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Copyright of Cuaternario y Geomorfología is the property of Cuaternario y Geomorfologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Comma shrimp, or cumaceans, are diverse benthic crustaceans, yet they are one of the groups with the poorest fossil record, hindering our understanding of the evolution of the group in deep time. Here, we describe a new species of fossil comma shrimp, Makrokylindrus itoi sp. nov., from the Plio‐Pleistocene of Japan. The singular fossil is exceptionally preserved, including details of the carapace, cuticle, and some appendages, and it represents the first known fossil of the family Diastylidae and only the fourth fossil crown group cumacean known to date. We suggest that the scarce and sparsely known fossil record of cumaceans likely reflects a lack of recognition due to their small size and unfamiliar anatomy, making fossil cumaceans easy to misidentify, be confused with crustacean larvae of unknown affinities, or be interpreted as fragments of other crustaceans (taxonomic bias), rather than a lack of fossilization potential (taphonomic bias). [ABSTRACT FROM AUTHOR]

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Los sistemas fluviales del Gran Chaco, América del Sur, constituyen un tipo de registro fluvial significativo para la cuenca de antepaís andina moderna. El mega-abanico fluvial del Salado-Juramento (MAFSJ), uno de los sistemas más grandes de Sudamérica, presenta características morfológicas y sedimentológicas distintivas. El MAFSJ, desarrollado por el desplazamiento del río Salado-Juramento hacia el sureste, presenta numerosos paleocauces en un patrón distributivo hacia el E desde su ápice en las Sierras Subandinas. En este trabajo se estudian atributos paleohidrológicos y la sedimentología de dos secciones ubicadas en paleocauces del área distal del MAFSJ, con el objetivo de generar información estratigráfica y sedimentológica de los rellenos de paleocauces que permita inferir su dinámica. De cada sucesión, se obtuvieron muestras de sedimentos para diferentes análisis: sedimentológicos (mineralogía y granulometría de sedimentos), y cronológicos. El cociente entre los atributos paleohidrológicos como la anchura del cauce-W y el espesor-T (W/T) presenta valores en un rango de 9,4 a 16,1 (media 12,75) para el área distal del MAFSJ. Estos valores indican cauces en cinta (ribbon channels). El relleno de los paleocauces estudiados está conformado por arenas muy finas a finas, con una mineralogía de arcillas y arenas consistente con los depósitos generados por el río Salado. Estos depósitos son cubiertos por niveles limo-arcillosos de carácter eólico. La geomorfología, los atributos paleohidrológicos, la sedimentología y los fechados numéricos, sugieren un paleodrenaje distributivo con cauces activos durante el MIS 3 (62–28 Ka AP). Se interpreta una fase de agradación fluvial durante el MIS 3, representada en gran parte por los rellenos de canales sinuosos que sugieren numerosos ríos divergentes en el área distal del MAFSJ. El sistema fluvial disminuye y domina la actividad eólica hacia el MIS 2, siendo cubierto por depósitos limo-arcillosos.

Here I reviewed the Pleistocene caviomorphs collected by Santiago Roth (collection from Catalog No. 5) and housed at the paleontological collection of the Paläontologisches Institut und Museum, Universität Zürich, Zurich (Switzerland). The fossils were found in Pleistocene strata from Buenos Aires and Santa Fé provinces (Argentina) during the late nineteenth century. The material includes craniomandibular remains assigned to Lagostomus maximus (Chinchilloidea: Chinchillidae), craniomandibular and postcranial (thoracic and sacral vertebra, left scapula, left femur, and right tibia) bones identified as Dolichotis sp. (Cavioidea: Caviidae), and a fragmented hemimandible and isolated tooth of Myocastor sp. (Octodontoidea: Echimyidae). Other rodent specimens from this collection (Ctenomys sp. and Cavia sp.) are possibly sub-recent materials. [ABSTRACT FROM AUTHOR]

