& Planetary Science 40, Nr 3, 445–459 (2005) Abstract available online at http://meteoritics.org

Revisiting spectral parameters of silicate-bearing

RenË DUFFARD,1* Daniela LAZZARO,1 and Julia DE LEµN2

1ObservatÕrio Nacional Rua Gal. JosË Cristino 77, Rio de Janeiro, 20921-400 RJ, Brazil 2Instituto de AstrofÏVLFDde Canarias, c/ Via LÃctea s/n, E38200, La Laguna, Tenerife, Spain *Corresponding author. E-mail: [email protected] (Received 16 July 2004; revision accepted 31 January 2005)

Abstract–Visible and near-infrared reflectance spectra of a sample of silicate-bearing meteorites have been used to evaluate the spectral parameters space defined in the pioneering work of Gaffey et al. (1993). The studied sample consisted of 91 ordinary , 47 basaltic , and 21 different laboratory mixtures obtained from the RELAB database. Our results indicate that the spectral parameter space, in particular the BAR versus band I center, is not suitable enough to identify the mineralogy of meteorites and . The grain size of the sample also appears as a very sensitive parameter and can play an important role in locating an object in the spectral parameter space. Finally, the application of our study to the question of a genetic link between V-type asteroids and HED meteorites shows that these bodies plot in distinct regions in the BAR versus band I center space. This result further confirms that those spectral parameters cannot uniquely define the mineralogy of a sample.

INTRODUCTION type asteroids and compared them to ordinary chondrites and basaltic meteorites using data from the combined Olivine and pyroxene are very common rock-forming ECAS (Zellner et al. 1985), the 52-channel data (Bell et al. minerals in the solar system. Several classes of meteorites, 1988), and the combined 24-color (Chapmann et al. 1979) such as the ordinary and the achondrites, are rich in surveys. In the space BAR versus band I center, the authors both of these minerals. The spectral signatures due to olivine defined an “Ol” rectangular region, which encompasses the and/or pyroxene are also detected when the surfaces of olivine assemblages, an “OC” polygonal region, which asteroids belonging to several taxonomic classes are remotely represents the mafic silicate components of ordinary probed. Since meteorites are believed to derive from chondrites, and a “BA” rectangular zone, which includes the asteroids, the comparison of remote spectrophotometry of pyroxene-dominated basaltic achondritic assemblage. The asteroids and laboratory reflectance spectra of meteorites can BA and OC regions were defined with 20 and 44 meteorites, help constrain genetic relations between these two respectively. However, no reference was given to the specific populations. meteorites used or to the grain size of the samples. The spectrum of olivine is dominated by a complex Apparently, this data was obtained from the work of Gaffey absorption band centered near 1.0 Pm. Pyroxene, on the other (1976), where an extensive analysis of spectra was hand, presents absorption features near 1.0 Pm (band I) and performed using the Beckmann DK2A ratio recording 2.0 Pm (band II) for low-calcium pyroxenes and a broad 1 Pm spectroreflectometer described by Adams et al. (1970). An feature with a double minimum for certain calcic pyroxenes. offset in wavelength was applied to this original data because In the spectra of olivine-pyroxene mixtures, the wavelength of systematic calibration errors, as reported by McFadden position of band II is only sensitive to pyroxene composition, et al. (1982) and Gaffey (1984). while the position of band I is a function of the relative The band area plots introduced by Gaffey et al. (1993) abundance and composition of olivine and pyroxene phases. have been used in several works aiming to characterize the Cloutis et al. (1986) have shown that the relative contrast of mineralogy of basaltic asteroids (Kelley et al. 2003; band I and band II (BII/BI area ratio, or BAR) may be useful Hardersen et al. 2004; Duffard et al. 2004), to analyze the in estimating the relative olivine and orthopyroxene spectral properties of 433 Eros (Murchie et al. 1996), and to abundances in a mixture. study the reflectance spectra of olivine-orthopyroxene- Aiming of establishing a mineralogical link between bearing assemblages at different temperatures (Moroz et al. meteorites and asteroids, Gaffey et al. (1993) analyzed 40 S- 2000).

445 © The Meteoritical Society, 2005. Printed in USA. 446 R. Duffard et al.

Fig. 1. BAR versus band I center for ordinary chondrites and achondrites meteorites obtained from the RELAB database.

This implies that a precise definition of where the samples were crushed into diverse particle sizes to obtain the different classes of meteorites plot is necessary in order to reflectance spectra. correctly interpret the results obtained for asteroids or The extraction of the spectral parameters was done laboratory mineral analysis. Considering the large dataset of following the procedure first outlined by Cloutis et al. (1986) spectral parameters for meteorites now available, we decided and used by Gaffey et al. (1993). Among the most important to repeat the calculations of Gaffey et al. (1993). The main parameters in characterizing the mineralogy associated with point of the present work, therefore, is that all meteorite the reflectance spectra of an or meteorite are the band spectra were obtained using the same instrumental minimum and the band centers. These are defined as the configuration and wavelength calibration. wavelength position of the point of lowest reflectance before The analysis of the data and extraction of the parameters and after the removal of the continuum, respectively. are presented in the Analysis of the Data section. The study of Using the meteorite reflectance spectra, we determined some laboratory mixtures and the effects of different grain the two maxima, near 0.7 and 1.4 Pm, and with the reflectance sizes are presented in the Laboratory Mixtures and Grain Size values and positions of the maxima, we computed a linear Effects sections. Finally, an application to V-type asteroids continuum in this region. A similar procedure was done in the and a discussion of the results are outlined in the last section. interval between 1.4 and 2.4 Pm. These continua were then extracted from the spectra by dividing each linear continuum ANALYSIS OF THE DATA in the corresponding region for each object. We note that, although the entire sample has spectra up to longer The reflectance spectra of meteorites in the range of 0.3 wavelengths than 2.4 Pm, this limit was used to compare our to 2.4 Pm at a 0.005 Pm sampling resolution were obtained results with other works. Moreover, all of the remote asteroid from the Reflectance Experiment Laboratory (RELAB) reflectance spectra obtained in the near-infrared region have a database (http://www.planetary.brown.edu/relab). The technical CCD limitation of 2.5 Pm. RELAB instrument is designed to simulate the diverse The spectra obtained after the removal of the continuum viewing geometries in remote telescopic measurements. A were used to compute the band centers, band areas, and band 30° incident angle and a 0° emission angle (measured from depths. The center determination was done by fitting a second the vertical) were the default parameters for the measured order polynomia in the region of the minimum. Following spectra. The details of RELAB and how the spectra were Cloutis et al. (1986), the band area is defined as the area obtained are described in Pieters (1983) and in the RELAB enclosed by the spectral curve and a straight-line tangent to users manual. As explained in that document, the meteorite the respective maxima. Band area I is between the maxima of Spectral parameters of silicate-bearing meteorites 447

