SlideShare a Scribd company logo
Topography and sediments
of the floor of the
Bay of Bengal
Submitted By:
Md Hasan Tareq
Dept. of Oceanography
Noakhali Science and Technology University
Content
1. Overview
2. Origin/Evolution of Bay of Bengal
3. Bottom Topography
4. Topographic Features
5. BengalDeep SeaFan (BDSF) with morphologicalfeatures
6. Sediments in the Bay of Bengal
7. Sediment DepositionandTransport
8. Sediment Distribution Patterns
9. Tectonic Activity
10. Marine Life andSediment Interactions
11. GeohazardsandSeabedStability
12. Summary
Overview
01
Bottom Topography
02
Bengal Deep Sea Fan (BDSF)
Largesedimentary feature formedby
the depositionof sediment carriedby
the Ganges-BrahmaputraRiver systemin the
Bay of Bengal.
03
Sediments
consist of variousparticlesand
debrisaccumulatedover time,
includingminerals, organic
matter, andremnantsof marine
life.
04
Origin/ Evolution
shapedby geologicalprocesses
andtectonicforcesactingover
millionsof years
Underwater terrainor
landscapeof the oceanfloor
What is Origin and
Evolution?
Origin refers to the beginning or
creation of something,
While evolution denotes that
entity's gradual development
and transformation over time.
Origin/Evolution of the Bay of Bengal
The Bay of Bengal is a relatively young geological feature with a complex evolution over
millions of years. Plate tectonics and various geological processes can explain its origin and
development.
• Formation of Gondwanaland: Around 300 million years ago, the supercontinent
Gondwanaland began to break apart due to tectonic movements. This breakup
eventually led to the separationof the Indian Plate from Antarctica andAustralia.
• Rifting and Seafloor Spreading: Approximately 180 to 150 million years ago, during
the Mesozoic era, the Indian Plate drifted northwards, causing seafloor spreading in the
Tethys Ocean, whichwas situated between Gondwanaland andLaurasia.
• Collision with the Eurasian Plate: Around 50 million years ago, the Indian Plate
began to collide with the Eurasian Plate. This collision initiated the closure of the
Tethys Ocean andledto the formationof the Himalayanmountainrange.
• During the Tertiary period (approximately 65 to 2.6 million years ago), the Indian Plate
moved northward and pushed against the Eurasian Plate. This tectonic activity led to the
forming tray basin, whichlater evolved into the Bay of Bengal.
• Over millions of years, sediment erosion from the rising Himalayas and surrounding
landmasses filled the basin, with major rivers like the Ganges, Brahmaputra, and
Irrawaddy playing a significant role in sediment transport and deposition in the Bay of
Bengal.
• Late Cenozoic Changes: During the Late Cenozoic era (approximately 25 to 2.6 million
years ago), further tectonic movements and changes in sea level continued to shape the
Bay of Bengal's topography andsedimentary deposition.
• Modern Configuration: The modern configuration of the Bay of Bengal took shape over
the last few million years, with the continued influence of tectonic processes and
sedimentation fromrivers.
Origin/Evolution of the Bay of Bengal cont.
Size and shape of the Bay of Bengal
• Location: South Asia
andSoutheast Asia
• Area: 2,172,000 square
kilometers (839,000 sq
mi)
• Average depth 2,600m
(8,500 ft)
• Shape is generally
triangular, with the
northern boundary
Topographic Features
• The Continental Shelf width of the continental shelf off the coast of Bangladesh varies
considerably. It is less than 100 km off the south coast between Hiron Point and the
swatchof no groundandmore than250 km off the coast of Cox’s Bazar.
• The continental shelf is a shallow, gently sloping underwater area extending from the
coastline to deeper oceanic waters.
• Deep Oceanic Trenches: The northern and eastern boundaries of the Bay of Bengal
are marked by deep oceanic trenches, such as the Sunda Trench and the Andaman
Trench.
• Sedimentary Plains: The bay's floor is covered by extensive sedimentary plains, which
are the result of the accumulation of sediments carried by significant rivers like the
Ganges, Brahmaputra, and Irrawaddy. These sediments contribute to the formation
of vast delta regions.
Topography refers to the physical features
and elevation of the Earth's surface, including
mountains, valleys, hills, plains, and other
landforms.
It provides a detailed description of the shape,
height, and relief of the terrain in a given area,
both on landandunder the ocean.
What is
Topography?
Bottom Topography
• It is characterised by a broad U-shaped
basin with its south opening to the Indian
Ocean.
• A thick uniform abyssal plain occupies
almost the entire Bay of Bengal, gently
sloping southwardat an angle of 8°-10°.
• In many places, underwater valleys dissect
thisplainmass.
• Continental Slope: The transition between the continental shelf and the deep ocean
floor is known as the continental slope. The steeper region marks the beginning of the
deeper oceanicbasin.
• Submarine Canyons and Channels: Along the eastern boundary of the bay, some
underwater canyons and channels have been carved by sediment transport and turbidity
currents. These featurescreate ruggedandsteepslopes in certainareas
• Coral Reefs: Some areas within the Bay of Bengal host coral reefs, particularly in the
Andaman and Nicobar Islands. These reefs are critical marine ecosystems and support rich
biodiversity.
Topographic Features cont.
What is
Deep-sea Fan?
A deep-sea fan is a fan-shaped
sediment deposit formedby
turbidity currents andlocatedin
submarine canyons or basinplains
on the ocean floor.
Bengal Deep Sea Fan (BDSF)
• The BDSF isa cone or fan-shapedsediment deposit in the N-E part of the Bay of
Bengal.
• The fan extendsfrom approx. 20°N to 10°S latitude.
• The avg. Length is3000 km andwidth of 1445 km.
• The avg. Elevation of the fan is1400 m.
• Thisisthe largest deep-sea fan in the world, 2.8-3.0 × 106 sq. km.
• The fan post datesin the collisionof the Indianplate with the Eurasianplate & uplift
of the ancestral Himalaya at the endof the Paleocene.
• Underlying the fan, the continental rise sediments up to 20 km thick.
• The gently slopingfan isalmost even a gradient of 1.5 m/km.
• Many anastomosing channels crossit with low levees on the side.
Bengal Deep Sea Fan (BDSF) cont.
• The gently sloping plain extending for 2000 km from the slope base of the
Ganges-Brahmaputra delta to the far south of Srilanka isunique.
• Surface of BDSF is smooth. Based on the valley gradient can be divided into 3 parts
:
a. Upper fan - valley gradient 2.3 m/km
b. Middle fan - Valley gradient 1.68 m/km
c. Lower fan - Valley gradient < 1 m/km
Morphological features of BDSF
1. The Swatch of No Ground(SoNG)/GangesTrough.
2. The 90 East Ridge.
3. Leveesandabandonedchannels
4. Offshore islands– Bhola, Kutubdia, St. Martin Island
Swatch of No Ground (SoNG)/ Ganges Trough
• In the northern Bay of Bengal are deep valleys, with one notable valley called the
"Swatch of No Ground" crossing the shelf diagonally in a south-westerly direction.
Swatch of No Ground (SoNG)/ Ganges Trough cont.
• The Ganges trough, characterized by a comparatively flat floor (5-7 km wide) and walls
with approximately 10° inclination, lies at the edge of the shelf, with a depth of about
1200m.
• As indicated by Coleman (1969), the bars and channels of the mouth of the combined
river point towards this trough and undoubtedly allow sediments to be carried into the
headof the trough.
• This explains why delta and bars are not being built seaward, despite the enormous load
of sedimentscoming to the seaat thislocality.
Ninety East Ridge/ 90°E Ridge
• The NER (Naturaliste–Esperance Ridge) is an elongated volcanic ridge in the eastern Indian
Ocean, stretching approximately 5200 km from 30°S (intersecting Broken Ridge) to
around 17°N (beneath the Bengal Deep Sea Fan). It divides the Bengal Deep Sea Fan into
two parts: the mainBengal fan andthe Nicobar fan in the east.
• This ridge rises about 2-3 km above the surrounding seafloor, with a width varying
between 150 to 250 km, making it the world's longest straight ridge.
• The formation of NER is attributed to magmatism associated with the deep-seated
Kerguelen mantle plume, as the Indian plate rapidly drifted northward during the Late
Cretaceous.
• Drilling results revealed that the rocks on the NER become progressively younger from
north to south. The ridge's age is estimated to be around 40 million in the south and
approximately 80 million in the north.
Levees and abandoned channels
• Abandoned Channel
A former stream channel through which water
no longer flows (e.g., a cut-off).
• Levees
A ridge of sediment is deposited naturally
alongside a river by overflowingwater.
St. Martin’s Island (Coral Island)
• St. Martin’s Island is the only coral island in
Bangladesh.
are small particles of solid material, such as
sand, silt, and clay, that are transported and
deposited by water, wind, or ice,
accumulating in layers over time.
Sediments
