Welcome to visit Geoscience!

Geoscience ›› 2018, Vol. 32 ›› Issue (04): 718-726.DOI: 10.19657/j.geoscience.1000-8527.2018.04.08

• Petrology • Previous Articles     Next Articles

Classification and Geological Significance of the Upper Jurassic Haritaolegai Formation Basalt in the Northern Da Hinggan Mountains

ZHAO Shengjin1,2(), GAO Lidong2, YU Haiyang2, PIAO Lili2, LIU Zhihui2, ZHOU Yingshuai2, ZHANG Meng2, ZHANG Yulong2, YANG Haixing2, ZHAO Wanli2   

  1. 1. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
    2. No.10 Institute of Geological Exploration, Inner Mongolia Bureau of Geology and Mineral Resources, Chifeng, Inner Mongolia 024005, China
  • Received:2017-12-15 Revised:2018-05-20 Online:2018-08-10 Published:2018-09-19

Abstract:

The Upper Jurassic basaltic rocks of the Haritaolegai Formation were firstly identified in the western part of the northern Da Hinggan Mountains, with the rock assemblage including black/dark gray/purplish brown basalt, amygdaloid basalt, alkaline olivine basalt and basaltic trachy and esite. SHRIMP zircon U-Pb dating of the basalt yielded Late Jurassic age of (146.7±3.1) Ma.Lithogeochemical data show that the rocks are high-K calc-alkaline. The basalts contain low content of Sr,and show enrichments in high large ion lithophile elements (LILEs,such as Rb, K and Ba) and depletions in high field strength elements (HFSEs, such as Nb and Ti).The rare-earth element (REE) contents are generally high,yet the REE fractionation is unclear and the rocks contain slightly negative Eu anomalies. Based on the regional geological survey and strata contrast, the Upper Jurassic Haritaolegai Formation basalt is confirmed to fit the definition of the ever used Yiliekede Formation, so they are the same petrographic composition. Therefore, this study suggests that the Yiliekede Formation should be resumed, and the confirmation of this formation is of great geological significance for the study of tectonic-magmatic activities in the Mesozoic and the comparison of Mesozoic volcanic strata in the study area.

Key words: basalt in the Haritaolegai Formation, Upper Jurassic, U-Pb dating, lithogeochemical characteristic, north Da Hinggan Mountains

CLC Number: