Cenozoic tectono-thermal evolution of the Weihe Basin, Central China

ABSTRACT

As a passive rift basin in the Cenozoic, the formation and evolution process of the Weihe Basin has not been well explained. Here we estimate the stretching factor and basal heat flow for each rift period along four geological profiles using a 2D multi-stage finite extension model. The modelling is based on a reconstruction of pre-rift crustal and lithospheric thicknesses, and is calibrated with the current heat flow. The Xi’an Depression had the biggest stretching factor while the Pucheng Uplift had the smallest throughout the Cenozoic period, which saw a range of stretching factors from 1.02 to 2.06. The basal heat flow in the Weihe Basin exhibits a corresponding change. At the end of the Oligocene, Miocene, and Pliocene periods, the basal heat flow varied between 58.5 ~ 64.0 mW·m⁻², 59.2 ~ 67.0 mW·m⁻², and 59.6 ~ 78.7 mW·m⁻², respectively. Increasing stretching factor and basal heat flow indicate that the Weihe Basin is currently in a state of sustained extension. The formation and development of the Weihe Basin are analysed in the context of larger tectonic changes, and it is considered that the Weihe Basin is controlled by pre-existing faults, and formed in a regional tectonic context of sliding and pulling apart first, and tensioning and lifting up later. Since the late Miocene (7.3 Ma), anomalously rapid subsidence has occurred, induced by a new phase of rifting and depth-related lithospheric extension. The thermal genesis of the geothermal system in the Weihe Basin is also thought to be closely related to the latest phase of extension.

KEYWORDS:

• Tectono-thermal modelling
• stretching factors
• basal heat flow
• thermal genesis of the geothermal system
• Weihe Basin

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00206814.2024.2324482

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (No. 41877210, 41502236), Natural Science Foundation of Hubei Province (No. 2017CFB531), and the Project of Young Innovation Team, Key Laboratory of Exploration Technologies for Oil and Gas Resources, Ministry of Education (No. PI2018-04).