Sediments in the Bay of Bengal
The sedimentary section in the Bay of Bengalisdivided into two parts:
1. Eocene through Holocene, sediments and sedimentary rocks which post-date the
initialIndia-Asiacollision:
• volume = 12.5 x 106 km3; mass = 2.88 x 1016 t;
• this is most of the Bengal Fan, including its eastern lobe, the Nicobar Fan, plus some of
the outer BengalDelta.
2. Early Cretaceous through Paleocene, pre-collision sedimentary and
metasedimentary rocks:
• volume = 4.36x 106 km3; mass = 1.13 to 1.18 X 1016t;
• these are interpreted ascontinentalrise andpelagicdeposits
Sediments of the floor of the Bay of Bengal
• Terrigenous Deposits The Bay of Bengal sediments are predominantly
terrigenous, consisting of clayey silt and silty clay, transported by the Ganges-
Brahmaputra-Meghna rivers and other major rivers from the Himalayas,
amounting to over a billiontonnesannually.
• Turbidites: Unveiling Deep-Sea Sediments: Deep-sea sediments in the Bay of
Bengal are mainly diverse Turbidites, confirmed through the analysis of core samples
from the Deep Sea Drilling Program (DSDP) and Ocean Drilling Program
(ODP).
• Biogenous sediments like Calcareous Clays and Oozes are abundant near the
Andaman and Nicobar Islands and atop the Ninety East Ridge, while the organic
matter content in the continental-shelf sediment of the northern part of the east
coast isrelatively low compared to the globalaverage for near-shore sediments.
Sediments of the floor of the Bay of Bengal cont.
• Chemogenous sediments in the Bay of Bengal include authigenic green clays
(glaucony and verdine facies), phosphorites, ferromanganese nodules, and
hydrothermal and organic-rich sediments. While sparse, their distribution and origin in
the regionhave been identified.
• Volcanogenic components in Bay of Bengal
sediments from Cretaceous to Recent
periods. Cretaceous sediments contain
volcanogenic Smectite, likely originating from
Rajmahal Traps, while cores from the Ninety
East Ridge reveal abundant volcanogenic
sediments over basaltic basement.
Sediment Deposition and Transport
Sediment Transport Processes in the Bay of Bengal:
• Monsoon Currents: The Bay of Bengal experiences seasonal monsoon winds, which
play a significant role in sediment transport. During the southwest monsoon (June to
September), strong onshore winds blow from the Indian Ocean, pushing surface
waterstowardsthe coast.
• Tidal Currents: Tides are another crucial factor influencing sediment transport in the
Bay of Bengal. Tidal currents occur due to the gravitational pull of the moon and the
sun.
• River Discharge: The discharge of sediments from major rivers, such as the Ganges,
Brahmaputra, and Meghna, contributes significantly to sediment transport in the Bay
of Bengal.
• Ocean Circulation, Storm Surges, Seafloor Topography also affects sediment
transport.
Sediment transport pathways Sediment deposition areas
Sediments Depositional Features and Distribution Patterns
• Coastal Sedimentation: Sediment deposition along the coast occurs due to the
influx of terrigenous sediments from the rivers, especially during the monsoon
season. The sediments carried by the rivers settle along the coastline, forming
mudflats, deltas, andestuaries.
• Continental Shelf Sediments: The continental shelf of the Bay of Bengal is a
significant area for sediment deposition. Terrigenous sediments brought by rivers are
spread across the shallow shelf regions, creating a vast depositional area.
Additionally, biogenous sediments and chemogenous sediments, such as
phosphorites and ferromanganese nodules, contribute to the shelf
sedimentation.
• Deep-Sea Fan Formation: The Bay of Bengal is renowned for its extensive deep-
sea fan formations. These fans are created by the deposition of sediments carried
by turbidity currents that flow down the continentalslope.
Sediments Distribution Patterns of the Bay of Bengal
refers to the movement and
interactions of Earth's lithospheric
plates, leading to processes such as
earthquakes, volcanoes, mountain
building, and oceanic crust
formation.
Tectonic
activity
Tectonic activity in the Bay of Bengal is driven by the movement of tectonic plates in the
region. The Bay of Bengal is part of the larger Indian Plate, which is surrounded by several
other tectonic plates, includingthe Eurasian Plate, Australian Plate, andBurma Plate.
• Subduction Zones: The eastern boundary of the Bay of Bengal is marked by subduction
zones, where the IndianPlate isconverging with the BurmaPlate andthe SundaPlate.
• Island Arcs: The subduction of the Indo-Australian Plate beneath the Eurasian Plate has
given rise to volcanicislandarcsin the western Bay of Bengal.
• Rift Zones: The western boundary of the Bay of Bengal is characterized by rift zones,
where the IndianPlate ispulling away from the AfricanPlate.
• Earthquakes: The interaction between tectonic plates in the Bay of Bengal region gives
rise to frequent seismicactivity, leading to earthquakes.
• Tsunamis: Tectonicactivity in the Bay of Bengalcanalsotrigger tsunamis.
Tectonic activity
Marine Life and Sediment Interactions in the Bay of Bengal
The Bay of Bengalisa biologically diverse andecologically richmarine region, where marine
life andsediment interactionsplay a crucialrole in shaping the ecosystem.
• Nutrient Enrichment: Terrigenoussediments, carriedby major rivers into the bay, are
richin nutrients like nitrogen andphosphorus.
• Coastal Mangroves and Wetlands: The depositionof sedimentsinthe coastalregions
createsideal conditionsfor mangrovesandwetlandsto thrive. These unique ecosystems
serve ascriticalhabitatsfor variousmarine species, acting asnurseriesfor juvenile fish
andproviding refuge for many migratory birds.
• Benthic Communities: Sedimentsonthe oceanfloor provide habitat for a diverse
range of benthic organisms, such asworms, mollusks, andcrustaceans.
• Coral Reefs: In areaswith clear andshallow waters, coralreefscanform.
• Sediment Dependent Fish Species: Some fishspeciesin the Bay of Bengalare
dependent onspecific sediment typesfor spawning andfeeding.
Geohazards and Seabed Stability
Geohazards in the context of the Bay of Bengal refer to natural phenomena or processes that
pose risks to human activities and infrastructure due to the region's geological
characteristics.
• Submarine Landslides: The steep underwater slopes and sediment accumulation in the
Bay of Bengal make it susceptible to submarine landslides, which can result in tsunamis
andaffect seabedstability.
• Cyclones and Storm Surges: The Bay of Bengal is prone to tropical cyclones and
associated storm surges. These weather events can cause significant erosion, sediment
transport, andsedimentation, impacting the stability of the seabed.
• Submarine Volcanoes: Some areas in the Bay of Bengal may host submarine volcanoes,
whichcanleadto the release of volcanic materialsandalter the seabed's stability.
Geohazards and Seabed Stability
• Sediment Mobilization: Heavy rainfall, river flooding, and coastal erosion can
mobilize large amounts of sediment, leading to sediment deposition and
reshaping of the seabed.
• Seafloor Subsidence and Uplift: Tectonic processes can cause seafloor
subsidence or uplift, altering the seabed's elevationandaffectingits stability.
Sediment properties play a critical role in influencing the stability of the
seafloor in variousmarine environments, including the Bay of Bengal.
• GrainSize
• ConsolidationandCompaction
• Shear Strength
• Cementation
• Presence of Organisms
• Sediment Load
• Presence of Gas
Summary
• The Bay of Bengal exhibits a diverse and complex topography on its seafloor,
characterized by deep trenches, abyssal plains, submarine canyons,
seamounts, andvolcanic ridges.
• The topography is influenced by tectonic processes, sediment accumulation from
the Himalayas, and river transport.
• The deep-sea fan in the Bay of Bengal is known as the "Bengal Deep Sea Fan." It is a
large sedimentary deposit formed by the accumulation of sediments eroded from the
Himalayasandtransportedby major riverslike the GangesandBrahmaputra.
• Sediments in the bay consist of a wide range of grain sizes, primarily eroded from the
rising Himalayasandtransportedby major rivers like the GangesandBrahmaputra.
• These sediments contribute to the formation of extensive sedimentary plains and
delta regions.
• The sediment distribution patterns in the Bay of Bengal are influenced by various
factors, includingriver inputs, oceancurrents, andseafloor topography.
• Tectonic activity in the Bay of Bengal is characterized by the ongoing movement and
interaction of tectonic plates, leading to geological processes such as subduction, seafloor
spreading, andcollision.
• The interaction of topography and sediments in the Bay of Bengal plays a crucial role
in shaping itsgeologicalandecologicalcharacteristics.
• Geohazards in the Bay of Bengal pose risks to human activities and infrastructure due to
its geologicalcharacteristics.
Summary cont.
Thank
You