Fig. 2. BAR versus band I center for the different achondrite meteorites: , , and (HED), shergottites, and .

0.7 and 1.4 Pm and band area II is between 1.4 and 2.4 Pm. plotted the band II center versus band I center for all the HED The ratio between band area II and band area I is defined as meteorites studied (9 diogenites, 25 eucrites, and 13 the BAR parameter. howardites) as done previously by Gaffey (1997) when We selected a large sample composed of 91 ordinary analyzing the surface composition of 4 Vesta. In Fig. 3, values chondrites, 47 basaltic achondrites, and 21 different for the howardites, diogenites, and eucrites are superimposed laboratory mixtures. The complete set of results indicating the on the regions for diogenites and eucrites from Gaffey (1997) RELAB file, reference, meteorite name, sample grain size, (dashed line). Note that Gaffey (1997) used values taken from centers of bands I and II, and BAR parameter is given in Gaffey (1976) and applied a wavelength correction of Appendix 1. +0.025 Pm as discussed in Gaffey (1984). The BAR versus band I center for all meteorites in our The difference between the two determinations of the work is given in Fig. 1, defining regions for the different and regions is a small displacement of both classes of meteorites. The regions defined by Gaffey et al. band centers to shorter wavelengths. As can be seen, the (1993) are given for comparison (dashed lines). We observe eucrite region plots at larger wavelength in both bands than that most of our HED meteorites are outside the region the howardites and diogenites, respectively. It is worth defined by Gaffey et al. (1993) as BA and the region defined recalling that the crust of the HED is associated as OC are moved to smaller BAR and band I center values, with two different mineralogies: (i) a diogenite lower crust, maintaining its overall shape. and (ii) a eucrite upper crust (Takeda 1997). This kind of plot Since most recent works using spectral parameter space can, therefore, give information about the depth in the parent are related to the HED–V-type asteroids issue, we plotted in body where a specific meteorite came from. The discrepancy Fig. 2 only the achondrite meteorites identifying each class. between our determination and that of Gaffey et al. (1993) is The HED meteorites, some shergottite and naklite, and difficult to explain, but our points fit the pyroxene data members of the group of SNC meteorites, are shown in this modified by Cloutis and Gaffey (1991) after Adams (1974) plot. The eucrites occupy the upper-left portion of the HED well. region, the diogenites are in the lower-right portion, and the The olivine region is difficult to define in a plot BAR howardites are located between the eucrites and the versus band I center, since pure olivine reflectance spectra diogenites, as shown previously by Gaffey et al. (1993). The present just one absorption band centered in 1 Pm. Therefore, localization of the howardites is somewhat expected since it is not possible to calculate the band area II in order to these are breccias composed of eucrite and diogenite material. determine the BAR value. Moreover, we found in the RELAB To further characterize this class of meteorites, we database only two meteorite spectra classified as pure olivine. 448 R. Duffard et al.

Fig. 3. Position of the band centers for the observed sample compared to the region for the basaltic achondrite assemblages as given by Gaffey (1997). Circles and triangles are diogenites and eucrites meteorites, respectively. Howardites assemblages (filled squares) occupy the region between those of the eucrite and diogenite.

Fig. 4: BAR versus band I center for different laboratory mixtures. Lines A and B are mixtures of different weight proportions of orthopyroxene (Opx) and clinopyroxene (Cpx) (Opx/Cpx = 85/15, 75/25, 60/40, 50/50, 40/60, 25/75, and 15/85) for two different grain sizes. Line C is a mixture of olivine, bronzite, and anorthosite in different weight proportions. The following weight proportions of Ol/Opx/An were used: 16/ 66/16, 16/41/41, 41/41/16, 33/33/33, 16/16/66, 41/16/41, and 66/16/16. Line D is the olivine-orthopyroxene mixing line (Cloutis et al. 1986). Spectral parameters of silicate-bearing meteorites 449

Fig. 5. Variations with the grain size of the following spectral parameters: a) BAR, b) band I center, c) depth I, and d) depth II. All the plots are for four eucrites (numbers 1 to 4) and one diogenite (number 5).

Using other terrestrial pure olivine and the results from respectively. In both cases, the higher values of BAR (points Sunshine et al. (1998), we can define the olivine zone with a labeled 1) correspond to mixtures with higher proportions of variation of band I center between 1.05 and 1.10 Pm, as orthopyroxene; this value decreases with decreasing Gaffey et al. (1993). The increment in the BAR parameter is orthopyroxene content. It is important to note that for due to the presence of pyroxene. mixtures with orthopyroxene content greater than 50% (points 1, 2, and 3) the effect of increasing grain size, i.e., LABORATORY MIXTURES moving from line A to line B, is to increase the BAR and band I center values. However, the inverse effect in the BAR value To evaluate the change in the spectral parameters due to occurs for mixtures with orthopyroxene content less than 50% the mineralogical composition, we selected and analyzed (points 5, 6, and 7). laboratory mixtures from the RELAB database containing We then analyzed the effect of including olivine (Ol) in a low-calcium pyroxene (orthopyroxene), high-calcium mixture of pyroxene, selecting seven other laboratory pyroxene (clinopyroxene), and olivine. We computed the mixtures of olivine, bronzite (an orthopyroxene), and band centers and BAR parameter following the procedure anorthosite (a plagioclase). The results for these mixtures are previously described; the resulting values are given in represented by line C in Fig. 4. As can be seen, the decrease of Appendix 2. olivine content in the mixtures produces an increase of the We first analyzed how the spectral parameters change for BAR value and a decrease of the band I center value. This the different mixtures of orthopyroxene (Opx) and result was already noted in previous works (Cloutis et al. clinopyroxene (Cpx) and for two distinct grain sizes. The 1986). obtained results are shown in Fig. 4, where the points labeled For comparison, we also included the Ol/Opx line 1 to 7 indicate mixtures in different weight proportions of (marked as D) originally defined by Cloutis et al. (1986). Opx and Cpx, while the lines A and B connect points obtained These authors used an olivine-orthopyroxene mixture in four with small ( 45 Pm) and large (75–145 Pm) grain size, particle sizes: 38–53 Pm, wet-sieved; 63–90 Pm, wet-sieved; 450 R. Duffard et al.

