ERRA MATTI DIBBALU ,VISAKHAPATNAM,ANDHRA PRADESH

• Some scientists are of the opinion that the initial chapter of this epic story took place in the "Pleistocene" period from around 1.8 million years ago to around 10,000 years ago. 

• During that time the sea level rose to as much as 50 meters above the current level and fell away below the current level many times. 

• Between these oscillating sea levels the coast was submerged and exposed over and over again. When the sea receded it left behind huge volumes of clay and silt. 

               

                               

• Subsequently, the beach sand swept over the clay and silt, and over time this "Aeolian" (carried by wind) sand covered the earlier soil forming large sand dunes. 

• The clay and silt under the sand then "baked" in the sun much like a brick gets baked in a kiln leading to the peculiar red earth. Later, action of the wind and flowing water caused the deeply gullied characteristic landscape. The red colour of the dunes is said to be due to the "ferrogination" of "haemitite". 

           

                                    

• This simply means that iron rich material haemitite coated the loose sand grains and when it got exposed to the elements the stuff oxidized over a period of time. Just like a nail exposed to salty air would get corroded and appear red in colour.