The 6,542 m Nevado del Sajama is Bolivia’s highest mountain.  It is a prominent, glacier clad cone rising 2,200 m above the surrounding plain.  It borders Volcan Cholcani to the SE.   Nevado del Sajama is located in the Sajama Province of the Oruro Department of Bolivia.  It is some 20 km E of the Chile border and 60 km E from the Peru border.  The volcano rises 2,200 m from the surrounding plain with its summit permanently covered with ice and snow down to 5,600 m. 

The cone was heavily eroded by recent glaciation, with moraines common.  For a relatively dry part of Bolivia, there is a lot of water associated with Sajama.  There are wetlands on the mountain and small lakes at its foot.  These feed several rivers which drain the region.  Sajama has an active hydrothermal system with geysers and hot springs found at its foot.  Sajama comes from the Aymara language “Chak-jjana”, which means “West.” 

The region is sparsely populated, with some 63,000 within 100 km of it.  There is a major E-W road S of the volcano.  Other smaller roads complete a circle around it.  Three villages are located NW, W and SW of the summit.  There are a number of farms surrounding it. 

Sajama is located between two climate regimes, a dry one to the W, and a moister one to the E.  Easterly winds during the summer brings moisture powering showers and thundershowers.  Dry W winds prevail during the winter, occasionally triggering intense snowfall.  Due to its high altitude, the region is generally cold.  Average temperatures in the neighboring villages range 4° – 7° C, with highs in the summer approaching 40° C.  Precipitation averages around 33 cm/yr.

Sajama is surrounded by the 1,002 km2 Parque National Sajama), established in 1939, Bolivia’s oldest national park.  It borders Lauca National Park in Chile to the W.  The park is home to the indigenous Aymara, plants and animals unique to the alpine Andes, and numerous hydrothermal features (geysers and hot springs).  The park is managed by locals and conservationists.  It is popular with ecotourists.  There are perhaps 300 Aymara families living in the park

The Sajama Lines are also located in the region.  These are similar to the Nazca lines, estimated to be up to 16,000 km in length.  They are thought to be used as ancient pilgrimage routes, being constructed by the Aymara ancestors some 3 ka.  These are considered to be the largest artwork in the world, most certainly the largest archaeological site in the Andes. 

As with most other volcanoes in the Andes, Sajama is a popular target for climbers.  There are multiple web sites advertising guided hikes up and down the peak.  Typical trip takes four days, reaching the summit early on day three.  An Andean Ascents climb includes relaxing in thermal waters following descent from the mountain.  The climb is classified as very physically demanding due to extreme altitude and steepness of many sections of the climb.  Penitentes are also a prominent climbing obstacle on the icecap. 

Volcanoes in Chile are monitored by SERNAGEOMIN (Servicio Nacional de Geologia y Minera).  There is no obvious similar activity in Bolivia that I could fine.  There does not appear to be active webcam or webicorder dedicated to Nevado del Sajama. 

Region

While Nevado del Sajama is considered by some to be extinct, it is surrounded by a variety of recently active volcanic systems.  Most of these are located E, W and S of it.  There is a 100 km wide break in volcanic systems to the N from Nevado Anallajsi 21 km N and Quaternary volcanoes in S Peru. 

The following list is based on Volcano Discovery’s listed quaternary volcanoes in Peru, Chile and Bolivia.  There are a large number of much older volcanic systems not listed that show up nicely on Google Maps.  The dry climate tends to preserve these systems.  Lava flows, domes and other eruptive products that may be tens to hundreds of thousands of years old look relatively new but aren’t.  As usual, distances are measured from Nevado del Sajama.  We most recently covered this region in our Taacapa post Nov 2023. 

Nevado Anallajsi

Nevado Anallajsi is a heavily eroded 5,750 m high stratovolcano located some 21 km N of Sajama.  It is an andesitic to dacitic stratovolcano built on an ignimbrite plateau.  Younger basaltic lava flows erupted from a N flank vent.  Current thinking is no eruptions from this system over the last 10 ka.  The volcano covers nearly 370 km2.  There is a wide range of estimated ages 10.2 – 2.6 Ma. 

