GSA DATA REPOSITORY

Transcription

1 GSA DATA REPOSITORY Apatites in lunar KREEP basalts: The missing link to understanding the H isotope systematics of the Moon R. Tartèse, M. Anand, F. M. McCubbin, S. M. Elardo, C. K. Shearer, I. A. Franchi KREEP BASALTS The last dregs of magma, after ~ % solidification of the putative lunar magma ocean (LMO) (e.g., Snyder et al., 1992, and references therein), known as the urkreep liquid, was likely highly enriched in incompatible elements such as potassium (K), rare earth elements (REE) and phosphorus (P). KREEP basalts are characterized by isotopic ratios and ratios of incompatible trace elements indicating their genetic link to this urkreep reservoir (Warren, 1989; Warren and Wasson, 1979). KREEP basalts are rare in the lunar sample collection but they are a very important type of lunar rock. Most of the Apennine Bench Formation at the Apollo 15 landing site is composed of KREEP basalts, for example, which could represent 1000 to km 3 (Taylor et al., 2012). Samples of KREEP basalts were primarily returned by the Apollo 15 and Apollo 17 missions, although small and rare fragments of KREEPy basalts among samples from the Apollo 14 and 16 and Luna 20 sites have been documented (e.g., Nyquist and Shih, 1992; Salpas et al., 1987). However, only the Apollo 15 and 17 KREEP basalts are considered pristine because they lack elevated siderophile element abundances attributed to meteoritic contamination. Only three KREEP basalt samples returned by Apollo missions weigh over 1 g: (7.5 g), (3.2 g) and clast 91 in breccia (2.73 g). Further insights into basaltic magmatism on the Moon involving KREEP are also provided by the olivine-gabbro lithology that is found within the NWA 773 clan of lunar meteorites (e.g., Borg et al., 2004; Jolliff et al., 2003). On the basis of mineral and bulk compositions, Jolliff et al. (2003) interpreted this olivine-gabbro lithology as a hypabyssal igneous rock, compositionally related to KREEP volcanic components. In this study we analyzed OH contents and D/H ratios of apatites in two of these large Apollo KREEP basalts, and 72275, and in the olivine-gabbro lithology (OG) of NWA 773. Among the Apollo KREEP basalts, is more Fe-rich and depleted in incompatible trace elements and REEs compared to (Fig. DR1). KREEP basalt from has a crystallization age of 4091 ± 49 Ma and is older than 15386, which crystallized at 3912 ± 25 Ma ago (weighted average dates calculated by combining Rb-Sr and Sm-Nd isochron dates, recalculated using the Isoplot 3.7 add-in for Excel (Ludwig, 2008) and the revised 87 Rb decay constant of a -1 (Rotenberg et al., 2012), from data of Carlson and Lugmair (1979), Nyquist et al. (1975) and Shih et al. (1992)). In NWA 773 and paired meteorite NWA 2977, whole-rock and mineral Sm-Nd dating and baddeleyite Pb/Pb dating indicates a crystallization age of ~ Ga for the OG lithology (Borg et al., 2004, 2009; Zhang et al., 2011), extending the occurrence of KREEP-rich magmatism on the Moon over a period of 1 Ga.

2 Figure DR1. Elemental concentrations in the studied KREEP basalts normalized to concentrations in CI-chondrites. Data are from Rhodes and Hubbard (1973) and Neal and Kramer (2003) for 15386, Salpas and Taylor (1987) for 72275, Joliff et al. (2003) for NWA 773 (OG) and Barrat et al. (2012) for CI-chondrites.

3 Figure DR2. Back-scattered electron images of the textural context of some apatite occurrences in samples (A) and (B-D). Scale bars represent 50 microns. Abbreviations are: ap: apatite; au: gold (coating remnants); ilm: ilmenite; K-gl: K-rich glass; Kfs: K-feldspar; mer: merrillite; pl: plagioclase; px: pyroxene. Two SIMS spots are visible in image D (overall spots are larger than apatite due to pre-sputtering before analysis). Figure DR3. Profiles of the 1 H and 19 F intensity recorded through the assemblage glassapatite-melt inclusions displayed in Fig. 3C.

4 Table DR1: Electron microprobe analyses (wt.%) of apatites in the studied KREEP basalts. Sample 15386,45 Analysis Ap3 Ap5 Ap6 Ap7 Ap8 Ap9 Ap12 Ap14 Ap15 Ap16 Ap17 Ap18 Ap19 P 2 O SiO Ce 2 O Y 2 O FeO MnO MgO CaO Na 2 O F Cl S F = -O Cl = -O S = -O Total Structural formula based on 13 anions P Si Ce Y Fe Mn Mg Ca Na F Cl OH* Total P site Ca site *OH calculated assuming that [F + Cl + OH = 1] in the X-site.

