geomorphological evolution of teknaf peninsula
TRANSCRIPT
NISHAT FALGUNEE
SHAHREEN MUNTAHA NAWFEE
JUEL RANA KUTUB
GEOMORPHOLOGICAL EVOLUTION OF TEKNAF PENINSULA
4TH YEAR 2012
DEPARTMENT OF GEOGRAPHY AND
ENVIRONMENT
UNIVERSITY OF DHAKA
INTRODUCTION
TWO BROAD CATEGORIES OF
GEOMORPHIC PROCESSES
ARE:
ENDOGENIC PROCESS:
WORKS FROM WITHIN THE
EARTH.
EXOGENIC PROCESS: WORKS
ON THE SURFACE OF THE
EARTH.
GEOMORPHIC EVOLUTION MEANS THE ORIGIN AND DEVELOPMENT OF A PARTICULAR AREA BY THE GEOMORPHIC PROCESSES ACTIVE IN THAT REGION
EXOGENIC
PROCESSES
ENDOGENIC PROCESSES
EARTH SURFACE
RATIONALE OF THE STUDY
THE COASTAL AREA OF BANGLADESH HAS BEEN CHANGED SIGNIFICANTLY DURING THE GEOLOGICAL TIME.
THE NATURE AND THE EXTENT OF SUCH CHANGES WILL HELP TO UNDERSTAND THE FUTURE CONDITION OF THAT AREA AND HOW THIS WILL AFFECT THE LIVES OF PEOPLE.
THE AIM OF THIS STUDY IS TO EXPLORE THE GEOMORPHOLOGICAL EVOLUTION OF TEKNAF PENINSULA.
OBJECTIVES
TO KNOW THE MAJOR GEOMORPHOLOGICAL TYPES OF THE
AREA
TO KNOW THE CHANGES OF THE BATHYMETRY OF THE
AREA
TO KNOW THE LITHOLOGICAL SEQUENCES OF THE AREA
TO UNDERSTAND THE EVOLUTION HISTORY OF THE STUDY
AREA FROM THE FORMER EVIDENCES
METHODOLOGY
SATELLITE IMAGERY
GIS
STUDY OF BATHYMETRIC
CHART
FIELD WORK:
VEGETATION SURVEY
BORING
LITHOLOGICAL SECTION
TOPOGRAPHIC SURVEY
BATHYMETRIC SURVEY
OBSERVATION
DATA PRESENTATION
GEOMORPHOLOGICAL DATA
(REF: GROUP A)
FEATURES AREA (SQUARE KM)
PERCENTAGE (%)
ALLUVIAL PLAIN 33.350198 59.5
HILL 0.889527 1.5
PIEDMONT 0.922201 1.6
MUD FLAT 1.305136 2.2
RIVER 1.375803 2.3
ROAD (LENGTH) 238.149796 -
SALT MARSH 0.115901 0.2
SAND DUNE 0.534496 0.9
SANDY BEACH 2.658234 4.6
SPIT BAR 0.348413 .05
TIDAL FLAT 15.376546 27.5
WATER BODIES 0.010943 0.02
DATA PRESENTATION
LANDUSE DATA
( REF: GROUP B)
Name of the Features Percentage (%)
Forest (Plain Land, Hilly & Tidal) 16.87%
Agriculture 45.47%
Settlement 7.24%
Water bodies (River & Others) 2.59%
Barren (Hill, Sandy sea beach & Tidal Flat)
13.78%
Salt cultivated land & Spit Bar 13.07%
DATA PRESENTATION
BATHYMETRY DATA
(REF: GROUP C)
DATA PRESENTATION
BOTTOM TOPOGRAPHY OF THE SHELF AREA, 1982
BOTTOM TOPOGRAPHY OF THE SHELF AREA, 2009
DATA PRESENTATION
BATHYMETRY DATA
(REF: GROUP C)
DATA PRESENTATION
DATA PRESENTATION
LITHOLOGICAL DATASOIL PROFILE OF EASTERN PART OF THE EMBANKMENT AND AGRICULTURAL LAND
DIFFERENT SOIL LAYERS
DATA PRESENTATION
lost lost
LITHOLOGICAL DATA
DATA PRESENTATION
SOIL PROFILE OF WESTERN PART OF THE TEKNAF SEA BEACH
DATA PRESENTATION
ANALYSIS OF THE DATA
MORPHOLOGICAL EVIDENCES
THE PRESENCE OF HILL SHOWS
TECTONIC INFLUENCE.
PIEDMONT AND ALLUVIAL PLAIN
IS FORMED BY FLUVIAL
PORCESS
THE TIDAL FLAT, SALT MARSH,
SPIT BAR ETC. ARE FORMED BY
OCEANOGRAPHIC PORCESS
(REF: GROUP A)
ANALYSIS OF THE DATA
CONTINUOUS ELONGATED
BEACH ON THE EASTERN SIDE
OF THE PENINSULA.
