Geologists suggest protecting the site of red sand dunes

Geologists have suggested to protect the site of Coastal Red Sand Dunes, of Visakhapatnam, Andhra Pradesh.The Coastal Red Sand Dunes is also known as ‘Erra Matti Dibbalu’. It is one of the many sites of Visakhapatnam, which have geological importance.The site is located along the coast and is about 20 km north-east of Visakhapatnam city and about 4 km south-west of Bheemunipatnam.The site needs to be preserved to study the impact of climate change, as Era Matti Dibbalu has witnessed both Ice Age and Warm Age periods.The site is approximately 18,500 to 20,000 years old and may belong to the last Ice Age.Such sand deposits are rare and have been found at only three sites in tropical regions in South Asia; Terry sands are found in Tamil Nadu, Era Matty Dibbalu in Visakhapatnam and another site in Sri Lanka.Many are not obtained in equatorial regions or temperate regions for scientific reasons.The site also has archaeological significance, as the study of artefacts indicates an Upper Palaeolithic age.

Distribution

• Such 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.

Uniqueness of these Sediments

Continuous Evolution

• The red sediments are a part of the continuation of the evolution of the earth and represent the late quaternary geologic age.
• The Quaternary Period is a period on the Geologic Time Scale that’s known mainly for the spread of humanity and climate change. This period runs from about 2.6 million years ago to the Present Day.

Different Geomorphic Features

• 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.
• Badland topography is a dry terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded by wind and water.

Geochemically Unaltered

• The top light-yellow sand unit, which is 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 (not containing fossils) and deposited over the khondalite basement.
• Khondalite is a regional rock with high-grade metamorphism and granulite rock formation. It was named after the Khond tribe of Odisha.