Introduction to Journal of South American Earth Sciences special issue on “Magmatism of southernmost South America”

complex magmatic history due to the occurrence of multiple large-scalegeological processes that include mantle plumes impingements, slabwindows opening, collisional episodes, normal and flat subductionevents, mantle transition zone-derived melts ascent, slab break-offevents, etc. (e.g., Mpodozis and Kay, 1992; Gorring et al., 1997; Rileyet al., 2001; Pankhurst et al., 2006; Kay et al., 2007; Ramos, 2008;Breitsprecher and Thorkerlson, 2009; Arag´on et al., 2013; Gianni et al.,2018; Navarrete et al., 2019; 2020; Iannelli et al., 2020). Although thismagmatic history began during the Neoproterozoic, the igneous activityof the last 300 Myr has been remarkably intense and voluminous,constituting one of the most distinctive geological features of this region.So much so that three Phanerozoic Large Igneous Provinces (LIPs) havebeen proposed (Kay et al., 1989; Pankhurst et al., 1998; Kay et al., 2007;Bastías-Mercado et al., 2020 ? this special issue). The first of them linkedto the Permian-Triassic subduction events (Choiyoi SLIP - Bastías-Mercado et al. this especial issue, and references therein; Oliveroset al., 2019), although there are also proposals that have suggested anorigin related to slab-breakoff episodes (e.g., Mpodozis and Kay, 1992;Pankhurst et al., 2006). The second would have been generated by theJurassic Karoo mantle plume impingement added to the paleo-pacificsubduction during the beginning of the Gondwana breakup (ChonAike SLIP - e.g., Kay et al., 1989; Pankhurst et al., 1998), whereas theorigin of the Oligocene-Miocene third province (Somuncura LIP ? Kayet al., 2007) is still under discussion. There are proposals that invoke amantle plume impingement (Kay et al., 2007), a lithospheric delaminationevent (Remesal et al., 2012), as well as the mantle transitionzone-derived melts ascent due to the Farallon slab stagnation (Navarreteet al., 2020), between others. In this special issue, most of the articles arelinked to these Permian-Triassic, Jurassic and mid-Cenozoic LIPs(Fig. 1), although multiple subduction-related magmatic events are alsoincluded, such as the formation of the Patagonian Batholith (e.g., Pankhurstet al., 1999) and the eruption of the volcanic products linked tothe magmatism of the Andean subduction zone (e.g., Rapela et al., 1984;1988).From the economic point of view, the socio-economic developmentof Chile and Argentina was marked by the magmatism of the southernmostSouth American region. In this sense, the Jurassic magmatismof Patagonia gave rise to numerous precious metals hydro-thermal largemineral deposits (e.g., Schalamuk et al., 1997; Echavarría et al., 2005;Guido and Campbell, 2011; Permuy Vidal et al., 2016; Tassara et al.,2017), whereas the Cenozoic intraplate magmatism of Patagoniafavored the hydrocarbon maturation in Patagonian oil and gas producingMesozoic basins (e.g., Rodriguez and Littke, 2001; Spacapan et al.,2018). Also, giant porphyry copper deposits were produced by theMeso-Cenozoic subduction-related magmatism in the Andean region (e.g., Mpodozis and Cornejo, 2012; Lee and Tang, 2020).Therefore, new contributions that improve the comprehension of thelarge magmatic episodes of southernmost South America are highlyrelevant for the general geological knowledge of this region, and theirinterest exceeds that of the academic geological community.Fil: Navarrete Granzotto, César Rodrigo. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zaffarana, Claudia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentin

Study of the pre-cretaceous deformation in the Gastre region, southern north-patagonian massif