THE ALLUVIAL PLAIN OF
SHAHPURI ISLAND IS
SEPARATED FROM THE ALLUVIAL
PLAIN OF THE MAINLAND ISLAND
BY AN EXTENSIVE TIDAL FLAT
THE PRESENCE OF THE SPIT
BAR
(REF: GROUP A)
MORPHOLOGICAL EVIDENCES
SUCCESSIVE LAYERS SAND, SILT AND CLAY
DEPOSTION SUGGESTS STEADY PROCESS OF
SEDIMENTATION
RENEWED DEPOSITION OF SAND OVER CLAY
REPRESENTS RAPID ENVIRONMENTAL CHAGE
A THICK LAYER INDICATES LONG TERM
SEDIMENTATION PROCESS
A THIN LAYER OF SEDIMENT REPRESENTS SHORT
TERM DEPOSITIONAL PROCESS
( REF: GROUP B)
LITHOLOGICAL EVIDENCES
ANALYSIS OF THE DATA
( REF: GROUP B)
ANALYSIS OF THE DATA
FOR BEACH AREA
¤ COMBINATION OF BOREHOLE AND SECTION DATA SHOWS
¤ THICKLAYER OF SANDY SOIL OVERLAIN BY VERY THIN
CLAYEY SILT AND PRESENCE OF CONSIDERABLE AMOUNT
OF ORGANIC MATTER INDICATES:
i. DEPOSITION OF SAND IN HIGH ENERGY ENVIRONMENT
ii. DEPOSITION OF FINE GRAINED SEDIMENTS POSSIBLY
DUE TO TIDAL INFLUENCE/ EROSION
iii. PRESENCE OF MARSHY ENVIRONMENT IN PAST
LITHOLOGICAL EVIDENCES
FOR SHAHPARIR DWIP
LITHOLOGICAL EVIDENCES
COMBINATION OF BOREHOLE AND SECTION DATA
SHOWS
SAND OVERLAIN BY CLAYEY SILT
WHICH IS AGAIN OVERLAIN BY CLAYEY AND SILTY
TOPSOIL.
THIS INDICATES:-
i. CHANGES IN DEPOSITIONAL ENVIRONMENT
ii. SAND LAYER FORMED WHEN CLIMATE WAS
POSSIBLY WET
iii. DECREASE IN ENERGY OF THE ENVIRONMENT
iv. SEA LEVEL CHANGE
SIGNIFICANT CHANGES
IN THE UNDERWATER
TOPOGRAPHY OF THE
SHELF.
ALTERNATING BANDS OF
EROSIONAL AND
DEPOSITIONAL AREAS.
(REF: GROUP C)
BATHYMETRIC EVIDENCES
ANALYSIS OF THE DATA
ANALYSIS OF THE DATABATHYMETRIC EVIDENCES
Cross Profile for the shelf area from 1982 - 2009
• Depth of the ocean has increased on average
• Top of the underwater shoals have been eroded away
• This sediments have accumulated in the adjacent low areas of the shelf.
LANDUSE OF TEKNAF PENINSULA HAS
BEEN INFLUENCED BY ITS
GEOMORPHOLOGICAL CHARACTERISTICS.
THE HILLY AREA AND TIDAL FLAT AREA ARE
BARREN LAND. THE TIDAL FLAT BETWEEN
THE SOUTHERN AND NORTHERN ALLUVIAL
PLAIN IS USED FOR SALT CULTIVATION.
ALLUVIAL PLAINS ARE USED FOR
SETTLEMENT AND AGRICULTURE.
THE CHANGES IN LAND USE SIGNIFICANTLY
CHANGES THE MORPHOLOGICAL
CHARACTERISTICS OF THE PENINSULA
( REF: GROUP B)
ANALYSIS OF THE DATA
LANDUSE EVIDENCES
THERE IS VARIATION IN VEGETATION COMPOSITION
ACCORDING TO GEOMORPHOLOGIC CHARACTERISTICS.
THE SAND DUNES OF THE BEACH AREA ARE MOSTLY
OCCUPIED BY HERB, SHRUB INCLUDING CLIMBING SPECIES.
THE SMALL SHRUBS AND HERBS ARE MOST COMMON
VEGETATION AND PALM SPECIES CONSTITUTE THE LARGER
PART OF THE TREE SPECIES.
THE NATURAL VEGETATION IS DISTURBED BY HUMAN
INTERVENTION. VARIOUS HOMESTEAD FORESTS HAVE BEEN
FOUND.
