^1,2Jennifer Buz,^1,3Benjamin P. Weiss,^3,4Sonia M. Tikoo,^3,4David L. Shuster,⁵Jérôme Gattacceca,¹Timothy L. Grove
¹Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
²Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA
³Department of Earth and Planetary Science, University of California, Berkeley, CA, USA
⁴Berkeley Geochronology Center, Berkeley, CA, USA
⁵CNRS, Aix-Marseille University, Aix-en-Provence, France

Recent paleomagnetic studies of Apollo samples have established that a core dynamo existed on the Moon from at least 4.2 to 3.56 billion years ago (Ga). Because there is no lunar dynamo today, a longstanding mystery has been the origin of magnetization in very young lunar samples [<~200 million years old (Ma)]. Possible sources of this magnetization include transient fields generated by meteoroid impacts, remanent fields from nearby rocks magnetized during an earlier dynamo epoch, a weak late dynamo, and spontaneous remanence formed in a near-zero field. To further understand the source of the magnetization in young lunar samples, we conducted paleomagnetic, petrographic, and 40Ar/39Ar geochronometry analyses on a young impact melt glass rind from the exterior of ~3.35 Ga mare basalt 12017. Cosmic ray track densities and our 40Ar/39Ar and cosmogenic 38Ar analyses constrain the glass formation age to be 10 μT) core dynamo field nor impact-generated fields.

Reference
Buz J, Weiss BP, Tikoo SM, Shuster DL, Gattacceca J, Grove TL (2015) Magnetism of a Very Young Lunar Glass. Journal of Geophysical Research (Planets)
Link to Article [DOI: 10.1002/2015JE004878]
Published by arrangement with John Wiley & Sons