GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 275-5
Presentation Time: 9:00 AM-6:30 PM


LAW, Ka-Ming1, CARTWRIGHT, Julia A.2, HAUSER, Adam J.1, BRIGGS, Sydney A.2, PAVELITES, Joseph J.2, GHOSH, Ayanjeet3 and DEB, Sanghamitra4, (1)Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487, (2)Department of Geological Sciences,, University of Alabama, Bevill Energy Building,, Tuscaloosa, AL 35487-0338, (3)Department of Chemistry, University of Alabama, Tuscaloosa, AL 35487, (4)Department of Chemistry, University of Alabama, Tuscaloosa, AL 35401; Central Analytical Facility, University of Alabama, Tuscaloosa, AL 35487

Meteorites are precious materials that often exhibit unique compositional and textural features not observed in terrestrial materials. Many analytical techniques rely on destructive procedures to produce viable datasets, which significantly limits the opportunity to perform multiple analyses on the same material. Here, we are developing an analytical protocol to determine compositional information for meteorite samples with a strong consideration for sample preservation. We are using the following spectroscopic methods: Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and X-ray fluorescence (XRF) spectroscopy. While XRF spectra contain element-specific responses that are useful for composition analyses, infrared (IR) and Raman spectra give a list of molecular vibrational frequencies that is characteristic to individual minerals. In addition to conventional spectroscopic measurements, we are using an infrared microscope to map out the spatial distributions of the molecular signatures as identified from spectra. Thus, a combination of Raman spectra, IR images, and petrographic images can be used to comprehensively characterize mineral grains in-situ. Some of these techniques were used in recent missions including NASA’s Dawn mission, which featured a visual and IR spectrometer [1], and the upcoming NASA Mars 2020 and ESA ExoMars 2020 both featuring a Raman instrument [2]. Thus, proper documentation of our analytical protocol may help us better calibrate surface compositional information to those in the laboratory.

We have selected two materials to develop our protocol and test a proof of concept: 1) Basaltic lava material from Lathrop Wells [3]; 2) Pyroxenite material from the terrestrial analog for Martian nakhlite material, Theo’s Flow [4]. Our preliminary measurements are underway. Once our technique is developed, we plan to extend this to analyses of regolithic meteorites such as howardites, which show definitive regolithic textural and compositional features that correlate with noble gas data [5-6].

[1] De Sanctis, M. C. et al. (2012) ApJL 758:L36.

[2] Courrèges-Lacoste, G. B. et al. (2007) SCA A: 68(4):1023-1028.

[3] Genareau, K., et al. (2010) Bul. of Volc. 72(5):593-607.

[4] Lentz, R. C. F., et al. (2011) GSA 483.

[5] Cartwright, J. A. et al. (2013) GCA 105:395-421.

[6] Cartwright, J. A. et al. (2014) GCA 140:488-508.