Petrographic and mid-infrared spectroscopy study of shocked feldspar in the Asuka-881757 Lunar gabbro meteorite sample

Abstract

We investigated three types of shocked feldspar in the Asuka-881757,531-2 sample with midinfrared spectroscopy (reflectance mode). Under the petrographic microscope three types of site were characterized by (1) undulatory extinction, (2) undulatory extinction with isotropic patches and decreased interference color, and (3) isotropic, lath-shaped feldspars, which is indicative of maskelynite. The IR emissivity maximum (Christiansen feature=CF) changes with the chemical composition of feldspar. One of the Christiansen composition features exhibits a wave length peak of 1234 cm -1 for anorthite; another feature appears at 1245 cm -1 for maskelynite (Palomba et al. 2006).With the help of IR spectroscopy we observed three vibrational types in our spectra: (1) peaks of depolimerization of SiO 4 tetrahedra (500-650 cm -1 , 950-1150 cm -1 ), (2) peaks of stretching and bending vibrational modes of SiO 6 octahedra (750-850 cm -1 ), and (3) Si-O stretching vibration of SiO 4 units Johnson et al. , 2007. All these vibration types were observed at the less shocked sites. In the spectrum of highly shocked maskelynite only a broader band close to 1000 cm -1 was observed, which is the main vibrational band of maskelynite (Palomba et al. 2006). The calculated FWHM showed the disordering rate of shocked feldspars. On the basis of the measurements it could be concluded that the estimated shock pressure range gradually increases from 17-35 GPa for different degrees of undulatory sites, to 35-45 GPa for maskelynite sites.

Shock heterogeneity and shock history of the recently found ordinary Csátalja chondrite in Hungary

“…While the shock-re lated spec tral fea tures could be iden ti fied in py rox enes and olivines both by Raman and in fra red meth ods, for feld spars only the infra red method was pos si ble for this. This dif fer ence is prob a bly not re lated to the small size of the feld spars as Raman has better spa tial res o lu tion than the in fra red method, but may be con nected to the better abil ity of in fra red ob ser va tion to iden tify the dam aged crys tal line struc ture of feld spars, in agree ment with some ear lier find ings (Gyollai et al, 2012).…”

Raman and Infrared Microspectroscopy of Experimentally Shocked Basalts

“…Fritz et al, 2017;Grieve et al, 1996;Stöffler & Langenhorst, 1994;Thoma et al, 2005). These types of investigations have included samples ranging from meteorites (e.g., Stöffler et al, 1991Stöffler et al, , 2018Bischoff & Stöffler, 1992;Cooney et al, 1999;Sharp & DeCarli, 2006;Gyollai et al, 2012;Rubin, 2015;Filiberto et al, 2018;Herd et al, 2017;Sharp et al, 2019;Chen et al, 2019) to lunar regolith samples (e.g., Fernandes et al, 2009Fernandes et al, , 2013Hörz & Cintala, 1997;Zeng et al, 2019) and terrestrial impact crater materials (e.g., Dence et al, 1977;Reimold, 1982;Short, 1970), all to better constrain their shock and thermal metamorphic histories. When plagioclase feldspars experience high pressures from impacts, disordering of the mineral lattice and increased abundance of amorphous phases typically occur at shock pressures above ~20 GPa (Ahrens et al, 1969;Arndt et al, 1982;Bunch et al, 1967Bunch et al, , 1968Johnson, 2012;Lyon, 1963;Ostertag, 1983;Stöffler, 1971Stöffler, , 1972Stöffler, , 1974Stöffler & Hornemann, 1972).…”

“…Previous petrographic investigations of experimentally and naturally shocked minerals attributed shock pressures to specific deformation features, the abundance of diaplectic glass, and variable degrees of melting (cf.Fritz et al, ; Grieve et al, ; Stöffler & Langenhorst, ; Thoma et al, ). These types of investigations have included samples ranging from meteorites (e.g., Stöffler et al, , ; Bischoff & Stöffler, ; Cooney et al, ; Sharp & DeCarli, ; Gyollai et al, ; Rubin, ; Filiberto et al, ; Herd et al, ; Sharp et al, ; Chen et al, ) to lunar regolith samples (e.g.,Fernandes et al, , ; Hörz & Cintala, ; Pickersgill et al, ; Zeng et al, ) and terrestrial impact crater materials (e.g.,Dence et al, ; Pickersgill, Osinski, & Flemming, ; Pickersgill, Flemming, & Osinski, ; Reimold, ; Short, ), all to better constrain their shock and thermal metamorphic histories. When plagioclase feldspars experience high pressures from impacts, disordering of the mineral lattice and increased abundance of amorphous phases typically occur at shock pressures above ~20 GPa (Ahrens et al, ; Arndt et al, ; Bunch et al, , ; Johnson, ; Lyon, ; Ostertag, ; Stöffler, , , ; Stöffler & Hornemann, ).…”

Bioactivity Improvement of Forsterite-Based Scaffolds with nano-58S Bioactive Glass

“…6(a)), the FTIR spectrum of the composite scaffold exhibited the characteristic spectral bands related to forsterite and BG. The peaks related to the typical peaks of forsterite occurred at 888.05, 952.93 (SiO 4 stretching), at 467.29, 509.35 (SiO 4 bending) and at 419.63 cm À1 (MgO 6 modes) [17][18][19]. In addition, the bands at 551.40, 607.67 and 1037.25 cm À1 were assigned to PÀO bending vibration of BG [20,21].…”