Qinghai Cross Section

Qinghai Cross Section

China’s Qinghai Province is high, dry, and barely dotted by sparse vegetation. The rocks and fossils buried in this rugged landscape tell an intriguing story of an ancient collision that shaped the modern topography, climate, and plant life.

The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite took this picture on December 12, 2010. This image has been rotated, with north to the left. The northernmost part of the scene shows flat land, while to the south lies a tapestry of mountains and valleys, with some peaks capped with snow and ice.

About 70 or 80 million years ago, most of the planet’s landmasses sat in roughly the same regions that they occupy today, but India was a glaring exception. Seventy million years ago, India lay south of the Equator. It was headed north, though, and by continental-drift standards, it was moving fast. Between 40 and 50 million years ago, India drifted right into Eurasia, raising the Himalayan Range.

India’s tectonic journey not only changed the Indian Subcontinent, it also changed the environment of land to the north. The collision of the Indian and Eurasian tectonic plates pushed the Qinghai Province both northward and upward.

Before the India-Eurasia collision elevated this land, the climate and vegetation were quite different. A study published in 1996 examined geologic evidence of the Qinghai-Tibet Plateau’s rise, including fossil plants. Fossil plants from the Eocene and Oligocene Epochs indicate that what’s now the Qinghai-Tibet Plateau enjoyed a tropical-subtropical rainforest environment with growing areas of temperate flora in some mountainous areas. Global climate was much warmer in the Eocene, but this area was also at a lower elevation.

Today, the climate of Qinghai Province is generally arid, with annual precipitation ranging from 50 millimeters (2 inches) in the west to 400 millimeters (16 inches) in the southeast. Average temperatures range from -16 to -10 degrees Celsius (3 to 14 degrees Fahrenheit) in January, and 8 to 16 degrees Celsius (46 to 60 Fahrenheit) in July. Even the flat terrain in this image is at least 1,664 meters (5,459 feet) above sea level.

A 2008 study using data from the Moderate Resolution Imaging Spectroradiometer (MODIS) developed a vegetation map of this region. The researchers classified large portions of Qinghai Province as desert or semi-desert, especially in the west and north. The eastern and southern parts of the province hold more mountains and more plants, especially grasslands and shrubs well-adapted to a cold climate.

Qinghai’s changed vegetation can largely be explained by increasing elevation. The author of the 1996 study remarked, “The temporal-spatial distribution of Cenozoic faunas and floras on the Plateau not only shows the climatic conditions in various periods of time, but it also indirectly indicates changes in elevation of the Plateau in various periods.”

Though home to fewer plants now, the Qinghai-Tibet Plateau possesses other attractions. West and south of the area shown above lies a multitude of jewel-toned lakes.

NASA Earth Observatory image created by Jesse Allen and Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Michon Scott.

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