Coastal Red Sand Dunes

Scientists recently urged the Government of Andhra Pradesh to protect the coastal red sand dunes of Visakhapatnam of the glacial period.

Major Points:

• Visakhapatnam is fortunate to have a number of significant geological sites. One of them is the Erra Matti Dibbalu, or "red sand dunes" of the coast.
• Location and Extent: The site is situated on the coast, about 20 km to the northeast of Visakhapatnam City and 4 km to the southwest of Bheemunipatnam.
• 20 sq km is the approximate size of the area where the Erra Matti Dibbalu is located, and the entire area has been designated as a Geo Heritage Site.

About Geo Heritage Site:

• The Geological Survey of India (GSI) designated this site as a geo-heritage site in 2014, and the Andhra Pradesh government added it to the list of "protected sites" in 2016.
• This site is geologically, archaeologically, and anthropologically significant, and it should be preserved for future study and evaluation.

Site Individuality:

• The late quaternary geologic age is represented by the red sediments, which are part of the earth's evolution.
• They have badland topography with various geomorphic landforms and features, such as gullies, sand dunes, buried channels, beach ridges, paired terraces, the valley in the valley, wave-cut terrace, knick point, and waterfalls.

Shows the real-time consequences of climate change:

• The sea (Bay of Bengal) was at least 5 kilometres behind the current coastline around 18,500 years ago.
• Since then, it has been undergoing continuous active changes until approximately 3,000 years ago, and the changes are still ongoing.

Geochemically unchanged:

• Because the sediments were geochemically unaltered, the top light-yellow sand unit, which is thought to have been deposited around 3,000 years ago, could not achieve the red coloration.
• These sediments are nonfossiliferous and have been deposited on top of the khondalite basement.
• The dunes are made up of light yellow sand dunes at the top, a brick red sand unit in the middle, and a reddish brown concretion bearing sand unit with yellow sand at the bottom.
• The bottom yellow sand unit is fluvial, while the three units above it are aeolian in origin.

The Site's Importance:

• Examine the effects of climate change, as Erra Matti Dibbalu has lived through both glacial and warm periods.
• The site is approximately 18,500 to 20,000 years old, can be linked to the last glacial period, and will provide information about the archaeological history.
• The site is also archaeologically significant, with artifact studies indicating an Upper Palaeolithic horizon and cross dating assigned to the Late Pleistocene epoch, which is 20,000 BC.
• The site was inhabited by prehistoric man, as excavations in the area revealed stone implements from three distinct periods, as well as Neolithic pottery.
• Such sand deposits are uncommon and have only been reported from three locations in south Asia's tropical regions: Teri Sands in Tamil Nadu, Erra Matti Dibbalu in Visakhapatnam, and one more in Sri Lanka.
• They do not occur in equatorial or temperate regions for a variety of scientific reasons, making them geologically significant.