Direct age constraints on the magnetism of Jack Hills zircon
Name
sciadv.add1511.pdf
Description
Published version
Size
627.05 KB
Format
Adobe PDF
Checksum (MD5)
b3539b7e668be7be5a1c476cd2b2699a
Author(s)
Taylor, Richard JM
Reddy, Steven M
Saxey, David W
Rickard, William DA
Tang, Fengzai
Borlina, Cauê S
Fu, Roger R
Weiss, Benjamin P
Bagot, Paul
Williams, Helen M
Date Issued
January 6, 2023
Journal
Science Advances
Publisher
American Association for the Advancement of Science (AAAS)
Citation
Taylor, Richard JM, Reddy, Steven M, Saxey, David W, Rickard, William DA, Tang, Fengzai et al. 2023. "Direct age constraints on the magnetism of Jack Hills zircon." Science Advances, 9 (1).
Version
Final published version
Abstract
A potential record of Earth’s magnetic field going back 4.2 billion years (Ga) ago is carried by magnetite inclusions in zircon grains from the Jack Hills. This magnetite may be secondary in nature, however, meaning that the magnetic record is much younger than the zircon crystallization age. Here, we use atom probe tomography to show that Pb-bearing nanoclusters in magnetite-bearing Jack Hills zircons formed during two discrete events at 3.4 and <2 Ga. The older population of clusters contains no detectable Fe, whereas roughly half of the younger population of clusters is Fe bearing. This result shows that the Fe required to form secondary magnetite entered the zircon sometime after 3.4 Ga and that remobilization of Pb and Fe during an annealing event occurred more than 1 Ga after deposition of the Jack Hills sediment at 3 Ga. The ability to date Fe mobility linked to secondary magnetite formation provides new possibilities to improve our knowledge of the Archean geodynamo.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution 4.0 International license
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1126/sciadv.add1511