The closest Holocene volcanoes to the NW in Peru are Nevados Casiri, Cerros Purupuruni and Yucamane.  All of these lie 113 – 140 km NW from Nevado del Sajama.

Patilla Pata

Patilla Pata is a 5,300 m heavily eroded stratovolcano that erupted andesites and basaltic lava flows.  It is located 17 km WNW from Nevado del Sajama.  It has been recently active and has an active hydrothermal system that heats water in local rivers.  Glaciation during the last ice age eroded the cone. 

While there is no evidence for eruptions over the last 10 ka, the Junt’uma K’uchu river originating S of Patilla Pata flows hot / warm water into the neighboring Sajama River.  Date of the last eruption is unclear, it did not erupt during the last glaciation.   

Larancauga 

Larancagua is a 5,580 m volcanic edifice immediately NW of Patilla Pata, 23 km NW from Nevado del Sajama.  There is little published on it.  The peak the most NW of the multiple peak edifice that includes Patilla Pata.  From W to E, these peaks include Larancauga, Kunturiri, Patilla Pata, Jisk’s Kunturiri and Pumuta.  The Geiseres de Junthuma are located on the SE flank of Patilla Pata.  Recent lava flows are visible on the E flank of the edifice.  There are another three geyser and hot springs fields immediately S of the flank of the greater edifice.

Nevados del Payachata Group

The 6,336 m Parinacota is the southernmost and youngest of a pair of andesitic volcanoes forming the Nevados de Payachata group along the Chile – Bolivian border.  They are located 27 km W from Nevado del Sajama.  The second cone, Pomerape (6,282 m) is connected by a saddle.  It is glacially eroded, constructed on a base of dacitic – rhyolitic domes.  Parinacota had a flank collapse some 8,000 years ago, producing a 6 km3 debris avalanche that traveled 22 km W, blocking local drainages.  Recent activity rebuilt the volcano.  It is topped with a 300 m summit crater and young lava flows on its W flanks.  There are satellite cones and lava flows on the S and SW flanks.   

Caquena is an eruptive center about 12 km NW from the Nevados del Payachata Group, 36 km WNW from Nevado del Sajama.  It is considered to be part of the overall system and consists of a dacite dome and lava flow complex that may have been active as long ago as 7 Ma.  More recent activity dates around 290 ka.

Vilacollo is another satellite eruptive center of The Nevados del Payachata Group, some 19 km SW from it, 12 km S from Caquena, 47 km WSW from Nevado del Sajama.  Activity here started with andesite cinder cones around 285 ka.  There are some lava flows associated with the cones. 

Taapaca 

The 5,860 m Taapaca volcano is located some 64 km W of Nevado del Sajama.  We took a detailed look at this volcano in our Taapaca post Nov 2023. 

Lexone 

Lexone is an eroded group of young domes located some 70 km NW from Nevado del Sajama.  They top out at 5,340 m.  Domes were initially thought to have erupted in the last 10 ka (Holocene) but have been more recently dated at 70 – 60 ka.  I found no description of rock types for the domes, but most domes in this part of the Altiplano are dacite. 

Tacora 

Volcano Tacora is a 5,960 m twin volcano located some 103 km WNW from Nevado del Sajama.  It is the farthest N volcano in Chile.  The older Chupiquina is located some 6 km NNW from the summit.  It anchors a line of smaller edifices, with seven distinct peaks extending N some 10 km.  The two main volcanoes are connected by a saddle.  The volcanoes are built on an ignimbrite platform forming the Arica Altiplano.  Steep lava flows form most of the cone.  There are domes and pyroclastics.  The cone is heavily eroded by glaciers.  There is a sector collapse scar and debris avalanche from the SE flank. 

The volcano was heavily glaciated during the last ice age with glacial valleys, moraines and cirques found as low as 4,300 m on the cone.  There are disputed reports of glaciers in the crater.  The dispute is over the presence of permanent snow or ice on the cone. 

Volcanoes of this system erupt andesite to basaltic andesite.  There is an active hydrothermal system with fumaroles, solfataras and hot springs on the E side of Tacora.  There are numerous sulfur mines on the saddle between the two volcanoes.  Hot springs are located on the E flank of Tacora.  The volcano has an active hydrothermal system that has altered its internal rocks. 

