Geochronology Definition of Jian'ancun Formation in Wutai Hutuo Group and Its Implications

Abstract

Purposes The Hutuo Group belongs to the Early Proterozoic strata. As one of the most typical Paleoproterozoic strata in North China, the timing redefinition of the Hutuo Group is of great significance to the establishment of the early Precambrian stratigraphic chronology framework, the discussion of the early Precambrian geological evolution process in North China and the study of plate assembly. Methods This article conducts a detailed study of the Dongye Subgroup strata of the Hutuo Group, collecting 24 detrital zircon samples from the Jian'ancun Formation of the Hutuo Group. From 23 similar age detrital zircons, we define the weighted average age of the bottom boundary of the Hutuo Group is 2 469 Ma, and regional tectonic movements occurred in the Wutai area around 1 855 Ma. According to the 1 109 zircon ages in Hutuo Group from previous studies, we considered that the ages of >2.5 Ga are from underlying Gaofan subgroup and the maximum depositional age of Hutuo Group was early Paleoproterozoic. Findings The results show that the crust of the Wutai area was unstable at 2 376, 2 170, 2 066, 1 988, and 1 825 Ma, resulting in multiple magmatic events. The 1 825 Ma zircon age can further indicate the occurrence of the Lyuliang movement, and provide a basis for the early Proterozoic North China Craton integration.

Keywords

• wutai mountain
• jian'ancun formation
• zircon u-pb dating
• hutuo group
• early paleoproterozoic