Sample 77515
77515 Micropoikilitic Impact Melt Breccia 337.6 grams
Section titled “77515 Micropoikilitic Impact Melt Breccia 337.6 grams”
Figure 1: Photo of bottom surface of 77515 showing thick patina and numerous zap pits. S73-23496. Scale and cube are 1 cm.
Introduction
Section titled “Introduction”77515 was collected from the lunar surface a few meters from the station 7 boulder (figure 2). It is an impact melt breccia apparently similar to 77135. There is a patina with micrometeoite craters on all surfaces (figure 1). Numerous small vesicles are also apparent.
This large sample deserves more study and should be dated by someone.
Petrography
Section titled “Petrography”The texture of 77515 is poikiloblastic with irregular pigenoite oikocrysts enclosing abundant euhedral plagioclase laths and tablets and minor rounded olivine grains (figure 3). Ilmenite is dispersed throughout and is also poikilitic. Warner et al (1977) found the mineral mode to be 52.7% plagioclase, 44.5% pyroxene and
Figure 2: Map of station 7, Apollo 17.
Figure 3a: Photomicrographs of thin section 77515,11 by C Meyer @50x.
Figure 3b: Micropoikilitic texture of 77515 (from Meyer 1994). Partially crossed nicols.
2% ilmenite. Mineral compositions are given in figure 4.
Chemistry
Section titled “Chemistry”Laul and Schmitt (1975) reported the chemical composition, finding that it was the same as for 77135 (figure 5).
Processing
Section titled “Processing”77515 was chipped, not sawn. There are only two thin sections.
77515 (Warner et al. 1977).
Figure 5: Normalized rare-earth-element diagram for 77515 compared with nearby breccia 77135.
Mineral Mode ( Warner et al. 1977)
Section titled “Mineral Mode ( Warner et al. 1977)”| Vol. % | |
|---|---|
| Matrix | 87 |
| Mineral clasts | 10.9 |
| Lithic clasts | 2.1 |
| Mineral clasts | |
| Plagioclase | 7.7 |
| Olivine/Pyroxene | 3 |
| Opaque | |
| Metal/troilite | 02 |
| Other | |
| Lithic Clasts | |
| ANT | 0.4 |
| Devit. Anorthosite | 0.8 |
| Breccia | 0.4 |
| Other | 0.5 |
| Percent of matrix | |
| Plagioclase | 52.7 |
| Olivine/pyroxene | 44.5 |
| Opaque | 2 |
| Metal/troilite | 0.2 |
Other 0.7
Lunar Sample Compendium C Meyer 2011
Table 1. Chemical composition of 77515.
| reference | Laul 1975 | Warner77 | |||
|---|---|---|---|---|---|
| weight SiO2 % TiO2 Al2O3 FeO MnO MgO CaO Na2O K2O P2O5 S % sum | 1.4 18.6 8.4 0.1 11 11 0.68 0.24 | (a) (a) (a) (a) (a) (a) (a) | 48.3 1.51 18.2 8.1 0.9 11 11.4 0.7 0.28 0.27 | (b) (b) (b) (b) (b) (b) (b) (b) (b) (b) | |
| Sc ppm V Cr Co Ni Cu Zn Ga ppb As Se Rb Sr Y Zr Nb Mo Ru ppb ppb ppb Ag ppb Te ppb Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Re ppb Ir ppb Ir ppb Pt ppb Pt ppb Pt ppb | 14 30 1163 38.6 450 | (a) (a) (a) (a) | 1300 | (b) | |
| 350 29.8 73 | (a) (a) (a) | ||||
| 14.7 1.93 | (a) (a) | ||||
| 2.7 17 | (a) (a) | ||||
| 9.6 1.4 9.8 1.4 | (a) (a) (a) (a) | ||||
| Au ppb Th ppm U ppm | 4.1 | (a) | |||
| technique: (a) INAA, (b) broad beam e. probe |
References for 77515
Section titled “References for 77515”Butler P. (1973) Lunar Sample Information Catalog Apollo 17. Lunar Receiving Laboratory. MSC 03211 Curator’s Catalog. pp. 447.
Laul J.C. and Schmitt R.A. (1975c) Chemical composition of Apollo 17 samples: Boulder breccias (2), rake breccias (8), and others (abs). Lunar Sci. VI, 489-491. Lunar Planetary Institute, Houston.
LSPET (1973) Apollo 17 lunar samples: Chemical and petrographic description. Science 182, 659-672.
LSPET (1973) Preliminary Examination of lunar samples. Apollo 17 Preliminary Science Rpt. NASA SP-330. 7-1 – 7-46.
Meyer C. (1994) Catalog of Apollo 17 rocks: Volume 4. Curator’s Office JSC 26088 pp. 644 76 78
Meyer C. (2010) Lunar Sample Compendium (abs#1016). The 41st Lunar Planet. Sci. Conf. @ The Woodlands
Muehlberger W.R. and many others (1973) Preliminary Geological Investigation of the Apollo 17 Landing Site. In Apollo 17 Preliminary Science Report. NASA SP-330.
Warner R.D., Taylor G.J. and Keil K. (1977b) Petrology of crystalline matrix breccias from Apollo 17 rake samples. Proc. 8th Lunar Sci. Conf. 1987-2006.
Warner R.D., Keil K., Nehru C.E. and Taylor G.J. (1978) Catalogue of Apollo 17 rake samples from Stations la, 2, 7, and 8. Spec. Publ. #18, UNM Institute of Meteoritics, Albuquerque, 88 pp.
Wolfe E.W., Bailey N.G., Lucchitta B.K., Muehlberger W.R., Scott D.H., Sutton R.L and Wilshire H.G. (1981) The geologic investigation of the Taurus-Littrow Valley: Apollo 17 Landing Site. US Geol. Survey Prof. Paper, 1080, pp. 280.
