近日，美国哈佛大学Alec R. Brenner团队报道了3.5 Ga时相对板块运动的古地磁探测和不常反转的磁芯发电机。相关论文于2026年3月19日发表在《科学》杂志上。

早期地球是否存在活动性岩石圈及板块构造尚无定论。研究组通过古地磁数据量化了约34.8亿年前岩石圈块体之间的相对运动：西澳大利亚东皮尔巴拉克拉通在高纬度地区呈现出每年47₋₃₅⁺⁶⁹厘米的纬度方向运动，而南非巴伯顿绿岩带则稳定于低纬度地区。

将该板块运动与候选类比模型对比表明，其可能对应快速碰撞型板块构造（即"活动盖层"机制），或表现为幕式活动的岩石圈。研究组还记录了已知最古老的约34.6亿年前地磁反转事件，这与反转频率低于现代、具有轴向偶极特征的地球发电机过程相符。这些地表与地核地球物理现象的存在及其活动速率，为地球早期地球物理演化与生物演化提供了地球动力学背景。

附：英文原文

Title: Paleomagnetic detection of relative plate motions and an infrequently reversing core dynamo at 3.5 Ga

Author: Alec R. Brenner, Roger R. Fu, Bradford J. Foley, Diogo L. Loureno, Jasmine Palma-Gomez, Zheng Gong, Sarah C. Steele, Joanna Li, David T. Flannery, Adrian J. Brown, Eben B. Hodgin

Issue&Volume: 2026-03-19

Abstract: Whether early Earth had a mobile lithosphere and plate tectonics is debated. We present paleomagnetic data quantifying differential motion between lithospheric blocks at ~3.48 billion years ago (Ga). This manifested as 47+69-35 centimeters per year latitudinal motion of the East Pilbara Craton (Western Australia) across high latitudes, whereas the Barberton Greenstone Belt (South Africa) was stationary at low latitudes. Comparison of this plate motion with candidate analogs suggests either rapid collisional plate tectonics (i.e., an “active-lid”) or an episodically mobile lithosphere. We also document the oldest known geomagnetic reversal at ~3.46 Ga, consistent with an axial dipolar dynamo that reversed less frequently than today’s. The existence and rates of these surface and core geophysical phenomena provide geodynamic context to Earth’s early geophysical and biological evolution.

DOI: adw9250

Source: https://www.science.org/doi/10.1126/science.adw9250