Un Maar en las cercanías de Río Gallegos, Santa Cruz.

No abstract availabl

Estructura y mineralización en la Cordillera Patagónica

El segmento de la Cordillera Patagónica situado entre paralelos de 43° y 44° de latitud sur, constituye unárea de difícil acceso, con alturas que alcanzan los 2.300metros s.n.m. La densa vegetación -plena selva valdiviana-constituye otro obstáculo para el levantamiento geológicoregular. La sucesión estratigráfica de la región comienza posiblementecon las rocas del denominado Complejo Marino-Volcánico Indiferenciado, aflorante en el sector chileno de lacomarca, al cual se refiere una sola cita bibliográfica. Probablemente, estas rocas estén vinculadas a la Formación Lago La Plata, cuyos asomos están situados en el sector oriental,constituida por una sucesión volcanoclástica, decomposición predominantemente mesosilícea. Sobre ella seapoyan las sedimentitas marinas con intercalaciones volcánicasdel Grupo Coyhaique. Continúa una potente secuenciavolcanoclástica denominada Formación Cordón de las Tobas. Esta sucesión, que abarca el lapso Jurásico medio-Neocomiano,está intruida por las rocas graníticas del Batolito Andino,de composición predominantemente mesosilícea, con algunoscuerpos básicos subordinados. Las unidades cenozoicasde la región, son de escaso desarrollo areal, no mediarelación de campo entre ellas y su conocimiento es, en general,aún incompleto. El Eoceno está representado por la Formación La Cascada, integrada por ruditas y areniscasfosilíferas y que aflora en el sector central de la comarca. Durante el Oligoceno-Mioceno inferior, se desarrollaronen los contrafuertes orientales los depósitos continentales -ruditas y areniscas- de la Formación Ñorquinco. Enel límite Terciario-Cuartario se depositaron en el sectorcentro-occidental los Estratos de la Silla del Diablo,constituidos por sedimentitas continentales interestratificadascon vulcanitas. Durante el Cuartario hubo un intensovulcanismo en el sector occidental. En el Pleistoceno, lasglaciaciones dejaron importantes depósitos morénicos y glacifluviales. La estructura de la comarca, una serie de bloques falladosy volcados suavemente al naciente, está controladapor una serie de megafracturas. El estudio de los rasgosmorfoestructurales de imágenes satelitarias de la región,mostró una concordancia con los datos de campo. Los rumbospredominates corresponden a los cuadrantes Norte, Noroestey Este-suroeste y subordinados al Noreste. Una serie de manifestaciones de minerales de cobre,plomo, oro y molibdeno --diseminados y vetiformes-- estánemplazados en las secuencias volcano-clásticas jurásico-cretácicasy vinculadas al plutonismo mesozoico. Estasmineralizaciones estarian relacionadas a fracturas desarrolladasdurante el ciclo Patagonídico y reactivadas durante la orogenia Andica. Hay una marcada relación entrelos sistemas de fracturas noreste y este-sureste y la distribución de las manifestaciones minerales. Del mismo modo, hay una coincidencia con las zonas de mayor fracturación. Estas relaciones permiten señalar la presencia depotenciales áreas de mineralización en la cordillera Patagónica.Fil: Haller, Miguel J.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Understanding the evolution of maar craters

No abstract availabl

Late Quaternary sediment dynamics in the Gulf of San Jorge (Patagonia): A multi-proxy approach

