The reporter learned from the geological research department on the 9th that geological experts found the Cambrian (500 million years ago) Ocean Island arc in the Lhasa Mountain area on the northeast edge of the Qinghai-Tibet Plateau, which is also the oldest Ocean Island arc of the Phanerozoic of the Qinghai-Tibet Plateau.
It is reported that Fu Changlei, an associate researcher at the Institute of Geology of the Chinese Academy of Geological Sciences, and his collaborators identified a large number of blocky and pillow-shaped basalts, andesites, volcanic breccia and a small amount of acidic volcanic rocks during the geological investigation of The Ridge Mountain in Qinghai.
Geochemical and isotopic analysis showed that the above rocks had a close genesis relationship and exhibited characteristics consistent with the arc volcanic rocks of Ocean Island. In situ analysis of zircon in acid volcanic rocks using high-precision ion probes and laser ablation plasma mass spectrometers showed that the volcanic arc was formed between 510 million and 520 million years ago.
The research progress of Fu Changlei's research team in the aspects of ophiolite and hypertrophic hybrid rocks has proved that there was a relatively wide ocean in the Cambrian period of the Ridge Mountain region, which subducted to form the ocean island arc 500 million years ago, and the characteristics of the ancient ocean island arc of the Ridge Mountain are consistent with the current Tonga volcanic arc.
The Ocean Island Arc is a volcanic chain formed by the subduction of the oceanic plates, which is a significant symbol of earth activity, and the recent eruption of the volcano in the South Pacific island country of Tonga is a typical representative of the current Ocean Island Arc.
It is reported that the ancient ocean island arc records rich and complex ocean basin evolution information, which is the key evidence to determine the existence of the ancient ocean basin. Therefore, the identification and systematic study of the ocean island arc of the ancient orogenic belt are of great scientific significance for the in-depth understanding of the tectonic pattern of the paleo-plate, the ocean-land conversion and the orogenic process.
Source: China News Network
Disclaimer: This article is reproduced for the purpose of transmitting more information and facilitating the popularization of law. If there is a source labeling error or infringement of your legitimate rights and interests, please contact qinghai pufa with the ownership certificate of the author, we will correct and delete it in time, thank you.
![In the early spring of March 2011, Jude Xingxing, the secretary of the party branch in Guanxi Village, Nanchang City, heard abnormal dog barking for several consecutive days, and there were strong flashes of light and horses on The Ancestral Tomb Mountain not far away, Dundun Mountain[fig]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)