Earth Science Frontiers ›› 2025, Vol. 32 ›› Issue (5): 68-84.DOI: 10.13745/j.esf.sf.2024.12.130

Previous Articles     Next Articles

Characteristics and formation mechanism of the Hongshiwan dome in Beijing

WEN Guotao(), SU Shangguo*(), DU Jinxue, ZHANG Yanan, WANG Wenbo   

  1. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China
  • Received:2024-11-14 Revised:2024-12-28 Online:2025-09-25 Published:2025-10-14
  • Contact: SU Shangguo

Abstract:

The Hongshiwan dome in Yanqing, Beijing, is located in the central-south segment of the Yanshan tectonic belt on the northern edge of the Trans-North China Orogen. The Hongshiwan dome comprises Lower Archean gneiss and Upper Proterozoic metamorphic quartzite, covering an area of ~45 km2. Research indicates that the granulite exposed in the core of the dome records three metamorphic stages: an early prograde stage (M1), a peak stage (M2), and a retrograde stage (M3). The characteristic mineral assemblages are clinopyroxene + plagioclase + quartz + biotite for M1, clinopyroxene + garnet + quartz for M2, and amphibole + albite for M3. Thermobarometric estimates yield conditions of 784-816 ℃ and 760-850 MPa for M1, 715-770 ℃ and 1220-1380 MPa for M2, and 506-548 ℃ and 700-810 MPa for M3. Phase equilibrium modeling suggests peak granulite-facies conditions of ~780 ℃ and ~1500 MPa, indicating a counterclockwise p-T trajectory. Within the gneissic core of the Hongshiwan dome structure, the intensity of potash feldspar alteration decreases noticeably from the center towards the margins. The Changcheng Formation quartzite of the dome’s cover has undergone low-grade metamorphism, exhibiting features such as the development of melt erosion pores. Regional comparisons suggest that the dome formed primarily by magmatic diapirism of deep-seated magma chambers induced by fluid overpressure during the middle to late Early Cretaceous, followed by superimposed extension.

Key words: granulite, thermobaromete, metamorphic p-T path, diapirism, dome

CLC Number: