Discovery of metamorphic diamonds in central China: an indication of a > 4000-km-long zone of deep subduction resulting from multiple continental collisions
✍ Scribed by Jingsui Yang; Zhiqin Xu; Larissa F. Dobrzhinetskaya; Harry W. Green II; Xianzhi Pei; Rendeng Shi; Cailai Wu; Joseph L. Wooden; Jianxin Zhang; Yusheng Wan; Haibing Li
- Book ID
- 104463443
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 658 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0954-4879
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✦ Synopsis
Abstract
The Central Orogenic Belt (COB) of China is a major continental collision zone that contains extensive outcrops of deeply subducted and exhumed rocks at both the eastern and the western end of the belt. Here we report discovery of microdiamonds from both eclogites and felsic gneisses in the North Qinling zone in the central portion of the COB. This discovery demonstrates that the country rocks of continental affinity shared in the ultra‐high‐pressure metamorphic (UHPM) event and provides a bridge connecting the two previously recognized UHPM terranes, thereby establishing the existence of a UHPM belt extending more than 4000 km. Geochronological dating yields Early Palaeozoic ages in the west and Early Mesozoic ages in the east, recording two separate continental collisions overprinted within the COB. Occurrence of UHP metamorphism during recurrent continental collision here and in the Alps suggests that deep subduction of continental material during such collisions is probably common rather than exceptional, with significant implications for processes of plate tectonic reorganization and mantle mixing over time.