Water input and water release from the subducting Nazca Plate along southern Central Chile (33°S-46°S)

The hypothesis of a subduction-related Miyashiro-type paired metamorphic belt for the origin of the late Paleozoic igneous and metamorphic complex in the Andean Coastal Cordillera has remained unquestioned since its proposal in the early seventies. A synthesis of the advances in the study of these metamorphic rocks between 33°S and 42°S, revising field relations among geological units, and geochemical and geochronological data from the contemporaneous granitoids of the Coastal Batholith, highlights inconsistencies in this model. The record of short-lived forearc magmatism in the late Paleozoic intruding the partially synchronous accretionary prism, and geochemical and isotopic data from the igneous rocks indicating sources from the accretionary prism sediments and the back-top lithosphere, suggest a departure from typical subduction settings. I conclude that the anomalous configuration of the paired metamorphic belt and the associated Coastal Batholith resulted from a complex geodynamic process involving a near-trench thermal anomaly caused by the subduction of a trench parallel mid-ocean ridge.

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WEAP21 based modelling under climate change considerations for a semi-arid region in southern-central Chile

MASKANA ◽

10.18537/mskn.08.02.10 ◽

2017 ◽

Vol 8 (2) ◽

pp. 125-146 ◽

Cited By ~ 1

Author(s):

Luis Duque ◽

Raúl Vázquez

Keyword(s):

Climate Change ◽

Arid Region ◽

Central Chile ◽

Southern Central ◽

Semi Arid Region ◽

Semi Arid

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Hiking trails as conduits for the spread of non-native species in mountain areas

Biological Invasions ◽

10.1007/s10530-019-02165-9 ◽

2019 ◽

Vol 22 (3) ◽

pp. 1121-1134 ◽

Cited By ~ 2

Author(s):

Rebecca Liedtke ◽

Agustina Barros ◽

Franz Essl ◽

Jonas J. Lembrechts ◽

Ronja E. M. Wedegärtner ◽

...

Keyword(s):

Native Species ◽

Control Plant ◽

Plant Invasions ◽

Native Plant ◽

Mountain Areas ◽

Central Chile ◽

Hiking Trails ◽

Local Plant ◽

Southern Central ◽

Recreational Use

AbstractRoadsides are major pathways of plant invasions in mountain regions. However, the increasing importance of tourism may also turn hiking trails into conduits of non-native plant spread to remote mountain landscapes. Here, we evaluated the importance of such trails for plant invasion in five protected mountain areas of southern central Chile. We therefore sampled native and non-native species along 17 trails and in the adjacent undisturbed vegetation. We analyzed whether the number and cover of non-native species in local plant assemblages is related to distance to trail and a number of additional variables that characterize the abiotic and biotic environment as well as the usage of the trail. We found that non-native species at higher elevations are a subset of the lowland source pool and that their number and cover decreases with increasing elevation and with distance to trails, although this latter variable only explained 4–8% of the variation in the data. In addition, non-native richness and cover were positively correlated with signs of livestock presence but negatively with the presence of intact forest vegetation. These results suggest that, at least in the region studied, hiking trails have indeed fostered non-native species spread to higher elevations, although less efficiently than roadsides. As a corollary, appropriate planning and management of trails could become increasingly important to control plant invasions into mountains in a world which is warming and where visitation and recreational use of mountainous areas is expected to increase.

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The Chile Biliary Longitudinal Study: A Gallstone Cohort

American Journal of Epidemiology ◽

10.1093/aje/kwaa199 ◽

2020 ◽

Author(s):

Jill Koshiol ◽

Vanessa Van De Wyngard ◽

Emma E McGee ◽

Paz Cook ◽

Ruth M Pfeiffer ◽

...

