If you get the chance, come visit Chiang Mai.
It is an enthralling place for nature lovers, adventure seekers, culture explorers and (naturally) researchers. For decades, geologists and archaeologists have been exploring and excavating the region to reconstruct its past, discovering a plethora of interesting and important information. Yet, as travellers ascend the northern mountains, lounge in hot springs, scale waterfalls and gaze temples, the fascinating background of these places may go unnoticed, lying beneath your feet.
So if you do visit, do not miss the opportunity to dig a little deeper. Here is some of the fascinating geology and archaeology behind (and below) four popular travel activities in Chiang Mai, Thailand.
Exploring mountains
Mountain ranges stand guard around the Chiang Mai valley. Doi Inthanon, the tallest mountain in Thailand, hovers amongst the western peaks (Doi means mountain in Thai). Not to be thwarted, the nearby Doi Suthep sits impressively next to the Old City. Reach their mountaintops and you will be rewarded with vistas of green mountains and valleys. Beneath the canopy of the forests, activities such as hiking, camping, river kayaking and mountain biking allow a more intimate exploration of these mountains.
But to truly know these mountains is to know how they came to be. It can be said that their story begins 2000 kilometres northwest, at the Himalayas.
50 million years ago, the Indian continent began its slow but dramatic collision into Eurasia. Land at the boundary has since been compressing and rising to form the immense Himalayan range. In the process, in a movement known as indenter tectonics, Southeast Asia was also deformed. The northeastern push of the Indian continent coincidently pulled the western edge of Southeast Asia along with it, applying a tectonic stress that wrinkled and stretched the landscape throughout southern China down to Indonesia.
Satellite imagery of the region is literally a freeze frame of a giant collision in motion.
As pieced together by geologists, this tectonic stress helped form the mountains of northern Thailand. In some places, where tectonic crusts were stretched, thinned and weakened, hot magma beneath welled upward and protruded into the crust above. These magma protrusions, known as metamorphic core complexes, have long since cooled and solidified, now remaining as granitic mountains such as Doi Inthanon and Doi Suthep.
Letting off steam at hot springs
Along the foot of the eastern mountains are the San Kamphaeng and Doi Saket hot springs. Visiting these hot springs is a relaxing and therapeutic treat, with traditional mineral baths, a mineral swimming pool and a hot, lazy river to soak your legs. At San Kamphaeng, little stands sell eggs for visitors to boil in the spring water and snack on, as geysers of steaming water spout behind.
While boiling your eggs or dipping your feet, it is intriguing to realise that the water has travelled from possibly several kilometres below the surface.
Both the San Kamphaeng and Doi Saket hot springs are located next to the Mae Tha fault, a crack in the tectonic crust. The fault is one of many across northern Thailand, all of which are the result of tectonic pressure. Hot springs often occur at faults, as these cracks become a pathway for deep groundwater to surge towards the surface and emerge as hot springs. Deep groundwater is hot because the temperature of the Earth increases with depth. The water that surfaces is boiling, but cools as it flows further from the spring.
Other than recreation, hot springs offer another valuable use. As the demand for renewable energy increases, geothermal explorations have accelerated in Thailand. Since 1977, Chiang Mai University, the Electrical Generating Authority for Thailand, and the Department of Mineral Resources have been working together to find the potential for geothermal energy from hot springs around Thailand. In fact, the country’s first geothermal exploration well was drilled at San Kamphaeng in 1981. In Fang, northern Chiang Mai, the country’s pilot geothermal power plant uses the movement of steam to rotate turbines connected to an electricity generator.
Climbing sticky waterfalls
Of the many waterfalls in Chiang Mai, the Buatong “Sticky” Waterfall is the most unique. Originating from a mid-sized stream, it does not look like a typical waterfall. Instead of rocks, the surface behind the cascade of water appears smooth. It is as if a thick eggshell-coloured cement was poured down a strip of the mountain slope, moulding a hard blanket between the underlying rock and the water flowing on top.
Surprisingly, the waterfall is not slippery to climb, hence the nickname (nevertheless, caution is always advised). To the touch, the surface is slightly rough and grainy.
Most visitors will know that the surface is made of limestone. Specifically, the waterfall is made of tufa, a type of limestone that is formed when tiny carbonate minerals, dissolved in the ambient-temperature stream water, accumulate into larger crystals and rock. The sand-sized crystals embedded within the tufa make the surface rough. This chemical process, known as precipitation, created the tufa over hundreds or thousands of years. At the University of Hong Kong, laboratory simulations of tufa formation revealed that precipitation often occurs at waterfalls because the tumbling of water increases the water’s oxygen content, which leads to a slight increase of acidity that promotes precipitation.
The carbonate minerals dissolved in the stream water may have come from marine organisms that died hundreds of millions of years ago.
Upstream from the Buatong Waterfalls, inside the mountain, are large bodies of limestone called the Doi Chiang Dao Limestone. Found in many of the northern mountains of Chiang Mai, travellers can see the source limestone themselves in caves such as the Chiang Dao Cave (incidentally, stalagmites and stalactites are also forms of tufa). The groundwater that feeds the Buatong Waterfalls has likely collected carbonates from these limestones. According to scientists from Japan and Thailand, the Doi Chiang Dao Limestone is compacted and pressurised seabed debris from the Paleo-Tethys Ocean, an ocean that existed 600 to 200 million years ago, and spanned the Indian Ocean and southern Asia.
Discovering ancient temples
In the 1980s, villagers and archaeologists uncovered temple ruins buried next to the Ping River. They had found Wiang Kum Kam, a lost city built 700 years ago by the ancient Lanna civilisation. Today, many red brick temples and structures have been excavated, speckled throughout a modern-day village. The area is best explored armed with a map, either on foot or by bicycle. Weaving through the village roads, there is a certain adventurous thrill to find the ancient temples yourself, hidden around the corner or behind the trees.
Wiang Kum Kam was not only lost in time, but also in space. According to sediment and archaeological evidence by Chiang Mai University and the National University of Singapore, severe flooding led to the abandonment of the Lanna capital, which was then relocated to what is now the Old City. Over the years, Wiang Kum Kam was buried by metres of sand brought by floods, and new villages were built above.
But what may go unnoticed are the curious orientation of the temples, and a buried river.
Most temples in Chiang Mai are oriented east to west or west to east, either pointing towards the south-flowing rivers or towards the sunrise. Yet, researchers noticed that several excavated temples were facing northeast (such as Wat Phaya Mangrai and Wat Phrachao Ongdam). Further excavations revealed that these temples were directed towards a now-abandoned river. During the heyday of Wiang Kum Kam, the Ping River flowed on the eastern side of the city, but has since rerouted to flow on the western side. According to sediment dating, this channel switch, known as an avulsion, was associated with a flood that ultimately concealed the city 550 years ago. Luckily, the avulsion occurred after the city was already deserted. Today, almost the entire Chiang Mai valley is populated – if an avulsion happens again, it may be a catastrophic event. To assess the danger, further research on avulsions in Chiang Mai is currently underway.
… and much more
Of course, this is only a taste of some of the science behind Chiang Mai. Beyond geology and archaeology, research in other fields such as animal conservation, zoology, social science and art are also abundant – all equally able to enrich your travel experience. Hopefully, this not only inspires you to visit Chiang Mai and to discover more about the place, but also unearths a deeper curiosity wherever you may go.
Elisha Anne Teo, PhD 