New evidence confirms pre-continental sedimentsin Kutch and Cambay

Vasco-da-Gama (India Science Wire): Researchers have found the presence of thick sediment layers dating back to pre-continental era in the Cambay and Kutch basins of Gujarat. 

Using electromagnetic geophysical methods, scientists from Allahabad centre of the Indian Institute of Geomagnetism found presence of pre and post continental sediment layersin the region. 

Researchers measured the earth’s natural electric and magnetic variations and observed two high conductive and one high resistive layer. The high resistive layer shows volcanic eruptions known as Deccan Traps,is about 0.5 to 1.5 kilometrethick. 

The top conductive layer is about 2 to 6 kilometresthick Cenozoic sediment, while bottom layer is the pre-continental Mesozoic sediment. 

Scientist carried out the magneto telluric surveys along four east-west corridors in the two basins passing through major geographical locations at Sanchore, Tharad, Diyodar, Patan and Mehsana. 

The earth’s electric and magnetic field variations were measured at 68 points to understand the basement configuration and sediment thickness. 

The thickness of pre-continental sediment could not be measured but these are very thick at Mehsana site and thin at other sites, researchers said. The basement of Cambay and Kutch basins is approximately5 to 7.7 kilometresdeep. 

“The deephigh conductive zone observed near Mehsanasupports the evidence of thick pre-continental sediments as suggested by deep seismic and other studies. 

Thick Cenozoic and Mesozoic sediments play a role in tectonics and generation of intraplate earthquakes in these basins,” explained Dr CK Rao, leader of research team,while speaking to India Science Wire.

The Mesozoic and Cenozoic sediments are records of evolutionary history of continents. The present continents evolved from one supercontinent Pangea during the Mesozoic era.It broke up into two parts -Gondwana and Eurasia. 

These two parts further broke up into continents and started drifting. The Cambay and Kutch rift basins record the earth’s evolutionary history as they evolved in the Mesozoic time, underwent changes with basaltic lava eruptions and Indo-Eurasian continental plate collision which formed the Himalaya.