Maskelynite-hosted apatite in the Chassigny meteorite: Insights into late-stage magmatic volatile evolution in martian magmas

McCubbin, F. M.; Nekvasil, H.

doi:10.2138/am.2008.2558

Cited by 88 publications

(106 citation statements)

References 49 publications

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“…The same relationship occurs in the evolution of Martian magma [8]. In hot Cl-rich fluids that are equilibrated with the residual melt, Cl is more strongly partitioned into the melt (after F is exhausted), which involves the loss of water to the fluid phase [8,15,64]. In NWA 2975, the residual melt was degassed before F was depleted.…”

Section: Discussionmentioning

confidence: 79%

“…This type of apatite was previously considered rare among the studied Martian apatites, which were mostly recognized as chlorapatites with an average Cl-F-OH molar ratio of 5:3:2 [28]. However, McCubbin and Nekvasil [8] reported two generations of apatite, and one of them i.e., F-rich apatite, was considered a product of late magmatic differentiation. The second one, the Cl-F-rich apatite, was attributed to crystallization from an exsolved Cl-H 2 O-rich fluid phase.…”

Section: Discussionmentioning

confidence: 97%

“…Phosphates that occur in extra-terrestrial mafic rocks may provide information regarding water (volatiles) content in the environment leading to their formation and transformation (e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]). The magma source for Martian basalts is the Martian mantle; thus, the basaltic phosphates provide information on the Martian mantle composition as well as its evolution in the course of melting progression [11,[18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

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Validity of the Apatite/Merrillite Relationship in Evaluating the Water Content in the Martian Mantle: Implications from Shergottite Northwest Africa (NWA) 2975

et al. 2017

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Abstract:Phosphates from the Martian shergottite NWA 2975 were used to obtain insights into the source and subsequence differentiation of the melt/melts. The crystallization of two generations of fluorapatite (F > Cl~OH and F-rich), chlorapatite and ferromerrillite-merrillite were reconstructed from TEM (Transmission Electron Microscopy) and geochemical analyses. The research results indicated that the recognized volatiles budget of the two generations of fluorapatite was related to their magmatic origin. The apatite crystals crystallized from an evolved magma during its final differentiation and degassing stage. In turn, chlorapatite replaced ferromerrillite-merrillite and was not related to, mantle-derived shergottite magma. The relationship between merrillite and apatite indicates that apatite is most probably a product of merrillite reacting with fluids. REE (rare earth elements) pattern of Cl-apatite might point to an origin associated with exogenous fluids mixed with fluids exsolved from evolved magma. The study shows that, among the three types of apatite, only the fluorapatite (F > Cl~OH) is a reliable source for assessing the degree of Martian mantle hydration. The occurrence of apatite with merrillite requires detailed recognition of their relationship. Consequently, the automatic use of apatite to assess the water content of the magma source can lead to false assumptions if the origin of the apatite is not precisely determined.

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Section: Discussionmentioning

confidence: 79%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Validity of the Apatite/Merrillite Relationship in Evaluating the Water Content in the Martian Mantle: Implications from Shergottite Northwest Africa (NWA) 2975

et al. 2017

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“…Apatites in the NWA 2977 meteorite do not show evidence for having been affected by postcrystallization reequilibration; however, some of the plagioclase appears to have been transformed to maskelynite, indicating peak shock pressures between 25 and 30 GPa (59). As a comparison, many martian meteorites also have maskelynite, and the apatites within these samples are stoichiometric (i.e., F þ Cl þ OH ¼ 1), indicating that shock has not played much of a role in changing apatite chemistry in these samples (60)(61)(62). Therefore, impact-induced shock will likely have minimal affects on the volatile contents of the lunar apatites in this sample.…”

