The Carboniferous of northest Thailand: a review with new data

Abstract

A synthesis is provided of the many papers published on the Carboniferous of northeast Thailand since 1960, which have been restricted to localities north of latitude 17°10′N. In addition, new data are provided on Carboniferous localities recently discovered south of latitude 17°10′N. All stages of the Carboniferous are represented in northeast Thailand and their exposures are delimited in this paper.

In northeast Thailand, Carboniferous rocks are widely exposed in an area where Loei and Wang Saphung are the main towns, an area 20–40 km wide and 140 km long. In parts of this area, they are overlain by Permian strata (mainly limestone) in the core of a syncline. Middle-Upper Devonian limestone, shale and chert occur occasionally in the central and northern parts of the area. They are less widely distributed than the Carboniferous rocks but are obvious features because the limestone forms karstic hills and the chert outcrops are prominent.

An important development of shale during the Middle-Upper Carboniferous has favoured differential erosion so that today these rocks are distributed commonly in flat areas with paddy fields; the shale concealed under a few meters of earth. Their discovery has been due to farmers digging ponds at several places.