El objetivo de esta tesis fue conocer el tipo y la edad de la deformación en la zona de Gastre, sector sur del Macizo Norpatagónico, donde se ha sugerido aflora la expresión de un sistema de fallas transcurrentes de escala intercontinental que habría controlado movimientos dextrales de gran magnitud entre el sur de Patagonia y la plataforma estable sudamericana. Se realizó un mapeo detallado de la estructura interna de las rocas intrusivas de la región (conocidas como Batolito de la Patagonia Central) combinando estudios petrográficos, microestructurales, de anisotropía de susceptibilidad magnética (ASM) y de magnetismo de rocas. Se propone que las mismas pueden dividirse en dos asociaciones de granitoides, donde la primera contiene enclaves máficos microgranulares y titanita como mineral accesorio y la segunda es intrusiva en la anterior y posterior al magmatismo máfico de la región. Se mantienen los nombres que les habían otorgado Rapela et al. (1992) (Superunidad Gastre para la unidad más antigua y Superunidad Lipetrén para la más joven), pero el criterio de clasificación de este trabajo es diferente. Asimismo, se caracterizó la mineralogía magnética de cada facies granítica. El mapeo de la estructura interna de las rocas permitió delinear la presencia de un angosto corredor estructuralsubvertical de foliaciones magmáticas de rumbo noroeste-sudeste con lineaciones magnéticas empinadas, someras e intermedias que es común a todas las litologías. Las áreas ubicadas afuera del lineamiento tienen fábrica magnética discordante. Los representantes del magma máfico en la región de Gastre adoptan la forma de enclaves, diques o pequeños stocks debido a la mezcla de magmas de diferente composición en diferentes estadíos de cristalización del magma félsico hospedante. Este proceso permitió también explicar algunas texturas de desequilibrio como oikocristales, xenocristales y cristales corroídos. Se describieron enjambres de enclaves monogénicos hasta ahora no mencionados en la literatura geológica de la zona. Los estudios de ASM en enclaves máficos y su roca hospedante indican que los enclaves constituyen marcadores pasivos de la deformación magmática. Se encontraron diques máficos con fábrica magnética anómala debido a la sobreimposición de deformación tectónica. Se describieron afloramientos de rocas de basamento que registran una foliación metamórfica previa al desarrollo de la foliación tectónica NO-SE subvertical. La deformación tectónica se concentra en afloramientos pequeños dispersos entre granitoides tectónicamente indeformados, y los planos de foliación tectónica y la lineación de estiramiento son altamente heterogéneos entre sí y con respecto al corredor. Se obtuvo un polo paleomagnético a partir de las rocas volcánicas jurásicas de la zona cuya ubicación coincide con la de otros polos de áreas estables de Sudamérica de similar edad, así que se descarta la posibilidad de grandes rotaciones tectónicas en el período Jurásico Temprano-reciente. Se concluye que el Sistema de Fallas de Gastre fue una estructura que controló el emplazamiento diacrónico de algunos cuerpos ígneos tabulares pertenecientes al Batolito de la Patagonia Central, y que también canalizó deformación subsólida post-emplazamiento, pero no fue una zona de movimientos transcurrentes de gran magnitud. Debe recurrirse a otros modelos para reconstruir la paleogeografía jurásica de Gondwana Occidental.The aim of this work was to explain the history of deformation in the Gastre Fault System, Central Patagonia. Some authors had proposed that this was an intercontinental strike-slip system that accommodated important dextral displacements in the Jurassic between the patagonian and the stable South American blocks. A detailed mapping of the internal structure of the granitoids of the region (the Central Patagonian Batholith) was performed combining petrographic, microstructural, anisotropy of the magnetic susceptibility (AMS) and rock magnetic studies. These granitoids can be divided in two groups: an older set of granitoids, which has mafic microgranular enclaves and titanite as an accessory mineral, and an intrusive set of granitoids which postdates the mafic magmatism of the region. The intrusive groups are still called Gastre Superunit and Lipetrén Superunit, because the names formerly given by Rapela et al. (1992) are kept, although the classification scheme of this work is different. The magnetic mineralogy of each granitoid facies was also characterized. The mapping of the internal structure of the magmatic rocks showed the existence of a narrow structural corridor of subvertical NW-SE foliation planes shared by all granitoid facies. Magnetic lineations inside this corridor are of shallow, subvertical and intermediate inclination. The areas outside the lineament have discordant magnetic fabric. The mafic magma in the Gastre region is represented by enclaves, dikes and small stocks; the different morphologies arise from magma mingling at different crystallization stages of the felsic magma host. Magma mingling also explains some disequilibrium textures such as oikocrysts, xenocrysts and crystal corrosion. Undescribed spectacular monogenic enclave swarms were found and described. AMS studies of mafic microgranular enclaves and their host rock showed that enclaves constitute passive markers of magmatic deformation. Anomalous magnetic fabric that can be ascribed to tectonic deformation was found in mafic dikes and felsic veins. Small basement outcrops having metamorphic foliation prior to the development of the NW-SE tectonic foliation were described. Tectonic deformation is constrained to small outcrops scattered among tectonically undeformed granitoids. Foliation planes and stretching lineations are highly heterogeneous. A paleomagnetic pole was calculated from the overlying Jurassic rocks of the region and its position coincides with other paleomagnetic poles of similar age coming from stable areas of South America. Major tectonic rotations did not occur from the Lower Jurassic to recent (only small counterclockwise rotations would be expected). In conclusion, the Gastre Fault System was a structure which controlled the diachronic emplacement of some tabular igneous bodies of the Central Patagonian Batholith, and which also channeled some subsolid post-emplacement deformation, but it was not a major transcurrent fault zone and consequently other tectonic models need to be considered when reconstructing the Jurassic paleogeography of Western Gondwana.Fil: Zaffarana, Claudia Beatriz. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

