Next Article in Journal
Use of Macroseismic Intensity Data to Validate a Regionally Adjustable Ground Motion Prediction Model
Previous Article in Journal
Pressure Dependence of Magnesite Creep
Open AccessArticle

Petrologic History of Lunar Phosphates Accounts for the Water Content of the Moon’s Mare Basalts

1
Department of Geology, University of Salamanca, 37008 Salamanca, Spain
2
School of Earth and Environmental Sciences, University of Manchester, M13 9PL Manchester, UK
3
Department of Research & Education, Naturalis Biodiversity Center, 2333 CR Leiden, The Netherlands
4
Department of Earth Sciences, University of Utrecht, 3584 CB Utrecht, The Netherlands
*
Author to whom correspondence should be addressed.
Geosciences 2019, 9(10), 421; https://doi.org/10.3390/geosciences9100421
Received: 7 June 2019 / Revised: 18 September 2019 / Accepted: 26 September 2019 / Published: 28 September 2019
We present reaction balancing and thermodynamic modeling based on microtextural observations and mineral chemistry, to constrain the history of phosphate crystallization within two lunar mare basalts, 10003 and 14053. Phosphates are typically found within intercumulus melt pockets (mesostasis), representing the final stages of basaltic crystallization. In addition to phosphates, these pockets typically consist of Fe-rich clinopyroxene, fayalite, plagioclase, ilmenite, SiO2, and a residual K-rich glass. Some pockets also display evidence for unmixing into two immiscible melts: A Si-K-rich and an Fe-rich liquid. In these cases, the crystallization sequence is not always clear. Despite petrologic complications associated with mesostasis pockets (e.g., unmixing), the phosphates (apatite and merrillite) within these areas have been recently used for constraining the water content in the lunar mantle. We compute mineral reaction balancing for mesostasis pockets from Apollo high-Ti basalt 10003 and high-Al basalt 14053 to suggest that their parental magmas have an H2O content of 25 ± 10 ppm, consistent with reported estimates based on directly measured H2O abundances from these samples. Our results permit to constrain in which immiscible liquid a phosphate of interest crystallizes, and allows us to estimate the extent to which volatiles may have partitioned into other phases such as K-rich glass or surrounding clinopyroxene and plagioclase using a non-destructive method. View Full-Text
Keywords: Mare basalt; Mass balance; Lunar hydration; Mesostasis; Planetary geology; Apatite; Apollo Mare basalt; Mass balance; Lunar hydration; Mesostasis; Planetary geology; Apatite; Apollo
Show Figures

Figure 1

MDPI and ACS Style

Álvarez-Valero, A.M.; Pernet-Fisher, J.F.; Kriegsman, L.M. Petrologic History of Lunar Phosphates Accounts for the Water Content of the Moon’s Mare Basalts. Geosciences 2019, 9, 421.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop