Atsumi Peninsula

Japanese: 渥美半島 - あつみはんとう

A peninsula that runs east to west and extends west from Toyohashi City in southern Aichi Prefecture. Together with the Chita Peninsula, it embraces Mikawa Bay. It separates the Enshu Nada Sea from Mikawa Bay, with the Enshu Nada side called Omotehama (also called Sotohama) and the Mikawa Bay side called Urahama. Omotehama is a straight line of sea cliffs and is also called Katahama Jusanri (about 50 km between Cape Irago and Imagire), while Urahama is rich in variety, with the ports of Tahara and Fukue. The entire peninsula has an inverted slope, with the Omotehama receding due to marine erosion and the Urahama being a delta, sand spit, and shallow sea caused by sedimentation. The geology of the peninsula is a gentle plateau, with the Chichibu Mesozoic and Paleozoic bedrock covered unconformably with Quaternary Pleistocene (Pleistocene) sediments. The bedrock is an extension of the Yana and Yumihari mountain ranges, with Mt. Zao, Mt. Oyama, Mt. Miyayama, and Mt. Koyama protruding from it. The Chichibu Mesozoic and Paleozoic bedrock is mainly chert, sandstone, shale, and diabase tuff, and at the tip of the cape is Hiinosekimon, a tourist symbol. Sekimon is made of hard chert. The Takashihara and Tenpakubara plateaus in Toyohashi City at the base of the peninsula form a gentle wave-like plateau. The climate is in the Tokai climate zone and is warm with a frost-free period of about 270 days, and Miyayama Primeval Forest (warm climate plants) has been designated a national natural monument. Water scarcity has been eliminated by the Toyokawa Irrigation Canal, and greenhouse horticulture has flourished in Tahara City, making it the number one producer of illuminated chrysanthemums, melons, and tomatoes in the country. The Takashibara and Tenpakubara Plateaus at the base are famous for their cabbage and watermelon produced through field irrigation, and for large-scale chicken farming. Cape Irago is a tourist hub in Mikawa Bay Quasi-National Park and has well-developed tourist facilities.

[Gohei Ito]

Cape Irago
A cape located at the westernmost tip of the Atsumi Peninsula. It juts out into the Irago Strait and offers a magnificent view of the inland bay and the open ocean. It is part of the Mikawa Bay Quasi-National Park. The photo shows the view from the east side, with the beautiful sandy beach of Koijigahama stretching for about 1 km on Omotehama (Enshu Nada side). At the end of the Irago Strait lies Kamishima (Mie Prefecture). Tahara City, Aichi Prefecture © Atsumi Peninsula Tourism Bureau ">

Cape Irago

Stone Gate of the Rising Sun
These strangely shaped rocks are found on the coast facing the Enshu Sea, east of Cape Irago. The rocks were eroded by the waves to form a reef, and a sea cave was formed in the center. There are two rock formations: "Kishi no Ishimon" (foreground of the photo) and "Oki no Ishimon." It is included in the Mikawa Bay Quasi-National Park and is one of the tourist attractions. Tahara City, Aichi Prefecture © Atsumi Peninsula Tourism Bureau ">

Stone Gate of the Rising Sun

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

愛知県南部、豊橋(とよはし)市から西へ延びた東西走向の半島。知多(ちた)半島とともに三河湾を抱く。遠州灘(えんしゅうなだ)と三河湾を分離し、遠州灘側を表浜(おもてはま)（外浜とも）、三河湾側を裏浜(うらはま)とよんでいる。表浜は直線状の海食崖(がい)が続き、片浜(かたはま)十三里（伊良湖(いらご)岬―今切(いまぎれ)間約50キロメートル）ともいわれ、裏浜は田原、福江の港もあり変化に富む。半島全体が逆傾斜地形をなし、表浜は海食で後退、裏浜は土砂堆積(たいせき)によるデルタ、砂嘴(さし)、浅海となっている。半島の地質は、基盤岩は秩父中・古生層、その上を不整合に覆うのが第四紀更新世（洪積世）の堆積物で、緩やかな台地状をしている。基盤岩は八名(やな)、弓張(ゆみはり)山地の延長線上に蔵王(ざおう)山、大山(おおやま)、宮山、古山(こやま)などを突出させている。秩父中・古生層はチャートを主体に砂岩、頁(けつ)岩、輝緑凝灰(きりょくぎょうかい)岩で、岬端(こうたん)部には観光シンボルの日出の石門(ひいのせきもん)がある。石門は硬質なチャートである。半島基部の豊橋市の高師原(たかしはら)、天伯原(てんぱくばら)台地は緩やかな波浪状台地をなしている。気候は東海式気候区に属し、無霜期間約270日という温暖な気候で、宮山原始林（暖地性植物）は国の天然記念物に指定されている。豊川用水によって乏水性が解消され、田原(たはら)市は温室園芸が盛んとなり、全国一の電照ギク、メロン、トマトの産地となっている。基部の高師原、天伯原台地は畑地灌漑(かんがい)によるキャベツ、スイカの特産地、大規模養鶏で有名。伊良湖岬は三河湾国定公園の観光拠点で観光施設も整備されている。

［伊藤郷平］