|
Palpana (from ''pparpana'', ram) is a volcano in the Andes of Chile. It has a summit elevation of 6,040 metres above sea level and is part of the dividing range between Upper Loa River basin and Salar de Ascotán basin. Together with Inacaliri and ''Azufre'', it forms a long volcanic chain constructed along the Inacaliri lineament. The volcano rises above an ignimbrite plain that in the area reaches an altitude of . A lava dome cluster is recognizable in the central sector of the volcano, forming a flat area with a surface of . The volcano contains basaltic rocks with an extrusion formed from more silicic rock. Layers of mafic andesite, scoria and some pumice extend outwards away from the central sector. The volcano rises above its terrain and its average summit slope is 26°. The western flank underwent a collapse, leaving a wide and long scar and a deposit at the volcano's foot. Olivine and plagioclase phenocrysts are found in the andesites, the overall SiO2 content is 57.6-58.9% in samples from the southern ridge.〔 The volcano probably formed in a short timespan, given the montonous composition and form. The volcano is no more than 1-2 mya old, but there is no evidence of postglacial material and erosion has carved radial ridges into the volcano.〔 Precise dating methods performed on the southeastern flank have found ages of 3.65±0.15 mya and 3.81±0.30 for lavas and scoria.〔 The snowline altitude in the area is Four moraine stages are found on the mountain, with the lowest moraines on the southern flank at altitude.〔 Nowadays, Block glaciers have been identified in the area, one of which is found at . A minor vegetation cover of 20-25% is present.〔 ==See also== * Cerro Chela * List of mountains in the Andes * List of Ultras of South America 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Palpana」の詳細全文を読む スポンサード リンク
|