Geological and evolutionary characteristics of the Gagarin Region on the far side of the Moon

• Main Authors: SHAO Tianrui, HAN Kunying, JIN Ming, SHI Chenglong, PANG Jianfeng, DING Xiaozhong
• Format: Article in Journal/Newspaper
• Language: Chinese
• Published: Institute of Geomechanics, Chinese Academy of Geological Sciences 2023
• Subjects: lunar geology; gagarin basin; multi-source remote sensing data; geological evolution; Geology; QE1-996.5; South pole
• Online Access: https://doi.org/10.12090/j.issn.1006-6616.2023035; https://doaj.org/article/ec589ac38eb245628f172ce6423f3871

Objective This study focuses on the Gagarin region on the far side of the Moon, aiming to reveal the geological characteristics, distribution features, and genesis of typical areas on the lunar far side. Additionally, it seeks to explore the regional geological evolution history of the Gagarin region. Methods The study primarily employs methods such as multi-source remote sensing data interpretation, regional geological mapping, and quantitative analysis of geological elements' quantity and distribution characteristics. Results (1) 656 impact craters were discovered in the study area, of which 552 have diameters greater than 20 kilometers. Approximately 71.5% of the Gagarin region is covered by ancient basins and their ejecta from the Aitken period. Based on comprehensive area and diameter data, the Aitken period is identified as the geological era with the largest proportion of large impact craters (diameter greater than 70 kilometers) and the largest average diameter. From the Aitken period to the Copernican period, the total area of impact craters in each geological era shows a decreasing trend from old to new. (2) In the study area, six parallel lunar grabens, 62 lobate scarps, one sinuous rille , 50 crater floor fractures, and 70 shallow faults were discovered. It also includes parts of the two longest inferred deep faults on the Moon, originating from the South Pole–Aitken tectonic zone and almost spanning the entire highland tectonic zone. According to Bouguer gravity anomalies and crustal thickness data, linear crustal thickness anomalies extending outward from the South Pole–Aitken basin reach the major basins on the near side of the Moon. (3) The Gagarin region is primarily located in the anorthositic highlands on the far side of the Moon. The rocks mainly consist of ferroan anorthosite (fa) suites, with some crater floors showing magnesium anorthosite (ma) suites. In the central and southern parts of the Gagarin region, low-titanium (TiO2 > 1.5 and < 4.5) and very low-titanium (TiO2 < 1.5) ...