Chapter 3: Marine Provinces

Essential of Oceanography

Table of Contents

Chapter Overview

  • The study of bathymetry determines ocean depths and ocean floor topography.
  • Echo sounding and satellites are efficient bathymetric tools.
  • Most ocean floor features are generated by plate tectonic processes.
  • Different sea floor features exist in different oceanographic locations.

Bathymetry

  • Measures the vertical distance from the ocean surface to mountains, valleys, plains, and other sea floor features

Measuring Bathymetry

  • Soundings
    – Poseidonus made first sounding in 85 B.C.
    – Line with heavy weight
    – Sounding lines used for 2000 years
  • Fathom
    – Unit of measure
    – 1.8 meters (6 feet)
  • HMS Challenger
    – Made first systematic measurements in 1872
  • Deep ocean floor has relief
    – Variations in sea floor depth
  • Echo Soundings
    – Echo sounder or fathometer
    – Reflection of sound signals
    – German ship Meteor identified mid-Atlantic
    ridge in 1925
  • Lacks detail
  • May provide inaccurate view of sea floor
Echo Soundings
Echo Soundings
  • Precision Depth Recorder (PDR)
    – 1950s
    – Focused high-frequency sound beam
    – First reliable sea floor maps produced
    – Helped confirm sea floor spreading

Modern Bathymetry Measuring

  • Multibeam Echo
    Sounders
    – Multiple simultaneous sound frequencies
  • Seabeam
    – First multibeam echo sounder
    – Map sea floor strips up to 60 km (37 mi) wide
  • Sonar
    – Sound navigation and ranging acronym
  • Side scan sonar
    – GLORIA (Geological Long-range Inclined Acoustical instrument)
    – Sea MARC (Sea Mapping and Remote Characterization)
  • Can be towed behind ship to provide very detailed bathymetric strip map
READ ALSO  Chapter 8 Lecture Waves and WaterDynamics

GLORIA Side Scanning Sonar

Sea Floor Mapping from Space

  • Uses satellite measurements
  • Measures sea floor features based on gravitational bulges in sea surface
  • Indirectly reveals bathymetry
  • Satellite-derived cean surface gravity
  • Reveals bathymetry where ships have not conducted research

Seismic Reflection Profiles

  • Air guns
  • Strong, low-frequency sounds
  • Details ocean structure beneath sea floor

Hypsographic Curve

  • Shows relationship between height of land and depth of ocean
  • 70.8% of Earth covered by oceans
  • Average ocean depth is 3729 meters
  • Average land elevation is 840 meters
  • Uneven distribution of areas of different depths/elevations
  • Variations suggest plate tectonics at work

Ocean Provinces

  • Three Major Provinces
  1. Continental margins
    –Shallow-water areas close to shore
  2. Deep-ocean basins
    – Deep-water areas farther from land
  3. Mid-ocean ridge
    –Submarine mountain range

Continental Margins

  • Passive
    – Not close to any plate boundary
    – No major tectonic activity
    – East coast of United States
  • Active
    – Associated with convergent or transform plate boundaries
    – Much tectonic activity

Active Continental Margins

  • Convergent Active Margin
    – Oceanic-continent convergent plate boundaries
    – Active continental volcanoes
    – Narrow shelf
    – Offshore trench
    – Western South America
  • Transform Continental Margin
    – Less common
    – Transform plate boundaries
    – Linear islands, banks, and deep basins close
    to shore
    – Coastal California along San Andreas Fault

Continental Margin Features

  • Continental shelf
  • Shelf break
  • Continental slope
  • Continental rise

Continental Shelf

  • Flat zone from shore to shelf break
    – Shelf break is where marked increase in slope angle occurs.
  • Geologically part of continent
  • Average width is 70 km (43 miles) but can extend to 1500 km (930 miles)
  • Average depth of shelf break is 135 meters (443 feet).
  • Type of continental margin determines shelf features.
  • Passive margins have wider shelves.
  • California’s transform active margin has a continental borderland.

Continental Slope

  • Where deep ocean basins begin
  • Topography similar to land mountain ranges
  • Greater slope than continental shelf
    – Averages 4° but varies from 1–25° gradient
  • Marked by submarine canyons

Submarine Canyons

  • Narrow, deep, V-shaped in profile
  • Steep to overhanging walls
  • Extend to base of continental slope, 3500 meters (11,500 feet) below sea level
  • Carved by turbidity currents
Turbidity Currents
  • Underwater avalanches mixed with rocks and other debris
  • Sediment from continental shelf
  • Moves under influence of gravity
  • Sediments deposited at slope base

Continental Rise

  • Transition between continental crust and oceanic crust
  • Marked by turbidite deposits from turbidity currents
  • Graded bedding in turbidite deposits
  • Deposits generate deepsea fans, or submarine fans
  • Distal ends of submarine fans become flat abyssal plains

Abyssal Plains

  • Extend from base of continental rise
  • Some of the deepest, flattest parts of Earth
  • Suspension settling of very fine particles
  • Sediments cover ocean crust irregularities
  • Well-developed in Atlantic and Indian oceans

Abyssal Plain Volcanic Peaks

  • Poke through sediment cover
  • Below sea level:
    – Seamounts, tablemounts, or guyots at least
    1 km (0.6 mile) above sea floor
    – Abyssal hills or seaknolls are less
    than 1 km (0.6 mile) above sea floor
  • Above sea level:
    – Volcanic islands

