The Tibetan Plateau is the highest plateau on Earth, known as the "Roof of the World". However, coral is an animal that lives in the ocean. So why can coral and other marine shell fossils be found on the Tibetan Plateau? If you understand the geological history of the Tibetan Plateau and its history of sea-land changes, you will be able to answer this question.
The Tibetan Plateau is a natural "laboratory" for studying geological history, having undergone a developmental history from sea to land and eventually becoming the world's highest mountain range. The earliest marine sedimentary records of the Tibetan Plateau can be traced back to the early Precambrian (2.2 billion years ago). However, from that time until the early Ordovician (480 million years ago), those early sedimentary strata have undergone metamorphism under high temperatures and pressures in the subsoil, so no fossils have been preserved. Marine sedimentary rocks with definite fossil evidence formed in the middle and late Ordovician (460 million years ago). From the limestone sediments, abundant marine corals and other marine shell fossils can be collected. At that time, the main part of the Tibetan Plateau was a sea called the Paleo-Tethys Sea. However, from the middle Carboniferous (320 million years ago) to the early Triassic (280 million years ago), marine sedimentary strata and fossils on the Tibetan Plateau were missing. This was due to a global temperature drop, which led to the formation of large-scale glaciers in the Southern Hemisphere. The southern part of the Tibetan Plateau, which was located in the Southern Hemisphere at that time, was also covered by glaciers. From the late Triassic (250 million years ago), with global warming, seawater re-submerged most of the Tibetan Plateau. But by the end of the Cretaceous (250 million years ago), the Tibetan Plateau experienced a large-scale crustal uplift movement. In the early and middle Triassic (250 million to 220 million years ago), only a few areas of the Tibetan Plateau still retained marine environments. Only in the northern Himalayas, where a narrow strip of limestone sedimentary strata was distributed, could some newly emerged hexacorallites and other marine fossils be preserved.
By the late Triassic (210 million years ago), due to crustal rifting, a new ocean, called the Neo-Tethys Sea, appeared along the present-day Brahmaputra River. This new ocean lasted for a long time. In the sedimentary strata of the late Cretaceous (70 million years ago), coral fossils and abundant ammonites and marine bivalves could still be found, indicating that the climate was warm and marine life was abundant at that time. It was not until the middle Eocene of the Paleogene (40 million years ago) that the southern continent, separated from the Indian plate, drifted north at a rapid pace and collided with the Eurasian plate, causing intense folding, faulting, and uplifting. The Neo-Tethys Sea gradually turned into the present-day Tibetan Plateau, and the seawater finally disappeared completely.
The geomorphological changes of the earth have been ongoing throughout its history. The discovery of marine animal fossils such as coral on the Tibetan Plateau is just one example of this.