Research Journal of Earth Sciences 2 (2): 30-35, 2010
ISSN 1995-9044
© IDOSI Publications, 2010
Coastal Geomorphology and Evolution of
Rameswaram Island, Tamil Nadu, India
K. Prabakaran and K. Anbarasu
Department of Geology, National College, Tiruchirapalli-620 001, Tamilnadu, India
Abstract: Rameshwaram, a strategically and socially important island in the east coast of India, is an
excellent place for the study of coastal evolution during Quaternary. It has landforms like beaches, beach
ridges, mudflats, raised coral terraces, lagoons, spit etc. along with l iving corals. The evolution of
coastal landforms could b e clearly traced by integrating the landform distribution with available C14 dates.
It is clear that sea level has played a major role in the evolution of landforms of the island. The raised terraces
that has been dated to 125000 years BP indicates that the there was only fringing reefs during that period. The
emerged coral during the subsequent regressive phase of the sea had been serving as place for marine
sedimentation as indicated by mudflats and beach ridges of latter period. The spit is the recently formed
landform of the island.
Key words: Rameshwaram % Geomorphology % Evolution % Sea level % Quaternary
INTRODUCTION
Rameshwaram island of the scale 1: 50,000 were
interpreted, from them the geomorphic entities were also
mapped and the features were confirmed by field checks.
Data was also obtained from the satellite imagery of IRS
1C and 1D and using Arc view 3.2a, Arc GIS 9.1 software.
It is by compilation of data from field map, aerial photos
and imagery a geomorphic map of the Rameshwaram
Island was prepared. The evolution of coastal landforms
could be clearly traced by integrating the landform
distribution with available C14 dates.
Rameshwaram Island is located on the eastern part of
Ramanathapuram district of TamilNadu (Fig. 1). It is
bound between the latitudes E 79°12' 30" and E 79° 27' 30"
and longitudes N 9° 8' 55" and N 9° 19'. The coast of
Rameshwaram has several topographic expressions,
which are the signatures of the interaction of marine and
aeolian processes [1]. These topographic features can
serve as ecosystems, which have components of
terrestrial, marine and atmospheric processes [2].
Ecosystems favor and support rich and diversified fauna
and flora apart from serving as areas to protect the coast
from the activities of tides and cyclones. It is in this
context there is a need for the scientific study of coastal
geomorphic features, which can be utilized as sites for
promotion of better environmental conditions. A widely
varying nature of landforms and their disposition along
the beaches and inland represents the successive phase
of transgression and regression of sea level. [3]. Along
the eastern coast of peninsular India, narrow belts of sand
dunes, coastal dunes and beach ridges are present [4].
Constructional and Destructional Landforms:
Constructional landforms include deltas, deltaic coastal
plains, beaches, bars, spits, reefs, dunes, mudflats and
many minor features. Also included in this group are
structures of organic origin. Along the coasts of warm
seas, algae, coral and other organisms may accumulate in
huge quantities to form reefs, which sometimes extend
considerable distance offshore. The position and
development of these features are related to the stand of
the sea during their formation. Destructional or erosional
landforms include sea cliffs, wave cut beaches, arches and
caves near sea level, detached masses of rock which form
islands and sea stacks and many other forms whose
characteristic features have developed under the
dominant influence of local topography, rock type and
structure. The Gulf of Mannar (south-eastern area)
Methodology: A field study involving identification and
mapping of the various geomorphic features present in
the area was conducted with the help of Survey of India
toposheets 58 O/7 and 58 O/11. The aerial photos of the
Corresponding Author: K. Prabakaran, Department of Geology, National College, Tiruchirapalli-620 001, Tamilnadu, India.
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Res. J. Earth Sci., 2 (2): 30-35, 2010
Fig. 1: Location map of the Study area
was devoid of suspended sediments throughout the year
whereas the Palk Bay (area North - East of the Gulf of
mannar) is under high suspended sediment concentration
throughout the year and is under heavy siltation [5].
the east coast of India in pulses to +4.5 m above LTL and
fell back in short pulses between longer intervals of
stillstand and occasional small jumps, Banerjee [8].
In the Rameswaram Island the beach ridges are found to
present on land at about 0.5 Km from the present shore
line. Hence the shoreline can be classified as emergence
type. The shoreline is relatively straight and smooth.
The Coast of Rameswaram Island can be classified in
to two sectors which is Northern and Southern sectors.
Northern coast extends from Pamban through
Rameswaram town to Dhanushkodi and the Southern
coast extends from Pamban through Ramakrishnapruram
to Dhanushkodi. Cuspate shoreline configuration is
observed in the Northern coast between Peikkarumbu and
Rameswaram town and in the Southern coast between
Pamban and Ayyanthopu. Besides these portions the
shoreline is generally straight. The direction of the
shoreline configuration is generally towards North westsoutheast. However the shoreline is observed in the E-W
direction between Pamban and Peikkarumbu and north
east south west direction between Peikkarumbu and
Rameswaram town. Erosional coast is observed in the
areas of cuspate shoreline and depositional coast is
observed in the areas of straight shoreline.
