Tucked away in a remote corner of Karnataka, an invaluable piece of India’s metal heritage is being damaged permanently, thanks to its proximity to the Arabian Sea.
The 8.7-metre-tall iron pillar, weighing 500 kg, is located at the Adi-Mookambika temple at Kodachadri in Karnataka. It is one of the oldest examples of ancient Indian metallurgy, which culminated in key achievements between the second and sixth century AD.
Though the pillar’s antiquity remains unknown, scientists said iron-making process used was the same as the ones used for making the so-called Adivasi (tribal) iron. But, unlike the more famous iron pillars at Delhi and Dhar (Madhya Pradesh), the Karnataka mast did not receive much scientific attention in the past.
The pillar exhibits more corrosion compared to the other two pillars at Delhi and Dhar. The roughness (corrosion) of the pillar increases with height. The top 1.25 metre of the pillar exhibits extensive erosion or corrosion.
T R Anantharaman, one of India’s eminent metallurgists and a former emeritus professor with National Physical Laboratory, Delhi, first studied the pillar almost 15 years ago. He said the pillar deserved a “detailed and serious study” because it presented a period in India’s iron-making skills before the Delhi and Dhar era.
Nuclear scientists at Indira Gandhi Centre for Atomic Research, Kalpakkam and Atomic Minerals Directorate, Bangalore, have now scientifically inspected the ancient pillar only to discover that the top one metre of the pillar (a little less than 4 feet) was severely corroded by the onslaught of nature.
The damage was maximum on the western side of the pillar, which is being hit continuously by high speed wind from the Arabian Sea, only 30 km away.
“The top 1 metre of the pillar shows excessive erosion or corrosion specially on the surface facing west towards the Arabian Sea, which is attributed to the direct exposure to saline atmosphere with high wind velocity,” the scientists reported in the December 25 issue of the journal Current Science.
Popularly known as the Dwajasthamba (flag staff), the iron pillar is located next to the Adi-Mookambika temple at Kodachadri, about 40 km from Kollur, a town located about 120 km north of Mangalore in the Dakshina Kannada district of Karnataka.
Local tradition indicates the flag staff was actually the top portion of a trishul (trident) with which the “Mother Goddess” nailed a demon into the bowels of earth.
When the IGCAR team carried out several non-destructive testings on the pillar and observed a small sample under a scanning tunnelling microscope, they found the Karnataka pillar was starkly different from the Delhi iron pillar in one key aspect, it had less phosphorous than the one on the Qutab Minar complex. Moreover, it contained less carbon.
The presence of iron oxide particles in the pillar and other scientific analysis demonstrated the iron pillar at Kodachadri was produced by the ancient Indian iron-making route using solid-state reduction process, the scientists reported.