Keyword(s):

Longitudinal Study ◽

Blood Cells ◽

Blood Clot ◽

Buffy Coat ◽

Central Chile ◽

Southern Central ◽

Risk Areas ◽

Detection Strategies ◽

Primary Risk Factor

Abstract Gallbladder cancer (GBC) is a highly fatal cancer that can be cured through cholecystectomy if identified early. The presence of gallstones is the primary risk factor for GBC, but few people with gallstones develop GBC. A key question is what drives the development of GBC among persons with gallstones. We initiated the Chile Biliary Longitudinal Study (Chile BiLS) to address this question. From 2016 to 2019, Chile BiLS enrolled 4,726 women aged 50–74 years with ultrasound-detected gallstones from southern-central Chile, accounting for an estimated 36% of eligible women with gallstones in the study area. The median age was 59 years; 25% of the women were Amerindian (Mapuche), 60% were obese, 25% had diabetes, and 6% had cardiovascular disease. Participants will be followed for gallbladder dysplasia or cancer for 6 years. As of April 30, 2020, over 91% of those eligible completed the year 2 follow-up visit. Data being collected include epidemiologic and sociodemographic information, anthropometric measurements, blood pressure, and tooth counts. Biosamples being taken include baseline plasma, buffy coat, red blood cells, serum, blood clot from serum, and PAXgene whole blood (PreAnalytiX GmbH, Hombrechtikon, Switzerland). Complete gallbladder sampling is conducted for most participants undergoing cholecystectomy. The Chile BiLS cohort study will increase our understanding of GBC etiology and could identify potential risk stratification and early detection strategies in high-risk areas.

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The October 15, 1997 Punitaqui earthquake (Mw=7.1): a destructive event within the subducting Nazca plate in central Chile

Tectonophysics ◽

10.1016/s0040-1951(01)00213-x ◽

2002 ◽

Vol 345 (1-4) ◽

pp. 199-210 ◽

Cited By ~ 28

Author(s):

Mario Pardo ◽

Diana Comte ◽

Tony Monfret ◽

Rubén Boroschek ◽

Maximiliano Astroza

Keyword(s):

Nazca Plate ◽

Central Chile ◽

Destructive Event

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Lithospheric density structure of the Southern Central Andes and their forelands constrained by 3D gravity modelling

10.5194/egusphere-egu2020-3313 ◽

2020 ◽

Author(s):

Constanza Rodriguez Piceda ◽

Magdalena Scheck-Wenderoth ◽

Maria Laura Gómez Dacal ◽

Judith Bott ◽

Claudia Prezzi ◽

...

Keyword(s):

Central Andes ◽

Crustal Thickening ◽

Velocity Variation ◽

Mountain Range ◽

South American ◽

The South ◽

Complex Deformation ◽

Nazca Plate ◽

Southern Central ◽

The Relationship

<p>The Andean orogeny is a ~7000 km long N-S trending mountain range developed along the South American western margin. The formation of this mountain range is driven by the subduction of the oceanic Nazca plate beneath the continental South American plate, being the only known present-day case of subduction-type orogeny. In this tectonic setting, the intrinsic physical properties of the overriding plate govern the formation of zones of crustal strength and weakness and control the localization and the style of deformation. Furthermore, the dynamics of the subducting oceanic lithosphere is strongly conditioned by the properties of the continental counterpart. The southern segment of the Central Andes (29&#176;S-39&#176;S) is a suitable scenario to investigate the relationship between the two plates for several reasons. It is characterized by a complex deformation pattern with variations in horizontal shortening, crustal thickening and mean topographic elevation. In addition, the subduction angle changes at 33&#176;S-35&#176;S latitude from flat in the North to normal in the South. To gain insight into this geodynamic system, a detailed characterization of the lithosphere is needed. Therefore, we constructed a 3D model of the entire segment of the Southern Central Andes that is consistent with the available geological, seismic and gravity data in order to assess the geometry and density variation within the lithosphere. The derived configuration shows a spatial correlation between density domains and known tectonic features. It is also consistent with other independent observations such as S wave velocity variation and surface deformation. The generated structural model allows us to reach the first conclusions about the relationship between the characteristics of the overriding plate and the crustal deformation and dynamics of the subduction system. It is also useful to constrain thermomechanical experiments and therefore contributes to discussions about the crustal thermal and rheological fields within the region.</p>

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