Description of the OLIVINE LABORATORY INFRARED ABSORBANCE SPECTRA bundle V1.0 ========================================================= Bundle Generation Date: 2020-02-28 Peer Review: 2012 Asteroid Review, Wed May 30 00:00:00 MST 2012 Discipline node: Small Bodies Node Content description based on the data set catalog file description for the PDS3 version, EAR-X-I1485-3-OLIVSPEC-V1.0 ==================================================================================================================== Note: for PDS3 data sets migrated to PDS4, the following text is taken verbatim from the data set description and confidence level note of the PDS3 data set catalog file. In these cases, some details may not be correct as a description of the PDS4 bundle. This data set includes laboratory infrared room temperature (18-19 degrees Celsius) diamond anvil cell thin film absorption spectra of 18 different natural, synthetic, and meteoritic olivines whose compositions are roughly evenly spaced from 100% Mg to 100% Fe content. These electronic data were published by Pitman et al. 2010, Monthly Notices of the Royal Astronomical Society 406, 460-481 [PITMANETAL2010], and band analyses were published by Hofmeister & Pitman 2007, Physics and Chemistry of Minerals 34, 319-333 [HOFMEISTER&PITMA2007]. Parameters ========== In each file, the left hand column is the frequency in wave numbers (units: cm**-1). The right hand column is the common logarithm absorbance (a, units: none), defined by the equation a = -log( I_tra / I_0), where I_tra is intensity of light transmitted with the sample in the DAC, and I_0 is the intensity of light through an empty diamond anvil cell sample holder. Processing ========== All natural samples were either mineral powders (grain size of approximately 0.1 mm) or mm-sized single crystals, except for Fo9 through Fo31, which were ground down from rocks by S. A. Morse to approximately the same size. The Fo81 meteoritic sample, from the Alice Springs fragment of the Huckitta pallasite, was similar in size to the natural samples. Synthetic samples were finely ground powders. For each sample, optically thin (approximately 1 micron) films were created via compression in a diamond anvil cell (DAC) sample mount. Each cylindrical component of the DAC (a hollow stainless steel barrel nested about an inner piston) contains a tungsten carbide rocker onto which is mounted a Type II diamond anvil of about 1/3 carat with a culet (or tip) diameter of approximately 0.6 mm. When the DAC is fully assembled, the two culets are aligned to be concentric, and also parallel by minimizing the interference fringes observed through a binocular microscope. To create a thin film, the bulk sample is first mechanically crushed into nearly micron-sized particulates. The crushed sample is mounded onto one of the diamond tips. Surface tension holds the crushed particulates onto the diamond tip; further compression yields a thin film (thickness of approximately 0.4 to 2 microns) with no visible crosshatching or cracks and little granularity. For each thin film, efforts were made to cover the entire diamond tip with an even layer of sample, but slight irregularities in the thickness were inevitable, partly due to less than perfect alignment of the diamond faces. Mid-IR (450-4,000 cm**-1) absorbance spectra were acquired using a liquid-nitrogen-cooled HgCdTe detector, a KBr beamsplitter, and an evacuated Bomem DA 3.02 Fourier transform spectrometer (Bomem Inc., QC, Canada). For the far-IR region (50-650 cm**-1), a Si-bolometer and a coated, broadband mylar beamsplitter were used. Resolution was 1 cm**-1, except for the far-IR spectrum of Fo50 and mid-IR spectra of Fo38, Fo67, and Fo68, which were collected at 2 cm**-1 resolution. Both ranges are accurate to 0.01 cm**-1. Mid- and far-IR absorbance values were scaled to match in the region of overlap and merged. Interference fringes, created by reflections from the polished faces of the diamonds, and/or red noise were removed at 600 and 800 cm**-l, above 1,000 cm**-1, and below 150 cm**-1. See [HOFMEISTER&PITMA2007] for further details. Data ==== 18 laboratory absorbance spectral files are included in this data set. 'foX' stands for forsterite, with X denoting the percent Mg content of each sample. 