Ocean Trenches and Volcanic Arcs

  • Convergent margins generate ocean
    trenches.
    – Deepest part of oceans
    – Most in Pacific Ocean
    – Deepest trench – Mariana Trench at
    11,022 meters (36,161 feet)

Island and Continental Arcs

  • Volcanic arc on nonsubducted ocean plate
  • Island arc
    – Islands in ocean
    – Japan
  • Continental arc
    – Mountains on land
    – Andes Mountains

Pacific Ring of Fire

  • Margins of Pacific Ocean
  • Majority of world’s active volcanoes and
    earthquakes
  • Marked by convergent boundaries

Mid-Ocean Ridge

  • Longest mountain chain
  • On average, 2.5 km (1.5 miles) above
    surrounding sea floor
  • Volcanic
  • Basaltic lava
  • Divergent plate boundary

Mid-Ocean Ridge Features

  • Rift Valley
    – Downdropped area on crest of ridge
    – Marked by fissures and faults
    – Small earthquakes
  • Seamounts – tall volcanoes
  • Pillow lava or pillow basalt – shapes formed when hot basaltic lava quickly cools
  • Hydrothermal Vents
  • Sea floor hot springs
  • Foster unusual deep-ocean ecosystems able to survive without sunlight

Hydrothermal Vents

  • Warm water vents – temperatures below 30°C (86°F)
  • White smokers – temperatures from 30–350°C (86–662°F)
  • Black smokers – temperatures above 350°C (662°F)

Fracture Zones and Transform Faults

  • Transform faults along mid-ocean ridge offset spreading zones.
    – Linear ridge on spherical Earth
    – Seismically active
  • Fracture zones along Pacific Ocean midocean rise
    – Seismically inactive
    – Occur beyond offset fragments of rise

Comparison Between Transform Faults and Fracture Zones

Fracture Zones and Transform Faults

Fracture Zones and Transform Faults
Fracture Zones and Transform Faults

Oceanic Islands

  • Volcanic activity
  • Hotspots
  • Island arcs
  • Islands that are part of continents

Reference: All images and content are taken from Essentials of Oceanography by Alan P. Trujillo and Harold V. Thurman, 12th Edition.

Leave a Reply

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.

 

How Study Hub Can Help You Prepare for the Earth, Atmospheric, Ocean, and Planetary Sciences Syllabus

Preparing for the extensive and demanding syllabus of Earth, Atmospheric, Ocean, and Planetary Sciences (702) requires a strategic approach and access to comprehensive study resources. Study Hub (accessible at studyhub.net.in) offers unparalleled support to help candidates excel in this challenging domain. Here’s how Study Hub can guide your preparation:


Comprehensive Coverage of Topics

At Study Hub, we provide in-depth study materials, mock tests, and curated articles to help candidates grasp even the most complex topics. Our resources are designed to address every aspect of the syllabus, including:

  1. Meteorology: Understand critical concepts like the thermal structure of the atmosphere, radiative transfer, vertical stability, numerical weather prediction, general circulation and climate modelling, and the role of satellite meteorology in observing weather systems such as cyclones, monsoons, and thunderstorms.

  2. Ocean Sciences: Dive into topics such as physical oceanography, chemical oceanography, geological oceanography, and biological oceanography. Study Hub’s resources emphasize key aspects like upwelling processes, estuarine circulation, ocean eddies, Ekman theory, and global conveyor belt circulation—helping you understand the intricate processes of ocean systems.

  3. Atmospheric Dynamics and Energetics: Through articles, conceptual guides, and practice questions, candidates gain a strong grasp of fundamental equations, vorticity, geostrophic winds, Rossby waves, atmospheric turbulence, and barotropic and baroclinic instabilities.

  4. Planetary Sciences: Our expertly crafted content helps students explore planetary structures, processes, and phenomena with precision, complementing other topics under Earth Sciences for an interdisciplinary understanding.


Mock Tests and Evaluation Framework

We align our mock tests and sample papers with the pattern of the Earth Sciences examination:

  • Objective Analysis for Numerical Weather Prediction (NWP): Test your knowledge of filtered forecasting models and data assimilation techniques.
  • Synoptic Meteorology Practices: Work on real-world weather data and forecast exercises involving tropical cyclones, ITCZ systems, monsoon depressions, and jet streams.
  • Topic-specific tests ensure mastery in areas like atmospheric optics, biochemical nutrient cycling, and the impact of human activities on ecosystems.

Why Study Hub is the Perfect Partner for Your Earth Sciences Preparation

  1. Academic Rigor: Study Hub maintains an academic tone throughout its resources, ensuring in-depth coverage of essential keywords such as radiative budget, MJO (Madden-Julian Oscillation), Quasi-Biennial Oscillation (QBO), and ENSO phenomena.
  2. Focused on Practical Applications: Be it radar observations, wave refraction techniques, or the impact of anthropogenic inputs on marine biodiversity, we emphasize the practical relevance of each topic for better comprehension.
  3. Adaptive Materials: From simple T-S diagrams to advanced topics like geopotential variation and numerical baroclinic models, we tailor our resources to match both beginner and advanced levels of understanding.
Scroll to Top