<Notes>Saline Soils in Northeast Thailand : Their Possible Origin as Deduced from Field Evidence

Abstract

The selected profiles of saline soils in the vicinity of Khorat, Northeast Thailand, are described. Geomorphological interpretation of the profiles make the following points clear regarding the origin of the salt : 1) Some shales and sandstones belonging to the Mahasarakam Formation of the Mesozoic Khorat Group retain in-situ salt even when they are located as little as 1 to 2m below the ground surface. The salt is released by erosion and weathering. This is the mechanism of extraction of salt from the source rock. 2) Only the Mahasarakam Formation seems to be a source of salt. Other rocks, including the older formations of the Khorat Group, appear not to contribute the development of salinity in the area, because they do not contain salt.