Fig. 6. BAR versus band I center for four different eucrites and the diogenite. For each meteorite, the points correspond to different grain sizes. Smaller grain sizes are at the left of the figure and larger grain sizes are at the right. See Appendix 3 for values.

63–90 Pm, dry-sieved; and 90–125 Pm, wet-sieved. This line size affects the spectral parameters of meteorites, we analyzed is parallel to line A, which is for the smallest grain size of an a sample of basaltic achondrites. We selected four eucrites Opx/Cpx mixture, indicating that these different mixtures (numbers 1 to 4 in Fig. 5) and one diogenite (number 5), each give very similar results. one crushed to powders of different sizes. In principle, we could use the location of the laboratory The complete set of computed parameters is given in mixtures in this plot to identify the mineralogy of a meteorite Appendix 3 and plotted in Fig. 5. As can be seen in plots A or asteroid. However, this procedure does not always give a and B (Fig. 5), the BAR parameter increases with the grain unique solution. Consider, for example, lines A and C, size while the band I center shows a more complex behavior, representing mixtures of Opx/Cpx and Ol/Opx/An. For BAR with some samples presenting a significant increase with the values around 1.2, the two lines intercept each other, implying grain size and very small variations with others. that we cannot distinguish between a small amount of olivine Another important parameter to be analyzed is the band or clinopyroxene. Therefore, this kind of plot does not always depth which, according to Cloutis and Gaffey (1991), is give a unique mineralogical composition and must be used expected to increase with increasing mean grain size. These with care when trying to interpret the mineralogy of an object. authors define the band depth I as the ratio of the reflectance However, in their original work, Cloutis et al. (1986) maximum at the peak between band I and band II to the recognized that the trend was good for estimating the relative reflectance of the band I minimum. From the analysis of a amount of olivine and orthopyroxene. More recently, large sample of orthopyroxene spectra, they conclude that the Sunshine et al. (2002) demonstrated that high-calcium band depth does indeed increase with the grain size. This pyroxene contributes to the spectra of S-type asteroids and trend is more significant for grain sizes larger than 200 Pm, silicate-rich meteorites. According to these authors a ternary although the spectral data for large grain size pyroxenes were of olivine, orthopyroxene, and clinopyroxene must be very limited, using just two samples. considered when analyzing the spectra of these objects. To see how this result applies to the meteorite spectra, we then computed the band depths for our sample of four eucrites GRAIN SIZE EFFECTS and one diogenite. The results are shown in plots C and D (Fig. 5), where for grain sizes up to around 100 Pm, an In the previous section, changes were observed in the increase of both band depths with increasing mean grain size values of the spectral parameters when evaluating diverse is noticeable. However, for larger grain sizes, a decrease in mineral compositions. To further investigate how the grain these parameters is apparent. This change in reflectance Spectral parameters of silicate-bearing meteorites 451

Fig. 7. BAR versus band I center for different V-type asteroids. Different pure orthopyroxenes like bronzites, enstatites, and hypersthenes are plotted for reference. The value for 4 Vesta is from Gaffey (1997), 1929 Kollaa is from Kelley et al. (2003), 1459 Magnya is from Hardersen et al. (2004), and the rest are from Duffard et al. (2004).

parameters with grain size is in agreement with results Vesta, but some are also in near-Earth orbits (for a obtained by Adams and Filice (1967). In this classic paper, it compilation of references, see Binzel et al. 2002), and one is is shown that reflectance parameters can be explained by in the outer part of the main belt (Lazzaro et al. 2000). The variations in the amount of selective wavelength absorption issue is to determine whether the HED meteorites found on resulting from differences in the mean optical path length Earth and the small V-type asteroids are all genetically linked through the powders. to 4 Vesta. For a detailed description of the HED–Vesta It is important to note that the region where the HED association, we refer to Drake (2001). meteorites plot in Figs. 1 and 2 is valid for grain sizes smaller To get a better insight into the above issue, we gathered than 25 Pm and for a temperature of 300 K. From the above all the mineralogical data on V-type asteroids present in the results, we can conclude that this region would shift to greater literature. The result is plotted in Fig. 7 along with the BAR values with increasing grain size of the HED meteorites, meteorite region defined by Gaffey et al. (1993) and the HED approaching, therefore, the BA region defined by Gaffey et al. region from Fig. 1. In this plot, the data for 4 Vesta is from (1993), as can be seen in Fig. 6. Gaffey (1997), that for 1929 Kollaa is from Kelley et al. (2003), that for 1459 Magnya (the unique V-type asteroid in APPLICATION TO V-TYPE ASTEROIDS the outer main belt) is from Hardersen et al. (2004), and the rest are from Duffard et al. (2004). The most remarkable The correlation between specific meteorites and asteroids aspect of this figure is that most of the V-type asteroids, is a long-standing problem and the study of which is the main 4 Vesta included, plots outside the BA and the HED regions. purpose of this work. Therefore, this last section is devoted to Moreover, the majority of V-type asteroids, for which spectral the application of our study to the Vesta–V-type–HED issue. parameters are available, have greater BAR values than the This issue can be summarized as follows: asteroid HED meteorites. They also present a greater dispersion in the 4 Vesta is the largest unique asteroid (nearly 500 km in band I center values. diameter) with a basaltic crust surface. However, a number of In analyzing this very surprising result, we must first of small asteroids (a10 km in diameter) exist with the same all keep in mind that the HED region is valid for the grain size spectral characteristics as 4 Vesta, and classified as V-type. of the selected meteorites and also for room temperature. These small asteroids are mostly found in the region near With regards to the first point, we have shown in the Grain 452 R. Duffard et al.

