Unravelling the evolutionary history of coastal Kerala

The implication:The study will fill the missing knowledge gaps from the past 20,000 years to the present.— photo: SPECIAL ARRANGEMENT  

Geoscientists are peering into the geological and evolutionary history of the coastal belt of Kerala to predict possible climatic and geomorphologic changes. 

A group of researchers from the Thiruvananthapuram-based National Centre for Earth Sciences, led by D. Padmalal, are reading the sedimentary columns collected from boreholes drilled along the coastline. 

Bore holes are drilled up to 50 metres to obtain undisturbed sediment samples. The sedimentological, palynological and geo-chronological analysis of the sediments collected from these boreholes will reveal the palaeoclimate and palaeoenvironment. Around 30 such boreholes have been dug along the coastline. Currently, research is progressing in the Kodungalloor area in Thrissur district, explained Dr. Padmalal.

The focus is to understand the evolutionary process of the Kerala coast. Since climate changes are cyclic in nature, there is a need to know the climatological data going back to at least 20,000 years to precisely predict the future and possible climate and geomorphological changes. The study will fill the missing knowledge gaps from the past 20,000 years to present, he explained.

The chronological profiling and analysis of sediments dating back to over 20,000 years is of utmost importance as the scientific community has climate data including rain and temperature of the past 150 years.

Pollen grains and spores found embedded in sediments and pulled out from beneath the earth’s surfaces (they are classified as proxies, which are considered as the indirect indicators of climatic conditions) will reveal information about trees and vegetation present then.

The stable isotopic examinations of shells found in sediments can provide us information about temperature of water, productivity and influx of fresh water from the land to water bodies. Historical data about sea level rises, mineral deposits and receding sea level can also be read out of the data, he said.

“A full sediment column can be considered as pages of a book. The geoscientists can read the sediment pages of a borehole core and tell the evolutionary details of a given location,” he explained.

The “drilling studies in the coastal lands (areas below 10m from mean sea level) of Periyar River basin could unfold the channel migration over the years and also provide insights into human migration and related aspects,” he said.

The coastal lands of the entire west coast will be covered under the ongoing research project. These studies will reveal how the coastal areas evolved over the years and the climatic and environmental conditions that influenced these changes, Dr. Padmalal explained.