ââLearning about the degree of aqueous alteration of NEOs from ...

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PRELIMINARY RESULTS • Significant differences in the reflectance spectra of CCs reflects a remarkable compositional diversity – The ATR technique is very sensitive to OH and other bonds absorption bands, but also provides information about organic features • CC groups exhibit components with distinctive abundance ratios – Chondrules are the abundant ingredients, but they vary in average size and proportions, such as the Ca-Al rich inclusions (CAIs) and other components – Metal grain abundances are highly variable from being almost absent to ubiquitous depending of the chondrite group, and their presence inside the chondrules or in the matrix has direct implications to reflectance • Laboratory analyses of the reflectance of Antarctic CCs provide useful information for remote characterization of Marco Polo-R target – An accurate IR spectrum provides very significant features and absorption bands that have direct application: • The depth of the OH bands are directly related with the extent of aqueous alteration: how much water is bounded in phyllosilicates • The distinctive features allow to make reasonable distinction of the different surface mineralogy (if it is a complex breccia) • Consequently, IR spectroscopy of the target in a small scale is essential for sampling pristine carbonaceous materials (Marco Polo-R goal)
CONCLUSIONS • Laboratory analyses of the reflectance of Antarctic CCs provide useful information for remote characterization of the presumably complex surface of Marco Polo-R and Osiris-Rex missions – IR spectra provide very significant features and absorption bands that have direct application: • The depth of the OH bands are directly related with the extent of aqueous alteration: how much water is bounded in phyllosilicates • The distinctive features allow to make reasonable distinction of the different surface mineralogy (if it is a complex breccia) • Consequently, IR spectroscopy of the target in a small scale is essential for sampling pristine carbonaceous materials (Marco Polo-R goal) – Carbon-rich asteroids are sources of all biogenic elements and have minerals that probably synthesized complex organics (Martins, 2011): • Some features of the most abundant organics are also identifiable by using high-res IR spectra • We thank NASA Meteorite Working group and JSC curators for providing us with the samples to complete these analyses.
Page 1 and 2: “Learning about the degree of aqu
Page 3 and 4: WHAT WE KNOW ABOUT CARBON-RICH RICH
Page 5 and 6: IR SPECTROMETER IR BEAM SAMPLE haz
Page 7 and 8: ADDITIONAL STUDIED CHONDRITES • S
Page 9 and 10: MAIN ABSORPTION BANDS • The absor
Page 11: CO and CV CHONDRITE GROUPS • The

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