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Ca. 110 Ma adakite-like magmatism along the Bangong–Nujiang suture zone: Implications for crustal thickening and early uplift in the central Tibetan Plateau.
- Source :
-
Palaeogeography, Palaeoclimatology, Palaeoecology . Dec2021, Vol. 584, pN.PAG-N.PAG. 1p. - Publication Year :
- 2021
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Abstract
- The suggested Early Cretaceous timing of early formation of the Tibetan Plateau remains controversial. This study investigates this uncertainty by examining newly identified Early Cretaceous adakite-like magmatic rocks in the Rutog and Nyima areas of the northern–central Tibetan Plateau. Zircon U Pb dating indicates that these rocks formed at ca. 110 Ma and have negative to positive zircon ε Hf (t) values. They contain high concentrations of Sr and have high Sr/Y values, but contain low concentrations of Y and Yb and have low (La/Yb) N , suggesting they have an adakite affinity. They also have ε Nd (t) values that range from −4.5 to +1.3. These geochemical and isotopic data indicate that the adakite-like rocks probably formed from magmas generated by the partial melting of garnet-bearing amphibolite within a thickened region of juvenile and ancient crustal material. This magmatism also most likely occurred during the Lhasa–Qiangtang collisional event. Crustal thicknesses along the Bangong–Nujiang suture zone (BNSZ) were > 40 km in places at ca. 110 Ma, and most likely had a significant impact on the initial uplift of the Tibetan Plateau. In summary, the Early Cretaceous adakite-like magmatic rocks in the Rutog and Nyima areas suggest that the Tibetan Plateau started to form during the Early Cretaceous. • Early Cretaceous adakite-like rocks occur in the north-central Tibet. • Adakite-like rocks were derived from the thickened crust. • The Lhasa–Qiangtang collision happened before ca. 110 Ma. • The significant crustal thickening led to the early uplift in the Early Cretaceous. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00310182
- Volume :
- 584
- Database :
- Academic Search Index
- Journal :
- Palaeogeography, Palaeoclimatology, Palaeoecology
- Publication Type :
- Academic Journal
- Accession number :
- 153322594
- Full Text :
- https://doi.org/10.1016/j.palaeo.2021.110661