Английская Википедия:Cerro Morado
Шаблон:Coord Cerro Morado is a monogenetic volcanic field,[1] in Argentina. It is part of a group of mafic volcanic centres in the Altiplano-Puna region, which is dominated by silicic rocks such as dacitic - rhyolitic rocks.
The field was formed during eruptions 6.4 million years ago which probably lasted from half a year to several years. These eruptions formed scoria cones and a plateau of lava flows.
Geology and geography
The Cerro Morado volcanic field is located in northwestern Argentina, in the Jujuy Province. The town of Шаблон:Lang is located within the volcanic field.Шаблон:Sfn The frontier with Chile lies approximately Шаблон:Convert west of the volcanic field.Шаблон:Sfn
The Altiplano and the adjacent southern Puna has experienced mafic volcanism during the Cenozoic. Most of this volcanism occurred in the southern segment, but the northern segment has also experienced mafic volcanism mostly associated with major volcanic centres and smaller volcanic fields such as Cerro Morado and Cerro Bitiche.Шаблон:Sfn Mafic lava flows however tend to constitute the minority of volcanic rocks in this region; the bulk of the volcanic rocks are dacitic-rhyolitic in composition. Present day volcanism occurs in the volcanic arc called the Central Volcanic Zone approximately Шаблон:Convert farther west.Шаблон:Sfn The basement in the Cerro Morado area is formed by Ordovician rock formations and older lava flows of the Pairique volcanic complex and the Patahuasi flows. Volcanism in the area has been influenced by faults.Шаблон:Sfn
The field covers a surface area of Шаблон:Convert,Шаблон:Sfn alternatively stated as Шаблон:Convert.[1] Eight scoria cones form the volcanic field,Шаблон:Sfn but there may be more. With exceptions erosion has buried their bases.Шаблон:Sfn Layered deposits containing ash, lava bombs and lapilli are found around them.Шаблон:Sfn These cones are frequently aligned and an average diameter of Шаблон:Convert and the heights range Шаблон:Convert.Шаблон:Sfn Other structures associated with the cones are clastogenic lava flows and eroded pyroclastic mounds, as well as dykes that cut the cones.Шаблон:Sfn
The volcanic field is dominated by a plateau made of lobate lava flows, typically having thicknesses of Шаблон:Convert.Шаблон:Sfn The lava flows contain folding and flow structures.Шаблон:Sfn Various layers of lava flows lie on top of each other and on the basement, and pyroclastic deposits can also be found.Шаблон:Sfn The volcanic field has a north-south extension.Шаблон:Sfn
The volcano has erupted andesite and basaltic andesite.Шаблон:Sfn Most cones are constructed from basaltic andesite,Шаблон:Sfn most lava flow lithofacies are andesitic.Шаблон:Sfn The andesites have a dark-blue to gray colour,Шаблон:Sfn with variable amounts of vesicles.Шаблон:Sfn Minerals found in the rocks include bytownite, clinopyroxene, iron-titanium oxides, labradorite, orthopyroxene and plagioclase.Шаблон:Sfn Olivine is more common in the basaltic andesite than the andesite.Шаблон:Sfn Overall, the composition is potassium-rich calc-alkaline.Шаблон:Sfn Xenoliths of quartz are contained in the andesite.Шаблон:Sfn Some of the rocks that form the cones are hydrothermally altered.Шаблон:Sfn
The volcanic field was formed during the Upper Miocene.Шаблон:Sfn Dates of 6.7 ± 0.4 million years ago have been obtained.Шаблон:Sfn The field was formed by energetic effusive eruptions; lava supply rates of up to Шаблон:Convert and an emplacement time of 84-18 months for the northern and 48-7 months for the southern parts of the field have been estimated.Шаблон:Sfn The field was probably formed by Strombolian eruptions accompanied by lava fountaining. Magma was transported along fractures and faults,Шаблон:Sfn resulting in the eruption of several different batches of magma without long stalling in the upper crust.Шаблон:Sfn
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