Fig. 8. Band II versus band I centers for different V-type asteroids compared to the regions for eucrite and diogenite obtained in this work (see Fig. 3). The values for 4 Vesta (solid line polygon) are from Gaffey (1997), those for 1929 Kollaa are from Kelley et al. (2003), those for 1459 Magnya (open circles) are from Hardersen et al. (2004), and the rest are from Duffard et al. (2004).

Size Effects section that the grain size affects several spectral increase the BII/BI ratio. This increase, however, is relatively parameters, particularly by increasing the BAR value for small and cannot account for the dispersion in the BAR value larger grains. This means that in a BAR versus band I center displayed by the V-type asteroids. plot, a meteorite would move to the right with increasing A possible explanation for the mismatch between grain size. Although this increase seems to stop for grain sizes spectral parameters of HED meteorites and V-type asteroids larger than 200 Pm, the result is based on just two meteorite is a difference in the mineralogy. The relationships between samples and should be confirmed with more data. the absorption band center and the pyroxene composition Regarding the temperature, it has been shown by several (molar calcium content Wo and molar iron content Fs) can be authors (Singer and Roush 1985; Roush and Singer 1986; computed using the list of equations cited in Gaffey et al. Moroz et al. 2000) that temperature variations do have (2002). Burns (1970) showed that the centers of the olivine important secondary effects on near-infrared spectra. and pyroxene absorptions migrate systematically toward However, Moroz et al. (2000) concluded that the influence of longer wavelengths, with the increasing substitution of large the temperature on the band I center position and BAR value cations (Fe2+, Ca2+) for the smaller Mg2+ cations in the silicate are rather moderate. They show that the band area ratio sites. Band I center is related to the Wo number (Gaffey et al. moderately rises and the band I center decreases with 2002), which indicates the calcium content. Vertical decreasing temperature. But they concluded that, in the movements in the BAR versus band I center plot are due to specific case of orthopyroxene-rich asteroid surfaces, a the calcium content, while and horizontal movements could misinterpretation of the relative silicate abundances due to be due to a variety of reasons, such as grain size, temperature temperature-induced effects is not expected. effects, space weathering, and mineralogical composition, Among the other processes that might contribute to like Fs number. Fig. 7 also plots some pure orthopyroxenes, modify an asteroid spectrum is space weathering. As such as enstatites (very low Fs number), bronzites (low Fs demonstrated in several works (Wetherill and Chapmann number), and hypersthenes (high Fs number). The dispersion 1988; Pieters et al. 1993; Moroz et al. 1996; Bell 1997; of these points indicates that the Fs content cannot be Yamada et al. 1998) space weathering processes may distinguished in this kind of plot. optically alter the uppermost layer of regolith present on the A better way to compare mineralogies for the HED– surface of an asteroid. In particular, Ueda et al. (2002) Vesta association is the plot band II versus band I center. This concluded that the effect of the space weathering is to is done in Fig. 8, where we plot both parameters for 4 Vesta Spectral parameters of silicate-bearing meteorites 453 taken from Gaffey (1997), for 1929 Kollaa from Kelley et al. in the solar system. Journal of Geophysical Research 79:4829– (2003), for 1459 Magnya from Hardersen et al. (2004) and the 4836. rest from Duffard et al. (2004). Vesta and Magnya are the only Bell J. F., Owensby P. D., Hawke B. R., and Gaffey M. J. 1988. 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Hiroi T., Pieters C. M., and Takeda H. 1994. Grain size of the surface Pieters C. M., Fischer E. M., Rode O. D., and Basu A. 1993. Space regolith of asteroid 4 Vesta estimated from its reflectance weathering on meteorite parent bodies: Issues raised by new spectrum in comparison with HED meteorites. Meteoritics 29: lunar soil analyses (abstract). Meteoritics 28:419. 394–396. Roush T. L. and Singer R. B. 1986. Gaussian analysis of temperature Hiroi T. and Pieters C. M. 1998. Origin of vestoids suggested from effects on the reflectance spectra of mafic minerals in the 1 Pm the space weathering trend in the visible reflectance spectra of region. Journal of Geophysical Research 91:10,301–10,308. HED meteorites and lunar soils. Antarctic Meteorite Research Singer R. B. and Roush T. L. 1985. Effects of temperature on 11:163–172. remotely sensed mineral absorption features. Journal of Hiroi T., Pieters C. M., Vilas F., Sasaki S., Hamabe Y., and Kurahashi Geophysical Research 90:12,434–12,444. E. 2001. The mystery of 506.5 nm feature of reflectance spectra Sunshine J., Pieters C., and Pratt S. 1990. Deconvolution of mineral of Vesta and vestoids: Evidence of space weathering. Earth, absorption bands: An improved approach. Journal of Planets and Space 53:1071–1075. Geophysical Research 95:6955–6966. Kelley M. S., Vilas F., Gaffey M. J., and Abell P. A. 2003. Quantified Sunshine J. M. and Pieters C. M. 1998. Determining the composition mineralogical evidence for a common origin of 1929 Kollaa with of olivine from reflectance spectroscopy. Journal of Geophysical 4 Vesta and the HED meteorites. Icarus 165:215–218. Research 103:13,675–13,688. Lazzaro D., Michtchenko T., Carvano J. M., Binzel R. P., Bus S. J., Sunshine J., Bus S. J., Burbine T. H., McCoy T. J., and Binzel R. P. Burbine T. H., MothË-Diniz T., Florczak M., Angeli C. A., and 2002. Unambiguous spectral evidence for high- (and low-) Harris A. W. 2000. Discovery of a basaltic asteroid in the outer calcium pyroxene in asteroids and meteorites (abstract #1356). main belt. Science 288:2033–2035. 33rd Lunar and Planetary Science Conference. CD-ROM. McFadden L. A., Gaffey M. J., Takeda H., Jackowski T. L., and Takeda H. 1997. Mineralogical records of early planetary processes Reed K. L. 1982. Reflectance spectroscopy of diogenite on the HED parent body with reference to Vesta. Meteoritics & meteorite types from Antarctica and their relationship to Planetary Science 32:841–853. asteroids. Proceedings of the Seventh Symposium on Antarctic Ueda Y., Hiroi T., Pieters C. M., and Miyamoto M. 2002. Changes of Meteorites. pp.188–206. band I center and band II/band I area ratio in reflectance spectra Moroz L. V., Fisenko A. V., Semjonova L. F., Pieters C. M., and of olivine-pyroxene mixtures due to the space weathering and Korotaeva N. N. 1996. Optical effects of regolith processes on S- grain size effects (abstract #2023). 33rd Lunar and Planetary asteroids as simulated by laser shots on and Science Conference. CD-ROM. other mafic materials. Icarus 122:366–382. Wetherill G. and Chapmann C. 1988. Asteroids and meteorites. In Moroz L., Schade U., and WÆsch R. 2000. Reflectance spectra of Meteorites and the early solar system, edited by Kerridge J. and olivine-orthopyroxene bearing assemblages at decreased Matthews M. Tucson, Arizona: The University of Arizona Press. temperatures: Implications for remote sensing of asteroids. pp. 35–67. Icarus 147:79–93. Yamada M., Sasaki S., Nagahara H., Fujiwara A., Hasegawa S., Yano Murchie S. L. and Pieters C. M. 1996. Spectral properties and H., Ohashi H., and Ohtake H. 1998. Reflectance spectra change rotational spectral heterogeneity of 433 Eros. Journal of of planet-forming materials due to laser irradiation and proton Geophysical Research 101:2201–2214. implantation. Antarctic Meteorites 23:173–176. Pieters C. M. 1983. Strength of mineral absorption features in the Zellner B., Tholen D. J., and Tedesco E. F. 1985. The eight color transmitted component of near-infrared reflected light: First asteroid survey: Results for 589 minor planets. Icarus 61:355– results from RELAB. Journal of Geophysical Research 88: 416. 9534–9544.