One of the most abundant species of bivalves found on modern beaches and Quaternary deposits in the San Matías Gulf (Argentinian Patagonia, SW Atlantic Ocean) is Glycymeris longior. Its high abundance and broad geographical distribution turn G. longior into a target species for taphonomical studies. Here, we described the taphonomic signature registered on its shells from San Antonio Bay (San Matías Gulf, Río Negro). This study will contribute to future taphonomic comparisons in the SW Atlantic Ocean, as well as in other Quaternary deposits, and provide insight into the spatial variation of the taphonomic processes influenced by the environment. Glycymeris longior valves from the Holocene Punta Delgado deposits showed two taphonomic signatures whose shell assemblages were differentiated by fragmentation, rounding and cementation intensities. Shells from PD2018A and PD2018B (two sampling localities representing similar environments) were subject to continuous and low-energy water flow. Those remained in a low-intensity hydrodynamic sediment-water interface that would favor high shell cementation. On the other hand, shells from PD2016 were also subject to continuous but more energetic water flow. Those would remain in the taphonomic active zone for enough time to confer smooth edges and to be colonized by clionid sponges but not favorable enough for carbonate precipitation. The Punta Delgado site was interpreted as a protected area during the Holocene (last 4200 yrs.), similar to the modern one, but with differences in carbonate precipitation as the product of differences in water flow intensities. Finally, the high mechanical resistance of G. longior shells, together with its abundance and broad geographical distribution, turn this species into a suitable target taxon for further taphonomic and ecologic analyses and comparisons. [ABSTRACT FROM AUTHOR]

Copyright of Swiss Journal of Paleontology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

En el estado de Jalisco, localizado en el oeste de México, se encuentran yacimientos fósiles que abarcan desde el Cretácico inferior al Cuaternario. En este trabajo se presenta una lista sistemática del registro fósil de Jalisco, México, y se analiza la composición de su riqueza. Fue revisada la literatura global sobre el tema y consultadas las colecciones que poseen material fósil de la región. Se obtuvieron un total de 293 especies organizadas en tres reinos, seis phyla, 12 clases, 49 órdenes, 87 familias y 184 géneros. Un total de 67 especies (22,9%) son microfósiles y 226 (77,1%) son macrofósiles. Los microfósiles incluyen dos especies de foraminíferos (3%) y 65 de diatomeas (97%). Entre los macrofósiles, el grupo mayormente representado a nivel de clase es Mammalia con 110 especies (48,7%), seguido por Gastropoda con 37 (16,4%), Sauropsida con 35 (15,5%) y Teleostei con 30 (13,3%); las clases con menor representación son Isopoda, Scaphopoda, Amphibia y Magnoliopsida con un registro cada una. El periodo mejor representado es el Cuaternario, con 199 especies (67,9%), seguido por el Neógeno con 49 especies (16,7%) y, finalmente, el Cretácico con 45 (15,4%). Por localidad, la más rica es Chapala y Zacoalco para el Cuaternario, Tecolotlán para el Neógeno y Tamazula para el Cretácico. Las especies incluidas fueron registradas desde 1875 hasta el 2022.

Se proporciona una breve síntesis crítica en relación a estudios seleccionados de vertebrados continentales cuaternarios de Uruguay. su conocimiento se ha visto muy incrementado en diversidad del grupo dominante en el registro—los mamíferos—pero también en el de varios grupos de aves. El control temporal tiene en cuenta el esquema cronoestratigráfico propuesto para la región pampeana como herramienta de correlación bioestratigráfica y por un creciente número de edades numéricas (radiocarbono, luminiscencia ópticamente estimulada). Los sedimentos en el norte de Uruguay, Formación sopas, exhiben un rico y variado contenido fosilífero. se correlaciona con el Piso/Edad Lujanense y las edades numéricas de varios afloramientos se incluyen en el rango del Piso Marino Isotópico 3 (MIs 3). Los vertebrados sugieren diversos tipos de ambientes tales como cuerpos de agua dulce con importante desarrollo, floresta riparia, floresta semiabierta y áreas abiertas, no descartándose microambientes áridos y semiáridos. En el sur de Uruguay, se expresa la Formación Dolores, correlacionada con el Lujanense y con edades numéricas preponderantemente en el rango que incluye al Ultimo Máximo Glacial y Holoceno Temprano. Condiciones de aridez o semiaridez favorecidas por las condiciones frías del Ultimo máximo Glacial explican la presencia de algunos mamíferos que actualmente no viven en Uruguay. En barrancas costeras del Río de la Plata (sur-oeste de Uruguay), aflora la Formación Raigón, considerada de edad pliocena, pero con elementos que indican Pleistoceno Temprano y Medio (mamíferos y edades de luminiscencia ópticamente estimulada en facies terminales). Los mamíferos referidos al Pleistoceno sugieren contextos ambientales abiertos a semiabiertos tanto en base a sus adaptaciones dentarias como a estudios isotópicos. 2.11.0.0 2.11.0.0 2.11.0.0

