Tamba Highlands

This mountain range stretches from central Kyoto to eastern Hyogo. In the east, it is bordered by the Hira Mountains by the Hanaore Fault, which runs north-south along the Azumi River, and in the west, it is connected to the Chugoku Mountains. It is mainly composed of Paleozoic strata, and is a so-called uplifted quasi-plain that was created by folding of the Paleozoic strata, which then became a quasi-plain and was then uplifted and dissected again. Therefore, the summits show a constant height of 400 to 600 meters, and Mt. Atago (924 meters) and Mt. Mikuni (959 meters) are considered to be monadnocks left behind by erosion. The Tanba Highlands are cut by faults running vertically and horizontally, forming fault basins such as Kameoka, Fukuchiyama, and Sasayama. The area has been eroded and dissected by rivers such as the Yura River, which flows into the Sea of ​​Japan, and the Oi River and Kako River, which flow into the Seto Inland Sea, but it is difficult to trace clear watersheds on the plateau-like Tamba Highlands, and especially near Goma (Nantan City, Kyoto Prefecture), which is on the watershed between the Yura River and the Oi River, and Isou (Tamba City, Hyogo Prefecture), which is on the watershed between the Yura River and the Kako River, the altitude does not reach 100 meters. However, because the area is mountainous overall, there has not been much development of industries other than forestry, and the population density is extremely low in the former Kitakuwata District area of ​​Kyoto Prefecture. However, development in mountain basins such as Kameoka is long ago, and small cities have developed.

[Takeo Oda]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

京都府中央部から兵庫県東部にまたがる山地。東は安曇(あど)川に沿って南北に走る花折(はなおれ)断層によって比良(ひら)山地と境し、西は中国山地に連なる。主として古生層からなり、古生層の褶曲(しゅうきょく)によって生じた山地が準平原化されたのちに、ふたたび隆起開析されたいわゆる隆起準平原である。したがって山頂部は400～600メートルの定高性を示し、愛宕(あたご)山（924メートル）、三国(みくに)岳（959メートル）などは侵食から取り残された残丘（モナドノック）とみなされる。丹波高地は縦横に走る断層によって裁断され、亀岡(かめおか)、福知山(ふくちやま)、篠山(ささやま)などの断層盆地が形成されている。日本海に注ぐ由良(ゆら)川、瀬戸内海に注ぐ大堰(おおい)川、加古(かこ)川などの水系によって侵食開析されているが、高原状をなす丹波高地では明白な分水界をたどることは困難であり、ことに由良川、大堰川の分水界にあたる胡麻(ごま)（京都府南丹(なんたん)市）、由良川、加古川の分水界にあたる石生(いそう)（兵庫県丹波市）付近では標高100メートルに達しない。しかし全体としては山がちのため、林業以外の産業の発達はあまりみられず、人口密度も京都府旧北桑田郡地方などでは著しく低い。ただ亀岡などの山間盆地の開発は古く、小都市の発達がみられる。

［織田武雄］

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