More Related Content

What's hot

Channel Pattern (Fluvial Morphology).pdf
Channel Pattern (Fluvial Morphology).pdfChannel Pattern (Fluvial Morphology).pdf
Channel Pattern (Fluvial Morphology).pdf
Jannatul Ferdos
 
Formation of coastline
Formation of coastlineFormation of coastline
Formation of coastline
Pathan Farhan
 
Introduction to diagenesis
Introduction to diagenesisIntroduction to diagenesis
Introduction to diagenesis
Wajid09
 
Submarine canyons
Submarine canyonsSubmarine canyons
Submarine canyons
Prof. A.Balasubramanian
 
Fundamental and concept of environmental geology
Fundamental and concept of environmental geologyFundamental and concept of environmental geology
Fundamental and concept of environmental geology
Ghassan Hadi
 
Chemical oxygen demand. mujahid hussain
Chemical oxygen demand. mujahid hussainChemical oxygen demand. mujahid hussain
Chemical oxygen demand. mujahid hussain
mujahid hussain
 
Turbidity
TurbidityTurbidity
Turbidity
M.T.H Group
 
Principle of correlation and fossils
Principle of correlation and fossilsPrinciple of correlation and fossils
Principle of correlation and fossils
SYED NAWAZ
 
Marine sediments
Marine sediments Marine sediments
Marine sediments
Prof. A.Balasubramanian
 
Seawater and its properties
Seawater and its propertiesSeawater and its properties
Seawater and its properties
Prof. A.Balasubramanian
 
Foraminifera , micro fossil
Foraminifera , micro fossil Foraminifera , micro fossil
Foraminifera , micro fossil
University of Kerala
 
Lineation and foliation
Lineation and foliationLineation and foliation
Lineation and foliation
Pramoda Raj
 
