Early planetary evolution – a microanalytical perspective

Project overview

Project period: 2013 – 2026

Participating departments from the museum: Department of Geosciences, GEO

In recent years, the idea that the Earth and Moon share a common early history has gained widespread acceptance.

This concerns not only models for the origin of the Moon by the Giant Impact (i.e collision of a Mars size body with proto-Earth) which can explain close similarities in their chemical and isotopic compositions, as well as a remarkable match in the nature of magmatic processes that shaped the early history of the two planetary bodies and their history of bombardment by projectiles of different sizes.

Understanding processes in the Earth-Moon system also has implications for the early development of other terrestrial planets accessible currently only as meteorites (Mars, Vesta).

Project description

Dating ancient zircon on the terrestrial planets. The current project bridges the gap between lunar and terrestrial geology by applying the same micro-analytical methods to samples from both bodies. Of key importance is the mineral zircon, the only remnant of the Earth prior to 4 Ga (zircon <4.4 Ga is found in sediments from western Australia) and present on the Moon with ages up to 4.5 Ga in regolith soils. Zircon and its microscopic mineral inclusions will be studied using a wide variety of in situ analytical methods targeted to understanding its formation in melts and what it can tell us about its parent magma, constrained by parallel study of in situ zircon in some of Earth’s earliest preserved rocks from ca. 3.8 – 4.0 Ga.

Lunar basalts. A second aspect of this project focuses on lunar basalts, samples of the mantle of the Moon (and, by analogy, the long-lost early mantle of the Earth). Using a newly developed in situ Pb-isotope analytical protocol, our work is providing new dates of unprecedented precision for the lunar basalt suite (both Apollo samples and meteorites) and helping to constrain both lunar mantle reservoir evolution early magmatic processes on the early earth.

Dating glass spherules from impacts. A third sub-project is investigating the meteorite flux in the inner solar system using silicate glass beads preserved in lunar soils. These beads form from melt droplets during impacts and can be dated using similar methods to those applied to zircon, thus providing an impact chronology.

Funding

Swedish Research Council. External link, opens in new window.

Knut and Alice Wallenberg Foundation. External link, opens in new window.

Selected publications

1. Kouvatsis, I., Cartwright, J.A. and Whitehouse, M.J., 2023. Lead-Lead (Pb-Pb) Dating of Eucrites and Mesosiderites: Implications for the Formation and Evolution of Vesta. Geochimica et Cosmochimica Acta. 348, pp.369-380. https://doi.org/10.1016/j.gca.2023.03.026
2. Connelly, J.N., Nemchin, A.A., Merle, R.E., Snape, J.F., Whitehouse, M.J. and Bizzarro, M., 2022. Calibrating volatile loss from the Moon using the U-Pb system. Geochimica et Cosmochimica Acta, 324, pp.1-16. https://doi.org/10.1016/j.gca.2022.02.026
3. Demidova, S.I., Whitehouse, M.J., Merle, R., Nemchin, A.A., Kenny, G.G., Brandstätter, F., Ntaflos, T. and Dobryden, I., 2022. A micrometeorite from a stony asteroid identified in Luna 16 soil. Nature Astronomy, 6(5), pp.560-567. https://doi.org/10.1038/s41550-022-01623-0
4. Merle, R.E., Nemchin, A.A., Whitehouse, M.J., Snape, J.F., Kenny, G.G., Bellucci, J.J., Connelly, J.N. and Bizzarro, M., 2020. Pb‐Pb ages and initial Pb isotopic composition of lunar meteorites: NWA 773 clan, NWA 4734, and Dhofar 287. Meteoritics & Planetary Science, 55(8), pp.1808-1832. https://doi.org/10.1111/maps.13547
5. Snape, J.F., Nemchin, A.A., Whitehouse, M.J., Merle, R.E., Hopkinson, T. and Anand, M., 2019. The timing of basaltic volcanism at the Apollo landing sites. Geochimica et Cosmochimica Acta, 266, pp.29-53. https://doi.org/10.1016/j.gca.2019.07.042 External link.
6. Visser, R., John, T., Whitehouse, M.J., Patzek, M. and Bischoff, A., 2020. A short-lived 26Al induced hydrothermal alteration event in the outer solar system: Constraints from Mn/Cr ages of carbonates. Earth and Planetary Science Letters, 547, p.116440. https://doi.org/10.1016/j.epsl.2020.116440