APPENDIX 1

Spectral parameters and grain size for the different meteorites. Grain size Band I center Band II center RELAB sample ID Ref. Meteorite name (Pm) (Pm) (Pm) BAR Diogenites MB-TXH-067-A 1 EET A79002 0–25 0.920 1.889 1.59 MB-TXH-073-A 6 Y-74013 0–25 0.922 1.915 1.60 MB-TXH-074-A 6 Y-75032 0–25 0.927 1.934 1.41 MB-TXH-095-A 1 Johnstown 0–25 0.917 1.884 1.40 MP-TXH-068-A 2 GRO 95555 0–25 0.922 1.902 1.67 MP-TXH-077-A 2 LAP 91900 0–25 0.921 1.900 1.66 MP-TXH-081-A 2 Aioun el Atrouss 0–25 0.923 1.896 1.64 MP-TXH-088-A 2 Tatahouine 0–25 0.919 1.893 1.60 MP-TXH-095-A 2 A-881526 0–25 0.919 1.887 1.67 Eucrites MB-TXH-066-A 1 ALH A76005 0–25 0.935 1.960 1.45 MB-TXH-069-A 6 Millbillillie 0–25 0.938 1.994 1.17 MB-TXH-070-A 6 Juvinas 0–25 0.936 1.984 1.34 Spectral parameters of silicate-bearing meteorites 455

