日本列島の代表的砂岩のモード組成と造構場

We have selected seven specimens of Jurassic to Paleogene sandstones from the Japanese Islands, which represent different sedimentary basins and different tectonic settings. Firstly, some methodological problems concerning modal composition analysis have been checked by analysing the same specimens by nine of the above authors. As a result, the data show that the compositional variations of sandstones are quite high. Thus, we have to be careful when comparing the modal compositional data of different workers.It is also concluded that, in order to evaluate the provenance factor controlling the sandstone composition, the Gazzi-Dickinson point-counting method is better than the traditional one, although the latter is still useful for the description of sandstone. Secondly, we have examined the relationship between the modal composition of sandstone and its tectonic setting. The following five tectonic settings for magmatic arc provenance have been successfully discriminated: primitive volcanic island arc, evolved and mature magmatic are, dissected magmatic are, deeply dissected magmatic are, and renewed magmatic arc.Article地質学論集. 38:385-401 (1992)journal articl