'nat' indicates that the sample was from a natural, terrestrial source, 'met' indicates that the sample was meteoritic, and 'syn' indicates that the sample was created synthetically. Thus, fo0nat.tab is a natural 0 percent Mg content olivine (fayalite), and f0100syn.tab is a synthetic 100 percent Mg content olivine (forsterite). Chemical compositions and previous references for each sample are given in [PITMANETAL2010] and [HOFMEISTER&PITMA2007]. fo0nat.tab Sample: olivine Fo0Te5 (impurities: 3.20% MnO) Source: Rockport, MA; Bowen, Schairer, & Posnjak (1933) fo0syn.tab Sample: Fo0 synthetic fayalite chunks Source: Finch, Clark, & Koop (1980); Hofmeister (1997) fo9nat.tab Sample: olivine Fo9Te2 (impurities: 1.58% MnO, 0.04% CaO) Source: Kiglapait Intrusion, Labrador; Morse (1996) fo14nat.tab Sample: olivine Fo14Te2 (impurities: 1.33% MnO, 0.20% CaO) Source: Kiglapait Intrusion, Labrador; Morse (1996) fo31nat.tab Sample: olivine Fo31Te1 (impurities: 0.77% MnO, 0.09% CaO) Source: Kiglapait Intrusion, Labrador; Morse (1996) fo41nat.tab Sample: olivine Fo41 (impurities: 0.72% MnO, 0.06% CaO) Source: Rustenberg, Transvaal, S. Africa; Hofmeister & Pitman (2007) fo45nat.tab Sample: olivine Fo45 (impurities: 0.68% MnO, 0.81% CaO) Source: Camas Mor Muck, Scotland; Yoder & Sahama (1957) fo50syn.tab Sample: Fo50 synthetic hortonolite Source: B. Fegley/R. Burns; Burns & Huggins (1972) fo54nat.tab Sample: olivine Fo54 (impurities: 0.53% MnO) Source: Susimaki, Finland; Yoder & Sahama (1957) fo63nat.tab Sample: olivine Fo63 (impurities: 0.22% MnO, 0.02% CaO) Source: Skaergaard, E. Greenland; Yoder & Sahama (1957) fo67syn.tab Sample: olivine Fo67 synthetic forsterite powder Source: R.M. Hazen (1977) fo68nat.tab Sample: olivine Fo68 (impurities: 0.11% MnO, 0.26% CaO) Source: Bufumbira, Uganda; Yoder & Sahama (1957) fo75syn.tab Sample: olivine Fo75 synthetic powder Source: R.M. Hazen (1977) fo80syn.tab Sample: olivine Fo80 synthetic powder Source: R.M. Hazen (1977) fo81met.tab Sample: Fo81 meteoritic olivine (impurities: 1.26% CaO) Source: Alice Springs Meteorite; Yoder & Sahama (1957) fo91nat.tab Sample: Fo91 (impurities: 0.12% MnO, 0.07% CaO, 0.39% NiO) Source: Ward's Scientific -- San Carlos, AZ; Hofmeister & Pitman (2007) fo93nat.tab Sample: olivine Fo93 (impurities: 0.074% MnO, 0.30% NiO) Source: Balsam Gap, Jackson, NC; Hofmeister et al. (1989) fo100syn.tab Sample: Fo100 synthetic forsterite Source: C. Koike; Koike, Shibai, & Tuchiyama (1993) References ========== Hofmeister, A. M., and K. M. Pitman, Evidence for kinks in structural and thermodynamic properties across the forsterite-fayalite binary from thin-film IR absorption spectra, Physics and Chemistry of Minerals 34, 319-333, doi:10.1007/s00269-007-0150-1, 2007. Pitman, K.M., C. Dijkstra, A.M. Hofmeister, and A.K.Speck, Infrared laboratory absorbance spectra of olivine: using classical dispersion analysis to extract peak parameters, Monthly Notices of the Royal Astronomical Society 406, 460-481, doi:10.1111/j.1365-2966.2010.16669.x, 2010. (See Pitman et al. (2010) for the full citation of the sample source references.) Known issues or problems with the data ====================================== The uncertainty (i.e., noise in the spectrum), which varies for each absorbance spectrum, is better than 0.5 per cent in most cases. The uncertainty in the thickness of each sample is the largest source of error. We estimated the film thickness for each sample as 1 micron with an uncertainty of 40 per cent. The wavelength coverage for each spectrum varies because noisy sections or interference fringes have been removed. Interference fringes, created by reflections from the polished faces of the diamonds, and/or red noise were removed at 600 and 800 cm**-l, above 1,000 cm**-1, and below 150 cm**-1. To avoid fringes during the spectral merging of the mid- and far-IR segments, for a subset of the samples (Fo0 synthetic, Fo41, Fo45, Fo50, Fo75, Fo80, and Fo100), several spectra were acquired at different thicknesses. For these cases, we spliced the fringe-free segments obtained from thicker films into the transparent regions of the merged spectrum. Fringes and/or red noise were sometimes seen below 150 cm**-1 and were removed by truncating the data. The true absorbance near 100-150 cm**-1 is very close to null. PDS3 Source =========== Version 1.0 of this bundle was migrated from version 1.0 of the PDS3 data set EAR-X-I1485-3-OLIVSPEC-V1.0.