The Rio Grande Hydrographic Basin (BRG) is located in the west of the state of Bahia, being characterized mainly by the altimetric contrast of cuestas and areas of smooth topography, in addition to being a transition area between the Cerrado and Caatinga biomes. This study aims to understand the landscape dynamics and transformation in the middle course of the BRG during the Quaternary, based on the investigation of surface covers of river terraces, inferring variations in vegetation and geomorphological processes associated with episodes of climatic pulsations. The methodology consisted of an integrated analysis involving phytoliths, granulometric analysis, and chronology through dating by Optically Stimulated Luminescence. No major changes were recorded in the vegetation cover for BRG in the Holocene, with a predominance of open vegetation with the occasional occurrence of forest remnants. However, it was possible to observe small variations that identified relatively drier periods in the Late Pleistocene and the Middle Holocene, greater humidity around 1,430 years BP, and humidity variations in the last 420 years. [ABSTRACT FROM AUTHOR]

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Copyright of Cuaternario y Geomorfología is the property of Cuaternario y Geomorfologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

La división del tiempo geológico más reciente está basada en eventos de carácter climático provocados por variaciones en la órbita y el eje de rotación de la Tierra a escala de miles de años. Sin embargo, la magnitud del cambio geológico causado por la humanidad a través de su joven tecnosfera está afectando negativamente a las otras esferas clásicas (atmósfera, hidrosfera, biosfera y geosfera) con su creciente demanda de materias primas y el reciclaje incompleto de sus residuos (por ejemplo, los gases de efecto invernadero) particularmente desde mediados del siglo XX. El uso masivo de combustibles fósiles para impulsar el enorme desarrollo industrial reciente ha convertido a la humanidad en el nuevo agente del cambio climático a escala planetaria. Algunas alteraciones asociadas con este nuevo régimen climático antropoceno son ya irreversibles y superan la variabilidad natural de los últimos miles de años.

Copyright of Cuaternario y Geomorfología is the property of Cuaternario y Geomorfologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Subsidence is a highly destructive natural hazard, which can be caused by both natural and anthropogenic causes. Its impacts include the creation of cracks and fissures, damages to buildings and infrastructures, a decrease in storage capacity of aquifer systems, and an increase of the susceptibility to flooding. In this study, Persistent Scattered Interferometry (PSI) has been used to process Synthetic Aperture Radar (SAR) images, for the detection and analysis of ground deformation and subsidence processes in the island of Mallorca. The study database is composed of 120 images captured by the Sentinel 1A and 1B satellites (between May 2016 and December 2019), from which we derived a map of accumulated displacement rates occurred during a 3 years and a half period. The results show important subsidence processes of up to 30 mm year-1 in large areas of the sedimentary basin of Palma, and of lesser magnitude (between 10 and 20 mm year-1) in locations of the Central Depression and in basins in the Serra de Tramuntana, such as the Torrent Major at Sóller and the Torrent de Gorg Blau. A significant relationship has also been observed between the thickness of the Quaternary sediment and the observed subsidence rates. The results highlight the high degree of geomorphological dynamism at very short time scales that characterizes Mallorca, and the vulnerability of certain urban areas, such as the city of Palma (? 400000 inhabitants), and agricultural areas, such as the Central Depression, facing the risk of subsidence and associated damages. [ABSTRACT FROM AUTHOR]

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.

Se describe un cabalgamiento cuaternario, que corta a una brecha sedimentaria que recubre la terraza de +5 m del río Ibor, en el extremo occidental de los Montes de Toledo. El sistema de cabalgamientos descrito ha condicionado la localización de abanicos aluviales fini-neógenos (“raña”), por lo que ha de considerarse como activo durante los últimos 9 Ma. El sismo asociado, superficial, se estima de una magnitud entre M 6-6.5. La rotura se localiza a menos de 20 km de la Central Nuclear de Almaraz (Cáceres).

