Khao Sok history
435–380 million years ago…(Carboniferous period)
The erosion of the Shan-Thai landmass resulted in the deposition of sediments and pebbles into a large river delta system. Periodically these deposits would slide down the basin edge and into the sea. Over a period of millions of years the sea became shallower and thus warmer and resulted in good conditions for coral and other marine organisms to populate the area.
280–225 million years ago…(Permian period)
Limestone (calcium carbonate) deposits began to form as the marine life established a coral reef that is said to have been five times the length of the Great Barrier Reef in Australia, stretching from China to Borneo. This is the reason Khao Sok and Krabi (Thailand), Guilin (China) and Halong Bay (Vietnam) and Sarawak (Borneo) have such similar topographies.
The Karoo Ice age was between 350 and 260 million years ago, so as sea levels rose as a result of ice melt, the coral reefs grew, keeping pace with the water surface.
The marine ecosystem was eventually buried under another layer of sediments (the end of the ice age meant increased rainfall and thus increases in erosion/sedimentation). The resulting high pressure from being buried under hundreds of metres of sediments resulted in the formation of the limestone rocks we can still see today.
136–66 millions years ago…(Cretaceous period)
Magmatic intrusions of granite also formed, the chemical reaction between the molten granite and sedimentary rocks formed deposits of tungsten and tin.
66–3 millions years ago…(Tertiary period)
The Indian plate collided with the Eurasian plate, forming the Himalayas and causing the landmass of Thailand to rotate clockwise and move south east. The limestone, sandstone and granitic rocks were uplifted, folded and faulted, exposing them to erosion by rain and river waters.
The limestone rocks have been partially eroded, by acidified water (resulting from the rain water flowing through the rainforest leaf litter) leaving the beautiful karst formations we see today.
50000 – 37000 years ago
There is evidence of human inhabitation on Borneo between 37 000 and 50 000 years ago. The last ice age ended about 10 000 years ago, meaning there could have been migrations (by land) from Borneo to Thailand during the period of the ice age. Certainly, the habitat in both locations was similar enough to support these people. There is also biological evidence, for example, the bamboo species Gigantochloa balui is normally only found in cultivated areas of Borneo – never truly wild, yet this species has been discovered growing wild on the Thai peninsula. It is highly unlikely this species moved between these countries without being carried by human beings.
The first accounts of people living in Khao Sok date back to the reign of King Rama II, when the Burmese attacked south western coastal towns and many local people fled into the jungle for safety. As news spread that the region was rich in animal life, with fertile fluvial soils and good rainfall, more people came to the region.
A deadly epidemic swept through the region killing a large number of the population, those who survived moved back out of the area. The village became known as “Ban Sop” – which means “Village of the Dead”, although there is a mountain in the local area known as “Khao Sop” or “Corpse Mountain” which may also be the reason the village was named in this way.
The 401 road was constructed between Phun Pin (Surat Thani) and Takuapa (Phangnga). This opened up the whole area for settlements and plantations, the modern weapons and tools that came with the new peoples meant nature was in trouble. The logging and mining (tungsten and tin) industry soon followed, to the cost of the rainforest and the Sok river, which began to run brown with sediment runoff as a result of the soil erosion.
Thai students, who had joined the communist insurgency groups, set up a stronghold in Khao Sok, since it was ideal territory to hide and operate guerilla warfare. Between 1975 and 1982 these students not only kept the Thai Army at bay, but also kept the loggers, miners and hunters out. Had it not been for this seven year occupation, Khao Sok’s forests may well have gone the same way as much of the rest of Thailand’s wilderness – up in smoke.
Also during this period there was considerable interest from the government and the Electricity Generating Authority of Thailand (EGAT), since research had shown Khao Sok to be the largest watershed in southern Thailand.
The National Park Division also carried out some research and established the fact there was still considerable biodiversity worth protecting in the region.
22nd December 1980
Khao Sok National Park was established.
EGAT established the Rajjaprabha Dam – closing off the Pasaeng river and creating a 165 square kilometre lake, inside the National Park Boundaries.
This dam was built to guarantee a source of electricity to the south, which by now had become a major holiday destination. EGAT attempted the largest capture and release operation (to save the animals facing drowning in the lake) ever in Thailand. Unfortunately, this operation was largely unsuccessful and many of the species captured died from the stress. A World Bank study in 1995 revealed the loss of some 52 species of fish from the river, because they were not adapted to the deep waters of the lake.