Date | Sept 30, 2016:
Copper smelting processes in Karnataka could have started in the first century BCE, a new research has found. Rather than starting from the Chalukya-Pallava dynasties (5th Century), copper smelting started in Karnataka during the Satavahanas (1st BCE). Now it is also possible to date bronze statues to a particular age by checking their nickel content and lead isotope content.
Bronze statues in south India date from the dynasties of Chalukya, Pallava, Chola and Vijayanagara (fifth to eighteenth centuries). A researcher from the National Institute of Advanced Studies (NIAS), Bengaluru, has found copper smelting processes amid Satavahana (first century BCE) pottery near the old copper workings at Ingaldhal, Chitradurga, in Karnataka. Slag is waste matter separated from metals during the smelting or refining of ore. Copper smelting in south India can now be pushed back by 600 years.
The legacy of erstwhile dynasties of south India survives through the monumental temples they built and metal alloy images they produced. The study by Dr Sharada Srinivasan sheds light on the processes and techniques used. He studied around 130 bronze sculptures and found that lead isotope ratio and compositional analysis helped in finding the ‘finger-printing’ and pin-pointing these to a particular age and thus the dynasty. So bronzes with unknown provance can now be given an age and attributed to a dynasty.
Numerous ‘‘old workings’’ from the mining of copper and copper–lead ores in southern India were explored by the author. “Slag and archaeo-metallurgical investigations suggest the exploitation of some copper and lead-silver sources in the Andhra and Karnataka regions in the early historic Satavahana period and point to probable copper sources for the medieval images in Karnataka, Tamil Nadu, and Andhra Pradesh,” says Dr Srinivasan in her research paper, which has been published in “The Journal of The Minerals, Metals & Materials Society (JOM)”. She told Bangalore Mirror that this confirms prospecting and mining for copper base metals, at least by the early historic period in southern India.
“Preliminary analyses of copper slags from Somalaragada and Malapadu in Andhra Pradesh and bronze slags with seven per cent tin from Kalyadi in Karnataka indicated that they had similar nickel/copper ratios (three) to the Chola group. On the other hand, slags from Tintini, which is close to Hampi, the Vijayanagara capital, had nickel/copper ratios of around 30–35, more akin to the Vijayanagara group,” say the findings.
Lead isotope ratio and compositional analysis in the finger-printing and art historical study of the sculptures is highlighted in the study, including Nataraja, Buddha, Parvati, and Rama images made of copper, leaded bronze, brass, and gilt copper. “This study demonstrates how archaeo-metallurgical studies, with all their challenges and prospects, might throw further light on the stylistic intricacies, religious connotations, and origin of medieval and early historic copper alloy sculptures,” she added
The research, which spanned over two-and-a-half-decades, shows that the southern Indian region formed part of a vigorous maritime trade network in antiquity.
Further analysis could also help one locate the source of ores used in casting the images, thus shedding more light into trade relations that existed in the past. It uncovers other facts like leaded bronze being widely used for casting antique images in south India. Dr Srinivasan says that although brass and metallic zinc seems to have been in vogue by the early historic period, a preference for brass in ritual artefacts such as lamps over images may be detected. About 80 per cent of the 130 medieval and early historic South Indian images were leaded bronzes with tin ranging up to 15 per cent. The rest were leaded brasses with zinc varying up to 25 per cent and lead up to 25 per cent.
The findings further reveal that although several images had up to 20 per cent lead and between eight per cent and 15 per cent tin, several of the artistic masterpieces studied are in fact of low leaded, low tin bronze, indicating their mastery over making solid castings of such less fluid alloys too.
“We may surmise that the early historic and early medieval use of efficient moulding techniques and effective gating designs with multiple sprues and runners for distribution of metal had resulted in good castings that required less post-cast tooling,” says the study.
Significantly, the technical fingerprinting study suggested that the Nataraja bronze, depicting Siva dancing the “anandatandava with the lifted leg extended in bhujangatrasita karana”, might have been a Pallava rather than a Chola innovation. “Two Nataraja images previously classified as early Chola, better fitted the linear lead isotope trends for the Pallava group. One of these is a charming Nataraja image from Kunniyur, which from the absence of the flying matted locks, may be attributed to the pre-Chola or later Pallava periods,” it says.
(Source: http://www.bangaloremirror.com/)