岐阜県赤坂産石灰岩中の炭素質物質について

抄録

Electron paramagnetic resonance (EPR) technique was used for the study of carbonaceous materials in Akasaka limestones (Paleozoic) of Gifu Prefecture. The intensities and line- widths of the EPR spectra were measured for 31 samples and chemical analyses were also carried out on the contents of organic carbon, manganese, iron and acid-insoluble inorganic matters. The average values of organic carbon contents, spin concentrations and line-widths are estimated at 0.084%, 10²⁰ spins per gram of organic carbon and 3.2 gauss, respectively. And the g-values of the spectra are very nearly equal to that of DPPH. The carbonaceous materials in Akasaka limestones are distributed locally in the regions of the strontium concentrated and the low-crystallized limestones. Therefore, the carbonaceous materials are considered to be mainly derivatives of organic matters of ancient calcareous algae, which were pyrolized probably under relatively mild conditions. And it is also noted that the other Japanese Paleozoic limestones of 28 deposits (51 samples) do not exhibit paramagnetic characters owing to the presence of carbonaceous materials.