香川･小豆島 北東部 ｜ 大坂城と全国の三角点に使われた 良質な花崗岩の石切り場を見に行こう

Shodoshima, located northeast of Kagawa Prefecture, is a two-layered island with a foundation of granite dating back approximately 100 million years, topped by andesite erupted approximately 13 million years ago. Numerous granite quarries are found along the coast from the east to the north of the island, and are used for the stone walls of Osaka Castle and triangulation points across the country. 😙 We'll ride our motorcycles along the coast to visit high-quality granite quarries and learn about their geology and topography. 🌟Membership Registration    / @chiri_rider   ★Website: "Listen to the Voice of the Contour Lines!" http://chiririder.com/ ★Chiri Rider's Twitter (Follow now)   / chiri_rider   ★Question Box (For questions or requests unrelated to the video, please post here) https://peing.net/ja/chiri_rider Geological Map Source: AIST Geological Survey of Japan "1:200,000 Seamless Geological Map of Japan v2" https://gbank.gsj.jp/seamless/v2.html #Touring #Motorcycle #Shodoshima