Shore Line Configuration: Regardless of the nature of
an initial shoreline, it soon undergoes modification.
Most initial coasts are irregular and the general tendency
of marine gradation is to produce a more regular coast.
The shoreline evolution was proposed by Jhonson [6]
and Valentin [7] into submerged and emerged coasts.
More complicated shorelines were regarded as
submergent, in the belief that land had lowered to
some extent, permitting seas to drown complicated
topography which had been produced by weathering and
erosion of surfaces exposed to the atmosphere. Smooth
coasts were regarded by many geomorphologists as
exhibiting shorelines of emergence, based on the
hypothesis that sea bottoms are flat, so that when uplifted
to become coastal plains they formed relatively straight
shores.
Rameshwaram and the flight of erosional terraces on
the aeolinite ridge at manappad point is that during the
late Pleistocene highland here, relative sea level rise along
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Res. J. Earth Sci., 2 (2): 30-35, 2010
Fig. 2: Coastal geomorphology around Rameswaram Island
Coastal Geomorphology: Landforms observed in the
Rameswaram island are (Fig. 2)
C
Beaches
C
Beach ridges and swales
C
Dunes and Sandy plains
C
Lagoons and Mudflats
C
Creeks
C
Spits
Wide beaches are observed in the Southern coast
extending to a maximum of 1 Km around Natarajapuram
and in further south areas. In the Northern coast, beaches
are generally narrow and extend only to 5 to 10 Mts.
Beaches in the study area composed of fine and medium
sand. In the crenulated portions of the Northern coast,
the beaches are terminated by cliffed coral reefs and
Cuddalore Sandstone.
Over the cliff corals and
Sandstone form a terraced landform. A beach profile of
Rameswaram island in general exhibit the characteristics
(Table 1)
The tail like portion of Rameswaram Island observed
in the South Eastern portion is entirely made up of sandy
barrier beaches. Large portion of this land is submerged
under water during high tide.
Beaches: The landform that occurs through the total
length of 72Kms of the study area without any break is
sandy beach. The dominant wave actions with large
amount of input of sediments derived through the
longshore littoral currents from Southern Tamilnadu make
the beaches as a most dynamic landform of the area.
Table 1: A beach profile of Rameswaram island in general exhibit the characteristics
Near shore zone
Slope upto 5°
Situated in front of the beach, submerged under sea water even during low tide.
Fore shore zone
slope 5° to 15°
Situated between high tide and low tide mark.
Back shore zone
Flat
Rarely submerged during storm surge. Aeolian activity is common.
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Res. J. Earth Sci., 2 (2): 30-35, 2010
Beach Ridges and Swales: Beach ridges are defines as
linear sandy-shelly swash deposits with intervening
sandy plain occurring parallel or sub parallel to the shore
formed by periodic wave impounding action. Beach
ridges are observed between Peikkarumbu and
Pilloaikulam in the Northern coast and between Pamban
and Kodandaramaswami kovil in the Southern coast.
Beach ridges are generally parallel to the coast and are
followed in the back shore by sandy plains. Beach ridges
observed in the Northern coast are discontinuous in
nature while the beach ridges of Southern coast are
continuous in general. The height of the beach ridges
vary from 1M to 5 Mts. and the highest part is observed
near Ayyanthopu.
Swales are narrow linear depression with clay and
silty clay deposits occurring between the beach ridges.
Swales are noticed along the Southern shoreline and
along the way to Kodandaramaswami Kovil. They are
absent along the Northern shoreline of the island.
observed. The horns of all the dunes are pointing
towards North east direction (Wind ward direction). The
height of the dunes goes up to 12 Mts. near Kariyur. The
windward side is steep and leeward side is gentle in all the
parabolic dunes. Migration of dunes is noticed and
artificial measures for migration have been taken up by the
Government. Besides the above said areas, dunes are
observed in a scattered manner in places like
Susaipparpattinam,
Ayyanthopu
and
around
Natarajapuram. In the study area sandy plain are
observed in the central parts, almost flat terrain covered
with sandy plains.
Lagoons and Mudflats: Lagoon can be defines as a
shallow body of sea water as a pond or lake, separated
from the sea by barriers with a narrow inlet. The tail like
portion observed in the South eastern part of the island
extending up to Dhanushkodi consist of two barrier
ridges in the North and South side and linear lagoon in
between the two. The lagoon has inlet at number of
locations. Since the wave action disturbs the stagnant
water frequently mudflat have not developed. Salt
marshes are also notice in few places around the lagoon.