Ocean sediments
Ocean sedimentsOcean sediments
Ocean sediments
Dedy Aslam
 
Deccan traps
Deccan trapsDeccan traps
Deccan traps
Pramoda Raj
 
Classification of sedimentary
Classification of sedimentaryClassification of sedimentary
Classification of sedimentary
V Binoy Chakma
 
Sea level changes
Sea  level changesSea  level changes
Sea level changes
AkhilAG23
 
Properties of sea water
Properties of sea waterProperties of sea water
Properties of sea water
Prof. A.Balasubramanian
 
Continental Margins
Continental MarginsContinental Margins
Continental Margins
PRasad PK
 
Structural and Geological Study of a part of the Chitradurga Schist Belt
Structural and Geological Study of a part of the Chitradurga Schist BeltStructural and Geological Study of a part of the Chitradurga Schist Belt
Structural and Geological Study of a part of the Chitradurga Schist Belt
Sai Bhaskar Reddy Nakka
 
Heavy minerals full paper
Heavy minerals full paperHeavy minerals full paper
Heavy minerals full paper
Vadde Ramesh
 

What's hot (20)

Channel Pattern (Fluvial Morphology).pdf
Channel Pattern (Fluvial Morphology).pdfChannel Pattern (Fluvial Morphology).pdf
Channel Pattern (Fluvial Morphology).pdf
 
Formation of coastline
Formation of coastlineFormation of coastline
Formation of coastline
 
Introduction to diagenesis
Introduction to diagenesisIntroduction to diagenesis
Introduction to diagenesis
 
Submarine canyons
Submarine canyonsSubmarine canyons
Submarine canyons
 
Fundamental and concept of environmental geology
Fundamental and concept of environmental geologyFundamental and concept of environmental geology
Fundamental and concept of environmental geology
 
Chemical oxygen demand. mujahid hussain
Chemical oxygen demand. mujahid hussainChemical oxygen demand. mujahid hussain
Chemical oxygen demand. mujahid hussain
 
Turbidity
TurbidityTurbidity
Turbidity
 
Principle of correlation and fossils
Principle of correlation and fossilsPrinciple of correlation and fossils
Principle of correlation and fossils
 
Marine sediments
Marine sediments Marine sediments
Marine sediments
 
Seawater and its properties
Seawater and its propertiesSeawater and its properties
Seawater and its properties
 
Foraminifera , micro fossil
Foraminifera , micro fossil Foraminifera , micro fossil
Foraminifera , micro fossil
 
Lineation and foliation
Lineation and foliationLineation and foliation
Lineation and foliation
 
Ocean sediments
Ocean sedimentsOcean sediments
Ocean sediments
 
Deccan traps
Deccan trapsDeccan traps
Deccan traps
 
Classification of sedimentary
Classification of sedimentaryClassification of sedimentary
Classification of sedimentary
 
Sea level changes
Sea  level changesSea  level changes
Sea level changes
 
Properties of sea water
Properties of sea waterProperties of sea water
Properties of sea water
 
Continental Margins
Continental MarginsContinental Margins
Continental Margins
 
Structural and Geological Study of a part of the Chitradurga Schist Belt
Structural and Geological Study of a part of the Chitradurga Schist BeltStructural and Geological Study of a part of the Chitradurga Schist Belt
Structural and Geological Study of a part of the Chitradurga Schist Belt
 
Heavy minerals full paper
Heavy minerals full paperHeavy minerals full paper
Heavy minerals full paper
 

Similar to Topography and sediments of the floor of the Bay of Bengal

Paleozoic era bb-Geomorhology Chapter
Paleozoic era bb-Geomorhology ChapterPaleozoic era bb-Geomorhology Chapter
Paleozoic era bb-Geomorhology Chapter
Kaium Chowdhury
 
TheSubmarineCanyons.pdf
TheSubmarineCanyons.pdfTheSubmarineCanyons.pdf
TheSubmarineCanyons.pdf
Yogesh Rm
 
TheSubmarineCanyons.pdf
TheSubmarineCanyons.pdfTheSubmarineCanyons.pdf
TheSubmarineCanyons.pdf
Yogesh Rm
 
Basinal distribution of Pakistan and Evolution
Basinal distribution of Pakistan and EvolutionBasinal distribution of Pakistan and Evolution
Basinal distribution of Pakistan and Evolution
MUHAMMAD QASIM JAVED
 
Geography oceanography optional material.pptx
Geography oceanography optional material.pptxGeography oceanography optional material.pptx
Geography oceanography optional material.pptx
vijayapriya2001p
 
Alluvial &amp; forming process in baangladesh
Alluvial &amp; forming process in baangladeshAlluvial &amp; forming process in baangladesh
Alluvial &amp; forming process in baangladesh
md Siraj
 
Sedimentary basins
Sedimentary basinsSedimentary basins
Sedimentary basins
Sohail Nawab
 
TYPES OF SEDIMENTARY ENVIRONMENTS.ppt
TYPES OF SEDIMENTARY ENVIRONMENTS.pptTYPES OF SEDIMENTARY ENVIRONMENTS.ppt
TYPES OF SEDIMENTARY ENVIRONMENTS.ppt
SaadTaman
 
Donaoooo4b2
Donaoooo4b2Donaoooo4b2
Donaoooo4b2
Donado15
 
Tectonic control of sediments
Tectonic control of sedimentsTectonic control of sediments
Tectonic control of sediments
Arshad Ayub
 
Tectonic framework of Bangladesh
Tectonic framework of BangladeshTectonic framework of Bangladesh
Tectonic framework of Bangladesh
Rkosgaming
 
The oceans
The oceansThe oceans
The oceans
Lavina Bhardwaj
 
Transitional Environments
Transitional EnvironmentsTransitional Environments
Transitional Environments
Ubaidullah Shalmani
 
Hotspot,Margins
Hotspot,Margins Hotspot,Margins
Hotspot,Margins
Shah Naseer
 
Narmada, kutch & saurastra basin
Narmada, kutch & saurastra basinNarmada, kutch & saurastra basin
Narmada, kutch & saurastra basin
Kaneti Pramod
 
Oceans
OceansOceans
class16_ocean_sediment_transport.ppt
class16_ocean_sediment_transport.pptclass16_ocean_sediment_transport.ppt
class16_ocean_sediment_transport.ppt
HeroldRiwaldoSitinda1
 
Geology of cambay basin
Geology of cambay basin Geology of cambay basin
Geology of cambay basin
Ananya21Mittal
 
