Ekman layer, eddy transport of heat, moisture, and momentum.
  • Linear Perturbation Theory:
    • Internal and external gravity waves, inertia waves, gravity waves, Rossby waves, wave motion in the tropics, barotropic and baroclinic instabilities.
  • Atmospheric Energetics:
    • Kinetic, potential, and internal energies; conversion into kinetic energy; available potential energy.

6) Numerical Weather Prediction (NWP)

  • Computational instability, filtering of sound and gravity waves.
  • Filtered forecast equations, barotropic and baroclinic models.
  • Objective analysis, data assimilation techniques, satellite applications in NWP.

7) General Circulation and Climate Modelling

  • Observed zonally symmetric circulations, meridional circulation models.
  • General circulation modelling principles: grid-point and spectral GCMs.
  • Climate variability phenomena: ENSO, QBO, MJO, etc.
  • Ocean-atmosphere coupled models.

8) Synoptic Meteorology

  • Weather observations and transmission, synoptic charts.
  • Synoptic weather forecasting, prediction of weather elements, and hazardous weather phenomena.
  • Tropical Meteorology:
    • ITCZ, monsoons, tropical cyclones, jet streams.
  • Extra-Tropical Features:
    • Jet streams, extratropical cyclones, anticyclones.
  • Air masses and fronts: sources, classification, frontogenesis, and associated weather.

9) Aviation Meteorology

  • Meteorological role in aviation, weather hazards during takeoff, cruising, and landing.
  • In-flight hazards: icing, turbulence, visibility issues, gusts, wind shear, thunderstorms.

10) Satellite Meteorology

  • Polar orbiting and geostationary satellites.
  • Applications in identifying synoptic systems, cyclones, temperature estimation, rainfall prediction, and temperature/humidity soundings.

(V) OCEAN SCIENCES

1) Physical Oceanography

  • T-S diagrams, mixing processes, characteristics of water masses.
  • Wind-generated waves, shallow and deep-water wave dynamics.
  • Coastal processes: wave reflection, refraction, diffraction, littoral currents, rip currents, tsunami, and more.
  • Ocean Circulation:
    • Global conveyor belt circulation, Ekman’s theory, upwelling processes.

2) Chemical Oceanography

  • Composition of seawater, chemical exchanges, and classification of elements.
  • Element chemistry under special conditions (estuaries, vents, etc.).
  • Carbonate chemistry, biological pumps, and sedimentary deposit factors.

3) Geological Oceanography

  • Topics as listed under “Marine Geology & Paleoceanography.”

4) Biological Oceanography

  • Classification of marine environments and organisms.
  • Primary and secondary production, factors affecting biodiversity.
  • Human impacts on marine communities and climate change effects.

 

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