| Abstract: | An eventual correlation between petrologic type and porosity can only be found if measurements are made on unshocked or slightly shocked chondrites. The main advantage of the method (described earlier in this journal) is that it offers the possibility of correlating on a very small scale porosity with structural and petrographical features along with punctual chemical and isotopic data. Moreover, the method is relatively unpolluting and non destructive, and requires very small amounts of matter. Porosity measurements have been carried out on polished thin section of five H chondrites, after sample impregnation with a fluorescent resin. The microscope images were analysed with a Quantimet. Two types of information have been derived. First, the macroporosity of the material ranges up to 13% in Sena (H5) but falls to 4% in samples that have undergone slight shock or compression. Second, approximately 25% by volume of the stones consist of zones of great permeability which were fissured or filled with loose debris. This has been observed in all cases but the well-recrystallised Kernouve (H6) stone. Additional measurements are required to correlate petrology and porosity on a statistically significant basis. |
