近日，西北大学段亮团队报道了构造运动而非“雪球地球”冰川作用是造成大不整合面的原因。该研究于2026年2月23日发表在《美国科学院院刊》杂志上。
大不整合面——前寒武纪与寒武纪岩石之间广泛存在的沉积间断及相应的地层缺失——记录了全球性大陆暴露与侵蚀的重要时期，同时也以地球所有主要动物门类的首次出现而著称。然而，其成因至今仍是激烈争论的焦点。
研究组通过华北前寒武纪结晶基底的野外露头关系、锆石和独居石U-Pb定年、黑云母和白云母Rb-Sr定年以及锆石(U-Th)/He热年代学数据，约束了不整合面之下的剥露历史。多体系同位素定年与热史反演结果表明，大陆基底最显著的冷却发生在约21-16亿年期间。
通过与劳伦大陆、波罗的大陆和亚马孙大陆的热史数据对比，研究组认为控制不整合面之下地壳剥露的主导因素是受超大陆旋回广泛调节的长期板块构造作用，而非"雪球地球"冰期事件。热年代学记录与大陆风化地球化学指标所揭示的最显著侵蚀期，对应于地球第一个真正超大陆（哥伦比亚超大陆）的演化阶段，而非寒武纪生命大爆发或现代板块构造的出现。
附：英文原文
Title: Tectonism rather than “snowball Earth” glaciation is responsible for the Great Unconformity
Author: Zhan, Rong-Ruo, Duan, Liang, Zattin, Massimiliano, Christie-Blick, Nicholas, Wan, Bo, Wei, Rong-Hao, Yang, Zhao, Wang, Jianqiang, Gou, Longlong, Olivetti, Valerio, Chen, Kai-Yun, Zhang, Xingliang
Issue&Volume: 2026-2-23
Abstract: The Great Unconformity (GUn)—a widely recognized discontinuity and associated gap in the rock record between Precambrian and Cambrian rocks—represents a globally important interval of continental exposure and erosion that is notable also for the first appearance of all major animal phyla on Earth. However, its origin remains the subject of vigorous debate. Here, we present field relationships, and zircon and monazite U–Pb, biotite and muscovite Rb–Sr, and zircon (U–Th)/He thermochronology data for Precambrian crystalline basement rocks from North China to constrain the exhumation history below the unconformity. Dates from multichronometers and thermal history inversions show that the most substantial cooling of continental basement took place from ~2,100 to 1,600 Ma. Comparison with thermal history data from Laurentia, Baltica, and Amazonia suggests that protracted plate tectonics broadly modulated by supercontinent cycles, and not “snowball Earth” glaciation, is responsible for crustal exhumation below the unconformity. The most pronounced erosion evident in both the thermochronologic record and geochemical indicators of continental weathering is shown to correspond with development of Earth’s first true supercontinent (Columbia), rather than with either the Cambrian explosion or the emergence of modern plate tectonics.
DOI: 10.1073/pnas.2523891123
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2523891123