Browsing by Author "Cai, S"

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    A brief history of Angkor’s iron: reconstructing multi-scalar chronologies in the Phnom Dek metallurgical landscape, Cambodia
    (Australian Nuclear Science and Technology Organisation, 2021-11-17) Hendrickson, M; Hua, Q; Cai, S; Tauxe, L; Leroy, S; Phon, K
    Iron was an essential commodity in the rise of Angkor, the largest and most influential state in mainland Southeast Asia between the 9th to 13th centuries. Multidisciplinary research around Phnom Dek in northern Cambodia revealed an extensive metallurgical landscape spanning over 1300 years of production activity and a dramatic increase in the scale of smelting correlating with the expansion of the Khmer Empire. Extensive AMS radiocarbon dating of in-slag charcoals from across the Phnom Dek region and materials recovered from furnaces and occupation at the site of Tonle Bak are used here to reconstruct the multi-scalar chronologies of production (furnace, mound, site, region) during this important time in Southeast Asian history. By integrating geomagnetic intensity data from furnace bases, we demonstrate that it is possible to identify temporal differences between ‘contemporary’ smelting sites within a single mound. At the scale of the slag mound and site we posit that the terminal use relates to ritual while the regional pattern indicates the Khmer state’s desire to increase production and improve access to iron resources needed for temples, warfare and daily life.
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    First constraint on historical geomagnetic secular variation in Cambodia, Southeast Asia
    (American Geophysical Union (AGU), 2018-12-13) Doctor, RK; Cai, S; Tauxe, L; Hendrickson, M; Hua, Q
    The geomagnetic field is a consequential component of the Earth, most importantly acting as a deflector of harmful solar radiation. Studying variations over the past thousands of years allows reconstructed field models to be used as a tool for archaeological dating, and helping to constrain the structure of the Earth’s interior. In current geomagnetic field models, Southeast Asia has little empirical historic data; therefore, archaeomagnetic data from Cambodia, an area currently devoid of data, can be used to refine the models. The purpose of this study is to examine the viability of using ancient furnaces to determine the secular variation of the geomagnetic field in Cambodia. Our samples are taken from ancient furnaces used for smelting iron, from the Khmer Empire near Tonle Bak, Cambodia. Via radiocarbon techniques, these furnaces have been dated between the 12th to 13th century. Twenty-six oriented samples were collected from three furnaces. These samples can be analyzed using paleomagnetic methods to measure the magnetic remanence vector and reconstruct the ancient magnetic field. Using a step-wise thermal demagnetization method, the direction of the field during the cooling of the furnaces was determined. Based on preliminary results (~20), samples from the furnaces are good recorders of the ancient magnetic field, resulting in excellent demagnetization behavior. Additionally, paleointensity experiments on the same samples will be conducted and should result in scalar values of intensity. Together, this study will give the full vector information of the geomagnetic field around 12th to 13th century in Cambodia, which can be used to recreate the geomagnetic secular variation in this area. © AGU 2018