"Nah am Grabe ward mir's heller" : Das Motiv des Freitods in Goethes Werther und bei seinen dramatischen Nachfolgern

Die vorliegende Dissertation beschreibt das Phänomen der Selbsttötung in Goethes „Werther“ und bei seinen dramatischen Nachfolgern. Im Vordergrund steht die ausführliche Analyse der suizidalen Entwicklungen Werthers, Klingers Helden aus „Otto“, dem „Leidenden Weib“, der „Neuen Arria“ und den „Zwillingen“, Maler Müllers „Golo und Genoveva“, Wagners „Reue nach der That“ sowie Leisewitzens „Julius von Tarent“. Die Untersuchung kommt zu dem Ergebnis, dass Goethe den Freitod beziehungsweise die destruktive Veranlagung und Entfaltung seiner Titelfigur nach einem bestimmten Modell konzipiert hat: Werther durchläuft einen „innerseelischen Zerstörungsprozess“, der sich aus zehn Phasen zusammensetzt und der unweigerlich mit dem Suizid endet. Der Vergleich mit Werthers literarischen Leidensgenossen offenbart, dass sie sich alle sehr ähneln: Die Autoren haben ihre Figuren sämtlich rebellisch und sozialkritisch konzipiert. Alle Protagonisten sind durch ihre bis zum Rausch gesteigerte Gefühlsintensität melancholische Einzelgänger, deren tödliche Schwäche von Beginn an sichtbar wird. Nahezu exhibitionistisch stellen sie ihren Schmerz zur Schau, kurz vor dem finalen Schritt bemächtigt sich die Todesbegeisterung aller Helden. Ihre emotionale und körperliche Selbstaufgabe ist am Ende dieses Prozesses daher keine Verzweiflungstat, sondern eine überlegte und freiwillige Vernichtung des eigenen Lebens. Mit dem Suizid berufen sie sich ein letztes Mal auf ihr Selbstbestimmungsrecht. Sie nehmen sich das Recht und die Freiheit, selbst über ihr Leben zu verfügen und suchen im Tod die Freiheit

Tectonic segmentation across Patagonia controlled by the subduction of oceanic fracture zones

Fil: Orts, Darío Leandro. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología. Río Negro, ArgentinaFil: Orts, Darío Leandro. Consejo Nacional de Investigaciones científicas y Tecnológicas (CONICET). Buenos Aires, Argentina.Fil: Álvarez, Orlando. Universidad Nacional de San Juan. CONICET. Instituto Geofísico y Sismológico Ing. Volponi. San Juan, Argentina.Fil: Zaffarana, Claudia Beatriz. Universidad Nacional de Río Negro, Instituto de Investigación en Paleobiología y Geología. Río Negro, ArgentinaFil: Zaffarana, Claudia Beatriz. Consejo Nacional de Investigaciones científicas y Tecnológicas (CONICET). Buenos Aires, Argentina.Fil: Gimenez, Mario. Universidad Nacional de San Juan. CONICET. Instituto Geofísico y Sismológico Ing. Volponi. San Juan, Argentina.Fil: Folguera, Andrés. Universidad de Buenos Aires–CONICET. Instituto de Estudios Andinos “Don Pablo Groeber”. Buenos Aires, ArgentinaFil: Ruiz, Francisco. Universidad Nacional de San Juan. CONICET. Instituto Geofísico y Sismológico Ing. Volponi. San Juan, Argentina.A set of fracture zones left by transform faults segmenting the active Chile Ridge that separates the Nazca and Antarctica Plates has been subducting beneath western Patagonia in the last 18 Myr. The subduction direction of these fractures zones has remained almost unaltered during this time lapse since these intersected the Chilean trench. In this context, the analyzed Patagonian sector is associated with the subduction of a highly buoyant oceanic floor due to its relatively young age that contrasts with the ocean floor bathymetry to the north where oceanic crust gets progressively older up to the Eocene and consequently isostatically subsides. Short-term elastic deformational patterns associated with the earthquake cycle have been linked to this segmentation imposed by subducting fracture zones in previous works. Similarly, this work explores the relationship between long-term topography, seismicity, gravity, and magnetic anomalies as a proxy for upper crustal structure, deformation, exhumation, and consequently surface geology segmented nature associated with this pattern of oceanic fracture zones. Through these analyses, we have identified a series of ENE structural trends or lineaments across the continental crust that could be directly related to the segmented mechanical behavior of the plate interface and enhanced by particular climatic and tectonic history of the Patagonian region. These evidences could contribute to the understanding of how fracture zones can control, to a certain extent, the segmented nature of the upper plate in a subduction setting.

Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: implications for pluton emplacement and the Gastre fault system

The Central Patagonian batholith (CPB) comprises two Late Triassic calcalkaline plutonic suites (the Gastre superunit of 221 ± 2 Ma and the Lipetrén superunit of 215 ± 1 Ma) which have been interpreted as a record of major dextral motion along the transcontinental NW-SE-striking subvertical Gastre fault system in Jurassic times. We performed a detailed study of the internal structure of the CPB through structural and anisotropy of magnetic susceptibility (AMS) techniques. The Gastre superunit reveals a very consistent pattern of NW-SE-striking steeply dipping magmatic foliations. Tectonic fabrics within the CPB are scarce and generally parallel to the magmatic fabrics. The magmatic and solid-state lineations within the CPB are steeply, intermediately, or shallowly plunging. The combination of flattened magmatic and solid-state fabrics with subvertical orientations and with steep to shallow lineations, together with the kinematic indicators in two mylonite belts with suspected CPB protoliths, suggests that the Gastre superunit was emplaced within a sinistral transpressive regime. The shallower stocks of the Lipetrén superunit are more isotropic and have magmatic fabrics associated with magma chamber dynamics. The deformation of the CPB is coaxial with the late Paleozoic deformation in the hosting Calcatapul Formation. The late Paleozoic deformation in the North Patagonian Massif generated widespread NW-SE subvertical fractures which could have aided the emplacement of the CPB. The internal structure of the CPB does not support a model of dextral strike-slip movements on major Jurassic faults.Contiene material suplementario.Facultad de Ciencias Exacta

Internal structure of the Late Triassic Central Patagonian batholith at Gastre, southern Argentina: implications for pluton emplacement and the Gastre fault system

The Central Patagonian batholith (CPB) comprises two Late Triassic calcalkaline plutonic suites (the Gastre superunit of 221 ± 2 Ma and the Lipetrén superunit of 215 ± 1 Ma) which have been interpreted as a record of major dextral motion along the transcontinental NW-SE-striking subvertical Gastre fault system in Jurassic times. We performed a detailed study of the internal structure of the CPB through structural and anisotropy of magnetic susceptibility (AMS) techniques. The Gastre superunit reveals a very consistent pattern of NW-SE-striking steeply dipping magmatic foliations. Tectonic fabrics within the CPB are scarce and generally parallel to the magmatic fabrics. The magmatic and solid-state lineations within the CPB are steeply, intermediately, or shallowly plunging. The combination of flattened magmatic and solid-state fabrics with subvertical orientations and with steep to shallow lineations, together with the kinematic indicators in two mylonite belts with suspected CPB protoliths, suggests that the Gastre superunit was emplaced within a sinistral transpressive regime. The shallower stocks of the Lipetrén superunit are more isotropic and have magmatic fabrics associated with magma chamber dynamics. The deformation of the CPB is coaxial with the late Paleozoic deformation in the hosting Calcatapul Formation. The late Paleozoic deformation in the North Patagonian Massif generated widespread NW-SE subvertical fractures which could have aided the emplacement of the CPB. The internal structure of the CPB does not support a model of dextral strike-slip movements on major Jurassic faults.Contiene material suplementario.Facultad de Ciencias Exacta

Tectonic rotations in central Chile: New insights on the southern limit of the Maipo Orocline

