Structural geology of Thailand during the Cenozoic

Thailand's crustal properties from tele-seismic receiver function studies

“…Prior to this study, little was known about the crustal structure of Thailand, particularly its thickness and composition (Morley et al, 2011). Here, our discussion is therefore aimed at linking our results to Table 1. previous geological studies and the receiver functions studies from other regions outside of Thailand in order to determine the crustal properties of Thailand.…”

“…The thicker crust makes the Khorat Plateau a "unique" area of the Indochina terrane. Our simple possible explanation for the difference in crustal thickness within the same ICT terrane is the fact that the KP-ICT is a forefront for many past collision activities; it was subducted by the paleotethy in the west during the Triassic (Charusiri et al, 2002), and then uplift as a result of the derived force from the neighboring plate collisions in the west (Morley et al, 2011).…”

“…Although these previous studies were the first to reveal the difference in crustal thickness, they did not provide any reasons or interpretations to explain the difference. None of the previous geological and geophysical studies have mentioned the difference in crustal thickness between the two major terranes (see Milsom, 2011;Morley et al, 2011) Information gained from the receiver functions studies such as the crustal thickness and the Vp/Vs ratio has been known to be very powerful. They can provide clues and can be the key to a better understanding of the crustal composition, the crustal deformation/evolution between or in the upper crust and lower crust, magmatic underplating, and obtaining a isostatic relationship between the crust and upper mantle (e.g., Assumpcao et al, 2002;Christensen and Mooney, 1995;Nair et al, 2006;Nguyen et al, 2013;Tian and Zhang, 2013;Tugeme et al, 2012;Wang et al, 2010;Xu et al, 2007;Yuan et al, 2002;Zandt and Ammon, 1995).…”

The role of strike-slip faults in the displacement of the Palaeotethys suture zone in Southeast Thailand

“…Aeromagnetic data (e.g. Sangsomphong et al, 2008;Milsom, 2011;Morley et al, 2011) suggest that at least some of them connect via an E-W segment through Bangkok with the Three Pagodas Fault system of Western Thailand, and Ridd and Morley (2011) pointed out that strike-slip faults were responsible for the emplacement of allochthonous Carboniferous to Triassic fossiliferous rocks in what is here called Belt III. The two most important of these are the fault belts which bound Belt III, the Klaeng Fault on the west (e.g.…”

“…The Klaeng Zone, on the other hand, does qualify as a terrane, albeit with a more complex, branching Klaeng Fault alignment than that shown by Ueno and Charoentitirat (2011). Watkinson et al (2008) and Morley et al (2011) have discussed in detail the nature and timing of movements on the major strikeslip faults of Thailand, concluding that although there were heating events as well as some dextral movements in the Mesozoic, the main phase of sinistral wrench faulting occurred in the Palaeogene. The limited geochronological studies carried out in Southeast Thailand are consistent with that conclusion.…”