Bulletin of the Geological Society of Malaysia, Volume 43, Dec. 1999, pp. 291 – 298
Economic Geology Division, Department of Mineral Resources, Bangkok 10400 Thailand
Abstract: Exploration for mineral deposits in the Gulf of Thailand has been conducted for more than ten years in the joint project between the government of Thailand and the United Nations. Geophysical surveys were carried out along boat track lines with a total distance of several thousands of kilometers. Minerals were extracted from several thousands of drillholes samples recovered from coastal plains and shallow marine areas.
Minerals found in the Gulf of Thailand are titanium minerals (ilmenite, rutile, leucoxene), abrasive minerals (zircon, garnet, staurolite) and tin mineral (cassiterite). A total ore reserve of the assorted heavy minerals is more than one million metric tonnes.
Occurrence of the mineral deposits is interpreted from characteristics of the sediments by comparison with the sediments found on nearby coastal plains. Depositional periods of the mineral deposits were estimated by comparison with global sea-level curves. The unconsolidated sediments in the Gulf of Thailand are deposited in several environments of deposition, including marine, non-marine, and coastal environments. The minerals are concentrated in coarse-grained alluvium and alluvial gravel bed which were deposited under non-marine conditions.
The mineral deposits in the Gulf of Thailand were formed by materials transported from granitic mountains in the coastal areas, as non-marine heavy-mineral placers in the shallow marine areas, during periods of sea-level low-stands when the Gulf of Thailand was a dry land, in the Pleistocene Epoch between 10,000 – 1,600,000 years before present.