Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Science. 2012 Jan 27;335(6067):453-6. doi: 10.1126/science.1215359.
Paleomagnetic measurements indicate that a core dynamo probably existed on the Moon 4.2 billion years ago. However, the subsequent history of the lunar core dynamo is unknown. Here we report paleomagnetic, petrologic, and (40)Ar/(39)Ar thermochronometry measurements on the 3.7-billion-year-old mare basalt sample 10020. This sample contains a high-coercivity magnetization acquired in a stable field of at least ~12 microteslas. These data extend the known lifetime of the lunar dynamo by 500 million years. Such a long-lived lunar dynamo probably required a power source other than thermochemical convection from secular cooling of the lunar interior. The inferred strong intensity of the lunar paleofield presents a challenge to current dynamo theory.
古地磁测量表明，月球上的核心发电机可能在 42 亿年前就存在了。然而，月球核心发电机的后续历史是未知的。在这里，我们报告了对 37 亿年古老的海玄武岩样本 10020 的古地磁、岩石学和 (40)Ar/(39)Ar 热年代测定测量。该样本包含在至少约 12 微特斯拉的稳定磁场中获得的高矫顽力磁化强度。这些数据将月球发电机的已知寿命延长了 5 亿年。如此长寿命的月球发电机可能需要除了月球内部的热化学对流从长期冷却之外的其他动力源。推断出的月球古磁场的强烈强度对当前的发电机理论提出了挑战。
