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Iron Smelting Industry of Kedah Tua
Authors: Nazrin Rahman, Mokhtar Saidin, Najmiah Rosli, Nor Hidayah Ahmad & Rosli Saad
Kedah Tua in Bujang Valley (Malaysia) is the less familiar civilisation and was most distinguished for its global-scaled trading activities. Contrary to popular belief, Kedah Tua is the oldest civilisation in Southeast Asia that surpasses even the famous civilisations in Borobudur (Indonesia) and Angkor (Cambodia) such as illustrated in Fig. 1.
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Kedah Tua’s initial trading centre was at Sungai Mas entrepot, which sat at the river mouth of Muda River and faced the open sea during its peaked trading period. Due to global sea level regression and the ever-growing number of ships landing at Kedah Tua, Pengkalan Bujang offered better accessibility for traders with wider port, while Sungai Mas became further inland and less preferable (Fig. 2). Therefore, the trading centre migrated from Sungai Mas to Pengkalan Bujang during 11th AC. Nevertheless, Sungai Mas entrepot played a pivotal role in developing Kedah Tua.
Being one of the best iron producers in the prehistoric world, Sungai Mas of Kedah Tua was an entrepot for various world civilisations including China, India and Arab through iron industry. With Muda River as the backbone of Kedah Tua’s trading, the river connects numerous iron smelting sites to the entrepot for supply and to transport iron products from inner parts of Muda River to the entrepot. These iron smelting sites were within 20 km radius from the entrepot (Fig. 3).
As more iron smelting sites were traced along Muda River to map the extension of Kedah Tua’s iron producers, this consequently brought light upon Kuala Ketil. Kuala Ketil is 30 km up the river from Sungai Mas and is out of the typical 20 km radius of iron smelting sites from the entrepot. To verify the existence of iron smelting activity at Kuala Ketil, Global GeoExperts in collaboration with Centre for Global Archaeological Research employed 3D resistivity to identify indications of iron smelting activity at the area.
Referring to Fig. 4, the low resistivity anomaly (<350 Ωm) is predicted to be made of clay, which is one of the common materials used for refractory products. Post-burning process in the furnace altered the physical and chemical properties of the furnace wall by the displacement of fluid from the pore-spaces; therefore, becomes stiffer and increases in resistivity. Combination of clay and sand are commonly used in refractory products to withstand high temperature and pressure conditions. Iron leftovers are also often found inside the furnace in addition to irons embedded in its wall, which lowers resistivity values of the furnace.
The 3D resistivity (Figure 5) model indicates resistivity values of >350 Ωm, which represent the soil underlying the furnace while the hollow central top part indicates the location and shape of the suspected furnace (red circle). Clearly, only that specific part has low resistivity while surrounded by higher resistivity ground materials. This further shows that the anomaly is made of a different material as compared to the surrounding ground.
Based on this study done by our team, the location for the excavation was pinpointed. Indeed, the excavation successfully unearthed a furnace, bringing a great closure for our team by confirming the findings of the study.
Original paper: https://link.springer.com/article/10.1007/s11759-020-09402-x#citeas
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