Erosion
ErosionErosion
Erosion
londeka
 
Engineering Geology
Engineering GeologyEngineering Geology
Engineering Geology
GAURAV. H .TANDON
 

Similar to Topography and sediments of the floor of the Bay of Bengal (20)

Paleozoic era bb-Geomorhology Chapter
Paleozoic era bb-Geomorhology ChapterPaleozoic era bb-Geomorhology Chapter
Paleozoic era bb-Geomorhology Chapter
 
TheSubmarineCanyons.pdf
TheSubmarineCanyons.pdfTheSubmarineCanyons.pdf
TheSubmarineCanyons.pdf
 
TheSubmarineCanyons.pdf
TheSubmarineCanyons.pdfTheSubmarineCanyons.pdf
TheSubmarineCanyons.pdf
 
Basinal distribution of Pakistan and Evolution
Basinal distribution of Pakistan and EvolutionBasinal distribution of Pakistan and Evolution
Basinal distribution of Pakistan and Evolution
 
Geography oceanography optional material.pptx
Geography oceanography optional material.pptxGeography oceanography optional material.pptx
Geography oceanography optional material.pptx
 
Alluvial &amp; forming process in baangladesh
Alluvial &amp; forming process in baangladeshAlluvial &amp; forming process in baangladesh
Alluvial &amp; forming process in baangladesh
 
Sedimentary basins
Sedimentary basinsSedimentary basins
Sedimentary basins
 
TYPES OF SEDIMENTARY ENVIRONMENTS.ppt
TYPES OF SEDIMENTARY ENVIRONMENTS.pptTYPES OF SEDIMENTARY ENVIRONMENTS.ppt
TYPES OF SEDIMENTARY ENVIRONMENTS.ppt
 
Donaoooo4b2
Donaoooo4b2Donaoooo4b2
Donaoooo4b2
 
Tectonic control of sediments
Tectonic control of sedimentsTectonic control of sediments
Tectonic control of sediments
 
Tectonic framework of Bangladesh
Tectonic framework of BangladeshTectonic framework of Bangladesh
Tectonic framework of Bangladesh
 
The oceans
The oceansThe oceans
The oceans
 
Transitional Environments
Transitional EnvironmentsTransitional Environments
Transitional Environments
 
Hotspot,Margins
Hotspot,Margins Hotspot,Margins
Hotspot,Margins
 
Narmada, kutch & saurastra basin
Narmada, kutch & saurastra basinNarmada, kutch & saurastra basin
Narmada, kutch & saurastra basin
 
Oceans
OceansOceans
Oceans
 
class16_ocean_sediment_transport.ppt
class16_ocean_sediment_transport.pptclass16_ocean_sediment_transport.ppt
class16_ocean_sediment_transport.ppt
 
Geology of cambay basin
Geology of cambay basin Geology of cambay basin
Geology of cambay basin
 
Erosion
ErosionErosion
Erosion
 
Engineering Geology
Engineering GeologyEngineering Geology
Engineering Geology
 

Recently uploaded

The debris of the ‘last major merger’ is dynamically young
The debris of the ‘last major merger’ is dynamically youngThe debris of the ‘last major merger’ is dynamically young
The debris of the ‘last major merger’ is dynamically young
Sérgio Sacani
 
Summary Of transcription and Translation.pdf
Summary Of transcription and Translation.pdfSummary Of transcription and Translation.pdf
Summary Of transcription and Translation.pdf
vadgavevedant86
 
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
Sérgio Sacani
 
11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf
PirithiRaju
 
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
vluwdy49
 
HOW DO ORGANISMS REPRODUCE?reproduction part 1
HOW DO ORGANISMS REPRODUCE?reproduction part 1HOW DO ORGANISMS REPRODUCE?reproduction part 1
HOW DO ORGANISMS REPRODUCE?reproduction part 1
Shashank Shekhar Pandey
 
8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf
by6843629
 
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
PsychoTech Services
 
Alternate Wetting and Drying - Climate Smart Agriculture
Alternate Wetting and Drying - Climate Smart AgricultureAlternate Wetting and Drying - Climate Smart Agriculture
Alternate Wetting and Drying - Climate Smart Agriculture
International Food Policy Research Institute- South Asia Office
 
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
Scintica Instrumentation
 
Randomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNERandomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNE
University of Maribor
 
Microbiology of Central Nervous System INFECTIONS.pdf
Microbiology of Central Nervous System INFECTIONS.pdfMicrobiology of Central Nervous System INFECTIONS.pdf
Microbiology of Central Nervous System INFECTIONS.pdf
sammy700571
 
cathode ray oscilloscope and its applications
cathode ray oscilloscope and its applicationscathode ray oscilloscope and its applications
cathode ray oscilloscope and its applications
sandertein
 
Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...
Leonel Morgado
 
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills MN
 
The binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defectsThe binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defects
Sérgio Sacani
 
The cost of acquiring information by natural selection
The cost of acquiring information by natural selectionThe cost of acquiring information by natural selection
The cost of acquiring information by natural selection
Carl Bergstrom
 
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at  𝐳 = 2.9  wi...Discovery of An Apparent Red, High-Velocity Type Ia Supernova at  𝐳 = 2.9  wi...
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...
Sérgio Sacani
 
Methods of grain storage Structures in India.pdf
Methods of grain storage Structures in India.pdfMethods of grain storage Structures in India.pdf
Methods of grain storage Structures in India.pdf
PirithiRaju
 
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Sérgio Sacani
 

Recently uploaded (20)

The debris of the ‘last major merger’ is dynamically young
The debris of the ‘last major merger’ is dynamically youngThe debris of the ‘last major merger’ is dynamically young
The debris of the ‘last major merger’ is dynamically young
 
Summary Of transcription and Translation.pdf
Summary Of transcription and Translation.pdfSummary Of transcription and Translation.pdf
Summary Of transcription and Translation.pdf
 
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...
 
11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf11.1 Role of physical biological in deterioration of grains.pdf
11.1 Role of physical biological in deterioration of grains.pdf
 
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
在线办理(salfor毕业证书)索尔福德大学毕业证毕业完成信一模一样
 
HOW DO ORGANISMS REPRODUCE?reproduction part 1
HOW DO ORGANISMS REPRODUCE?reproduction part 1HOW DO ORGANISMS REPRODUCE?reproduction part 1
HOW DO ORGANISMS REPRODUCE?reproduction part 1
 
8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf8.Isolation of pure cultures and preservation of cultures.pdf
8.Isolation of pure cultures and preservation of cultures.pdf
 
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
Sexuality - Issues, Attitude and Behaviour - Applied Social Psychology - Psyc...
 