5 Table DR1: Electron microprobe analyses (wt.%) of apatites in the studied KREEP basalts (continued) Sample 15382,7 Analysis Ap1 Ap2 Ap4 Ap5 Ap6 Ap9 Ap10 Ap11 Ap12 Ap13 Ap14 Ap15 Ap16 P 2 O SiO Ce 2 O Y 2 O FeO MnO MgO CaO Na 2 O F Cl S F = -O Cl = -O S = -O Total Structural formula based on 13 anions P Si Ce Y Fe Mn Mg Ca Na F Cl OH* Total P site Ca site *OH calculated assuming that [F + Cl + OH = 1] in the X-site.

6 Table DR1: Electron microprobe analyses (wt.%) of apatites in the studied KREEP basalts (continued) Sample 15382, ,469 Analysis Ap17 Ap18 Ap20 Ap21 Ap22 Ap23 Ap3 Ap4 Ap5 Ap6 Ap7 Ap8 Ap9 P 2 O SiO Ce 2 O Y 2 O FeO MnO MgO CaO Na 2 O F Cl S F = -O Cl = -O S = -O Total Structural formula based on 13 anions P Si Ce Y Fe Mn Mg Ca Na F Cl OH* Total P site Ca site *OH calculated assuming that [F + Cl + OH = 1] in the X-site.

7 Table DR1: Electron microprobe analyses (wt.%) of apatites in the studied KREEP basalts (continued). Sample 72275, ,491 NWA 2977 Analysis Ap10 Ap11 Ap12 Ap13 Ap14 Ap15 Ap1 Ap2 Ap4 Ap5 Ap6 Ap1#1 Ap1#2 P 2 O SiO Ce 2 O Y 2 O FeO MnO MgO CaO Na 2 O F Cl S F = -O Cl = -O S = -O Total Structural formula based on 13 anions P Si Ce Y Fe Mn Mg Ca Na F Cl OH* Total P site Ca site *OH calculated assuming that [F + Cl + OH = 1] in the X-site.

8 Table DR1: Electron microprobe analyses (wt.%) of apatites in the studied KREEP basalts (continued). Sample NWA 2977 Analysis Ap2 Ap3 Ap4 Ap5 Ap6 Ap7 P 2 O SiO Ce 2 O Y 2 O FeO MnO MgO CaO Na 2 O F Cl S F = -O Cl = -O S = -O Total Structural formula based on 13 anions P Si Ce Y Fe Mn Mg Ca Na F Cl OH* Total P site Ca site *OH calculated assuming that [F + Cl + OH = 1] in the X-site.

9 Table DR2: OH content and H isotopic composition of apatites in the studied KREEP basalts. Analysis OH (ppm) 2 (ppm) D ( ) 2 ( ) Sample 72275,469 Ap2# Ap3# Ap4# Ap5# Ap6# Ap6# Ap7# Ap8# Ap9# Ap10# Ap10# Ap12# Sample 15386,45 Ap1# Ap2# Ap4# Ap5# Ap6# Ap7# Ap10# Ap11# Ap12# Ap13# Ap14# Ap15# Sample NWA 773 (olivine-gabbro lithology) Ap6# Ap6# Ap14# Ap14# Ap9# Ap15# Ap16# Ap16# Ap11# *Measured data have been corrected for spallation production of D and H using the cosmogenic production rates given in Merlivat et al. (1976) and the cosmic ray exposure ages of 52.5 ± 2 Ma for (Leich et al., 1975), 235 ± 5 Ma for (this is the CRE age for 15382, Stettler et al., 1973, Turner et al., 1973) and 73 ± 2 Ma for the olivine-gabbro lithology in NWA 773 (Fernandes et al., 2003).

