The western Thailand and the Baoshan area of western Yunnan, China, were both part of the Sibumasu Terrane during the Early Paleozoic, located at low-latitudes of the peri-Gondwana. In November 2019, the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), and Mahasarakham University in Thailand signed a Memorandum of Understanding, initiating an in-depth collaboration in the field of geology and paleontology. Supported by this memorandum, the Early Paleozoic research team from NIGPAS conducted field investigations in Thailand in January 2020 and March 2023. Together with colleagues from Thailand, the team collected abundant conodont samples from the Ordovician and Silurian strata.
Recently, Associate Professor Dr. CHEN Zhongyang, Dr. FANG Xiang, Assistant Professor Dr. LI Wenjie and other colleagues from the Early Paleozoic research team at NIGPAS, together with Professor Clive Burrett, Associate Professor Mongkol Udchachon, and Hathaithip Thassanapak from Mahasarakham University, Thailand, conducted analyses and systematic studies on these conodont samples. The significant findings, enriching the fossil records of Early Paleozoic conodonts in western Thailand and providing new insights into the paleobiological communities and paleogeographic environments. The research result was published in Journal of Palaeogeography and Palaeoworld.
(1) New insights into Ordovician conodonts from the Ban Tha Kradan area in western Thailand
Nine genera and 11 species of conodonts were reported in the Ban Tha Kradan area of western Thailand for the first time. By the analysis of lithology and stratigraphic ages, the upper part of the Tha Manao Formation in the western Thailand was revised as the Pa Kae Formation. Based on conodonts and macrofossils, the Tha Manao Formation in western Thailand is assigned to the upper Floian to Darriwilian, and the conformably overlying Pa Kae Formation to the Sandbian to lower Katian.
(2) First report of early Silurian conodont fauna in western Thailand
For the first time, the early Silurian conodonts were documented in western Thailand. Samples from the Kroeng Kravia Forest Park area revealed the upper Telychian Lower Pterospathodus amorphognathoides amorphognathoides Subzone. Analysis of microfacies and conodont fauna indicate that these fossils originated from a relatively deep marine environment. Furthermore, the conodont fauna is similar to that from Baoshan area of Yunnan Province and Langao area of Shaanxi Province in West China and resembles that from similar depositional environments in Australia, Laurentia, and peri-Gondwana, suggesting good connections among these regions by ocean currents.
This series of studies was supported by the National Key Research and Development Program of China, the Second Tibetan Plateau Scientific Expedition and Research Program, the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China, the Chinese Academy of Geological Sciences, and the Mahasarakham University.
Reference:
Chen, Z.Y., Li, W.J., Fang, X., Li, C., Burrett, C., Udchachon, M., Zhang, Y.D., 2024. Ordovician conodonts from the Ban Tha Kradan area, western Thailand. Palaeoworld, 33(3), 546-558. https://doi.org/10.1016/j.palwor.2022.12.004
Chen, Z.Y., Thassanapak, H., Li, W.J., Wu, X.J., Udchachon, M., Fang, X., Burrett, C., 2025. First documentation of early Silurian conodonts from western Thailand and its geological implications. Journal of Palaeogeography, 14(1): 157-171. https://doi.org/10.1016/j.jop.2024.08.010
Fig. 1. Ordovician conodonts from the Tha Manao Formation, Ban Tha Kradan area, western Thailand
Fig. 2. Silurian conodonts from the Kroeng Kravia Forest Park area, western Thailand
Fig. 3. Correlation of the stratigraphical successions of the Floian to Katian between the Sibumasu Terrane and the Upper Yangtze Platform of South China
Fig. 4. Distribution of the upper Telychian conodont faunas containing Pterospathodus pennatus procerus, Panderodus langkawiensis, and Dapsilodus spp.
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