Continued. Spectral parameters and grain size for the different meteorites. Grain size Band I center Band II center RELAB sample ID Ref. Meteorite name (Pm) (Pm) (Pm) BAR MB-TXH-071-A 6 Y-74450 0–25 0.935 1.972 1.09 MB-TXH-072-A 1 ALH 78132 0–25 0.931 1.952 1.60 MB-TXH-096-C 1 Padvarninkai 0–25 0.948 2.016 0.98 MB-TXH-097-A 1 0–25 0.938 1.994 1.45 MP-TXH-054-A 2 Ibitira 0–25 0.941 1.978 0.99 MP-TXH-066-A 2 GRO 95533 0–25 0.941 1.999 1.32 MP-TXH-072-A 2 EET A79005 0–25 0.934 1.960 1.61 MP-TXH-078-A 2 LEW 85303 0–25 0.945 2.007 1.21 MP-TXH-079-A 2 LEW 87004 0–25 0.935 1.963 1.36 MP-TXH-080-A 2 PCA 82502 0–25 0.941 1.999 1.64 MP-TXH-086-A 2 Moore County 0–25 0.938 1.971 1.23 MP-TXH-087-A 2 Pasamonte 0–25 0.940 1.990 1.24 MP-TXH-089-A 2 BËrËba 0–25 0.941 2.005 1.29 MP-TXH-090-A 2 Bouvante 0–25 0.943 1.994 1.64 MP-TXH-091-A 2 Jonzac 0–25 0.938 1.991 1.48 MP-TXH-092-A 2 Serra de MagË 0–25 0.930 1.953 1.41 MP-TXH-094-A 2 A-87272 0–25 0.941 1.957 1.13 MP-TXH-096-A 2 A-881819 0–25 0.931 1.956 1.38 MT-TXH-041-A 2 Y-792510 0–25 0.942 1.993 1.16 MT-TXH-042-A 2 Y-792769 0–25 0.940 1.995 1.33 MT-TXH-043-A 2 Y-793591 0–25 0.940 1.982 1.47 MT-TXH-044-A 2 Y-82082 0–25 0.947 1.989 1.32 Howardites MB-TXH-068-A 6 EET 87503 0–25 0.930 1.943 1.24 MP-TXH-053-A 1 Kapoeta 0–25 0.929 1.944 1.17 MP-TXH-067-A 2 GRO 95535 0–25 0.930 1.948 1.44 MP-TXH-069-A 2 QUE 94200 0–25 0.923 1.920 1.71 MP-TXH-073-A 2 EET 83376 0–25 0.934 1.955 1.49 MP-TXH-074-A 2 EET 87513 0–25 0.933 1.957 1.22 MP-TXH-082-A 2 Binda 0–25 0.927 1.931 1.60 MP-TXH-083-A 2 Bununu 0–25 0.930 1.941 1.29 MP-TXH-085-A 2 Frankfort 0–25 0.928 1.937 1.58 MP-TXH-093-A 2 Le Teilleul 0–25 0.928 1.933 1.66 MP-TXH-097-A 2 Y-7380 0–25 0.927 1.931 1.57 MP-TXH-098-A 2 Y-790727 0–25 0.932 1.945 1.58 MP-TXH-099-A 2 Y-791573 0–25 0.927 1.933 1.64 H ordinary chondrite MB-DTB-030-E 10 Acfer 0–125 0.935 1.907 0.64 MH-CMP-007 11 Monroe 20–250 0.930 1.935 0.76 MH-CMP-008 11 Weston 20–250 0.932 1.925 0.71 MH-JFB-025 13 Sete Lagoas chip 0.944 1.907 1.02 MI-CMP-010 11 unknown chip 0.930 1.915 0.86 TB-TJM-066 3 Avanhandava 0–150 0.929 1.912 0.76 TB-TJM-078 3 Marilia 0–150 0.925 1.941 0.69 TB-TJM-082 3 São Jose do Rio Preto 0–150 0.915 1.886 0.85 TB-TJM-083 3 Schenectady 0–150 0.927 1.922 0.67 TB-TJM-093 3 Forest Vale 0–75 0.929 1.892 0.48 MB-CMP-014 11 Leighton 25–250 0.928 1.927 0.59 MB-TXH-044 12 MAC 88119 chip 0.928 1.901 0.77 MH-CMP-004-B 11 Cangas De Onis 20–250 0.934 1.913 0.61 MH-CMP-006 11 Ucera 20–250 0.933 1.901 0.63 MH-CMP-019-P1 11 Castalia 0–500 0.935 1.933 0.73 PS-PHS-097 3 El Hammami 0–250 0.931 1.905 0.70 TB-TJM-071 3 Chela 0–150 0.918 1.921 0.91 456 R. Duffard et al.

Continued. Spectral parameters and grain size for the different meteorites. Grain size Band I center Band II center RELAB sample ID Ref. Meteorite name (Pm) (Pm) (Pm) BAR TB-TJM-074 3 Ehole 0–150 0.927 1.945 0.85 TB-TJM-085 3 Uberaba 0–150 0.934 1.914 0.76 TB-TJM-097 3 Itapicuru-Mirim 0–150 0.930 1.894 0.70 TB-TJM-104 3 chip 0.924 1.901 0.99 TB-TJM-108 3 Magombedze 0–150 0.929 1.914 0.76 MB-CMP-003-D 11 Dwaleni 25–250 0.929 1.908 0.74 MB-CMP-003-L 11 Dwaleni 25–250 0.930 1.901 0.69 MB-DTB-048 10 Noblesville 20 -45 0.929 1.883 0.52 MH-FPF-051-A 14 Ozona 0–150 0.939 1.915 0.47 L ordinary chondrites MB-TXH-084-A 12 Y-74191 0–25 0.925 1.95 0.41 TB-TJM-076 3 Hallingeberg 0–150 0.967 2.004 0.46 MB-CMP-008 11 Rio Negro 25–250 0.947 1.931 0.60 MB-CMP-028-A 11 Saratov 0–10 0.939 1.983 0.62 MH-CMP-001 11 McKinney chip 0.944 1.928 0.90 MH-CMP-002 11 Barratta chip 0.993 1.928 0.21 MP-FPF-027 14 Bjurbole 0–1000 0.949 1.947 0.46 TB-TJM-065 3 Atarra 0–150 0.927 1.914 0.57 MB-CMP-001-P2 11 Tsarev 0–63 0.943 1.951 0.51 MB-CMP-004 11 Arapahoe chip 0.941 1.970 0.86 MB-CMP-011-D 11 Wittekrantz 25–250 0.961 1.887 0.85 MB-CMP-011-L 11 Wittekrantz 25–250 0.941 1.903 0.45 MB-DTB-035-A 10 Cat Mountain 20–250 0.966 1.944 0.34 MH-CMP-003 11 Farmington chip 0.931 1.899 0.34 MH-CMP-005 11 Ergheo 20–250 0.952 1.902 0.54 MH-CMP-011 11 Tadjera 0–250 0.954 1.909 0.79 MH-CMP-012 11 Taiban 0–250 0.956 1.930 0.44 MH-CMP-013 11 Lubbock 0–250 0.961 1.963 0.54 MH-CMP-018-P2 11 Orvinio Dark 0–500 0.930 1.926 0.87 TB-TJM-096 3 Honolulu 0–150 0.945 1.948 0.39 TB-TJM-107 3 Mabwe-Khoywa 0–150 0.934 1.941 0.63 TB-TJM-109 3 Malakal 0–150 0.936 1.948 0.54 TB-TJM-111 3 Mirzapur 0–150 0.932 1.935 0.61 MB-CMP-010-D 11 Paranaiba 25–250 0.945 1.913 0.38 MB-CMP-010-L 11 Paranaiba 25–250 0.943 1.920 0.48 MB-CMP-012-D 11 Jackalsfontein 25–250 0.967 1.915 0.61 MB-CMP-012-L 11 Jackalsfontein 25–250 0.934 1.915 0.65 MH-CMP-010 11 Wickenberg 0–250 0.943 1.938 0.45 MH-CMP-014 11 Peetz 0–250 0.951 1.927 0.45 MH-CMP-020 11 Potter 20–250 0.945 1.952 0.38 MH-FPF-063 14 metal from Tennasilm chip 0.924 1.918 0.94 MH-FPF-064 14 Wold Cottage metal chip 0.935 1.925 0.61 MI-CMP-009 11 Holbrook chip 0.955 1.945 0.52 MP-DTB-028-C 10 Orvinio clast melt 50–250 0.950 1.925 0.67 MP-DTB-028-M 10 Orvinio clast melt 50–250 0.964 1.967 0.34 MP-DTB-029-A 10 Walters clast melt 50–250 0.940 1.906 0.43 PS-PHS-098 15 Kuttippuram 0–75 0.941 1.914 0.57 RS-CMP-062 11 Kunashak chip 0.934 1.937 0.67 RS-CMP-064 11 Pervomaisky chip 0.964 1.922 0.35 TB-TJM-063 3 Aˆr 0–150 0.931 1.946 0.45 TB-TJM-064 3 Apt 0–150 0.940 1.935 0.43 TB-TJM-070 3 Chantonnay 0–150 0.935 1.941 0.46 TB-TJM-072 3 Denver 0–150 0.940 1.945 0.50 TB-TJM-084 3 Tuan Tuc 0–150 0.932 1.923 0.59 TB-TJM-086 3 Vouille 0–150 0.932 1.901 0.47 Spectral parameters of silicate-bearing meteorites 457