El S de la provincia de Santa Fe y el NO de la provincia de Buenos Aires forman parte del Mar de Arena Pampeano (Sistema Eólico Pampeano), que ha sufrido una secuencia de episodios áridos y húmedos a lo largo de los últimos períodos del Pleistoceno. El paisaje actual resulta fundamentalmente de la influencia del período húmedo del Estadio Isotópico 3 (EIO 3; 64-36 ka) y de la actividad eólica durante un clima seco del Holoceno tardío (3,5-1,4 ka). La secuencia de eventos sedimentológicos y geomorfológicos fue la siguiente: Durante el período húmedo del EIO 3 se desarrolló una red fluvial de llanura, que actualmente forma la alta cuenca del Río Salado de Buenos Aires, labrada sobre sedimentos de la Fm Carcarañá. Posteriormente se depositó la Formación Teodelina, por sedimentación eólica. Esta tiene 10 a 12 m de espesor típico y unos 5 m en áreas sometidas a erosión; está compuesta por limo grueso arenoso y arena fina limosa, con modas principales entre 125-250 y 53-62 ?m, color 10YR 6/4 (marrón amarillento) y similares. La composición mineralógica de la fracción entre 53 y 62 ?m está dominada por vidrio volcánico, con feldespato, cuarzo y alteritas como accesorios. La redondez y esfericidad de los granos varían entre bajas y moderadas, con dos poblaciones. En el Pleistoceno final ocurrió un episodio eólico predominantemente erosivo, dominado por vientos del oeste que labraron cientos de depresiones de miles de metros de extensión. Ocurrió una sedimentación discontinua de loess arenoso de hasta 2 m de espesor con granulometría bimodal. El período Hypsithermal del Holoceno Medio (8,5-3,5 ka) estuvo caracterizado por un clima cálido y húmedo con régimen údico, que generó un suelo en los terrenos loéssicos y produjo el ascenso del nivel del agua en las lagunas y pantanos. El Holoceno tardío, entre 3,5 y 1,4 ka, estuvo dominado por un clima seco, con formación de campos de dunas denominadas aquí Formación San Gregorio. Está formada por arena muy fina a fina, suelta, masiva, color marrón amarillento, y compuesta por trizas vítreas, alteritas y feldespatos como componentes principales y cuarzo como componente secundario; los minerales pesados son de procedencia serrana. La época actual está caracterizada por un exceso de agua en el paisaje; el proceso sedimentológico más relevante es la movilización de grandes volúmenes de sales disueltas, particularmente cloruros y sulfatos.

Esta contribución brinda elementos sedimentológico-estratigráficos de los depósitos cuaternarios que aparecen en los acantilados y plataformas en la costa rioplatense del Departamento de Canelones, Uruguay. Se constató la presencia de depósitos regresivos e ingresivos cuaternarios, materializados por los sedimentos pleistocénicos transicionales de la Formación Chuy y los continentales de las formaciones Libertad y Dolores, así como los transicionales holocénicos de la Formación Villa Soriano. Se caracteriza litológicamente cada unidad, se interpretan los procesos actuantes y se hacen inferencias acerca de los ambientes de sedimentación involucrados.

The presence of fossil camelids in Tucumán, northwestern Argentina, has been recognized for many years but its relevance has not been fully evaluated so far. Here, we review previous mentions of fossil camelids for this province, present new material, and compare it with fossil and extant specimens of South American camelids, clarifying its taxonomic context and discussing its paleobiogeographic significance. For Tucumán we recognize Vicugna vicugna (Tafí del Valle Formation, late Pleistocene-early Holocene) and Palaeolama sp. (Tucumán Formation, late Pleistocene), mainly based on size and dental features. The current distribution of V. vicugna is restricted to the Central Andes, in the Puna and High Andean environments over 3200 m altitude; there is no mention, neither current nor historical, for Tucumán. Its presence at around 2200 m in the Tafí valley during the Quaternary indicates cooler and drier conditions than those currently established. The observations made in the context of this contribution allow us to establish that the species V. provicugna is a synonym of V. vicugna. In turn, we consider that the validity of the species Palaeolama hoffstetteri, only based on postcranial remains, should be properly evaluated in the future. [ABSTRACT FROM AUTHOR]

Paramylodon harlani was a large ground sloth recorded across North America, from Canada to Mexico. In Mexico, it is known from several late Pleistocene localities, but most of these records just mention the taxon in passing and few specimens have been described or illustrated. In this work, we describe a left tibia from the Valsequillo Basin, Puebla state. Its morphology and measurements allowed us to identify it as Paramylodon harlani, adding a new record for Mexico. In Mexico, P. harlani occurred mainly in the Trans-Mexican Volcanic Belt, central Mexico, with some records in the north and southeastern part of the country. Most localities are located between 1500 to 2000 m.a.s.l. Paleoenvironmental and paleoclimatic inference in some localities of Mexico where P. harlani occurred, showed heterogenous vegetation dominated by grasslands, and agree with the preferred habitat proposed for this species based on localities in the United States. This indicates that P. harlani could inhabit different environments, from grasslands to more wooded areas, and this adaptation allowed it to extend its range from the north to the southeast of Mexico. [ABSTRACT FROM AUTHOR]

