Attached
Sea level have fluctuated throughout the geological history, intermittently inundating or
retreating coastal plains. Analysis on changes of such sea level oscillations recorded in
the coastal plains are important to predict future global sea level trends. Inland coral is
one of the most reliable proxy which provide clear evidence for Holocene sea level
change, since corals thrive in many low- latitude coastal environments, in the intertidal
zone. Several inland coral beds and beach rock submerged by surface soil layers
existing in southern coastal belt of Sri Lanka can be used to identify paleo-sea level
height and paleo-coastal position of the area. GPR survey along selected traverses in
Walgama area in Matara district were carried out to identify the extension and the
distribution of the submerged coral beds. Digital Elevation Modal (DEM) created using
Light Detection and Ranging (LiDAR) data was used to identify the coastal
geomorphology and to infer the paleo-sea level height and paleo-coastal position.
Processed GPR images indicate that the submerged coral beds and beach rock extend
up to 0.5 km towards inland and approximately 1.0 - 3.5 m in depth. These results were
confirmed in the field by using observations made at the wells and abandoned coral
mining pits in the vicinity. Further, GPR survey indicates that these submerged coral
beds do not extend as a continuous bed, however they appear as pockets. Using the
developed DEM, the paleo sea level was identified existing along the 5 m contour line.
For further confirmation, cross sectional profile sampling and measuring dielectric
properties are needed to be carried out in addition to constructing a detailed map
combined with chemical data as the next step of the research
