ケロジェンの熱分解による有機熟成作用の評価 –北海道北部地域に分布する白亜系・第三系中のケロジェンを例として– [in Japanese] An evaluation of organic maturation by pyrolysis of the kerogens from the Upper Cretaceous to Miocene formations in northern Hokkaido, Japan [in Japanese]
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Organic maturation of kerogen was discussed from the yielded n-alkanes and weight losses by the pyrolysis of 67 kerogens separated from the Upper Cretaceous to Miocene muddy rocks in the northern part of Hokkaido. The results are as follows; 1) Ratios of n-C<sub>4</sub>H<sub>10</sub>/CH<sub>4</sub> and n-C<sub>6</sub>H<sub>14</sub>/CH<sub>4</sub> of the pyrolyzed products increase with burial depth in the Miocene core samples of the MITI-Hamayuchi Borehole, but decrease in the Paleogene and Cretaceous core samples of the MITI-Sorachi Borehole. 2) n-Alkane composition generated from kerogens by pyrolysis at 200℃ depend on their geologic ages, though independent at 400℃. Ratios of C<sub>16</sub>〜C<sub>20</sub>/C<sub>10</sub>〜C<sub>15</sub> generated at the former condition decrease from the Neogene kerogens to the Cretaceous through the Paleogene. 3) There is the distinct correlation of the Carbon Preference Index of n-alkanes (C<sub>13</sub>〜C<sub>20</sub>) between the pyrolyzed products of each kerogen at 200℃ and 400℃, the former being smaller than the latter, though they do not show any relation with burial depth.
Chikyukagaku 14(2), 62-68, 1981
The Geochemical Society of Japan