Alternate Wetting and Drying - Climate Smart Agriculture
Alternate Wetting and Drying - Climate Smart AgricultureAlternate Wetting and Drying - Climate Smart Agriculture
Alternate Wetting and Drying - Climate Smart Agriculture
 
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
(June 12, 2024) Webinar: Development of PET theranostics targeting the molecu...
 
Randomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNERandomised Optimisation Algorithms in DAPHNE
Randomised Optimisation Algorithms in DAPHNE
 
Microbiology of Central Nervous System INFECTIONS.pdf
Microbiology of Central Nervous System INFECTIONS.pdfMicrobiology of Central Nervous System INFECTIONS.pdf
Microbiology of Central Nervous System INFECTIONS.pdf
 
cathode ray oscilloscope and its applications
cathode ray oscilloscope and its applicationscathode ray oscilloscope and its applications
cathode ray oscilloscope and its applications
 
Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...Authoring a personal GPT for your research and practice: How we created the Q...
Authoring a personal GPT for your research and practice: How we created the Q...
 
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
Travis Hills of MN is Making Clean Water Accessible to All Through High Flux ...
 
The binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defectsThe binding of cosmological structures by massless topological defects
The binding of cosmological structures by massless topological defects
 
The cost of acquiring information by natural selection
The cost of acquiring information by natural selectionThe cost of acquiring information by natural selection
The cost of acquiring information by natural selection
 
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at  𝐳 = 2.9  wi...Discovery of An Apparent Red, High-Velocity Type Ia Supernova at  𝐳 = 2.9  wi...
Discovery of An Apparent Red, High-Velocity Type Ia Supernova at 𝐳 = 2.9 wi...
 
Methods of grain storage Structures in India.pdf
Methods of grain storage Structures in India.pdfMethods of grain storage Structures in India.pdf
Methods of grain storage Structures in India.pdf
 
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...
 

Topography and sediments of the floor of the Bay of Bengal

  • 1. Topography and sediments of the floor of the Bay of Bengal Submitted By: Md Hasan Tareq Dept. of Oceanography Noakhali Science and Technology University
  • 2. Content 1. Overview 2. Origin/Evolution of Bay of Bengal 3. Bottom Topography 4. Topographic Features 5. BengalDeep SeaFan (BDSF) with morphologicalfeatures 6. Sediments in the Bay of Bengal 7. Sediment DepositionandTransport 8. Sediment Distribution Patterns 9. Tectonic Activity 10. Marine Life andSediment Interactions 11. GeohazardsandSeabedStability 12. Summary
  • 3. Overview 01 Bottom Topography 02 Bengal Deep Sea Fan (BDSF) Largesedimentary feature formedby the depositionof sediment carriedby the Ganges-BrahmaputraRiver systemin the Bay of Bengal. 03 Sediments consist of variousparticlesand debrisaccumulatedover time, includingminerals, organic matter, andremnantsof marine life. 04 Origin/ Evolution shapedby geologicalprocesses andtectonicforcesactingover millionsof years Underwater terrainor landscapeof the oceanfloor
  • 4. What is Origin and Evolution? Origin refers to the beginning or creation of something, While evolution denotes that entity's gradual development and transformation over time.
  • 5. Origin/Evolution of the Bay of Bengal The Bay of Bengal is a relatively young geological feature with a complex evolution over millions of years. Plate tectonics and various geological processes can explain its origin and development. • Formation of Gondwanaland: Around 300 million years ago, the supercontinent Gondwanaland began to break apart due to tectonic movements. This breakup eventually led to the separationof the Indian Plate from Antarctica andAustralia. • Rifting and Seafloor Spreading: Approximately 180 to 150 million years ago, during the Mesozoic era, the Indian Plate drifted northwards, causing seafloor spreading in the Tethys Ocean, whichwas situated between Gondwanaland andLaurasia. • Collision with the Eurasian Plate: Around 50 million years ago, the Indian Plate began to collide with the Eurasian Plate. This collision initiated the closure of the Tethys Ocean andledto the formationof the Himalayanmountainrange.
  • 6. • During the Tertiary period (approximately 65 to 2.6 million years ago), the Indian Plate moved northward and pushed against the Eurasian Plate. This tectonic activity led to the forming tray basin, whichlater evolved into the Bay of Bengal. • Over millions of years, sediment erosion from the rising Himalayas and surrounding landmasses filled the basin, with major rivers like the Ganges, Brahmaputra, and Irrawaddy playing a significant role in sediment transport and deposition in the Bay of Bengal. • Late Cenozoic Changes: During the Late Cenozoic era (approximately 25 to 2.6 million years ago), further tectonic movements and changes in sea level continued to shape the Bay of Bengal's topography andsedimentary deposition. • Modern Configuration: The modern configuration of the Bay of Bengal took shape over the last few million years, with the continued influence of tectonic processes and sedimentation fromrivers. Origin/Evolution of the Bay of Bengal cont.
  • 7. Size and shape of the Bay of Bengal • Location: South Asia andSoutheast Asia • Area: 2,172,000 square kilometers (839,000 sq mi) • Average depth 2,600m (8,500 ft) • Shape is generally triangular, with the northern boundary
  • 8. Topographic Features • The Continental Shelf width of the continental shelf off the coast of Bangladesh varies considerably. It is less than 100 km off the south coast between Hiron Point and the swatchof no groundandmore than250 km off the coast of Cox’s Bazar. • The continental shelf is a shallow, gently sloping underwater area extending from the coastline to deeper oceanic waters. • Deep Oceanic Trenches: The northern and eastern boundaries of the Bay of Bengal are marked by deep oceanic trenches, such as the Sunda Trench and the Andaman Trench. • Sedimentary Plains: The bay's floor is covered by extensive sedimentary plains, which are the result of the accumulation of sediments carried by significant rivers like the Ganges, Brahmaputra, and Irrawaddy. These sediments contribute to the formation of vast delta regions.
  • 9. Topography refers to the physical features and elevation of the Earth's surface, including mountains, valleys, hills, plains, and other landforms. It provides a detailed description of the shape, height, and relief of the terrain in a given area, both on landandunder the ocean. What is Topography?
  • 10. Bottom Topography • It is characterised by a broad U-shaped basin with its south opening to the Indian Ocean. • A thick uniform abyssal plain occupies almost the entire Bay of Bengal, gently sloping southwardat an angle of 8°-10°. • In many places, underwater valleys dissect thisplainmass.
  • 11. • Continental Slope: The transition between the continental shelf and the deep ocean floor is known as the continental slope. The steeper region marks the beginning of the deeper oceanicbasin. • Submarine Canyons and Channels: Along the eastern boundary of the bay, some underwater canyons and channels have been carved by sediment transport and turbidity currents. These featurescreate ruggedandsteepslopes in certainareas • Coral Reefs: Some areas within the Bay of Bengal host coral reefs, particularly in the Andaman and Nicobar Islands. These reefs are critical marine ecosystems and support rich biodiversity. Topographic Features cont.
  • 12. What is Deep-sea Fan? A deep-sea fan is a fan-shaped sediment deposit formedby turbidity currents andlocatedin submarine canyons or basinplains on the ocean floor.
  • 13. Bengal Deep Sea Fan (BDSF) • The BDSF isa cone or fan-shapedsediment deposit in the N-E part of the Bay of Bengal. • The fan extendsfrom approx. 20°N to 10°S latitude. • The avg. Length is3000 km andwidth of 1445 km. • The avg. Elevation of the fan is1400 m. • Thisisthe largest deep-sea fan in the world, 2.8-3.0 × 106 sq. km. • The fan post datesin the collisionof the Indianplate with the Eurasianplate & uplift of the ancestral Himalaya at the endof the Paleocene. • Underlying the fan, the continental rise sediments up to 20 km thick. • The gently slopingfan isalmost even a gradient of 1.5 m/km. • Many anastomosing channels crossit with low levees on the side.
  • 14. Bengal Deep Sea Fan (BDSF) cont. • The gently sloping plain extending for 2000 km from the slope base of the Ganges-Brahmaputra delta to the far south of Srilanka isunique. • Surface of BDSF is smooth. Based on the valley gradient can be divided into 3 parts : a. Upper fan - valley gradient 2.3 m/km b. Middle fan - Valley gradient 1.68 m/km c. Lower fan - Valley gradient < 1 m/km
  • 15. Morphological features of BDSF 1. The Swatch of No Ground(SoNG)/GangesTrough. 2. The 90 East Ridge. 3. Leveesandabandonedchannels 4. Offshore islands– Bhola, Kutubdia, St. Martin Island Swatch of No Ground (SoNG)/ Ganges Trough • In the northern Bay of Bengal are deep valleys, with one notable valley called the "Swatch of No Ground" crossing the shelf diagonally in a south-westerly direction.
  • 16. Swatch of No Ground (SoNG)/ Ganges Trough cont. • The Ganges trough, characterized by a comparatively flat floor (5-7 km wide) and walls with approximately 10° inclination, lies at the edge of the shelf, with a depth of about 1200m. • As indicated by Coleman (1969), the bars and channels of the mouth of the combined river point towards this trough and undoubtedly allow sediments to be carried into the headof the trough. • This explains why delta and bars are not being built seaward, despite the enormous load of sedimentscoming to the seaat thislocality.
  • 17. Ninety East Ridge/ 90°E Ridge • The NER (Naturaliste–Esperance Ridge) is an elongated volcanic ridge in the eastern Indian Ocean, stretching approximately 5200 km from 30°S (intersecting Broken Ridge) to around 17°N (beneath the Bengal Deep Sea Fan). It divides the Bengal Deep Sea Fan into two parts: the mainBengal fan andthe Nicobar fan in the east. • This ridge rises about 2-3 km above the surrounding seafloor, with a width varying between 150 to 250 km, making it the world's longest straight ridge. • The formation of NER is attributed to magmatism associated with the deep-seated Kerguelen mantle plume, as the Indian plate rapidly drifted northward during the Late Cretaceous. • Drilling results revealed that the rocks on the NER become progressively younger from north to south. The ridge's age is estimated to be around 40 million in the south and approximately 80 million in the north.
  • 18. Levees and abandoned channels • Abandoned Channel A former stream channel through which water no longer flows (e.g., a cut-off). • Levees A ridge of sediment is deposited naturally alongside a river by overflowingwater. St. Martin’s Island (Coral Island) • St. Martin’s Island is the only coral island in Bangladesh.
  • 19. are small particles of solid material, such as sand, silt, and clay, that are transported and deposited by water, wind, or ice, accumulating in layers over time. Sediments