The Patagonian coast of the Argentine Continental Shelf (ACS) extends along a relatively stable continental margin at the intersection of the present Antarctic ice sheet and the relic of the former Patagonian ice sheet. Since the Last Glacial Maximum (LGM), the sedimentation on the Atlantic shore of Patagonia has changed significantly due to the marine transgression at first, but also because of the decrease of glacial meltwater flows to the Atlantic derived from the Northern Patagonian Ice Field (NPIF) 1. The Patagonian shore of the ACS thus provides a preferential area to study the impact of post-LGM sea-level fluctuations and ice extent variations on sedimentary processes. In this context, we investigate Late Quaternary marine sediments from the Gulf of San Jorge (GSJ) to characterize the sedimentation in the central part of the Argentine Patagonian margin since the LGM. The GSJ is a semicircular basin forming an encroachment of the South Atlantic Ocean between latitudes 45°and 47° S, in which the sedimentation is presently controlled by oceanic and aeolian inputs, and inner Gulf erosion/runoffs 2. The post-glacial evolution of the sedimentary environments as well as the climatic and oceanographic variations were reconstructed using paleomagnetic parameters, major and trace elements, bulk and clay mineralogy, multi-sensor core logging and radiocarbon dating, coupled with the interpretation of seismic lines. The ~2000 km of geophysical data (subbottom profiler and sparker) and the 15 sediment cores (gravity and piston cores) used in this study were collected on board the R/V Coriolis II during the MARGES (Marine Geology of the Gulf of San Jorge) expedition in the GSJ and continental shelf in 2014. The base of the lithostratigraphy identified in the Gulf is characterized by a decametric-thick highly-indurated sediment layer corresponding to a high amplitude and laterally continuous seismic reflection extending through the entire GSJ. This facies most likely reflects both the sea-level lowstand and absence of seawater in this part of the GSJ during the LGM. Furthermore, our results illustrate two main sedimentary sequences: a Late glacial sequence with relatively high sedimentation rates (>65 cm/kyr) and an Early Holocene to present sequence with lower sedimentation rates (<25 cm/kyr). The former is associated with the marine transgression (e.g., tidal flat environment) coupled with the influence of the NPIF drainage system prior to 13 700 cal yr BP. The latter corresponds to the end of the marine transgression with a progressive decrease of energy to reach contemporary conditions between 10 250 and 7400 cal yr BP.Fil: Desiage, P. A.. Institut des Sciences de la Mer de Rimouski; CanadáFil: Onge, G.. Institut des Sciences de la Mer de Rimouski; CanadáFil: Montero Serrano, J. C.. Institut des Sciences de la Mer de Rimouski; CanadáFil: Haller, Miguel Jorge F.. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina20th International Sedimentological CongressQuebecCanadáInternational Association of SedimentogistsSociety for Sedimentary Geolog

Morfometría de los conos de escoria de la Provincia Volcánica de Payenia, Argentina.

El análisis morfométrico de los conos de escoria permite evaluar los procesos erosivos que los afectan e inferir la historia eruptiva de una región. Utilizando DEMs TanDEM-X de 12 m de resolución se midieron los parámetros morfológicos de 157 conos de escoria que integran diferentes campos volcánicos de la Provincia Volcánica de Payenia. Se calculó una tasa de erosión de 9,4° por Ma, es decir que la pendiente de los conos disminuye 9,4°cada millón de años. Esta tasa es similar a la obtenida en otros campos volcánicos monogenéticos con similares características climáticas. Con esta tasa se calcularon edades morfológicas para todos los conos estudiados, las que abarcan un rango entre 0,3 y 2,2 Ma

Late Pleistocene and Holocene transgression inferred from the sediments of the Gulf of San Jorge, central Patagonia, Argentina

This study presents the first detailed description of the upper sedimentary succession of the late Pleistocene and Holocene deposits in the Gulf of San Jorge (Patagonia) based on several hundred kilometers of high-resolution seismic (sparker) profiles and numerous sediment cores. High-resolution seismic stratigraphy confirms the existence of a paleo-fluvial network formed during sea-level lowstands and buried by central basin estuarine deposits during the last marine transgression. Analyses of lithostratigraphy and radiocarbon ages indicate the onset of subtidal sedimentation at ~14 cal ka bp. Before the onset of subtidal conditions, the first steps of marine incursion seem to have led to the development of lagoonal/wind–tidal flat environments, advocating for a sea-level stillstand. An abrupt increase in the log(Ti/Ca) ratio in a distinct multi-centimeter-thick layer and the identification of a wave-ravinement surface suggest rapid sea-level rise in the gulf prior to ~14 cal ka bp, consistent with Meltwater Pulse 1A. Overall, this study highlights the significant impact of sea-level rise on sedimentation in the gulf from the onset of marine incursions to the mid-Holocene, as well as the reduced contribution, as currently observed, of riverine inputs due to the progressive diminution and withdrawal of glacial drainage starting before the Holocene. -- Keywords : elemental geochemistry ; incised valleys ; MWP-1A ; Patagonia ; postglacial sea-level changes

