Export Mendeley
＜departmental bulletin paper＞
Geology of the Takakubo Lignite Field, Shimane Prefecture
| Creator | |
|---|---|
| Language | |
| Publisher | |
| Date | |
| Source Title | |
| Vol | |
| Issue | |
| First Page | |
| Last Page | |
| Publication Type | |
| Access Rights | |
| JaLC DOI | |
| Abstract | The Miocene sediments overlying unconformably the granitic and andesitic basements extend over a wide area of the Takakubo district, but, are not continuous to the southeastern part of Izumo city, Shi...mane Prefecture. The Miocene sediments of this district have been studied by previous workers from many points of view, but the di vision of the sedimentary rocks into stratigraphic units and the age determination have not yet been clarified owing to the scattered distribution and the variation of the rock facies of the sediments. The rock sequence of the Takakubo lignite-field and its adjacent area is divided into the following four units in ascending order as shown in the Table 1, and their distribution is shown in detail in the geological map. 1. Basement rocks 2. Takakubo coal-bearing formation 3. Kuri formation 4. Volcanic rocks In the western part of this area, mainly around Neba, the name Kawai formation has been given to the Miocene sediments consisting of conglomerate, pebble-bearing coarse grained sandstone, bluish-grey fine grained sandstone, and tuffaceous shale. In the eastern part, however, the Miocene sediments are distributed sporadically and contains lignite layers, and are called in this paper the Takakubo coal-bearing formation. Owing to the discontinuous development, and to the lateral and the vertical variation in lithofacies, the systematic study for subdivision or tracing of this coal-bearing formation have not yet been completely carried out, but, generalizing the result of the writer's study, this coal-bearing formation is able to be divided into the following six members in ascending order: a. Liparitic tuff b. Pebble-bearing coarse grained sandstone c. Tuffaceous sandstone and shale d. Pale brown coarse grained sandstone e. Alternation of sandstone and shal f. Dark brown shale The Kawai formations has been known to be of marine facies based on the stratigraphical and paleontological evidences, whereas the Takakubo coal-bearing formation is of non-marine facies. Nevertheless, there is some similarity in main lithofacies between these two formations. Therefore, the writer presumes that the sedimentary basin, in which the Takakubo coal-bearing formation was laid down, was not far from the sea, and that the Takakubo coal-bearing formation and the Kawai formation were supplied simultaneously their materials from the same source. The Kawai and the Kuri formations are, according to the previous works, dated to the late middle Miocene or the early late Miocene by the presence of three foraminiferal zones. Therefore, if the Takakubo coal-bearing formation is contemporaneous in age with the Kawai formation, as the writer concludes, the Takakubo coal-bearing formation is also dated to the late middle Miocene.show more |
Hide fulltext details.
| File | FileType | Size | Views | Description |
|---|---|---|---|---|
0603_p189
|
765 KB | 235 |
Details
| PISSN | |
|---|---|
| NCID | |
| Record ID | |
| Created Date | 2021.12.14 |
| Modified Date | 2022.06.20 |