Copyright of Spanish Journal of Palaeontology is the property of Socieadad Espanola de Paleontologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Boletin de Geologia is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El Museo de La Rinconada Legado arqueológico y paleontológico Francisco Sousa posee la peculiaridad de que sus colecciones proceden de hallazgos casuales que formaron parte de la didáctica de un instituto de secundaria durante las décadas de 1980 y 1990. Las piezas provienen de dos yacimientos de la localidad: las terrazas cuaternarias del Guadalquivir con útiles líticos y fauna fósil y del Cerro Macareno, un tell con evidencias desde el Calcolítico hasta el siglo i a.n.e. El Museo se inauguró en 2009 y en su proyecto y ejecución se contó con especialistas en cada una de los periodos y temáticas. En su nueva etapa como Museo municipal, la museografía potencia el carácter didáctico con el que se formaron sus fondos y trata de ser un dinamizador del patrimonio cultural del municipio proponiendo actividades para colectivos concretos.

El depósito paleontológico Las Llanadas es un manantial con sedimento rico en materia orgánica. Estudios del sitio a principios del siglo XX, dieron a conocer materiales fósiles de perezosos, cocodrilos, tortugas terrestres, y jutías. Dos especies de perezosos, Acratocnus antillensis y Neocnus gliriformis, fueron nuevas para la ciencia. En el presente trabajo se dan a conocer nuevos registros fósiles de anuros, un reptil y aves para el depósito: Peltophryne empusus, Osteopilus septentrionalis, Cyclura nubila, Tyto alba, Buteogallus borrasi y Boromys ofella. Huesos recientes de Lithobates catesbeianus y Capromys pilorides se encontraron entre los materiales, lo que indica que el depósito se mantiene activo en la recepción de especímenes. De un total de 2030 piezas solo 3% pudo ser identificado taxonómicamente, debido al alto nivel de fragmentación.

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Copyright of Boletín Geológico y Minero is the property of Instituto Tecnologico Geominero De Espana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Peatlands can be defined as a system that retains and preserves plant materials. For paleoenvironmental studies peatlands serve as databases of the climate and its states in the past, because they are formed by the accumulation of plant material in water-saturated environments, with low pH and mild temperatures, preventing or at least reducing decomposition by microorganisms. However, in Guarapuava region, studies focused on acquiring information about these environments are scarce. The aim of this study is to evaluate the distribution and patterns of the peatlands present in the topographic sheets of Guarapuava and Itapará (MI 2838-3 and 2838-4 MI, respectively) and relate them to the geomorphological features in order to find the reason for the high concentration of these environments in the region. The combination of morphostructural and morphoscultural elements acts as a strong influence on a peatland from its formation on towards its current process. In this study, the structural issue is crucial to the control of peaty environments. [ABSTRACT FROM AUTHOR]

The Gavà Neolithic Mining Complex (GNMC) located in Catalonia was devoted to the exploitation of green variscite used in the crafting of ornaments. Archaeological works in more than 100 mines indicated that this mining activity was carried out ~5800 years before present. GNMC constitutes (1) one of the earliest known examples of underground mining in Europe, (2) the earliest example of large-scale mining for ornamental use, and (C) the earliest of the application of complex geological and mining concepts. In the GNMC variscite is found as two distinct styles: (1) replacement of thin fluorapatite beds, which are interbedded with pyritic organic-rich black shales of Silurian age; and (2) veinlets crosscutting these materials. This set of geological materials is unconformably covered locally by Quaternary calcretes. Variscite formed as a result of Quaternary supergene processes, which oxidized the pyrite and produced acidic, oxidized solutions. The resulting fluids mobilized phosphate from apatite and leached Al and organic matter out of Silurian shales, thus leading to the precipitation of the Al-rich phosphates as vein infillings and strata-bound replacements after apatite. The formation of variscite is restricted to the extent of the oxidizing front, and variscite of both mineralization styles changes in color from yellowish green near the surface to deep green in depth. The study area contains two mining fields: Can Tintorer and Can Badosa-Les Ferreres range. The presence of abundant subvertical variscite veins in Can Tintorer allowed a complex development of galleries at different exploitation levels communicated by shafts and ramps, achieving 15 meters depth. The exploitation by Neolithic miners was by overhand and underhand stoping; they also used pillars and refilling of older exploitations to avoid the mine collapsing. These mines were opened in many cases by shafts that were dug directly through hard Quaternary calcretes, favoring the galleries' stability and revealing that miners understood that mineralization continues underneath the calcrete cover. Geological mapping reveals that exploitations in the Can Badosa-Les Ferreres area are simple, showing a single entrance to simple galleries or ramps attaining less than 5 m in depth and directly excavated on phosphate outcrops. Contrastingly, the mines in the Can Tintorer area have several entrances that consist of vertical shafts through a Quaternary cover, presenting an intricate geometry with many large and communicated galleries at different depths with a system of cameras and pillars. Although the development of both mining areas was essentially contemporaneous, the Can Badosa-Les Ferreres area can only be considered an exploration area. In addition, mining was carried out on minerals adjacent to variscite, not directly on variscite veins themselves, thus indicating that the miners were effectively using a wealth of geological knowledge that was previously acquired in the complex operations in the Can Tintorer mines. [ABSTRACT FROM AUTHOR]