MANGROVE FORESTS ARE FOUND ALONG THE EASTERN SIDE
OF THE PENINSULA BECAUSE OF THE TIDAL AREA ALONG THE
NAAF ESTUARY
(Ref: Group A)
ANALYSIS OF THE DATA
VEGETATION EVIDENCES
OCEANOGRAPHIC PROCESSES:
PROCESSES OF GEOMORPHOLOGICAL EVOLUTION
OCEANOGRAPHIC PROCESS
TIDAL MOVEMENTS
CURRENTS
STREAM OUTFLOW
WAVE ACTION
CLIMATIC PROCESS
PROCESSES OF GEOMORPHOLOGICAL
EVOLUTION
LONG TERM CHANGES IN SEA-LEVEL
THE MAIN REASONS BEHIND SEA LEVEL RISE ARE THE THERMAL EXPANSION OF OCEAN WATER
OTHER REASONS AERTHE GLACIERS AND ICE-CAPS MELTING, WITHDRAWAL OF GROUND WATER ETC.
HOLOCENE SEA LEVEL RISE ALONG THE EASTERN BANK OF THE COX’S BAZAAR & TEKNAF IS ACCOMPANIED BY COASTAL EROSION
SOURCE: SARWAR, 2005
PROCESSES OF GEOMORPHOLOGICAL EVOLUTION
TECTONIC PROCESSES
PROCESSES OF GEOMORPHOLOGICAL EVOLUTION
PLATE MOVEMENT
LOW TO MEDIUM INTENSITY EARTHQUAKES SUGGESTS THAT THE AREA IS TECTONICALLY ACTIVE. IT IS KNOWN THAT THE INDIAN PLATE IS SUBDUCTING UNDER THE EURASIAN AND BURMESE PLATES. AS A RESULT, THE COASTAL PLAIN FRINGING THE TERTIARY HILLS HAVE BEEN UNDERGOING UPLIFTMENT IN SOME PART WHILE SUBSIDENCE IN OTHER PARTS.
UPLIFTMENT AND SUBSIDENCE
• A SERIES OF STEP-FAULTS IN THE SOUTHERN PART OF TEKNAF SHOWS CHARACTERISTICS OF A DOWNTHROWN BLOCK. THE SUDDEN INCREASE IN SEDIMENT THICKNESS IN THE SOUTHERN PART SUGGESTS EXISTENCE OF ANOTHER BLOCK.
HUMAN INTERVENTION
HUMAN ACTIVITIES LIKE MINING,
CONSTRUCTION, AGRICULTURE AND WATER
MANAGEMENT PROJECTS AFFECT DIFFERENT
GEOMORPHIC PROCESSES. ALONG THE COAST,
EXCESSIVE LOGGING, DIRECT LAND
RECLAMATION FOR AGRICULTURE,
AQUACULTURE, SALT PONDS, PORT BUILDING
AND SHRIMP FARMING AGGRAVATE COASTAL
EROSION.BESIDES ACTIVITIES WITHIN RIVER
CATCHMENTS/WATERSHEDS LIKE- DAM
CONSTRUCTION AND RIVER DIVERSION CAUSE
REDUCTION OF SEDIMENT SUPPLY TO THE
COAST AND ULTIMATELY CONTRIBUTES TO
COASTAL EROSION
PROCESSES OF GEOMORPHOLOGICAL
EVOLUTIONSALT FARMING
SHRIMP FARMING
DRIED FISH
PROCESSES OF GEOMORPHOLOGICAL EVOLUTION
CONCLUSIONS
THE SHAHPURI ISLAND WAS ONCE SEPARATED FROM THE MAINLAND WHICH LATER WAS FILLED UP BY
SEDIMENTATION FROM THE NAAF RIVER AND TIDAL ACTION.
THE AREA IS UNDERGOING SIGNIFICANT CHANGES DUE TO ACCRETION AND EROSION AS WELL AS HUMAN INTERVENTION.
THAT THE RATE OF EROSION OUTWEIGHS ACCRETION IN OUR STUDY AREA.
CONCLUSIONS
REFERENCES
AHMED, S. 2005. RECENT CHANGES IN THE COASTAL REGION OF
BANGLADESH: STUDIES IN GEOMORPHOLOGY, UNPUBLISHED MS
THESIS, DEPT. OF GEOGRAPHY & ENVIRONMENT, UNIVERSITY OF
DHAKA.
PHILLIPS, J.D. 2006. EVOLUTIONARY GEOMORPHOLOGY:
THRESHOLDS AND NONLINEARITY IN LANDFORM RESPONSE TO
ENVIRONMENTAL CHANGE. TOBACCO ROAD RESEARCH TEAM,
DEPARTMENT OF GEOGRAPHY, UNIVERSITY OF KENTUCKY, USA.
SARWAR, MD. G.M., 2005. IMPACTS OF SEA LEVEL RISE ON THE
COASTAL ZONE OF BANGLADESH. UNPUBLISHED MS THESIS, DEPT.
OF INTERNATIONAL MASTERS PROGRAMME IN ENVIRONMENTAL
SCIENCE LUND UNIVERSITY, SWEDEN.
GOOGLE IMAGES.
THANK YOU FOR YOUR KIND ATTENTION