Coastal Red Sand Dunes of AP

Coastal Red Sand Dunes of AP

Subject: Geography

Context: Scientists urge Andhra Pradesh govt. to protect glacial-period coastal red sand dunes of Vizag to study the impact of climate change as it has seen both the glacial and the warm periods.

Content:

• The coastal red sand dunes is popularly known as ‘Erra Matti Dibbalu’.
• The site is about 18,500 to 20,000 years old and it can be related to the last glacial period.
• The uniqueness of this site is that the red sediments are a part of the continuation of the evolution of the earth and represent the late quaternary geologic age.
• With a height of up to 30 m, they exhibit badland topography with different geomorphic landforms and features, including gullies, sand dunes, buried channels, beach ridges, paired terraces, the valley in the valley, wave-cut terrace, knick point and waterfalls.
• The top light-yellow sand unit (estimated to have been deposited around 3,000 years ago) could not attain the red colouration as the sediments were geochemically unaltered.
• These sediments are unfossiliferous and deposited over the khondalite basement.
• The dunes consist of light-yellow sand dunes at the top followed by a brick red sand unit, a reddish-brown concretion bearing sand unit with yellow sand at the bottom. 
• The site also has archaeological significance, as studies of artefacts indicate an Upper Palaeolithic horizon and on cross dating assigned to Late Pleistocene epoch, which is 20,000 BC.
• This site was declared as a geo-heritage site by the Geological Survey of India (GSI) in 2014 and the Andhra Pradesh government has listed it under the category of ‘protected sites’ in 2016.
• These sand deposits are rare and have been reported only from three places in the tropical regions in south Asia such as Teri Sands in Tamil Nadu, Erra Matti Dibbalu in Visakhapatnam and one more site in Sri Lanka.
• They do not occur in equatorial regions or temperate regions due to many scientific reasons.