Accurate dating of ancient architectures is always an important but challenging task in not only archaeology but also science and technology. In this work, we developed an improved thermoluminescence dating technique, which was able to determine the chronology of ancient architectures with a very high accuracy (less than 5%). Our development was proposed based on a heterogeneous and multilayered model with cylindrical configuration for both excavated and buried status. Application of the proposed model to some ancient architectures at the Oc Eo – Ba The archaeological complex in Vietnam showed that our model was able to accurately determine the chronologies of architectures having heterogeneous, multilayered and overlapped structures, while conventional spherical and homogeneous model predicted the chronological results of ten to several hundred years higher. Our proposed model also explicitly exhibited the significant contributions of excavation, destruction, and radiation shielding to the accurate determination of chronology. In particular, with this newly proposed model, we have shown the first scientific evidence for the formation of an overlapped architecture in an architectural assembly at Oc Eo — Ba The, namely there was an (older) architecture constructed around AD 794 and lasted for about 159 years before being destroyed, probably by the kingdom’s historical upheavals. Since then, another (younger) architecture was built on top of the older one’s foundation [1]. Our findings, which are also in good agreement with the radiocarbon dating using accelerator mass spectrometry (AMS), are crucial for archaeology as they provide solid evidences for the historical argumentations associated to the mysterious ancient Funan kingdom that spread across many countries in Southeast Asia, including Southern Vietnam. They also open a new research approach towards re-dating the chronologies of controversial complex architectures, which can change our understanding on the history of many nations in the world.

[1] Phan Trong Phuc, Nguyen Thi Ngoc Hue, Pham Thi Hue, Tran Tuan Anh, Nguyen Khanh Trung Kien, Lo Thai Son, La Ly Nguyen, Tran Dong Xuan, Van-Phuc Dinh, Nguyen Hoang Long, Nguyen Van Tiep, Cao Dong Vu, Le Ngoc Thiem, Ngoc-Quynh Nguyen, Hoang Anh Tuan Kiet, Nguyen Quang Hung, and Luu Anh Tuyen, Improved thermoluminescence dating for heterogeneous, multilayered, and overlapped architectures: A case study with the Oc Eo archaeological site in Vietnam, Journal of Archaeological Science 155, 105800 (2023).