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

Phosphofructo-1-Kinase Deficiency Leads to a Severe Cardiac and Hematological Disorder in Addition to Skeletal Muscle Glycogenosis

Mutations in the gene for muscle phosphofructo-1-kinase (PFKM), a key regulatory enzyme of glycolysis, cause Type VII glycogen storage disease (GSDVII). Clinical manifestations of the disease span from the severe infantile form, leading to death during childhood, to the classical form, which presents mainly with exercise intolerance. PFKM deficiency is considered as a skeletal muscle glycogenosis, but the relative contribution of altered glucose metabolism in other tissues to the pathogenesis of the disease is not fully understood. To elucidate this issue, we have generated mice deficient for PFKM (Pfkm−/−). Here, we show that Pfkm−/− mice had high lethality around weaning and reduced lifespan, because of the metabolic alterations. In skeletal muscle, including respiratory muscles, the lack of PFK activity blocked glycolysis and resulted in considerable glycogen storage and low ATP content. Although erythrocytes of Pfkm−/− mice preserved 50% of PFK activity, they showed strong reduction of 2,3-biphosphoglycerate concentrations and hemolysis, which was associated with compensatory reticulocytosis and splenomegaly. As a consequence of these haematological alterations, and of reduced PFK activity in the heart, Pfkm−/− mice developed cardiac hypertrophy with age. Taken together, these alterations resulted in muscle hypoxia and hypervascularization, impaired oxidative metabolism, fiber necrosis, and exercise intolerance. These results indicate that, in GSDVII, marked alterations in muscle bioenergetics and erythrocyte metabolism interact to produce a complex systemic disorder. Therefore, GSDVII is not simply a muscle glycogenosis, and Pfkm−/− mice constitute a unique model of GSDVII which may be useful for the design and assessment of new therapies

To Help or Not to Help? Prosocial Behavior, Its Association With Well-Being, and Predictors of Prosocial Behavior During the Coronavirus Disease Pandemic

Funding Information: This work was supported by grants from the Swiss National Science Foundation awarded to ATG (PP00P1_ 163716/1 and PP00P1_190082). The funder provided support in the form of salaries for authors (EH and ATG) but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. Publisher Copyright: Copyright © 2022 Haller, Lubenko, Presti, Squatrito, Constantinou, Nicolaou, Papacostas, Aydın, Chong, Chien, Cheng, Ruiz, García-Martín, Obando-Posada, Segura-Vargas, Vasiliou, McHugh, Höfer, Baban, Dias Neto, da Silva, Monestès, Alvarez-Galvez, Paez-Blarrina, Montesinos, Valdivia-Salas, Ori, Kleszcz, Lappalainen, Ivanović, Gosar, Dionne, Merwin, Karekla, Kassianos and Gloster.The coronavirus disease (COVID-19) pandemic fundamentally disrupted humans’ social life and behavior. Public health measures may have inadvertently impacted how people care for each other. This study investigated prosocial behavior, its association well-being, and predictors of prosocial behavior during the first COVID-19 pandemic lockdown and sought to understand whether region-specific differences exist. Participants (N = 9,496) from eight regions clustering multiple countries around the world responded to a cross-sectional online-survey investigating the psychological consequences of the first upsurge of lockdowns in spring 2020. Prosocial behavior was reported to occur frequently. Multiple regression analyses showed that prosocial behavior was associated with better well-being consistently across regions. With regard to predictors of prosocial behavior, high levels of perceived social support were most strongly associated with prosocial behavior, followed by high levels of perceived stress, positive affect and psychological flexibility. Sociodemographic and psychosocial predictors of prosocial behavior were similar across regions.publishersversionPeer reviewe