Palomo

{{short description|Mountain in Chile}}

{{other uses}}

{{Infobox mountain

| name = Palomo

| photo = Palomo.jpg

| photo_caption = Palomo volcano

| elevation_m = 4860

| elevation_ref = {{cite gvp|vn=357022|name=Palomo}}

| location = Chile

| range = Andes

| coordinates = {{coord|34.608|S|70.295|W|type:mountain}}

| coordinates_ref =

| type = Stratovolcano

| age =

| last_eruption =

| first_ascent =

| easiest_route =

}}

Palomo ("dove"; after the shape of its glaciers{{cite journal |last1=Bobylyova |first1=E. S. |last2=Сергеевна |first2=Бобылева Елена |title=Structural-and-Semantic Analysis of Oronyms of Chile, Структурно-семантический анализ оронимов Чили |journal=RUDN Journal of Language Studies, Semiotics and Semantics, Вестник Российского университета дружбы народов. Серия: Теория языка. Семиотика. Семантика |date=15 December 2016 |issue=2 |page=124 |url=http://journals.rudn.ru/semiotics-semantics/article/view/7399/6852 |language=ru |issn=2411-1236}}) is a {{Convert|4860|m}} high Chilean stratovolcano located in the commune of Machali, Cachapoal province, Libertador General Bernardo O'Higgins Region, west of Caldera del Atuel. Together with Tinguiririca it is one of two volcanoes in the region with evidence of Holocene volcanism. The volcano is remote and knowledge on its geology and potential volcanic hazards is limited.{{Cite report|last1=Bertin|first1=Daniel|last2=Orozco|first2=Gabriel|date=October 2015|title=Petrografía, geoquímica y peligros volcánicos de los volcanes Palomo y Tinguiririca, VI Región|url=http://biblioteca.sernageomin.cl/opac/DataFiles/14905_v3_pp_124_127.pdf|archive-url=https://web.archive.org/web/20180613234253/http://biblioteca.sernageomin.cl/opac/DataFiles/14905_v3_pp_124_127.pdf|url-status=dead|archive-date=June 13, 2018|publisher=SERNAGEOMIN}}

The edifice of the volcano is irregular and various estimates of its volume exist, ranging {{convert|16.6|-|35.5|km3}}. The best estimate is considered to be {{convert|9.2|km3}}. Palomo rises from an elevation of about {{convert|3215|m}}, and it covers a surface area of {{convert|22.4|km2}}.{{Cite journal|last1=Völker|first1=David|last2=Kutterolf|first2=Steffen|last3=Wehrmann|first3=Heidi|date=2011-08-15|title=Comparative mass balance of volcanic edifices at the southern volcanic zone of the Andes between 33°S and 46°S|journal=Journal of Volcanology and Geothermal Research|volume=205|issue=3–4|page=119|doi=10.1016/j.jvolgeores.2011.03.011|bibcode=2011JVGR..205..114V}} Beneath the volcano lie two calderas with diameters of {{Convert|3|km}} and {{Convert|5|km}}; the summit has a double crater as well, which may reflect a northeastward migration of volcanic activity. {{Convert|4.5|km}} northeast of Palomo lies the {{convert|3300|m}} high Andrès subsidiary vent.{{Cite journal|last=Charrier|first=Reynaldo|date=2010-08-30|title=Los Volcanes Andres y Don Casimiro: Dos Centros Descubiertos en los Andes Entre 34° y 34°45' Latitud Sur|url=http://www.andeangeology.cl/index.php/revista1/article/view/V6n2-a04|journal=Andean Geology|language=es|issue=8|issn=0718-7106}}{{rp|83}} This vent features a {{Convert|500|m}} wide crater that opens to the south. Andrés is constructed on a granitoid basement that slopes into the valley of Rio Cortaderal,{{rp|84}} 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.{{rp|83}} 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 and Cenozoic geological formations.{{cite journal |last1=Charrier |first1=Reynaldo |last2=Iturrizaga |first2=Lasafam |last3=Carretier |first3=Sébastien |last4=Regard |first4=Vincent |last5=Charrier |first5=Reynaldo |last6=Iturrizaga |first6=Lasafam |last7=Carretier |first7=Sébastien |last8=Regard |first8=Vincent |title=Evolución geomorfológica y glaciar de las hoyas de los ríos Maipo superior y Cachapoal en la Cordillera Principal Andina, Chile central (34°-35° S) |journal=Andean Geology |date=May 2019 |volume=46 |issue=2 |pages=240–278 |doi=10.5027/andgeov46n2-3108 |url=https://scielo.conicyt.cl/scielo.php?pid=S0718-71062019000200240&script=sci_arttext |issn=0718-7106|doi-access=free }}