The Maipo Transition Zone or Maipo Orocline represents a change in strike of the topography from N–S between 30° and 33°S to an NNE-SSW trend to the south. The southern flank of the Maipo Orocline can be traced along strike to around 38°S. There the Andean margin exposes another orogen bending, the Arauco Orocline. Although the tectonic evolution of this segment of the Andean chain is relatively well constrained, the limit between both oroclines is unclear. In this paper, we show the results of a paleomagnetic study carried out in three plutons of Upper Triassic age located along the Coastal Cordillera of central Chile between 35° and 37°S. Paleomagnetic analysis from Constitución Granite and Cobquecura Pluton shows an increase of clockwise vertical-axis rotations from north to south consistent with previous data, whereas results obtained in the Hualpén Stock, located to the south, shows minors counter-clockwise rotations. This change in the rotation pattern would reflect the Maipo and Arauco Oroclines limit. The similar amounts of tectonic rotations recorded by Mesozoic and Miocene rocks indicate that the whole area behaved as a single block and constrains the maximum possible age for the occurrence of tectonic rotations to Miocene.Fil: Puigdomenech Negre, Carla Gimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Alarcón, S.. Universidad Andrés Bello; ChileFil: Ruiz González, Víctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Rossel, P.. Universidad Andrés Bello; ChileFil: Orts, Darío Leandro. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zaffarana, Claudia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentin

Using alternative or direct anthropometric measurements to assess risk for malnutrition in nursing homes.

AbstractObjectiveThe aim of this study was to use the Malnutrition Universal Screening Tool (MUST) to assess the applicability of alternative versus direct anthropometric measurements for evaluating the risk for malnutrition in older individuals living in nursing homes (NHs).MethodsWe conducted a cross-sectional survey in 67 NHs in Tuscany, Italy. We measured the weight, standing height (SH), knee height (KH), ulna length (UL), and middle-upper-arm circumference of 641 NH residents. Correlations between the different methods for calculating body mass index (BMI; using direct or alternative measurements) were evaluated by the intraclass correlation coefficient and the Bland-Altman method; agreement in the allocation of participants to the same risk category was assessed by squared weighted kappa statistic and indicators of internal relative validity.ResultsThe intraclass correlation coefficient for BMI calculated using KH was 0.839 (0.815–0.861), whereas those calculated by UL were 0.890 (0.872–0.905). The limits of agreement were ±6.13 kg/m2 using KH and ±4.66 kg/m2 using UL. For BMI calculated using SH, 79.9% of the patients were at low risk, 8.1% at medium risk, and 12.2% at high risk for malnutrition. The agreement between this classification and that obtained using BMI calculated by alternative measurements was “fair-good.”ConclusionWhen it is not possible to determine risk category by using SH, we suggest using the alternative measurements (primarily UL, due to its highest sensitivity) to predict the height and to compare these evaluations with those obtained by using middle-upper-arm-circumference to predict the BMI

A cross-sectional survey to investigate the quality of care in Tuscan (Italy) nursing homes: the structural, process and outcome indicators of nutritional care

BACKGROUND: Previous studies have investigated process and structure indicators of nutritional care as well as their use in nursing homes (NHs), but the relative weight of these indicators in predicting the risk of malnutrition remains unclear. Aims of the present study are to describe the quality indicators of nutritional care in older residents in a sample of NHs in Tuscany, Italy, and to evaluate the predictors of protein-energy malnutrition risk. METHODS: A cross-sectional survey was conducted in 67 NHs. Information was collected to evaluate quality indicators of nutritional care and the individual risk factors for malnutrition, which was assessed using the Malnutrition Universal Screening Tool. A multilevel model was used to analyse the association between risk and predictors. RESULTS: Out of 2395 participants, 23.7 % were at high, 11 % at medium, and 65.3 % at low risk for malnutrition. Forty-two percent of the NHs had only a personal scale to weigh residents; 88 % did not routinely use a screening test/tool for malnutrition; 60 % used some standardized approach for weight measurement; 43 % did not assess the severity of dysphagia; 12 % were not staffed with dietitians. Patients living in NHs where a chair or platform scale was available had a significantly lower risk of malnutrition (OR = 0.73; 95 % CI = 0.56–0.94). None of the other structural or process quality indicators showed a statistically significant association with malnutrition risk. CONCLUSIONS: Of all the process and structural indicators considered, only the absence of an adequate scale to weigh residents predicted the risk of malnutrition, after adjusting for case mix. These findings prompt the conduction of further investigations on the effectiveness of structural and process indicators that are used to describe quality of nutritional care in NHs

Prevalencia de obesidad en una cohorte de pacientes con artritis psoriásica y factores asociados

Se ha observado elevada prevalencia de obesidad en pacientes con Artritis Psoriásica (APs). También, ha sido descripta asociación con una mayor severidad de psoriasis cutánea, pero su relación con la severidad de la APs ha sido menos estudiada. Objetivos: Evaluar la prevalencia de obesidad en una cohorte de pacientes con APs y su asociación con características sociodemográficas y clínicas de la enfermedad