Another lagoon is observed in the north of dune complex
of Rameswaram town. Segmentation of lagoons is
observed due to the developments of ridges and dunes in
it. The lagoon has an inlet of north of Ariyankundu. The
lagoon is encircled by mudflats. Saltmarshes are also
observed.
Mudflat is a flat area containing a fluid to plastic
mixture of finely divided particles of solid material silt clay
and water. They are always associated with the sheltered
environment like lagoons, estuaries and other embayment.
The feature is predominantly observed around the lagoon
north of Rameshwaram town. The barrier beaches
occurring in the seaward side of the backwaters create a
sheltered environment, which has favored the
development of mudflat. In the southwest nearer to
Pamban and Ayyanthopu mudflat is formed around
creeks.
Marine/Coral Terraces: In the northeast portion of the
beaches are terminated by cliffed coral reefs and
cuddalore sandstone. Over the cliff corals and sandstone
from a terraced landforms.
Dunes and Sandy Plain: Dunes are ridge or mound of
loose sands formed by aeolian activity. Coastal dunes are
formed when dry sands on shore are blown to the back of
the beach. Coastal dunes are noticed in the area east of
Tangachchimadam and in the area north of Rameswaram
town. A large parabolic dune along with a dune complex
is observed in the area North of Rameswaram town. The
axis of the parabolic dune trends North east-South west.
The limb of the dune extends from Sudukattampatti
towards South west direction and culmination takes place
around Athikadu and extends further toward North West
upto Ariyankundu. The horns are pointing towards North
east direction. It has a length of 6 Kms and width ranges
from 0.5 Km near Kudiyiruppu. The height of the dune
raises upto 6 Mts. near Kalugupuli. The dune complex
observed around Olakude, Erakadu, Mangadu, Sambi,
Gandhamanaparvatam covers an area of 8 to 10 Sq.Kms.
The height of the individual dunes varies from 1M to 10
Mts. The highest dune is observed near Gandhamana,
over which the temple Ramarpatham is located. The wind
ward side of the parabolic dune and all the dunes of dune
complex exhibits steep slope and leeward side exhibits
gentle slope. The horns of the parabolic are pointing
towards windward side.
In the area East of
Tangachchimadam numbers of parabolic dunes are
Creeks: Tidal creeks are inlets, through which water
flows to and from a lagoon or other backwaters
during high and low tides respectively. Creeks are
observed in southwest part near Pamban and
Ayyanthopu. Near Pamban, the creek is of ‘Z’ shaped
in nature found nearer to the spit having a length of
1 km approximately. They are also noticed in the linear
portion of the island through which the seawater enters
into the lagoon.
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Res. J. Earth Sci., 2 (2): 30-35, 2010
Table 2: Radiometric dates of Coastal Quaternary deposits
Sl. No.
1
Reference
Site
Bruckner [11]
Rameshwaram
Specifications
Laboratory No.
Coral reef, noth
---
Age
112 ka (ESR)
side of the Island,
Remarks
Last interglacial
maximum
Porites.sp. upto
+2.5m above
2
Stoddart and
Rameshwaram
Gopinadha Pillai [12]
Porites.sp from
GAK-3187
the raised coral
Loveson [13]
Ariyankundu
---
yr. BP.
reef at Pamban
3
4020+/-160
(14C age)
Coral +0.55 m
30/248/C5
5440+/- 60
Middle Holocene
above MSL
yr. BP.
(14C age)
transgression
Spits: Spits are beaches which leave the main shoreline,
usually at estuary mouths or bays and project into deeper
water before terminating. When a shoreline following
by a littoral current turns abruptly landwards, as at the
entrance of a bay, the current dose not turn with it but
holds its course, the supply of shore drift brought to this
point by the littoral current dose not cease and the
necessary result is accumulation. In study area the spit is
observed near Pamban and Ayyanthopu. The projection
of spit near Pamban is in southern direction and in
Ayyanthopu in south west direction. The tail like portion
of Rameswaram Island itself is a spit that has been formed
by the movement of littoral current between Rameswaram
and Srilanka.
regression low. Recent marine processes construct Barrier
bars with enclosed lagoon at south eastern portion of the
Island.
REFERENCES
1.
2.
3.
Coastal Evolution: A proper interpretation of coastal
landforms will generate the details of the processes and
materials that were involved in the genesis of landforms,
which in turn will help in understanding the coastal
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Island is obtained by different researchers were collected
and these data were used for understanding the evolution
of coastal landforms of Rameswaram (Table 2).
Rajamanickam and Loveson [10], based on C14 results
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Quaternary sea level change aeolion process and resent
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4.
5.
6.
CONCLUSION
7.
In the origin of landforms the following sequence of
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sea level. The dunes were formed subsequent to the
8.
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35