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Se caracterizó el medio físico del ambiente, la fisiografía, régimen hidrológico y la historia geológica de la cubeta lagunar. La geología superficial está representada por seis unidades litoestratigráficas y dos pedoestratigráficas, que abarcan del Pleistoceno temprano al tardío y del Holoceno medio al presente. La más antigua, la Formación Ensenada, constituye el sustrato regional, sobre el cual se ubican cuatro unidades eólicas, las Formaciones Buenos Aires, La Postrera I, III y IV, los Geosuelos Sin Nombre y Puesto Berrondo y el Aluvio reciente. Los sedimentos colmatantes fueron obtenidos mediante perforaciones, reconociéndose siete unidades litoestratigráficas (cinco subácueas y dos subaéreas). Las subácueas corresponden a la Formación Luján, Miembros La Chumbiada, Lobos, Río Salado y Monte (Pleistoceno tardío al Holoceno tardío) y al Aluvio reciente. Los depósitos subaéreos a las Formaciones La Postrera I y IV del Pleistoceno tardío y Holoceno tardío-tardío, respectivamente. La excavación de la cubeta se inició en la etapa seca del ?Bonaerense?, la posterior alternancia climática: seco-húmedo facilitó la evolución. Las etapas secas se caracterizaron por deflación, generación de cubetas, sabkhas o lagos salados, precipitación de sales y acumulación de depósitos eólicos. En las húmedas predominó la sedimentación y la pedogénesis. De esta manera, el conjunto de depósitos posteriores a la Formación Ensenada está representado por cinco episodios de clima seco, que abarcan del Glacial Temprano a la Pequeña Edad de Hielo y cinco húmedos, cuyas acumulaciones límnicas conforman los cuatro miembros de la Formación Luján, el aluvio actual y los suelos sincrónicos S4, S1 y S0.

Tres lagunas integran el complejo, alojadas en cinco cubetas eólicas de diferente edad, que a nivel hídrico normal forman un ambiente único, donde se caracterizaron los aspectos fisiográficos, hidrológicos y geolimnológicos. En los afloramientos se reconocieron cinco unidades litoestratigráficas y tres pedoestratigráficas, que abarcan del Pleistoceno temprano/medio al tardío y del Pleistoceno final al presente. La Formación Ensenada, constituye el sustrato regional, sobre el cual se disponen cuatro unidades eólicas, las Formaciones Buenos Aires, La Postrera II, III, IV, los Geosuelos Sin Nombre, Puesto Callejón Viejo y Puesto Berrondo y, el aluvio reciente. En los lechos se registraron ocho unidades litoestratigráficas: cinco límnicas y tres eólicas. Las límnicas corresponden a los cuatro paleoambientes de la Formación Luján: Miembros La Chumbiada, Lobos, Río Salado y Monte, del Pleistoceno tardío al Holoceno tardío-tardío y el aluvio reciente; las unidades eólicas a las Formaciones La Postrera I y II del Pleistoceno tardío al Holoceno temprano y la IV del Holoceno tardío-tardío. El origen de las primeras cubetas se inició en la etapa seca del ?Bonaerense?, la posterior alternancia climática seco/húmedo generó las otras cubetas. Las etapas secas se caracterizaron por deflación, sabkhas, precipitación de sales y depósitos eólicos. En las húmedas predominó el aluvionamiento y la pedogénesis. Así, el conjunto de depósitos ?posensenadenses? está representado por cinco episodios secos (Glacial Temprano a la Pequeña Edad de Hielo) y cinco húmedos, con acumulaciones límnicas, desde el Miembro La Chumbiada al aluvio reciente y en los afloramientos los suelos sincrónicos S4, S2, S1 y S0.

