There are several examples of rainbow mountains in various countries. How were they made?


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Following is description of the formation of the rainbow mountains in China. Similar processes were involved in the formation of rainbow mountains elsewhere,

The Rainbow Mountains are cretaceous sandstones and siltstones that were deposited in China before the Himalayan Mountains were formed. The sand and silt was deposited with iron and trace minerals that provided it with the key ingredient to form the colors we see today.

What was once a layered horizontal and flat stratigraphy was disrupted by the Indian Plate colliding into the Eurasian Plate approximately 55 million years ago. Much like when two cars get in a wreck and the bumpers fold and break, a similar process folded what was once flat sandstones into the Rainbow Mountains we see today. This process uplifted mountains and exposed sedimentary rocks that were otherwise hidden well below the surface of the earth. Weathering and erosion removed the overlying layers of continental siliciclastic rocks and exposed underlying formations with different mineralogy and chemistry. This causes the striking variation in colors seen across the Rainbow Mountains.

Essentially, over time silt and sand sediments were deposited. Different sediments had different elements and minerals in them, giving them different colors. The sediments solidified over time. Ground stresses forced some of the sediments to break up, fold and move and over time what was once horizontal is now vertical, or near vertical.

  • $\begingroup$ Ok if that's the case ... Then the layers should be the same in surrounding areas correct? And how were the layers not mixed up in the massive earth quakes it must have taken to uplift them? And why aren't sediment layers so drastically different any where else? Why aren't the patterns of colors the same ..in the same order of it was all one set of layers? $\endgroup$ Commented Feb 13, 2023 at 21:37
  • $\begingroup$ @Americanwoman You seem to be asking so many rather basic geology questions... maybe you should get a book on geology instead of just trying to learn it one Stack Exchange question at a time, it sounds like you might enjoy it. By the way, it seems that what you say about layers being the same in different areas is basically true and in fact an important principle in geology, but it also depends what was deposited in different areas, e.g. if a layer is made from the sediments from the botton of an ancient lake, it will appear only in the area where that lake once was. $\endgroup$
    – A. B.
    Commented Feb 16, 2023 at 7:10

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