Section: Resultsmentioning

confidence: 99%

Nominally hydrous magmatism on the Moon

McCubbin

Steele

Hauri

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

272

185

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For the past 40 years, the Moon has been described as nearly devoid of indigenous water; however, evidence for water both on the lunar surface and within the lunar interior have recently emerged, calling into question this long-standing lunar dogma. In the present study, hydroxyl (as well as fluoride and chloride) was analyzed by secondary ion mass spectrometry in apatite [Ca 5 ðPO 4 Þ 3 ðF,Cl,OHÞ] from three different lunar samples in order to obtain quantitative constraints on the abundance of water in the lunar interior. This work confirms that hundreds to thousands of ppm water (of the structural form hydroxyl) is present in apatite from the Moon. Moreover, two of the studied samples likely had water preserved from magmatic processes, which would qualify the water as being indigenous to the Moon. The presence of hydroxyl in apatite from a number of different types of lunar rocks indicates that water may be ubiquitous within the lunar interior, potentially as early as the time of lunar formation. The water contents analyzed for the lunar apatite indicate minimum water contents of their lunar source region to range from 64 ppb to 5 ppm H 2 O. This lower limit range of water contents is at least two orders of magnitude greater than the previously reported value for the bulk Moon, and the actual source region water contents could be significantly higher. O ne of the scientific discoveries resulting from the Apollo missions was the pervasive waterless nature of the Moon and its rocks. The initial studies of the returned samples were pristine and showed no evidence of aqueous alteration, and water analyses were below detection limits. Moreover, hydrous phases were absent from the lunar rocks aside from a few unconfirmed reports of possible amphibole grains (1), which are now considered by many to represent either misidentifications or terrestrial contamination (as summarized by ref. 2). The subsequent forty years of lunar sample analysis have only supported and strengthened the idea that indigenous water was nearly absent from the Moon's interior. In fact, this conclusion has been incorporated into many petrologic and geophysical models constructed to aid in our understanding of lunar formation and lunar geology (3-11). The bulk water content of the Moon was recently estimated to be less than 1 ppb (11), which would make the Moon at least six orders of magnitude drier than the interiors of Earth (12, 13) and Mars (14). This extremely low water content is in keeping with the pervasive volatile-element depletion signature recorded in all lunar materials, because hydrogen is the most volatile of the elements. The exact cause for this volatile-element depletion is still under question; however, many have argued that it stems from the high temperatures associated with the Moon-forming giant-impact event at ∼4.5 Ga (i.e., refs. 3,8,15,and 16).Facilitated by advancements in analytical detection sensitivities for water, several recent discoveries have indicated that the story of water on the Moon is far from complete. Evi...

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“…Occasionally, other types of natural CaPO 4 are found as minerals, for example clinohydroxylapatite (Chakhmouradian and Medici 2006), staffelite (synonyms: staffelit, staffelita) belonging to carbonate-rich fluorapatites (chemical formula: Ca 5 [(F,O)(PO 4 ,CO 3 ) 3 ]) (Mason et al 2009; http:// www.mindat.org/gallery.php?min=9293) and DCPD (Klein 1901;Kaflak-Hachulska et al 2000). Furthermore, CaPO 4 were found in meteoric stones (Merrill 1917;McCubbin and Nekvasil 2008;McCubbin et al 2014). The world deposits of natural CaPO 4 are estimated to exceed 150 billion tons; from which approximately 85 % belong to phosphorites and the remaining *15 % belong to apatites (Cook et al 2005).…”

Section: Geological and Biological Occurrencesmentioning

confidence: 99%

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

Dorozhkin¹

2017

Morphologie

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Maskelynite-hosted apatite in the Chassigny meteorite: Insights into late-stage magmatic volatile evolution in martian magmas

Cited by 88 publications

References 49 publications

Validity of the Apatite/Merrillite Relationship in Evaluating the Water Content in the Martian Mantle: Implications from Shergottite Northwest Africa (NWA) 2975

Validity of the Apatite/Merrillite Relationship in Evaluating the Water Content in the Martian Mantle: Implications from Shergottite Northwest Africa (NWA) 2975

Nominally hydrous magmatism on the Moon

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

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