DOES RAMAN SPECTROSCOPY REVEAL SHOCKED TEXTURES IN MAFIC MINERALS?

Planar deformation features in common minerals have been used as indicators of bolide impacts in the geologic record. While diagnostic shock features in quartz and feldspar are well-known and easily recognizable, similar planar deformation features in mafic minerals are much more difficult to identify optically. Thus, spectroscopy may serve as a better tool for shock analysis of such minerals. Raman spectroscopic analysis of shocked quartz and feldspar has revealed that Raman peaks tend to be broader for shocked crystals than those of their corresponding unshocked parent species. Does Raman spectroscopy reveal broadened peaks in shocked mafic minerals as well? Gabbro samples, provided by Planetary and Space Science Centre of the University of New Brunswick, from Sudbury (1859 Ma), Slate Islands (450 Ma), Brent (395 Ma), and Haughton (39 Ma) impact sites were analyzed, and evidence of peak broadening was positively identified in samples from at least two of these impact sites. In samples that demonstrate shock, the broadening of the Raman peaks of the shocked mafic minerals were evaluated and measured. X-ray diffraction patterns and optical analysis of these minerals may additionally aid in understanding the effects of shock on the crystalline structure of the minerals of interest.