SHORT EPISODES OF CRUST GENERATION DURING PROTRACTED ACCRETIONARY PROCESSES: EVIDENCE FROM CENTRAL ASIAN OROGENIC BELT, NW CHINA
oleh: Gong-Jian Tang, Sun-Lin Chung, Chris J. Hawkesworth, P. A. Cawood, Qiang Wang, Derek A. Wyman, Yi-Gang Xu, Zhen-Hua Zhao
| Format: | Article |
|---|---|
| Diterbitkan: | Russian Academy of Sciences, Siberian Branch, Institute of the Earth's crust 2017-09-01 |
Deskripsi
continental crust but the spatial and temporal distribution of crust generation within individual orogens remains poorly constrained. Paleozoic (~540–270 Ma) granitic rocks from the Alati, Junggar and Chinese Tianshan segments of the Central Asian Orogenic Belt (CAOB) have markedly bimodal age frequency distributions with peaks of ages at ~400 Ma and 280 Ma for the Altai segment, and ~430 Ma and 300 Ma for the Junggar and Chinese Tianshan segments. Most of the magma was generated in short time intervals (~20–40 Ma), and variations in magma volumes and in Nd–Hf isotope ratios are taken to reflect variable rates of new crust generation within a long-lived convergent plate setting.