Continued. Spectral parameters and grain size for the different meteorites. Grain size Band I center Band II center RELAB sample ID Ref. Meteorite name (Pm) (Pm) (Pm) BAR TB-TJM-087 3 Valdinizza 0–150 0.928 1.918 0.45 TB-TJM-110 3 Maryville 0–150 0.945 1.928 0.60 TB-TJM-112 3 Nejo 0–150 0.943 1.926 0.50 TB-TJM-113 3 Patrimonio 0–150 0.937 1.941 0.58 LL ordinary chondrites MH-FPF-062 14 metal from Parnallee chip 0.949 1.952 0.52 RS-CMP-063 11 Krymka chip 0.960 1.987 0.62 MB-TXH-086-A 12 Y-74442 0–25 0.939 1.926 0.30 TB-TJM-075 3 Greenwell Springs 0–150 0.954 1.946 0.41 MB-CMP-002-D 11 Paragould 25–250 0.937 1.941 0.67 MB-CMP-002-L 11 Paragould 25–250 0.945 1.927 0.59 MB-CMP-013 11 Appley Bridge 25–250 0.997 1.951 0.28 MB-TXH-083 12 ALH 84096 0–125 0.966 2.068 0.67 MB-TXH-085-A 12 Y-74646 0–25 0.946 1.937 0.40 MB-TXH-089-A 12 Bison 0–63 0.971 1.934 0.30 MB-TXH-090-A 12 Dhurmsala 63–125 0.941 1.938 0.41 MB-TXH-091-A 12 NÆs 0–63 1.002 1.943 0.20 TB-TJM-067 3 Bandong 0–150 0.990 1.978 0.24 TB-TJM-077 3 Karatu 0–75 0.997 1.985 0.27 TB-TJM-090 3 Cherokee Springs 0–150 0.959 1.931 0.36 TB-TJM-092 3 Ensisheim 0–150 0.995 1.934 0.24 Shergotites LM-LAM-007-73 17 EET A79001 chip 0.951 2.012 0.47 LM-LAM-009-A 17 ALH A77005 chip 0.968 1.945 0.52 LM-LAM-021 17 Shergotty 0–125 0.968 2.018 0.76 MB-LAM-049-P 17 Zagami 0–125 0.978 2.057 0.63 Nakhlites LM-LAM-022 17 Nakhla 0–1000 1.024 2.206 0.18 LM-LAM-023 17 Lafayette 0–1000 1.024 2.196 0.21 Angrites TB-TJM-057 4 Sahara 99555 0–125 1.125 – 0.08 TB-TJM-062 4 D’Orbigny 0–125 1.140 – 0.01 MT-TXH-049-A 12 Brachina 0–45 1.050 – 0.00 MT-TXH-050-A 12 Eagles Nest 0–45 1.053 – 0.00 MB-TXH-087-A 12 Y-74659 0–25 0.931 1.935 0.05 MC-RPB-006 18 PCA 82506 0–500 0.937 1.909 0.77 MP-LAM-006-C1 17 MET A78008 chip 1.005 2.048 0.11 1 = T. Hiroi and C. M. Pieters (1998); 2 = T. Hiroi, C. M. Pieters, F. Vilas, S. Sasaki, Y. Hamabe, and E. Kurahashi (2001); 3 = T. H. Burbine, T. J. McCoy, E. Jarosewich, and J. M. Sunshine (2003); 4 = T. H. Burbine, T. J. McCoy, and R. P. Binzel (2001); 6 = T. Hiroi, C. M. Pieters, and H. Takeda (1994); 10 = Dan Britt; 11 = Carle M. Pieters; 12 = Takahiro Hiroi; 13 = Jeffery F. Bell; 14 = Fraser P. Fanale; 15 = Pete Schultz; 17 = Lucy Ann McFadden; 18 = Richard P. Binzel. 458 R. Duffard et al.

