Location of the tectonic boundary between the Paleoproterozoic Jiao–Liao–Ji Belt and the Archean Longgang Block in the Lianshanguan area, northeastern China

• Published in: Precambrian research Vol. 344; p. 105762
• Main Authors: Peng, Chong, Pan, Bao-Zhi, Xue, Lin-Fu, Ma, Yan-ni, Liu, Wen-Yu, Li, Tong-Lin, Liu, Hai-Yan, Zhu, Kai, Xu, Chun-hui
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.07.2020
• Subjects: Jiao–Liao–Ji Belt; Lianshanguan area; Longgang Block; Magnetotelluric sounding; Tectonic boundary; Magnetotelluric sounding; Longgang Block; Tectonic boundary; Jiao–Liao–Ji Belt; Lianshanguan area
• ISSN: 0301-9268; 1872-7433
• DOI: 10.1016/j.precamres.2020.105762

[Display omitted] •The southern margin of the Lianshanguan intrusion is the location of the tectonic boundary.•The southward dip of the tectonic boundary indicates the Liaoji Belt was a rift belt.•The northward dip of the tectonic boundary indicates the orogenic stage of the Liaoji Belt.•The tectonic boundary in the Lianshanguan area dips at 60–70°. The tectonic evolution of the Paleoproterozoic Jiao–Liao–Ji Belt, which is located in the North China Craton in northeastern China, is the subject of ongoing debate. Most previous studies on this belt have been based on traditional geological methods, with most of the data being obtained from the surface, leading to uncertainties regarding the deep geological structure of the belt. This has restricted our understanding of the tectonic character and development of the belt; however, this limitation could be overcome by geophysical studies. Here, we analyze and interpret newly collected rock physical property data (density, magnetic susceptibility, and resistivity) and non-seismic geophysical data (gravity, magnetic, and magnetotelluric sounding data) for the Lianshanguan area to infer the location, configuration, and nature of the tectonic boundary between the Paleoproterozoic Jiao–Liao–Ji Belt and the Archean Longgang Block. The Lianshanguan rock mass, which belongs to the Archean Longgang Block, shows a weak gravity anomaly (0–6 mGal) and high resistivity (103.6–104 Ω·m). The area south of the Lianshanguan rock mass consists of the Paleoproterozoic Liaohe Group and displays an intermediate magnetic anomaly (0–200 nT) and low resistivity (10–102.5 Ω·m). We therefore infer that the tectonic boundary of the Jiao–Liao–Ji Belt is located along the southern margin of the Lianshanguan intrusion. We also show that the tectonic boundary in the Eastern Liaoning–Southern Jilin area trends E–W and extends from Shuangtaling through Lianshanguan, Caohecheng, Balidianzi, and to Guaimozi. The boundary between the Longgang Block and the Jiao–Liao–Ji Belt dips predominantly to the south, suggesting an extensional tectonic regime during the Paleoproterozoic time.