Update of Observation Method of Fluvial Conglomerate in Teacher Training Course
| Autor: | Keiichi, HAYASHI |
|---|---|
| Jazyk: | japonština |
| Rok vydání: | 2023 |
| Předmět: | |
| Zdroj: | 甲南大学紀要. 理工学編 = Memoirs of Konan University. Science and Engineering Series. 69(1):1-12 |
| ISSN: | 2434-6446 |
| Popis: | 地層の観察で利用しやすい平野や盆地には，一般に河成層が広く分布しており，そこには礫層が何層も含まれているのが普通である．本稿ではこの礫層に焦点を当てて，近年地質学・堆積学で河川堆積物の見方に大きな転換があったことをレビューし，従来の記載的な観察法から最新の成因を解明する観察方法へのアップデートを図った．従来は，礫層はもっぱら礫を運搬してくる強い流水作用によって形成されるもので，河床の堆積物と理解されてきた．しかし，礫を含んだ堆積物はそのほかに，氾濫原内の自然堤防が決壊した場所や，山間部から排出された土石流が堆積する場所にも形成される．本稿では，これら３つのタイプの礫層を判別する観察法を，大学の教職課程を念頭に置いて，甲南大学の地学実験で利用している地質野外実習地の露頭を用いて具体的に示した．また，この観察法の転換により，河成層から過去のその場所での堆積・運搬・侵食現象と，その周辺の地形などの自然景観をよりダイナミックに再現できることも示した． Plains and basins, where are easy to use for observing strata observation, generally have a wide distribution of fluvial deposits, which usually contain many layers of gravel. Focusing on this gravel layer, this paper reviews that there has been a major shift in methods of deciphering fluvial sediments in recent years in geology and sedimentology. Based on this academic transformation, the author attempted to update the observation method from the conventional descriptive observation method to the latest observation method to elucidate the cause. In the past, the gravel layer was understood to be formed mainly by the strong water flow that carried the gravel and was understood as sediments on the riverbed. However, gravel-bearing sediments are also formed where natural levees has broken down and where debris flows discharged from mountains accumulate. In this paper, the observation method for discriminating these three types of gravel layers was concretely demonstrated using the outcrop of the geological field training sites used in the geoscience experiments of the teacher training course at Konan University. It was also shown that by changing this observation method, it is possible to dynamically reproduce the past geological natural phenomena of the region from the river strata. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|