Читать книгу Canyoning in the Alps. Graded routes in Northern Italy and Ticino, Austria, Slovenia and the Valais Alps онлайн

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To the south of the Insubric Line, from Lake Como to Slovenia, lie the Southern Limestone Alps, home to the limestone areas described in this guide. All limestone (and dolomite) in the Alps originated in the ancient seas that once separated Italy and Europe. It is formed from calcium-rich minerals mainly derived from the shells of marine organisms laid down throughout the Mesozoic Era (the ‘Age of the Dinosaurs’ – around 65–250 million years ago). Owing to the solubility of limestone in rainwater, limestone canyons tend to be narrow, twisting and deeply encased, resembling cave passages open to sunlight. Like their subterranean counterparts, karst features such as stalactites, flowstone and rock arches are common. Distinct bands are often visible on the canyon walls, each representing a different age of limestone formation, although the banding is now rarely horizontal owing to folding and buckling of the Earth’s crust. Older layers underlie more recent ones, and a descent through a limestone canyon may take you through several million years of Earth’s history.