Ladakh is the highest altitude plateau region in India (much of it being over 3,000 m), incorporating parts of the Himalayan and Karakoram mountain ranges and the upper Indus River valley. The mountain ranges in this region were formed over a period of 45 million years by the folding of the Indian Plate into the stationary landmass of Asia. While the Himalayas were formed from the base material of the Indian plate, the Zanskar Range consists of layers of sediment from the ocean floor, and the Ladakh Range of granite was born of the immense heat generated by the friction between the two plates. In Ladakh, the suture zone between the continental masses runs a little to the south of the Indus Valley. The drift continues and is the cause of the frequent earthquakes in the Himalayan region. Cro