Evolution of the impact origin hypotheses of Taihu Lake basin and research progress

This paper is to review several origin hypotheses of Taihu Lake basin, and mainly focus on the history of the impact origin hypotheses of Taihu Lake basin. First, several non-impact origin hypotheses of Taihu Lake basin are introduced and simple comments are given for each hypothesis which include lagoon origin hypothesis, tectonic origin hypothesis, barrier lake hypothesis, volcanic eruption hypothesis, polygenetic origin hypothesis, Then, we mainly focus on the evolution history of impact origin hypothesis explained briefly in three waves or three time-spans. The first wave started in early 90's of the 20th century. The impact origin of Taihu Lake basin was proposed, based on the deformation features well developed in quartz grains of sandstone of Taihu Lake area, and the impact hypothesis gradually turn into unfavorable due to the lack of understanding impact cratering features. The second wave came in early years of 21st century. The discovery of abundant unique Fe-rich concretions occurring in the mud layers of Taihu Lake basin revived the impact origin hypothesis. However, the conclusion that the impact origin of Taihu Lake was confirmed is not mature. The impact hypothesis was not accepted by many scholars due to the lack of convinced evidence of impact, and receive some critics. The third wave of impact-related origin hypothesis started in 2012, we realized our mistakes made in our previous work on sandstone and breccia of Taihu Lake area, and understood the difficulties of the impact origin hypothesis of Taihu Lake basin. The research was shifted back on mineralogy origin study of the Fe-rich concretions and the sedimentary characteristics of the marked silty mud layer of Taihu Lake area. The airburst impact origin hypothesis of Taihu Lake basin is proposed. The updated results and progresses show that there is one specific marked silty mud layer unknown by previous studies occurring in Taihu Lake vicinity containing unique Fe-rich concretions. The marked silty layer has unique morphology, and internal textures, which are the keys to reveal the origin of Taihu Lake basin. The Fe-rich concretions could be products either of sedimentary concretions formed in pore spaces of mud layer under huge water body when Taihu Lake were formed initially, or the fallout products of materials synthesized in the plume caused by airburst. The study of origin of Taihu Lake basin has significant science value and is worth to study more. © 2021, Science Press. All right reserved.