|
|||||
|
|
Transition from platemargin to intraplate environment: Geochemistry of basalts in Paleogene Liaohe basin,northeastern China |
|
| Authors: | Changzhi?Wu |
| Institution: | 1. State Key Laboratory of Mineral Deposit Research (Nanjing University), Department of Earth Sciences, Nanjing University, Nanjing210093, China 2. State Key Laboratory of Mineral Deposit Research (Nanjing University), Department of Earth Sciences, Nanjing University, Nanjing210093, China;Exploration and Development Research Institute of Liaohe Oilfield Branch Company, PetroChina, Panjin 124010, Chin 3. Exploration and Development Research Institute of Liaohe Oilfield Branch Company, PetroChina, Panjin 124010, China |
| Abstract: | Paleogene basalts from the Liaohe basin, northeastern China, are dominated by alkaline olivine basalts and olivine basalts. These basalts are generally enriched in high field strength elements (HFSE), depleted in large ion lithophile elements (LILE) and comparable to those of typical ocean island basalts (OIB). Positive anomalies of Ba, Sr and Zr with high Nb/U, U/Pb, Ce/Pb and Zr/Hf ratios imply that materials from an oceanic crust had been added to the mantle sources of the basalts. In addition, the basalts are generally depleted in Sr, Nd and Pb isotopes, indicating that an enriched mantle (EMI) and a depleted mantle (DM) sources were added to the OIB-like resource. Comprehensive research on lithosphere evolution and tectonic setting of the Liaohe basin and surrounding areas suggests that these basalts were derived by variable degrees of partial melt-ing from an upwelling asthenosphere mantle. Materials from an oceanic lithosphere were added to the source in company with Paleogene tectonic transition from platemargin to intraplate envi-ronment. Retreating and steepening of the subducting Pacific oceanic plate could be the main cause for the tectonic environment transition. |
| Keywords: | geochemistry basalt Paleogene Liaohe basin North China Block eastern China |
| 本文献已被 CNKI 万方数据 SpringerLink 等数据库收录！ | |