Structural restoration of an Eo-Mesoarchean (3.8–2.9 Ga) terrane, Eastern China, dissected by the Tanlu fault zone
journal contribution
posted on 2024-11-17, 16:18authored byZhonghua Tian, Allen P Nutman
Ancient gneissic terranes are critical rare materials that can reveal the Earth's early crustal evolution. This paper presents reconstruction of the oldest Eo-Mesoarchean gneissic terrane (3.8–2.9 Ga) in the eastern North China Craton that was partitioned by the ENE-WSW striking Tanghe-Hanling strike-slip fault (THF). The THF is a splay off the Tanlu fault zone and has been traced for 130 km and is 1–1.5 km wide. The THF has a 28 km sinistral offset, which has been established by detailed field observation. Restoring the 28 km offset, means that: (1) A sizeable potential area is recognized for searching for more 3.8–2.9 Ga Eo-Mesoarchean rocks; (2) A large NW-striking late Archean BIF belt is correlated with another at Anshan. Our data integrate with regional structural information of the Tanlu fault zone; we suggested that the Tanlu fault zone has an eastwards-fan splay pattern geometric feature in its northern part. Accordingly, we further restore the ancient tectonic configuration of eastern Asia before the Tanlu fault zone initiation. Eo-Mesoarchean rocks and 2.7–2.9 Ga terranes cropping out in Eastern Block of the North China Craton are arranged in line with NNW-SSE strike, which is consistent with their oriented gneissic foliations.
Funding
National Natural Science Foundation of China (J2009)