Southeast Asia map showing the distribution of Jurassic–Cretaceous non-marine sediments in Southeast Asia (modified from CCOP’s 1:2 million Geologic map of East and Southeast Asia), Number in circles = rock formations: 1, Lower Phu Kradung; 2, Upper Phu Kradung; 3, Phra Wihan; 4, ?Tembling Group; 5, Gagau Group; 6, Khok Kruat; 7, Grès Supérieurs; 8, Xinlong (Thanh and Khuc 2006; Department of Mineral Resources 2014; Uchida et al. 2017; Teng et al. 2019; Yan et al. 2019).