Mafic monogenetic vents at the Descabezado Grande volcanic field (35.5°S–70.8°W): the northernmost evidence of regional primitive volcanism in the Southern Volcanic Zone of Chile

Salas, Pablo A.; Rabbia, Osvaldo; Hernández, Laura B.; Ruprecht, Philipp

doi:10.1007/s00531-016-1357-5

Cited by 10 publications

(10 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous work 20 showed that the emplacement of each cone at Los Hornitos occurred in two distinct stages. An initial explosive stage generated a widely distributed tephra fall deposit (~1.5 km around the vent) that is composed of beds of variable amounts of lapilli and ash fragments.…”

Section: Introductionmentioning

confidence: 98%

“… 19 ) where erupted magmas reveal the dominance of storage and differentiation in the crust, Los Hornitos erupted primitive magma with olivine phenocrysts in equilibrium with mantle peridotite (up to Fo 92.5 ; ref. 20 ). Magnesian olivines in arc settings have been interpreted to represent deep crystallization near or below the Moho 3 , 18 on the grounds of thermal considerations as well as pyroxene-barometry.…”

Section: Introductionmentioning

confidence: 99%

“…Magnesian olivines in arc settings have been interpreted to represent deep crystallization near or below the Moho 3 , 18 on the grounds of thermal considerations as well as pyroxene-barometry. In the case of Los Hornitos, structural controls may facilitate their uninterrupted ascent to the surface with limited crustal residence despite the thick Andean crust 19 , 20 .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Out-of-sequence skeletal growth causing oscillatory zoning in arc olivines

et al. 2021

Self Cite

View full text Add to dashboard Cite

Primitive olivines from the monogenetic cones Los Hornitos, Central-South Andes, preserve dendritic, skeletal, and polyhedral growth textures. Consecutive stages of textural maturation occur along compositional gradients where high Fo–Ni cores of polyhedral olivines (Fo92.5, Ni ~3500 ppm) contrast with the composition of dendritic olivines (Fo < 91.5, Ni < 3000 ppm), indicating sequential nucleation. Here we present a new growth model for oscillatory Fo–Ni olivine zoning that contrasts with the standard interpretation of continuous, sequential core-to-rim growth. Olivine grows rapidly via concentric addition of open-structured crystal frames, leaving behind compositional boundary layers that subsequently fill-in with Fo–Ni-depleted olivine, causing reversals. Elemental diffusion modeling reveals growth of individual crystal frames and eruption at the surface occurred over 3.5–40 days. Those timescales constrain magma ascent rates of 40–500 m/h (0.011 to 0.14 m/s) from the deep crust. Compared to ocean island basalts, where dendritic and skeletal olivines have been often described, magmas erupted at arc settings, experiencing storage and degassing, may lack such textures due to fundamentally different ascent histories.

show abstract

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Out-of-sequence skeletal growth causing oscillatory zoning in arc olivines

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…This area is ideally suited for this task, as it has been a focus of magmatism at least during the last 18 m.y., containing a large compositional variety of plutonic and subvolcanic intrusions and volcanic products. Besides, it has been proposed that in this Andean segment, margin-oblique structures inherited from the Andean basement play a first-order role over the geometry of volcanic chains and minor eruptive vents alignments (Salas et al, 2017), and would be responsible for the exceptional width of the Transitional Southern Volcanic Zone (34.5-37 °S), while to the south the ~N-S volcanic arc is restricted and aligned over the margin-parallel Liquiñe-Ofqui Fault Zone (LOFZ; Cembrano et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal variability of magmatic products under a changing structural and tectonic context: a case study in the Andes of southern Central Chile