Tacora was active over the last 700 ka, with dated eruption products 490 – 340 ka.  The crater and lava flows on the S flank are probably the most recent eruptions.  There may not have been any eruptions over the last 10 ka, with the most recent dated some 50 ka.  There is an explosion crater on the NW side, 300 m below the summit.  The most recent looking lava flows are down the SSW flank covering glacial valleys. 

There were reported eruptions in 1930 and 1937, though these are listed as uncertain by the Smithsonian GVP.  There are single reports of activity 1830 – 1950 along with a reported collapse during the 1877 Inquiqe earthquake.  None of these have been confirmed as eruptions or flank collapse events.  Given the presence of fumaroles, these may have been vigorous fumarole plumes, speculation not supported in the literature.  

Acotango 

The 6,052 m Acotango is another group of volcanoes located some 34 km SW from Nevado del Sajama.  The other volcanoes are Volcan Humarata (Umurata, N, 5,730 m) and Cerro Capurata (Cerro Elena Capurata, 5,990 m) to the S.  The overall group is called Nevados de Quimsachata volcano group.  Quimsachata means ‘3’ in the indigenous Ayama language.  The group straddles the Chile – Bolivia border. 

The older Humarata and Acotango are heavily eroded.  The youngest feature is a lava flow on its N flank that dates 241 – 192 ka.  Glacial erosion exposed parts of the inner cone which are hydrothermally altered.  Glacial moraines are found down to 4,200 m on the clank.  The current ice cap is located above 6,000 m. 

Humarata has a summit crater breached to the ESE.  Capurata is a complex of domes and associated pyroclastic flow deposits.  Both of these may have been active during the last 10 ka. 

Guallatiri 

Volcan Guallatiri, 6,071 m, is a symmetrical ice-clad stratovolcano found immediately at the SW end of the previously mentioned Nevados de Quimsachata volcano group, some 40 km SW of Nevado del Sajama.  There is some dispute whether it is a member of the group.  It is listed differently in various places. 

Guallatiri is one of N Chile’s most active volcanoes.  It is topped with a central dacite dome complex with the currently active vent on the S side.  Thick lava flows are prominent on the lower N and W flanks of the volcano.  There is a permanent ice cap that formerly stretched to 5,500 m.  It has receded in recent decades. 

The summit may be a dome or plug.  The lower flanks are covered by lava flows and domes.  It erupts andesite, dacite and rhyolite.  There was a large eruption some 2.6 ka.  Total volume is around 50 km3.  Its footprint covers 85 km2.  Thick lava flows from the summit crater are found on all flanks.  They display levees, ogives, cracks and blocky surfaces.  Block and ash flow fans from flank domes are found on the S and SW flanks. Tephras are mainly located on the E and S side of the volcano.  Tuffs and pyroclastic flows are found on the summit and in radial valleys from the cone.  Glacial deposits cover large parts of the volcano.  There are traces of flank collapse events. 

Minor explosive eruptions have been reported since 1800 AD.  Smithsonian GVP reports VEI 2 eruptions in 1825, 1913, 1959 and 1960.  Eruptions in 1908 and 1985 are listed as uncertain. 

Guallatiri has an active hydrothermal system with both hot and cold springs on the cone.  Vigorous fumarole plumes were reported in 1985, 1990 and 1996.  Intense fumarole activity continues with numerous solfataras extending over 300 m down the W flank.  

Sacabaya (Tambo Quemada / Cerro Quemado) 

Volcan Sacabaya (Tambo Quermada, Cerro Quemado) is a 4,215 m low pyroclastic shield located 59 km S from Nevado del Sajama.  The shield measures 8 km in diameter and rises 360 m above the surrounding plain.  It is covered by material from explosive activity.  There are several pit craters 1.5 km in diameter.  The ignimbrite shield is topped by a 2 x 3.5 km vent area formed by three craters overlapping in a N-S trend.  The youngest crater is at the S end of the summit.  It contains a blocky lava dome.  Wind redistributed tephra to the E and S, forming dunes. 

