 The internal "Thai" elements, bordering the Indochina block, are of Cathaysian type and characterised by palaeo-tropical warm-water facies.The external "Shan" part has Gondwanan cold-water facies whilst the central "Sibumasu" part is transitional between the other two.The internal parts of Shan–Thai merged with Laurasia when the Nan-Uttaradit suture closed.