10 SUPPLEMENTARY REFERENCES Barrat, J.A., Zanda, B., Moynier, F., Bollinger, C., Liorzou, C., and Bayon, G., 2012, Geochemistry of CI chondrites: Major and trace elements, and Cu and Zn Isotopes: Geochimica et Cosmochimica Acta, v. 83, p Borg, L.E., Gaffney, A.M., Shearer, C.K., DePaolo, D.K., Hutcheon, I.D., Owens, T.L., Ramon, E., and Brennecka, G., 2009, Mechanisms for incompatible-element enrichment on the Moon deduced from the lunar basaltic meteorite Northwest Africa 032: Geochimica et Cosmochimica Acta, v. 73, p Borg, L.E., Shearer, C K., Asmerom, Y., and Papike, J J., 2004, Evidence for prolonged KREEP magmatism on the Moon from the youngest dated lunar igneous rock: Nature, v. 432, p Carlson, R.W., and Lugmair, G.W., 1979, Sm-Nd constraints on early lunar differentiation and the evolution of KREEP: Earth and Planetary Science Letters, v. 45, p Fernandes, V.A., Burgess, R., and Turner, G., 2003, 40Ar-39Ar chronology of lunar meteorites Northwest Africa 032 and 773: Meteoritics & Planetary Science, v. 38, p Jolliff, B.L., Korotev, R.L., Zeigler, R.A., and Floss, C., 2003, Northwest Africa 773: Lunar mare breccia with a shallow-formed olivine-cumulate component, inferred very-low-ti (VLT) heritage, and a KREEP connection: Geochimica et Cosmochimica Acta, v. 67, p Leich, D.A., Kahl, S.B., Kirschbaum, A.R., Niemeyer, S., and Phinney, D., 1975, Rare gas constraints on the history of Boulder 1, Station 2, Apollo 17: The Moon, v. 14, p Ludwig, K.R., 2008, Isoplot/Ex Version 3.70: A Geochronological Toolkit for Microsoft Excel: Berkeley Geochronology Center Special Publication, v. 4, 73 p. Merlivat, L., Lelu, M., Nief, G., and Roth, E., 1976, Spallation deuterium in rock 70215: Proceedings of 7th Lunar Science Conference, p Neal, C.R., and Kramer, G.Y., 2003, The composition of KREEP: A detailed study of KREEP basalt 15386: Houston, Texas, Lunar and Planetary Institute, Lunar and Planetary Science XXXIV, abstract Nyquist L.E., Bansal B.M., and Wiesmann H., 1975, Rb-Sr ages and initial 87 Sr/ 86 Sr for Apollo 17 basalts and KREEP basalt 15386: Proceedings of the 6 th Lunar Science Conference, p Nyquist, L.E., and Shih, C.-Y., 1992, The isotopic record of lunar volcanism: Geochimica et Cosmochimica Acta, v. 56, p Rhodes, J.M., and Hubbard, N.J., 1973, Chemistry, classification, and petrogenesis of Apollo 15 mare basalts: Proceedings of the 4 th Lunar Science Conference, Geochimica et Cosmochimica Acta, v. 2, p Rotenberg, E., Davis, D.W., Amelin, Y., Ghosha, S., and Bergquist, B.A., Determination of the decay-constant of 87 Rb by laboratory accumulation of 87 Sr: Geochimica et Cosmochimica Acta, v. 85, p

11 Salpas, P.A., Taylor, L.A., and Lindstrom, M.M., 1987, Apollo 17 KREEPy basalts: Evidence for the non-uniformity of KREEP: Journal of Geophysical Research, v. 92, p. E340-E348. Shih C.Y., Nyquist L.E., Bansal B.M., and Wiesmann H., 1992, Rb-Sr and Sm-Nd chronology of an Apollo 17 KREEP basalt: Earth and Planetary Science Letters, v. 108, p Snyder G.A., Taylor L.A., and Neal C.R., 1992, A chemical model for generating the sources of mare basalts: Combined equilibrium and fractional crystallization of the lunar magmasphere: Geochimica et Cosmochimica Acta, v. 56, p Stettler, A., Eberhardt, P., Geiss, J., Grogler, N., and Maurer, P., 1973, Ar 39 -Ar 40 ages and Ar 37 -Ar 38 exposure ages of lunar rocks: Proceedings of the 4 th Lunar Science Conference, Geochimica et Cosmochimica Acta, v. 2, p Taylor, G.J., Martel, L.M.V., and Spudis, P.D., 2012, The Hadley-Apennine KREEP basalt igneous province: Meteoritics & Planetary Science, v. 47, p Turner, G., Cadogan, P.H., and Yonge, C.J., 1973, Argon selenochronology: Proceedings of the 4 th Lunar Science Conference, Geochimica et Cosmochimica Acta, v. 2, p Warren, P.H., 1989, KREEP: major-element diversity, trace-element uniformity (almost): in Workshop on Moon in transition: Apollo 14, KREEP, and evolved lunar rocks (Taylor, G.J., and Warren, P.H., eds.), LPI Technical Report Number 89-03, p Warren, P.H., and Wasson, J.T., 1979, The origin of KREEP: Reviews of Geophysics and Space Physics, v. 17, p Zhang, A.C, Hsu, W.B., Floss, C., Li, X.H., Li, Q.L., Liu, Y, and Taylor, L.A., 2011, Petrogenesis of lunar meteorite Northwest Africa 2977: Constraints from in situ microprobe results: Meteoritics & Planetary Science, v. 45, p