The volcano has an active hydrothermal system with fumaroles.  There are no known dated eruptions, though it is thought to be active over the last 10 ka.  As a reminder, due to the dryness of this part of the world, young looking volcanic features often end up being hundreds of thousands of years old rather than thousands of years old. 

Arintica  

Volcan Arintica is a 5,597 m stratovolcano located some 73 km S Nevado del Sajama.  It is part a volcanic complex that rises N above the Salar de Surire (mostly) dry lake / playa.  The complex includes Cerro Puquintica (Poquentica), 5,760 m, 7 km E, Cerro Calajata 3 km SW and the Calajata dacite dome at the SW end of the complex.  The volcanoes are extensively eroded.

Initial analysis suggested a postglacial lava flow from its summit.  This was later identified as a collapse deposit from the summit crater.  Dating of its rocks find they erupted 637 – 486 ka.  The volcano was constructed in two phases.  It is considered to be a potentially dangerous volcano.  Cerro Puquintica is much older than Arintica. 

Moraines are found down to 4,400 m on its flanks.  Five glaciers surrounded the summit and drained S into the Salar de Surire.  Glaciers existed through 1977.  Both Arintica and Cerro Calajalata to the SE were depicted with permanent snow / ice cover in a 1996 map. 

Phasa Willk’i 

Phasa Willk’I is the highest peak in an extensive volcanic complex located some 39 km ESE from Nevado del Sajama.  The peak is located at the SW corner of the field that stretches another 40 km ENE.  There is little published about this heavily eroded volcanic complex.  Google Maps do not show anything that appears to be recent activity from this field. 

Nevado del Sajama

Nevado del Sajama is an andesitic stratovolcano built through a dome complex.  The entire complex may be a post-caldera field erupting after the caldera forming eruption that created the underlying Lauca – Perez Ignimbrite dating 2.7 Ma.  Rocks on the cone itself date 679 ka, which may end up being the most recent eruption.  Sajama is extensively glaciated.  While Sajama and neighboring volcanoes had much larger glaciers in the past, its actual glaciated history is poorly known.  There is no trace of a crater at the summit.  Glaciers are severely crevassed, steep and difficult to climb. 

The cone is built of lava flows and pyroclastics radiating from the center of the cone.  They are identified in outcrops around the cone.  Some parasitic cones SE of Sajama erupted lavas and extruded domes.  Parasitic vents outside the foot of the volcano are older than the main cone.  Their location is controlled by radial dikes and underlying regional faults and lineaments.  The main volcano erupted andesites to rhyodacites.  The magma chamber beneath Sajama shows signs of being stratified, with a rhyolite and mafic (basalt) layer) that mixed to form dacites. 

There is a group of at least 8 domes at the NW foot of the volcano.  The Chucacero dome SW of Sajama has been dismantled by glacial erosion.  The Huisalla, Khohuiri Tarakkollu lava clusters are sufficiently new and do not show glacial erosion.  There is a lava flow from the main cone stretching 2 km across the flat plain below the cone.  There are known deposits of copper, lead, gold, silver and sulfur in the vicinity.  All of these indicate extensive hydrothermal altering of volcanic rocks. 

One source mentioned a flank collapse from Sajama.  This is not supported by satellite photography, which does not show debris fans.  This would make Sajama one of the rare stratovolcanoes not to suffer a flank collapse.  There are multiple lava flows, domes and parasitic vents visible on the flanks. 

There are three major geologic lineaments in the region:  Sajama lineament, N-NW trending, W-SW aligned with high topography, and a W-NW one.  The W-SW lineament played an important role in development of the main stratocone. 

Growth

Activity at Nevado del Sajama should be considered in relation to that of its multiple neighboring volcanoes.  The entire region is built on ignimbrites of unknown thicknesses.  It then progressed to stratovolcanoes and dome fields.  Most recent activity has been continuing stratovolcano activity and dome field / lava flow fields.  Erosion by glaciers and lahars filled many of the low-lying plains between the stratovolcanoes with debris. 

