Three-dimensional observation of carbonaceous chondrites by synchrotron radiation X-ray CT – Quantitative analysis and developments for the future sample return missions

Carbonaceous chondrites were observed by synchrotron radiation X-ray computed tomography (SR-CT) three-dimensionally. We analyzed the chemical composition of the components of the carbonaceous chondrites, such as chondrules, matrix and iron inclusions, from the linear attenuation coefficient (LAC) of X-rays. Histograms of the LAC were used for the analysis of chemical composition of the internal material, and we could find a clear relation of the compositions between the chondrules and matrix. We also analyzed the size distribution of low-Fe inclusions (chondrules) using image processing of CT images. Cumulative size distribution of chondrules shows power-law distribution, and slopes of the distribution changed for different chondrite classes. Results of these analyses show that the chondrule and matrix would have formed from the same precursor, and were incorporated into the parent bodies without large scale mixing in the solar nebula.The method will also provide important information for the analysis of future sample return missions. Our examinations demonstrate great potential of the quantitative determination of chondrite class nondestructively, by SR-CT.