TY - JOUR
T1 - Micro-spectroscopic characterization of organic and hydrous components in weathered Antarctic micrometeorites
AU - Suzuki, A.
AU - Yamanoi, Y.
AU - Nakamura, T.
AU - Nakashima, S.
N1 - Funding Information:
Acknowledgments. We thank the members of the National Institute for Polar Research for giving us the micrometeorite samples. We are grateful to Janet Borg and Pierre-Ivan Raynal for providing Raman data on carbonaceous chondrites. We also thank Y. Kebukawa and M. Zolensky for providing me many kinds of carbonaceous chondrites. Detailed comments by an anonymous reviewer and Dr. T. Osawa greatly improved the manuscript. This work was financially supported by the research fellowship of Osaka University to A. S.
PY - 2010
Y1 - 2010
N2 - Eight unmelted Antarctic micrometeorite (AMMs) recovered from Kuwagata Nunatak were studied on Al-foils by infrared (IR), Raman, and visible reflection micro-spectroscopy in combination with electron microscopy. Major element abundances of the AMMs studied were found to be similar to solar abundance, although all have the common characteristic of Mg-depletion. Absorption bands around 500 nm were detected for some of the AMMs by the visible micro-spectroscopic method, and these AMMs can be assigned to Fe-hydroxide-like materials. These results suggest that the studied AMMs experienced weathering in Antarctica. Four grains showed the presence of IR H2O and CH bands similar to those of type 2 carbonaceous chondrites, while these were found to be absent in two grains, as in type 3 carbonaceous chondrites. D (disordered: 1360 cm-1) and G (graphite: 1600 cm-1) Raman band features of graphitic carbonaceous materials in these AMMs were not similar to those for type 3 but were rather close to those for type 2 and 1 carbonaceous chondrites, although some data showed a degree of deviation. The genetic classification of individual AMM grains can thus be studied by these methods, although the weathering effects and the atmospheric entry heating on organics and hydrous components need to be evaluated. These multiple micro-spectroscopic reflectance methods are useful for the characterization of precious small samples.
AB - Eight unmelted Antarctic micrometeorite (AMMs) recovered from Kuwagata Nunatak were studied on Al-foils by infrared (IR), Raman, and visible reflection micro-spectroscopy in combination with electron microscopy. Major element abundances of the AMMs studied were found to be similar to solar abundance, although all have the common characteristic of Mg-depletion. Absorption bands around 500 nm were detected for some of the AMMs by the visible micro-spectroscopic method, and these AMMs can be assigned to Fe-hydroxide-like materials. These results suggest that the studied AMMs experienced weathering in Antarctica. Four grains showed the presence of IR H2O and CH bands similar to those of type 2 carbonaceous chondrites, while these were found to be absent in two grains, as in type 3 carbonaceous chondrites. D (disordered: 1360 cm-1) and G (graphite: 1600 cm-1) Raman band features of graphitic carbonaceous materials in these AMMs were not similar to those for type 3 but were rather close to those for type 2 and 1 carbonaceous chondrites, although some data showed a degree of deviation. The genetic classification of individual AMM grains can thus be studied by these methods, although the weathering effects and the atmospheric entry heating on organics and hydrous components need to be evaluated. These multiple micro-spectroscopic reflectance methods are useful for the characterization of precious small samples.
KW - Antarctic micrometeorites (AMMs)
KW - Hydrous minerals
KW - IR
KW - Micro-spectroscopy
KW - Organics
KW - Raman
KW - Visible
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U2 - 10.5047/eps.2008.11.001
DO - 10.5047/eps.2008.11.001
M3 - Article
AN - SCOPUS:77949854969
VL - 62
SP - 33
EP - 46
JO - Earth, Planets and Space
JF - Earth, Planets and Space
SN - 1343-8832
IS - 1
ER -