The oldest dated volcanic materials in the region are at the Chullcani volcanic complex S of Sajama.  The base unit is the rhyolite Khalani tuff.  Chullcani is built of alternating basaltic andesite, andesite and dacite layers.  These date around 6.13 Ma similar in age to tuffs from the neighboring Turaquiri caldera. Multiple younger lavas are found in this area interlayered with ignimbrites until 2.23 Ma.  The ignimbrite basement is of unknown thickness.  The upper part of the ignimbrite is intensely fractured. 

Starting 2.23 Ma, the massive ignimbrites seem to end, and the activity becomes more effusive with lava layers interlayered with pyroclastic sequences from Oke Okeni and Quimsa Chata stratovolcanoes.   Activity continued building Quisi Quisini, Sajama and the Nevados del Payachata Group.  These andesite lavas cover over 90 km2.  The Payachata Group seems to be the youngest of these new stratovolcanoes and has been recently active. 

The most recent phase was partly explosive, with emissions of large quantities of andesitic lavas and pyroclastics.  Cerro Condoriri, Nevado Kakepe Junthuta and Nevado Payachata produced pyroclastics.  The most recent activity were significant lahars.  These are covered with paleosols and ash.  The last significant layer are 30 – 40 cm of uniformly thick pyroclastics, mostly ash and pumice.  The stack is topped with fine ash and medium ash flow material.  Most depressions of the Sajama Basin are filled with lahar and ash fall deposits from recent activity.  These are highly eroded. 

Kkota Kkotani lavas (17 km SE) are unrelated to eruptions from the main cone.  These date 81 – 25 ka.  The date of the most recent eruption here is unknown.  These are N and W from the heavily eroded, larger Macizo de Pacuni 23 km S.

Two more recent volcanic units are the Colquen Wilqui lavas (12 km NE) and Jacha Khala tuff.  Some of these are very young, perhaps erupted in the last 10 ka.  These lavas are located in a 24 x 14 km dome field NE from Sajama.  There are at least 11 domes.  7 of them sourced what appear to be recent lava flows.  The largest of these is 8 km long, 4 km wide, flowing SE from its source on the W end of the field.  8 domes are arranged in a circular shape at the NW corner of the field.  Activity here is undated but may end up being the most recent around Sajama. 

Hydrothermal

Google Maps satellite view shows the hydrothermal area of the park 13 km SW from the summit.  The main geyser field is at Gueiser’s Sajama 15 km W from the summit and 3 km N from there at Geiseres de Junthuma on the W flank of Patilla Pata. 

The area to the S shows up as whiter than the surrounding vegetated plain on satellite photos.  There are two rivers (streams?) flowing through the hot area flowing generally S.  Laguna Isla is located immediately N of the main highway, perhaps 3 km from the hot springs.  There is road access and a parking lot next to the hot springs / geysers.  It is not paved. 

Visitors are warned not to bathe directly in the thermal pools, as they are far too hot.  Deeper pools in the rivers are cool enough for bathing.  Geysers are described as particularly vigorous hot springs.  Heat here is able to boil eggs, which some visitors do.  Water in the rivers is warmed as it flows though the thermal area and are slightly sulfuric.  Some of the boiling pools have biological mats. 

The region has a relatively shallow magmatic body that is currently cooling.  The lahar deposits in the region form a hydrologic cap. 

Bolivian President Morales visited the Sajama area in 2014 and expressed interest in developing geothermal energy in the region, using it to power proposed mining.  His announced national goal was to export 1,000 MWe by 2020.  To date, there has been no additional progress. 

The most important thermal features from a geothermal perspective are located near Rio Junthuma.  These are directly related to the underlying NW-SE fault system.  There are additional features 7 km E and 200 m deeper.  The second group have lower salinity and are regarded as lateral outflow from the same system.  The outflow is diluted with meteoric water.  Reservoir temperatures are 230° – 250° C. 