APPENDIX 2

Spectral parameters and grain size for the laboratory mixtures. Band I center Band II center BAR RELAB sample ID Ref. Mixture Grain size proportion (Pm) (Pm) (Pm) XP-CMP-015 9 Opx:Cpx = 85:15 0–45 0.917 1.836 1.54 XP-CMP-013 9 Opx:Cpx = 75:25 0–45 0.921 1.847 1.27 XP-CMP-011 9 Opx:Cpx = 60:40 0–45 0.931 1.851 1.07 XP-CMP-010 9 Opx:Cpx = 50:50 0–45 0.940 1.857 0.91 XP-CMP-012 9 Opx:Cpx = 40:60 0–45 0.966 1.873 0.69 XP-CMP-014 9 Opx:Cpx = 25:75 0–45 1.003 1.916 0.44 XP-CMP-016 9 Opx:Cpx = 15:85 0–45 1.012 2.230 0.46 XP-CMP-006 9 Opx:Cpx = 85:15 70–145 0.920 1.838 1.92 XP-CMP-004 9 Opx:Cpx = 75:25 70–145 0.924 1.846 1.76 XP-CMP-002 9 Opx:Cpx = 60:40 70–145 0.944 1.868 1.28 XP-CMP-001 9 Opx:Cpx = 50:50 70–145 0.951 1.880 1.11 XP-CMP-003 9 Opx:Cpx = 40:60 70–145 0.964 1.904 0.90 XP-CMP-005 9 Opx:Cpx = 25:75 70–145 0.988 1.998 0.53 XP-CMP-007 9 Opx:Cpx = 15:85 70–145 1.008 2.203 0.43 XT-CMP-034 7 Ol:Opx:An = 16:66:16 45–75 0.923 1.902 1.49 XT-CMP-037 7 Ol:Opx:An = 16:41:41 45–75 0.924 1.927 1.16 XT-CMP-039 7 Ol:Opx:An = 41:41:16 45–75 0.934 1.920 0.78 XT-CMP-036 7 Ol:Opx:An = 33:33:33 45–75 0.934 1.929 0.74 XT-CMP-035 7 Ol:Opx:An = 16:16:66 45–75 0.934 1.940 0.56 XT-CMP-038 7 Ol:Opx:An = 41:16:41 45–75 0.976 1.939 0.31 XT-CMP-033 7 Ol:Opx:An = 66:16:16 45–75 1.019 1.936 0.24 Orthopyroxene bronzites PP-EAC-040 19 Opx 0–45 0.923 1.824 2.33 PP-EAC-044 19 Opx 0–45 0.921 1.871 2.11 PP-EAC-047-A 19 Opx 0–45 0.913 1.857 1.75 Orthopyroxene hypersthene JA-CMP-001 11 Opx chip 0.919 1.819 2.61 JA-CMP-015 11 Opx chip 0.915 1.793 2.35 PP-TXH-038-A 12 Opx 0–25 0.911 1.799 2.05 Orthopyroxene enstatite PE-CMP-019 11 Opx 25–45 0.912 1.845 1.82 PE-CMP-030 11 Opx 0–45 0.911 1.833 1.84 7 = T. Hiroi and C. M. Pieters (1994); 9 = J. Sunshine, C. Pieters and S. Pratt.(1990); 10 = Dan Britt; 11 = Carle M. Pieters; 12 = Takahiro Hiroi; 19 = Edward A. Cloutis.

APPENDIX 3

Spectral parameters for the four eucrites and one diogenite presented in this work. Grain size Band I center Band II center RELAB sample ID Ref. Meteorite name (Pm) (Pm) (Pm) Depth 1 Depth 2 BAR Eucrite 1 MB-TXH-066-A 1 ALH A76005 0–25 0.935 1.962 1.63 1.29 1.46 MB-TXH-066-B 1 ALH A76005 25–45 0.937 1.963 1.97 1.55 1.69 MB-TXH-066-C 1 ALH A76005 45–75 0.939 1.960 2.24 1.77 1.77 MB-TXH-066-D 1 ALH A76005 75–125 0.940 1.965 2.13 1.81 1.89 MB-TXH-066-E 1 ALH A76005 125–250 0.941 1.958 1.95 1.75 1.91 MB-TXH-066-F 1 ALH A76005 250–500 0.941 1.948 1.79 1.61 1.91 Eucrite 2 MB-TXH-069-A 6 Millbillillie 0–25 0.938 1.992 1.83 1.33 1.17 MB-TXH-069-B 6 Millbillillie 25–45 0.939 1.988 2.44 1.63 1.28 Spectral parameters of silicate-bearing meteorites 459

Continued. Spectral parameters for the four eucrites and one diogenite presented in this work. Grain size Band I center Band II center RELAB sample ID Ref. Meteorite name (Pm) (Pm) (Pm) Depth 1 Depth 2 BAR MB-TXH-069-C 6 Millbillillie 45–75 0.941 1.986 2.47 1.72 1.40 MB-TXH-069-D 6 Millbillillie 75–125 0.942 1.985 2.37 1.76 1.44 Eucrite 3 MB-TXH-070-A 6 Juvinas 0–25 0.936 1.982 1.88 1.38 1.34 MB-TXH-070-B 6 Juvinas 25–45 0.941 1.978 2.47 1.73 1.47 MB-TXH-070-C 6 Juvinas 45–75 0.944 1.969 2.65 1.93 1.56 MB-TXH-070-D 6 Juvinas 75–125 0.947 1.956 2.59 1.99 1.62 MB-TXH-070-E 6 Juvinas 125–250 0.950 1.955 2.39 1.92 1.59 Eucrite 4 MB-TXH-071-A 6 Y-74450 0–25 0.936 1.966 1.62 1.23 1.09 MB-TXH-071-B 6 Y-74450 25–45 0.937 1.956 2.15 1.50 1.29 MB-TXH-071-C 6 Y-74450 45–75 0.937 1.965 2.34 1.65 1.40 MB-TXH-071-D 6 Y-74450 75–125 0.939 1.967 2.24 1.70 1.52 Diogenite 5 MB-TXH-067-A 1 EET A79002 0–25 0.919 1.889 2.03 1.42 1.60 MB-TXH-067-B 1 EET A79002 25–45 0.918 1.891 2.82 1.82 1.73 MB-TXH-067-C 1 EET A79002 45–75 0.918 1.887 2.78 1.90 1.87 MB-TXH-067-D 1 EET A79002 75–125 0.918 1.895 2.60 1.90 1.92 MB-TXH-067-E 1 EET A79002 125–250 0.920 1.905 2.26 1.75 2.01 MB-TXH-067-F 1 EET A79002 250–500 0.920 1.900 2.15 1.74 2.04 1 = T. Hiroi and C. M. Pieters (1998); 6 = T. Hiroi, C. M. Pieters, and H. Takeda (1994).