Scientists have found a way to deconstruct the Himalayan Mountains and reconstruct the crust of India before it collided with Asia some 50 million years ago.
Using neodymium isotopes for whole rocks and uranium-lead in zircon crystals in the rocks, the researchers have essentially un-stirred part of the pot of rocks that crashed together into the uneven, and extremely complicated, geological monstrosity that is now the highest mountain range on the planet.
Geologist Catherine Mottram and her colleagues looked specifically at the rocks in the Sikkim Himalaya around what's called the Main Central Thrust (MCT). This is a major fault along which the crust of India was shortened and thickened as it piled up against Asia.
"As the rocks of the Indian plate were stuffed into the mountain belt, much of the movement of rock was along near-flat faults, known as thrusts," explained geologist Simon Wellings in his Metageologist blog.
So the collision was less like a train wreck and more like shoving together a line of flat, crumbly dominoes. Some of the dominoes appear to have been lined with ancient faults that were part of an old rift zone. These faults may have been re-used in the continental collision to help shuffle materials of different ages when they were pushed against Asia -- making reconstruction of the pre-collision situation very complicated.