Tectonics

Activity in the Andean Central Volcano Zone is driven by subduction of the Nazca Plate under the South American Plate.  Volcanism has been active over the last 180 Ma, increasing in intensity 25 – 20 Ma with the breakup of the Farallon Plate into the Cocos and Nazca Plates.  The magmatic arc migrated 150 km toward the east over time.  The Andes are divided into four segments:  Northern, Central, Southern and Austral.  There are gaps in volcanic activity between the segments, thought to be due to variations or tears in the subducting plate and its angle of descent into the mantle.  The Andes have been at the leading edge of the South American plate for at least the last 600 Ma, if not far, far longer.

The Andean Central Volcanic Zone (CVZ) punches volcanic activity through exceptionally thick crust, 60 – 80 km thick in most places.  Convergence speed has varied, with the most rapid convergence taking place around 32 – 30 Ma.  In the last 15 Ma, the convergence has grown the Andes, compressed and thickened the western part of the continent, uplifting and thickening it.  Today, the convergence is just over 6 cm/year, nearly perpendicular to northern Chile.  The Chile Trench is deep and mostly sediment free.  The current volcanic arc is located 250 – 300 km E of the trench, 120 – 130 km above the Wadati – Benioff plane.  The plate is generally descending around 30° beneath volcanic front.  Andesitic and dacitic magmas are due to significant crustal involvement and recycling.  Mantle basalts are thought to stagnate near the base of the crust, cool, crystalize, and melt adjacent crustal rock before making their way to the surface. 

The CVZ has 44 active volcanic complexes, over 18 active minor volcanic fields, and at least 6 potentially active Quaternary large silicic ignimbrite centers or caldera systems.  The volcanic systems include short lived (less than 0.5 Ma) andesite – dacite stratocones with central vents, and long-lived clusters (over 0.5 Ma) of dacite domes with pyroclastic aprons.  Active volcanism in the CVZ is mostly located at large composite volcanoes, 2-3 km high, 0.8 – 0.6 Ma, though they can be several Ma old. 

Conclusions

While activity at Nevado del Sajama seems to have ended, it is surrounded by recently active volcanic vents, all within 20 km.  Those to the S and E erupted domes and lava flows.  Activity continues at the Parinacola stratovolcano.  The area is remote and the systems are relatively unmonitored.  There is an extensive and active hydrothermal system associated with Sajama that has altered its rocks significantly over its lifetime.  While it has not suffered a significant flank collapse, it has been the source for multiple lahars. 

Additional information

Volcanic Debris Avalanches:  From Collapse to Hazard, Springer, 2020

The Nevados de Payachatas volcanic region (18° S / 69° W, N Chile), I. Geological, geochemical and isotopic observations, Worner, et al, 1988

The Nevados de Payachatas volcanic region (18° S / 69° W, N Chile), II. Evidence for widespread crustal involvement in Andean magmatism, Davidson, et al, 1990

Analysis of the magmatic – hydrothermal volcanic field of Tacora volcano, northern Chile using travel time tomography, Pavez, et al, Oct 2019

A lithic assemblage from Pueblo Sajama (Oruro Department, Bolivia), Koeszkoz, et al, 2020

Comment on “Climate in the western cordillera of the central Andes over the last 4300 years”, by Engel, et al, (2014), Saez, et al

Basalt utilization in the archaic period of Bolivia geological and archaeological background, Pentek & Farago, 2019

Magmatic processes in titanite – bearing dacites, central Andes of Chile and Bolivia, S Nakada, 1991

Geochemical report on the Sajama geothermal area, Bolivia, Scandiffio & Rodriguez, Nov 1990

Desarrollo rural y conservacion de la naturaleza en areas protegidas de Bolivie:  la Puna de Sajama (Bolivia), Olmo, et al, 2009

Ritualized memory and landscape at Pueblo Sajama, Bolivia:  A study of a sacred landscape and colonial encounter, A Birge, May 2016

Volcan Sajama (6542 M.), Andes Handbook, Apr 2003

Volcan Acotango, J Stone, Aug 2022

Conservacion de la naturaleza y Desarrollo en el Alitplano de Sajama (Bolivia), Tesis Doctoral, FJSC Mateos, Universidat Autonoma de Madrid, May 2013

Geothermal investigations with isotope and geochemical techniques in Latin America, Proceedings of a Final Research Co-ordination meeting, Organismo Internacional de Energia Atomica, Nov 1990