Volcanic rocks in Thailand are widely distributed in both time and space, although most occur in a broad swathe that extends from Northern to SE Thailand (Figs 15.1 & 15.2). They range in age from Carboniferous (and older) to Late Cenozoic, and have been key components in developing tectonic models for Thailand and for SE Asia as a whole (e.g. Bunopas & Vella 1978, 1983, 1992; Hutchison 1989; Barr & Macdonald 1991; Yang et al. 1994; Metcalfe 1996, 1997, 2002; Charusiri et al. 1997, 2002; Hada et al. 1999; Sone & Metcalfe 2008). Palaeozoic and Mesozoic volcanic rocks (Fig. 15.1) occur mainly in association with zones of deformed Palaeozoic and Mesozoic rocks generally referred to as the Sukhothai and Phetchabun fold belts (e.g. Bunopas 1981; Wielchowsky & Young 1985; Hahn et al. 1986). In contrast, Cenozoic volcanic rocks are more broadly distributed (Fig. 15.2).
The aim of this chapter is to summarize the available infor mation about these volcanic rocks and to highlight where uncer tainties exist. We build on earlier compilations such as those of Thanasuthipitak (1978a), Vichit et al. (1978), Panjasawatwong & Yaowanoiyothin (1983) and Jungyusuk & Khositanont (1992). Key information is summarized in tables that attempt to include all volcanic and volcaniclastic units,
Figures & Tables
The Geology of Thailand
This is the first volume in the English language to cover the entire range of the geology of Thailand since the joint Thai—US account by Brown et al. exactly 60 years ago. Over this period there has been a phenomenal growth in interest in this core area of SE Asia. This has been led by geologists in Thailand, but with important and highly significant input from geologists based elsewhere in Asia and in Europe, Australasia and North America. Some of that research was prompted by commercial considerations, since Thailand has important energy and mineral resources, while other research has sought to understand better the stratigraphic and structural history, including the plate-tectonic story which Thailand's rocks reveal. This new volume seeks to bring together all of this knowledge into a single accessible book; it is the work of an international team drawn from Thailand, Japan, Australia, USA, Canada, Germany and the UK.