Palomo ("

dove Columbidae () is a bird family consisting of doves and pigeons. It is the only family in the order Columbiformes. These are stout-bodied birds with short necks and short slender bills that in some species feature fleshy ceres. They primarily ...

"; after the shape of its glaciers) is a high

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and per ...

located in the

commune A commune is an alternative term for an intentional community. Commune or comună or comune or other derivations may also refer to: Administrative-territorial entities * Commune (administrative division), a municipality or township ** Communes of ...

of Machali, Cachapoal province,

Libertador General Bernardo O'Higgins Region The Libertador General Bernardo O'Higgins Region ( es, Región del Libertador General Bernardo O'Higgins, ), often shortened to O'Higgins Region ( es, Región de O'Higgins), is one of Chile's 16 first order administrative divisions. It is subdi ...

, west of

Caldera del Atuel Caldera del Atuel is a caldera in Argentina. It is the source of the Rio Atuel and has dimensions of . Sosneado, Cerro Sosneado is a volcano (best volume estimate ) located outside of the Atuel caldera, Volcan Overo (best volume estimate ) and L ...

. Together with Tinguiririca it is one of two volcanoes in the region with evidence of

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

volcanism. The volcano is remote and knowledge on its geology and potential volcanic hazards is limited. The edifice of the volcano is irregular and various estimates of its volume exist, ranging . The best estimate is considered to be . Palomo rises from an elevation of about , and it covers a surface area of . Beneath the volcano lie two calderas with diameters of and ; the summit has a double crater as well, which may reflect a northeastward migration of volcanic activity. northeast of Palomo lies the high Andrès subsidiary vent. This vent features a wide crater that opens to the south. Andrés is constructed on a

granitoid A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quartz ...

basement A basement or cellar is one or more floors of a building that are completely or partly below the ground floor. It generally is used as a utility space for a building, where such items as the furnace, water heater, breaker panel or fuse box, ...

that slopes into the valley of Rio Cortaderal, and its name relates to the son of Reynaldo Charrier, a geologist who described the subsidiary centre in 2010 and who hoped that his son would one day also know the mountain range. It and Palomo are located on the El Diablo fault; a number of other volcanoes and geothermal manifestations are located along its trace, which separates

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

and

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

geological formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

s. The volcano is flanked by

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...

s. Several of these sizeable glaciers form the Rio Blanco, Rio Cortaderal and Rio de los Cipreses on the northern flank, which drain into the

Cachapoal River Cachapoal River is tributary river of the Rapel River in Chile located in the Libertador General Bernardo O'Higgins Region. The river gives its name to the Cachapoal Province. Cachapoal Valley The valley takes its name from the Cachapoal River th ...

. A thermal event in the volcano in 1847 caused a meltwater flood on the Cachapoal River. The southern slope features the Universidad Glacier, which forms the Rio San Andrés which drains into the Tinguiririrca River. With a

snowline The climatic snow line is the boundary between a snow-covered and snow-free surface. The actual snow line may adjust seasonally, and be either significantly higher in elevation, or lower. The permanent snow line is the level above which snow wil ...

altitude of , it was the second longest glacier in Central

in 1958, but since then glaciers in the region have shrunk. The edifice is mainly constructed by

lava flows Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust, on land or un ...

that bury parts of the calderas in the foot of the volcano. Palomo has erupted

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomi ...

and

dacite Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...

, as well as

basaltic andesite Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central Ameri ...

. All rocks are

calc-alkaline The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic mag ...

rocks of medium

potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...

content. The main edifice rocks contain abundant

phenocryst 300px, feldspathic phenocrysts. This granite, from the Switzerland">Swiss side of the Mont Blanc massif, has large white plagioclase phenocrysts, triclinic minerals that give trapezoid shapes when cut through). 1 euro coins, 1 euro coin (diameter ...

s dominated by

plagioclase Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more prope ...

;

clinopyroxene The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...

orthopyroxene The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...

and other minerals are less prevalent. The Andrés edifice has a distinct composition, with more

amphibole Amphibole () is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is A ...

and

olivine The mineral olivine () is a magnesium iron silicate with the chemical formula . It is a type of nesosilicate or orthosilicate. The primary component of the Earth's upper mantle, it is a common mineral in Earth's subsurface, but weathers quickl ...

and less plagioclase than the main edifice.

Argon–argon dating Argon–argon (or 40Ar/39Ar) dating is a radiometric dating method invented to supersede potassiumargon (K/Ar) dating in accuracy. The older method required splitting samples into two for separate potassium and argon measurements, while the newer ...

has been used to date the rocks erupted by Palomo. The main summit yielded dates of 100,000 ± 40,000 years ago, while postglacial lavas of Andrés are dated at 40,000 ± 30,000 years ago, but volcanic activity at Palomo may have continued into

pre-Hispanic In the history of the Americas, the pre-Columbian era spans from the original settlement of North and South America in the Upper Paleolithic period through European colonization, which began with Christopher Columbus's voyage of 1492. Usually, th ...

times. A flood in the Cachapoal Valley in 1847 may have been triggered by a geothermal event on the Palomo volcano. Future activity at Palomo might generate

lahar A lahar (, from jv, ꦮ꧀ꦭꦲꦂ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley. Lahars are extreme ...

s through the melting of ice, which could affect the valleys of the rivers draining the volcano.

References

{{Reflist, 30em

External links

Cordón Granito – Topos (including Agujas del Palomo)

AVA of Palomo
Volcanoes of O'Higgins Region Mountains of Chile Stratovolcanoes of Chile Pleistocene stratovolcanoes

See also

References

External links