et al. 2023

View full text Add to dashboard Cite

In a subduction setting, the type of magmatic products which reach the upper crust, and eventually the surface, depends on several variables, among which some of the most relevant are the tectonic regime, and the orientation of magma pathways relative to the predominant stress tensor. To better understand this relationship, we studied in detail an area of the Andes of southern Central Chile in which subduction-related magmatism has been active at least during the last 18 m.y. The relationship between high-angle faults and magmatism was studied, and the spatiotemporal variations on the stress tensor were analyzed. The chemistry of the different magmatic products was used to evaluate the magma “fertility”, understood as its potential to form a giant porphyry-type deposit. The age of the studied units is constrained by new U-Pb zircon ages, complemented with previous geochronological studies. Three main high-angle fault systems are present: ∼NW striking structures control the emplacement of plutonic bodies, while ∼NE–ENE and N–NNE faults, more parallel to the prevailing orientation of σ1 since the middle Miocene, control the emplacement of dike swarms and volcanic alignments. Regarding the geochemical characterization, a transition towards steeper REE patterns and higher fertility indices is observed in the earliest facies of the La Invernada Plutonic Complex (∼15-14 Ma), coincident with a middle Miocene orogenic event described at this latitude by previous authors. The Pliocene La Resolana intrusions show higher magma fertility indices; however, they are still considerably lower than those typical for porphyry-forming magmas in the same Andean region. It is concluded that the contrasting fertility observed in coeval intrusions emplaced under the same tectonic context, cannot be explained by continental-scale processes; instead, they are related to differences in the local pathways of magma ascent through the crust. Fault systems which are miss-oriented relative to the predominant orientation of σ1 appear to favor longer magma residence times, achieving a higher degree of differentiation and fertility in most cases crystalizing within the upper crust, while magmas ascending through more favorably oriented faults are more primitive, and often reach the surface forming stratovolcanoes and alignments of monogenetic vents.

show abstract

“…The small (in terms of erup tive vol ume) vol ca noes, though, have re ceived rel a tively lim ited at ten tion. Good ex amples of such re search in South Amer ica are in ves ti ga tions of small mafic and silicic vol ca noes in Co lom bia (Borrero et al, 2017;Botero-Gómez et al, 2018;Murcia et al, 2019;Sánchez-Torres et al, 2019, 2022, re search on sev eral small-vol ume mafic to in ter me di ate vol ca noes in the CVZ in north ern Chile (Ureta et al, 2019) and doc u men ta tion of a few small, dis persed vol ca noes in the South ern Vol ca nic Zone of Chile (Salas et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Constraints on the nature and evolution of the volcanic fields of the Andahua Group, Central Volcanic Zone, southern Peru

Gałaś

Németh

Lewińska

2022

View full text Add to dashboard Cite

The Andahua Group is a dis tinct clus ter of typ i cally monogenetic vol ca noes lo cated in the north ern most part of the Cen tral Vol ca nic Zone in the An des, char ac ter ized by small-vol ume lava domes and sco ria cones. Seven vol ca nic clus ters have been dis tin guished. Us ing sat el lite im ag ery, geo log i cal map ping, and field work, we found a to tal of 103 lava domes, 43 sco ria cones, and 3 small com pos ite vol ca noes. Most of the lava domes are monogenetic but 9 were formed by mul ti ple erup tions. Petro gen etic mod els have been de vel oped for the magma evo lu tion of the Andahua Group. They show lo cal crustal in fluence on the mag mas gen er ated, and pos si ble con trols on the magma path way to the sur face, and po ten tial seg re ga tion. Local compositional vari a tion of the crustal rocks is in ferred to have a strong in flu ence on the magma that as cends through the thick con ti nen tal crust. As sim i la tion and con tam i na tion by deeply seated granitoids of the Arequipa and Paracas mas sifs are also in ferred to play a role in the fi nal mag matic prod ucts. Fu ture ac tiv ity with gas emis sions from the Andahua Group vol canoes may cause haz ard ous con di tions for tour ists.

show abstract

Mafic monogenetic vents at the Descabezado Grande volcanic field (35.5°S–70.8°W): the northernmost evidence of regional primitive volcanism in the Southern Volcanic Zone of Chile

Cited by 10 publications

References 46 publications

Out-of-sequence skeletal growth causing oscillatory zoning in arc olivines

Out-of-sequence skeletal growth causing oscillatory zoning in arc olivines

Spatiotemporal variability of magmatic products under a changing structural and tectonic context: a case study in the Andes of southern Central Chile

Constraints on the nature and evolution of the volcanic fields of the Andahua Group, Central Volcanic Zone, southern Peru

Contact Info

Product

Resources

About