The Himalayas and the Great Rivers

Southeast Asia has been described as the “Balkans of Asia.” In other words, this ensemble of nations seems to be an incomprehensible jumble of squabbling, unstable fiefdoms. Pick up the latest version of the incredible National Geographic Visual Atlas of the World, and turn to pages 24-25, the political map of the world. Based on proximity, you might wonder why this cluster of little countries did not turn into either provinces of China or states of India, or some combination of both.

Asian Tectonics

The Indian sub-continent pushes north and east, creating the Himalayas and the mountains of SE Asia. NASA’s Earth Observatory

Now turn back to pages 22-23, the “physical” world. Look at the northern border of India and China and you will see the huge wall of the Himalayan Mountains. Look east and you will see the mountain ranges “bend” south and extend over much of Southeast Asia. Though not as dramatic as the highest peaks of Nepal, these mountain ranges still made primitive land travel pretty difficult. Now turn to pages 32-33, Plate Tectonics. You can see the Indian/Australian plate colliding with the Eurasian plate right where all these mountains are being formed. You can also see that the colliding plates are creating the Indonesian islands as the Indian/Australian plate pushes northeast against the tail end of the Eurasian plate. This collision is also the source of the earthquake and tsunami that devastated Indonesia in 2004.

As the two continents collide, a process that has been on-going for the past 70 million years, it creates a more intense geologic impact than when one plate slides below another. This has caused the fairly rapid and continuing rise of the Himalayas. As a result, much of southern China and Southeast Asia is covered with mountain ranges.

The Water Cycle takes over from here. Precipitation in the high Himalayas, in the form of snow, piles up to form icefields and glaciers. Melting ice and glacial runoff collect in great rivers that wind their way through the mountains, carving gorges and valleys, meandering over wide plains and depositing their silt into big deltas when they reach the sea. In fact, three of the most powerful rivers in the world, the Yangtze, the Mekong, and the Salween, carve canyons in the eastern Himalayas of Southwestern China that are so close to each other, the area is called the Three Parallel Rivers of Yunnan.

Flowing from the glacial fields, these rivers fan out across the continent like highways until they reach the ocean. Following the Asian coast clockwise from Northern China, the rivers flowing from the Eastern Himalayas are:

Yellow (Northern China)

River valleys of SE Asia

The major river valleys formed the basis for the nations of SE Asia, separate from China and India. by M. Healy,

Yangtze (Central China)

Pearl (Southern China)

Hong, or Red (North Vietnam)

Mekong (Cambodia/Laos/ South Vietnam)

Chao Phraya (Thailand)

Salween (Myanmar/Burma)

Irrawaddy (Myanmar/Burma)

Brahmaputra (Bangladesh)

And from the western Himalayas, we have:

Ganges (India/Bangladesh)

Indus (Pakistan)

By the time they reach the coast, the habitable valleys and deltas of these great rivers are mostly separated from each other by mountain ranges of varying sizes. 50,000 years ago, when no one was around, each valley and delta represented its own, isolated opportunity for settlement.

And then along came Man. There is a fascinating summary of on-going research into the DNA patterns of man, called Deep Ancestry: Inside The Genographic Project, sponsored by National Geographic. The purpose of the study has been to identify the common DNA traits of the several races and cultures of man. You can send them a sample of your DNA and they will send you back an analysis of your composite ancestry. A by-product of the research has been a mapping of many of the migration patterns of early wanderers.

An illustration of the continents and sea levels at the last glacial maximum. By Muntuwandi at en.wikipedia, from Wikimedia Commons

The research suggests that about 50,000 years ago, during a major ice age, some of the early people migrated from Africa to India and into Southeast Asia and even down to Australia. Sea level was as much as 300 feet lower because fresh water was frozen in the expanded Arctic and Antarctic ice caps. This created land bridges that made it possible for people to walk or paddle south through Malaysia and Indonesia to within sight of Australia. If they were looking for warmer weather, they would have certainly made the trek.

You can imagine that migrating people would settle in the habitable valleys and coastal deltas they found along the way. Some would continue to the next valley/delta as they saw an opportunity for better living because of climate and food supplies, or just to get away from their neighbors or their mother-in-law. Moving eastward along the coast, they would populate the Ganges/Brahmaputra valley, then the Irrawaddy Valley, then the Chao Phraya Delta, and the Mekong Delta. From there, they may have headed south across the Indonesian land bridge to warmer weather. Some even made it to Australia.

As the Ice Age relented, populations moved back northward along the Asian coast, ultimately populating, the Hong (Red), Pearl, Yangtze and Yellow river valleys. The fossil records for many of these areas indicate human activity about 40,000 years ago.

So, the valleys of the great rivers of the Himalayas became the birthplaces of settlements, clans, tribes, nations and empires, up and down the Asian coast. The political lines on today’s map of Southeast Asia blur some of these geographic realities. However, the nations of Asia from India to China reflect these significant, distinct Himalayan river valleys.