En esta contribución se dan a conocer las técnicas empleadas para el procesamiento de testigos provenientes de turberas, con el fin de abordar estudios paleobrioflorísticos sobre la base de macrorrestos del Cuaternario. El procesamiento propuesto procura que los restos preservados sean dañados en la menor medida posible y realizar un conteo de los diferentes tipos de fragmentos de cada uno de los taxones/morfotipos con el objetivo de realizar estudios comparativos de la tafonomía y con ello enriquecer las interpretaciones paleoecológicas y la comprensión del desarrollo de la turbera. Se propone adoptar la digitalización de imágenes de las muestras, permitiendo comparar de forma simple los macrorrestos entre las alícuotas, entre las secciones del testigo y entre testigos de turberas de cualquier región, e incluso poder realizar determinaciones y cuantificaciones de parte de su material. Esta metodología ofrece una repetitividad necesaria para la comparación entre análisis de diferentes investigadores.

In this work, we have made a morphometric analysis of the Talacasto river basin (Central Precordillera), with emphasis on the La Burra River. The main structures with evidence of Quaternary tectonic activity are also described. The irregular morphology of the basin and the diversity of alluvial deposits found along the La Burra River allow the authors to infer that it is in an active tectonic environment with strong lithologic and structural controls. These main structures are located in the eastern piedmont of the Sierra de la Crucecita, and western piedmont of the sierra de Talacasto (30° 54'-31° S and 68° 47'-68° 55' W), about 70 km northwest of San Juan, in the Ullum Department. The faults located in both piedmonts are named from north to south: Las Crucecitas and Vertientes (in the eastern piedmont of the La Crucecita range) and the Western Talacasto fault system (in the western piedmont of the homonymous range). The faults affect alluvial deposits assigned to the Late Pleistocene and Holocene and show typical features of ongoing compressional Quaternary tectonic activity in the evaluated natural exposures. Faults exhibit the east-verging thin-skinned structural style typical of Central Precordillera. This deformation is related to the regional tectonics that affected and currently affects the Precordilleran region. Finally, the main geological structures were identified by the analysis and interpretation of gravimetric anomalies, employing data obtained from WGM12 (World Gravity Map 2012), which includes earth and satellite gravity data derived from the EGM2008 model. The gravimetric response of the crustal blocks that compose the study area shows a correlation with the outcropping crustal structure and could be associated to the different morphotectonic domains recognized in the region. [ABSTRACT FROM AUTHOR]

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Copyright of Cuaternario y Geomorfología is the property of Cuaternario y Geomorfologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During a paleontological excavation in Chalán Gorge (Chimborazo province), some fossil of micromammals where registered, including, five femurs, four humerus, eight pelvic bones and a fragment of maxilla of Cryptotis, with P4, M1 and M2 dental pieces. The fossils where collected in higher levels of cangagua formation of upper pleistocene. Nine measures of humerus and femurs fossil where obtained, and compared with the current Ecuadorian species. The results showed that the fossils belonged to Cryptotis niausa species, by the arcuate shape of the anterior segment of the mesopterygoid fossa, as well as similar dimensions in femurs, humerus and maxillary bone of C. niausa. In the upper pleistocene C. niausa was distributed 160 km south of its current distribution. This species is not currently distributed in the find locality, because the climate is warmer and drier than the wet Andean grasslands where C. niausa now lives. This finding demonstrates that Chalán Gorge had other vegetation in the late pleistocene during the second and third interglacial ages, similar to current Andean grasslands whose "pajonales" are above 3200 meters. Morphological analysis of fossil C. niausa shows individuals with bones structure and muscle more robust than the current populations. Some Cryptotis fossils individuals have wider dimensions of the femurs and humerus, associated with an increased ability to dig their burrows and channels on hard soils result of strong volcanic activity. [ABSTRACT FROM AUTHOR]

Copyright of Boletín de la Sociedad Argentina de Botánica is the property of Sociedad Argentina de Botanica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)