TY - JOUR
T1 - The origin of water in the primitive Moon as revealed by the lunar highlands samples
AU - Barnes, Jessica J.
AU - Tartèse, Romain
AU - Anand, Mahesh
AU - McCubbin, Francis M.
AU - Franchi, Ian A.
AU - Starkey, Natalie A.
AU - Russell, Sara S.
N1 - Funding Information:
Pete Lansberg and Diane Johnson are thanked for their help in sample preparation and SEM analysis, respectively. Andy Tindle is thanked for his assistance with EPMA. We would like to thank Bernard Marty for the editorial handling of the manuscript, Erik Hauri and an anonymous reviewer for their insightful reviews that helped in critical evaluation of the data and significant improvement in the quality of the manuscript. We thank NASA CAPTEM for allocation of lunar samples. STFC is thanked for a PhD studentship to J.J.B. and a research grant to M.A. (grant number ST/I001298/1 to M.A.). F.M.M. acknowledges support from the NASA LASER Program during this study ( NNX13AK32G to F.M.M.). NanoSIMS access was through UKCAN funded through STFC grant ST/1001964/1 .
PY - 2014/3/15
Y1 - 2014/3/15
N2 - The recent discoveries of hydrogen (H) bearing species on the lunar surface and in samples derived from the lunar interior have necessitated a paradigm shift in our understanding of the water inventory of the Moon, which was previously considered to be a 'bone-dry' planetary body. Most sample-based studies have focused on assessing the water contents of the younger mare basalts and pyroclastic glasses, which are partial-melting products of the lunar mantle. In contrast, little attention has been paid to the inventory and source(s) of water in the lunar highlands rocks which are some of the oldest and most pristine materials available for laboratory investigations, and that have the potential to reveal the original history of water in the Earth-Moon system. Here, we report in-situ measurements of hydroxyl (OH) content and H isotopic composition of the mineral apatite from four lunar highlands samples (two norites, a troctolite, and a granite clast) collected during the Apollo missions. Apart from troctolite in which the measured OH contents in apatite are close to our analytical detection limit and its H isotopic composition appears to be severely compromised by secondary processes, we have measured up to ~2200ppm OH in the granite clast with a weighted average δD of ~. - 105 ± 130-, and up to ~3400ppm OH in the two norites (77215 and 78235) with weighted average δD values of -281 ± 49- and -27 ± 98-, respectively. The apatites in the granite clast and the norites are characterised by higher OH contents than have been reported so far for highlands samples, and have H isotopic compositions similar to those of terrestrial materials and some carbonaceous chondrites, providing one of the strongest pieces of evidence yet for a common origin for water in the Earth-Moon system. In addition, the presence of water, of terrestrial affinity, in some samples of the earliest-formed lunar crust suggests that either primordial terrestrial water survived the aftermath of the putative impact-origin of the Moon or water was added to the Earth-Moon system by a common source immediately after the accretion of the Moon.
AB - The recent discoveries of hydrogen (H) bearing species on the lunar surface and in samples derived from the lunar interior have necessitated a paradigm shift in our understanding of the water inventory of the Moon, which was previously considered to be a 'bone-dry' planetary body. Most sample-based studies have focused on assessing the water contents of the younger mare basalts and pyroclastic glasses, which are partial-melting products of the lunar mantle. In contrast, little attention has been paid to the inventory and source(s) of water in the lunar highlands rocks which are some of the oldest and most pristine materials available for laboratory investigations, and that have the potential to reveal the original history of water in the Earth-Moon system. Here, we report in-situ measurements of hydroxyl (OH) content and H isotopic composition of the mineral apatite from four lunar highlands samples (two norites, a troctolite, and a granite clast) collected during the Apollo missions. Apart from troctolite in which the measured OH contents in apatite are close to our analytical detection limit and its H isotopic composition appears to be severely compromised by secondary processes, we have measured up to ~2200ppm OH in the granite clast with a weighted average δD of ~. - 105 ± 130-, and up to ~3400ppm OH in the two norites (77215 and 78235) with weighted average δD values of -281 ± 49- and -27 ± 98-, respectively. The apatites in the granite clast and the norites are characterised by higher OH contents than have been reported so far for highlands samples, and have H isotopic compositions similar to those of terrestrial materials and some carbonaceous chondrites, providing one of the strongest pieces of evidence yet for a common origin for water in the Earth-Moon system. In addition, the presence of water, of terrestrial affinity, in some samples of the earliest-formed lunar crust suggests that either primordial terrestrial water survived the aftermath of the putative impact-origin of the Moon or water was added to the Earth-Moon system by a common source immediately after the accretion of the Moon.
KW - Apatite
KW - Hydrogen isotopes
KW - Lunar highlands
KW - Moon
KW - Water
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U2 - 10.1016/j.epsl.2014.01.015
DO - 10.1016/j.epsl.2014.01.015
M3 - Article
AN - SCOPUS:84893365314
SN - 0012-821X
VL - 390
SP - 244
EP - 252
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
ER -