The volcano is flanked by glaciers.{{Cite journal|last1=Rivera|first1=A.|last2=Bown|first2=F.|last3=Brock|first3=B. W.|last4=Burger|first4=F.|last5=Carrión|first5=D.|last6=Cisternas|first6=S.|last7=Gacitúa|first7=G.|last8=Oberreuter|first8=J.|last9=Silva|first9=R.|date=2013-05-01|title=Outline of recent research on ice-volcano interactions in Southern Chile|bibcode=2013AGUSMGC44A..02R|journal=AGU Spring Meeting Abstracts|volume=44|pages=GC44A–02}}

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. A thermal event in the volcano in 1847 caused a meltwater flood on the Cachapoal River.{{Cite journal|last1=Rojas|first1=Octavio|last2=Mardones|first2=María|last3=Arumí|first3=José Luis|last4=Aguayo|first4=Mauricio|date=2014-05-01|title=Una revisión de inundaciones fluviales en Chile, período 1574–2012: causas, recurrencia y efectos geográficos|url=http://www.scielo.cl/scielo.php?script=sci_abstract&pid=S0718-34022014000100012&lng=es&nrm=iso&tlng=es|journal=Revista de Geografía Norte Grande|issue=57|pages=177–192|doi=10.4067/S0718-34022014000100012|issn=0718-3402|doi-access=free}} The southern slope features the {{Convert|10|km}} Universidad Glacier, which forms the Rio San Andrés which drains into the Tinguiririrca River. With a snowline altitude of {{Convert|3100|-|3300|m}},{{Cite book|url=https://books.google.com/books?id=P59sPiXnWpIC&pg=PA153|title=Dynamics of Mountain Geosystems|last=Singh|first=Ram Bali|date=1992-01-01|publisher=APH Publishing|isbn=9788170244721|pages=168}} it was the second longest glacier in Central Chile in 1958, but since then glaciers in the region have shrunk.{{Cite journal|last=Lliboutry|first=Louis|author-link=Louis Lliboutry|year=1958|title=Studies of the Shrinkage After a Sudden Advance, Blue Bands and Wave Ogives on Glaciar Universidad (Central Chilean Andes)|journal=Journal of Glaciology|volume=3|issue=24|page=261|doi=10.1017/S002214300002390X|issn=0022-1430|bibcode=1958JGlac...3..261L|doi-access=free}}

The edifice is mainly constructed by lava flows that bury parts of the calderas in the foot of the volcano. Palomo has erupted andesite and dacite,{{Cite journal|last1=Hickey-Vargas|first1=Rosemary|last2=Holbik|first2=Sven|last3=Tormey|first3=Daniel|last4=Frey|first4=Frederick A.|last5=Moreno Roa|first5=Hugo|author-link5=Hugo Moreno Roa|date=2016-08-01|title=Basaltic rocks from the Andean Southern Volcanic Zone: Insights from the comparison of along-strike and small-scale geochemical variations and their sources|journal=Lithos|volume=258–259|pages=120|doi=10.1016/j.lithos.2016.04.014|bibcode=2016Litho.258..115H}} as well as basaltic andesite. All rocks are calc-alkaline rocks of medium potassium content. The main edifice rocks contain abundant phenocrysts dominated by plagioclase; clinopyroxene, orthopyroxene and other minerals are less prevalent. The Andrés edifice has a distinct composition, with more amphibole and olivine and less plagioclase than the main edifice.

Argon–argon dating 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 times. A flood in the Cachapoal Valley in 1847 may have been triggered by a geothermal event on the Palomo volcano.{{cite journal |last1=Iturrizaga |first1=Lasafam |last2=Charrier |first2=Reynaldo |title=Sudden glacier advances in the Cachapoal Valley, Southern Central Andes of Chile (34°S) |journal=Journal of South American Earth Sciences |date=1 January 2021 |volume=105 |page=20 |doi=10.1016/j.jsames.2020.102787 |bibcode=2021JSAES.10502787I |s2cid=225396202 |url=https://www.sciencedirect.com/science/article/pii/S0895981120303308 |language=en |issn=0895-9811|url-access=subscription }} Future activity at Palomo might generate lahars through the melting of ice, which could affect the valleys of the rivers draining the volcano.