Presentation Information
[PPS12-P03]Chemical Structure and Alteration Processes of Insoluble Organic Matter in the Tarda and Tagish Lake Meteorites of Possible D-type Asteroid Origin
*Kenji Yoneda1, Immy Kennard2, Yoko Kebukawa1, Queenie Chan3, Michael Zolensky4 (1.Institute of Science Tokyo, 2.Imperial College London, 3.Royal Holloway University of London, 4.NASA-Johnson Space Center)
Keywords:
Meteorites,Organic matter
Meteorites preserve information regarding the early stages of solar system formation. Consequently, their analysis provides crucial clues for understanding the evolutionary processes that have occurred over approximately 4.6 billion years since the birth of the solar system. This study aims to elucidate the chemical evolution of organic matter within the solar system by analyzing organic components found in meteorites.
We specifically focused on the Tarda and Tagish Lake meteorites, which are believed to originate from D-type asteroids accreted in low-temperature regions in the early solar system. We analyzed the chemical structures and degrees of alteration of their insoluble organic matter (IOM), which constitutes the majority of their organic content.
IOM was extracted from the Tarda meteorite using the HF/HCl method. For the Tagish Lake meteorite, IOM was also extracted from samples subjected to hydrothermal experiments in both open and closed systems. The extracted IOM was analyzed using micro-Fourier transform infrared spectroscopy (micro-FTIR), micro-Raman spectroscopy, and Scanning Transmission X-ray Microscopy-based X-ray Absorption Near Edge Structure (STXM-XANES) spectroscopy.
The results indicated that the Tarda meteorite is less altered than the Tagish Lake meteorite. Raman spectral analysis of the hydrothermally treated Tagish Lake samples revealed that alteration proceeded further in the open system than in the closed system. Furthermore, C- and N-XANES analyses showed that Tarda IOM is rich in carboxyl groups and nitrogen-bearing functional groups. This supports the hypothesis that the Tarda meteorite possesses characteristics typical of primitive D-type asteroids.
We specifically focused on the Tarda and Tagish Lake meteorites, which are believed to originate from D-type asteroids accreted in low-temperature regions in the early solar system. We analyzed the chemical structures and degrees of alteration of their insoluble organic matter (IOM), which constitutes the majority of their organic content.
IOM was extracted from the Tarda meteorite using the HF/HCl method. For the Tagish Lake meteorite, IOM was also extracted from samples subjected to hydrothermal experiments in both open and closed systems. The extracted IOM was analyzed using micro-Fourier transform infrared spectroscopy (micro-FTIR), micro-Raman spectroscopy, and Scanning Transmission X-ray Microscopy-based X-ray Absorption Near Edge Structure (STXM-XANES) spectroscopy.
The results indicated that the Tarda meteorite is less altered than the Tagish Lake meteorite. Raman spectral analysis of the hydrothermally treated Tagish Lake samples revealed that alteration proceeded further in the open system than in the closed system. Furthermore, C- and N-XANES analyses showed that Tarda IOM is rich in carboxyl groups and nitrogen-bearing functional groups. This supports the hypothesis that the Tarda meteorite possesses characteristics typical of primitive D-type asteroids.