  • 20. Sediments in the Bay of Bengal The sedimentary section in the Bay of Bengalisdivided into two parts: 1. Eocene through Holocene, sediments and sedimentary rocks which post-date the initialIndia-Asiacollision: • volume = 12.5 x 106 km3; mass = 2.88 x 1016 t; • this is most of the Bengal Fan, including its eastern lobe, the Nicobar Fan, plus some of the outer BengalDelta. 2. Early Cretaceous through Paleocene, pre-collision sedimentary and metasedimentary rocks: • volume = 4.36x 106 km3; mass = 1.13 to 1.18 X 1016t; • these are interpreted ascontinentalrise andpelagicdeposits
  • 21. Sediments of the floor of the Bay of Bengal • Terrigenous Deposits The Bay of Bengal sediments are predominantly terrigenous, consisting of clayey silt and silty clay, transported by the Ganges- Brahmaputra-Meghna rivers and other major rivers from the Himalayas, amounting to over a billiontonnesannually. • Turbidites: Unveiling Deep-Sea Sediments: Deep-sea sediments in the Bay of Bengal are mainly diverse Turbidites, confirmed through the analysis of core samples from the Deep Sea Drilling Program (DSDP) and Ocean Drilling Program (ODP). • Biogenous sediments like Calcareous Clays and Oozes are abundant near the Andaman and Nicobar Islands and atop the Ninety East Ridge, while the organic matter content in the continental-shelf sediment of the northern part of the east coast isrelatively low compared to the globalaverage for near-shore sediments.
  • 22. Sediments of the floor of the Bay of Bengal cont. • Chemogenous sediments in the Bay of Bengal include authigenic green clays (glaucony and verdine facies), phosphorites, ferromanganese nodules, and hydrothermal and organic-rich sediments. While sparse, their distribution and origin in the regionhave been identified. • Volcanogenic components in Bay of Bengal sediments from Cretaceous to Recent periods. Cretaceous sediments contain volcanogenic Smectite, likely originating from Rajmahal Traps, while cores from the Ninety East Ridge reveal abundant volcanogenic sediments over basaltic basement.
  • 23. Sediment Deposition and Transport Sediment Transport Processes in the Bay of Bengal: • Monsoon Currents: The Bay of Bengal experiences seasonal monsoon winds, which play a significant role in sediment transport. During the southwest monsoon (June to September), strong onshore winds blow from the Indian Ocean, pushing surface waterstowardsthe coast. • Tidal Currents: Tides are another crucial factor influencing sediment transport in the Bay of Bengal. Tidal currents occur due to the gravitational pull of the moon and the sun. • River Discharge: The discharge of sediments from major rivers, such as the Ganges, Brahmaputra, and Meghna, contributes significantly to sediment transport in the Bay of Bengal. • Ocean Circulation, Storm Surges, Seafloor Topography also affects sediment transport.
  • 24. Sediment transport pathways Sediment deposition areas
  • 25. Sediments Depositional Features and Distribution Patterns • Coastal Sedimentation: Sediment deposition along the coast occurs due to the influx of terrigenous sediments from the rivers, especially during the monsoon season. The sediments carried by the rivers settle along the coastline, forming mudflats, deltas, andestuaries. • Continental Shelf Sediments: The continental shelf of the Bay of Bengal is a significant area for sediment deposition. Terrigenous sediments brought by rivers are spread across the shallow shelf regions, creating a vast depositional area. Additionally, biogenous sediments and chemogenous sediments, such as phosphorites and ferromanganese nodules, contribute to the shelf sedimentation. • Deep-Sea Fan Formation: The Bay of Bengal is renowned for its extensive deep- sea fan formations. These fans are created by the deposition of sediments carried by turbidity currents that flow down the continentalslope.
  • 26. Sediments Distribution Patterns of the Bay of Bengal
  • 27. refers to the movement and interactions of Earth's lithospheric plates, leading to processes such as earthquakes, volcanoes, mountain building, and oceanic crust formation. Tectonic activity
  • 28. Tectonic activity in the Bay of Bengal is driven by the movement of tectonic plates in the region. The Bay of Bengal is part of the larger Indian Plate, which is surrounded by several other tectonic plates, includingthe Eurasian Plate, Australian Plate, andBurma Plate. • Subduction Zones: The eastern boundary of the Bay of Bengal is marked by subduction zones, where the IndianPlate isconverging with the BurmaPlate andthe SundaPlate. • Island Arcs: The subduction of the Indo-Australian Plate beneath the Eurasian Plate has given rise to volcanicislandarcsin the western Bay of Bengal. • Rift Zones: The western boundary of the Bay of Bengal is characterized by rift zones, where the IndianPlate ispulling away from the AfricanPlate. • Earthquakes: The interaction between tectonic plates in the Bay of Bengal region gives rise to frequent seismicactivity, leading to earthquakes. • Tsunamis: Tectonicactivity in the Bay of Bengalcanalsotrigger tsunamis. Tectonic activity
  • 29. Marine Life and Sediment Interactions in the Bay of Bengal The Bay of Bengalisa biologically diverse andecologically richmarine region, where marine life andsediment interactionsplay a crucialrole in shaping the ecosystem. • Nutrient Enrichment: Terrigenoussediments, carriedby major rivers into the bay, are richin nutrients like nitrogen andphosphorus. • Coastal Mangroves and Wetlands: The depositionof sedimentsinthe coastalregions createsideal conditionsfor mangrovesandwetlandsto thrive. These unique ecosystems serve ascriticalhabitatsfor variousmarine species, acting asnurseriesfor juvenile fish andproviding refuge for many migratory birds. • Benthic Communities: Sedimentsonthe oceanfloor provide habitat for a diverse range of benthic organisms, such asworms, mollusks, andcrustaceans. • Coral Reefs: In areaswith clear andshallow waters, coralreefscanform. • Sediment Dependent Fish Species: Some fishspeciesin the Bay of Bengalare dependent onspecific sediment typesfor spawning andfeeding.
  • 30. Geohazards and Seabed Stability Geohazards in the context of the Bay of Bengal refer to natural phenomena or processes that pose risks to human activities and infrastructure due to the region's geological characteristics. • Submarine Landslides: The steep underwater slopes and sediment accumulation in the Bay of Bengal make it susceptible to submarine landslides, which can result in tsunamis andaffect seabedstability. • Cyclones and Storm Surges: The Bay of Bengal is prone to tropical cyclones and associated storm surges. These weather events can cause significant erosion, sediment transport, andsedimentation, impacting the stability of the seabed. • Submarine Volcanoes: Some areas in the Bay of Bengal may host submarine volcanoes, whichcanleadto the release of volcanic materialsandalter the seabed's stability.
  • 31. Geohazards and Seabed Stability • Sediment Mobilization: Heavy rainfall, river flooding, and coastal erosion can mobilize large amounts of sediment, leading to sediment deposition and reshaping of the seabed. • Seafloor Subsidence and Uplift: Tectonic processes can cause seafloor subsidence or uplift, altering the seabed's elevationandaffectingits stability. Sediment properties play a critical role in influencing the stability of the seafloor in variousmarine environments, including the Bay of Bengal. • GrainSize • ConsolidationandCompaction • Shear Strength • Cementation • Presence of Organisms • Sediment Load • Presence of Gas
  • 32. Summary • The Bay of Bengal exhibits a diverse and complex topography on its seafloor, characterized by deep trenches, abyssal plains, submarine canyons, seamounts, andvolcanic ridges. • The topography is influenced by tectonic processes, sediment accumulation from the Himalayas, and river transport. • The deep-sea fan in the Bay of Bengal is known as the "Bengal Deep Sea Fan." It is a large sedimentary deposit formed by the accumulation of sediments eroded from the Himalayasandtransportedby major riverslike the GangesandBrahmaputra. • Sediments in the bay consist of a wide range of grain sizes, primarily eroded from the rising Himalayasandtransportedby major rivers like the GangesandBrahmaputra.
  • 33. • These sediments contribute to the formation of extensive sedimentary plains and delta regions. • The sediment distribution patterns in the Bay of Bengal are influenced by various factors, includingriver inputs, oceancurrents, andseafloor topography. • Tectonic activity in the Bay of Bengal is characterized by the ongoing movement and interaction of tectonic plates, leading to geological processes such as subduction, seafloor spreading, andcollision. • The interaction of topography and sediments in the Bay of Bengal plays a crucial role in shaping itsgeologicalandecologicalcharacteristics. • Geohazards in the Bay of Bengal pose risks to human activities and infrastructure due to its geologicalcharacteristics. Summary cont.