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The first chitinozoan assemblages from the middle–late Silurian and Early Devonian strata of the Copo Formation in the Rivadavia borehole, Salta province, Argentina, are described. The studied interval was considered deposited in an offshore shelf environment and composed of micaceous dark-gray shales with pyrrhotite intercalated with fine-grained quartzitic sandstones. Thirty-nine core samples were processed, and 11 yielded chitinozoan specimens that allowed taxonomic classification. Seven genera and 13 species were identified; four were retained in open nomenclature, and the new species Cingulochitina chacoparanaense sp. nov. is erected. Three chitinozoan assemblages were recognized: Chitinozoan assemblage I of a middle–late Silurian age, Chitinozoan assemblage II of a late Silurian age, and Chitinozoan assemblage III of a late Lochkovian (Early Devonian) age. A new upper Lochkovian chitinozoan concurrent range biozone of Cingulochitina striata and Ancyrochitina asterigis is proposed for northwestern Argentina. The chitinozoan assemblages support Gondwanan affinities from the middle Silurian to Early Devonian of the Chacoparaná Basin. Se han descripto las primeras asociaciones de quitinozoos del Silúrico medio–tardío y Devónico Temprano de la Formación Copo en el pozo Rivadavia, provincia de Salta, Argentina. El intervalo estudiado fue depositado en un ambiente marino de plataforma y está compuesto por lutitas micáceas de color gris oscuro con pirrotina e intercalaciones de areniscas cuarcíticas de grano fino. Se procesaron 39 muestras de testigo corona, de las cuales en 11 se obtuvieron especímenes de quitinozoos que permitieron el estudio taxonómico. Se identificaron siete géneros y 13 especies, cuatro de ellas en nomenclatura abierta y se creó la nueva especie Cingulochitina chacoparanaense sp. nov. Se reconocieron tres asociaciones de quitinozoos: Asociación de quitinozoos I del Silúrico medio–tardío, Asociación de quitinozoos II del Silúrico tardío, Asociación de quitinozoos III del Lochkoviano tardío (Devónico Temprano). Se propone la nueva biozona de quitinozoos, de extensión coincidente, Cingulochitina striata y Ancyrochitina asterigis para el Lochkoviano superior del noroeste argentino. Las asociaciones de quitinozoos sugieren afinidades gondwánicas desde el Silúrico medio al Devónico Temprano para la cuenca Chacoparaná. [ABSTRACT FROM AUTHOR]

Copyright of Spal: Revista de Prehistoria y Arqueologia de la Universidad de Sevilla is the property of Spal. Revista de Prehistoria y Arqueologia de la Universidad de Sevilla 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.)

Recent excavations of Tel Yafo (Jaffa), Israel, underscore its role as an historically important Mediterranean port. In 2014, the Ioppa Maritima Project conducted a geological investigation determining that from ca. 5000–2000 years BP, a small estuarine system existed east and north of Tel Yafo that could have served as a harbour. The marine re-entrant formed through sea-level rise and flooding of a small valley, and the stream mouth was probably also partially blocked by coastal sands. Sediment aggradation, wetland development, and anthropogenic activity largely filled the embayment leaving only a depression east of Tel Yafo in the area of Bloomfield Stadium and Groningen Park. [ABSTRACT FROM AUTHOR]

En este trabajo presentamos un resumen de la estratigrafía y los restos paleontológicos descubiertos a lo largo de los últimos años en la Formación Campo Chico (Devónico), Sierra de Perijá, Venezuela. La Formación Campo Chico está compuesta por areniscas grises a blancas y conglomerados, intercalados con lutitas y algunos carbones. Los sedimentos de esta formación representan un ciclo continental marginal con influencia marina hacia el tope. El espesor total de la formación está cercano a los 450 m. La Formación Campo Chico fue datada en base a asociaciones de mioesporas como Givetiano medio–Frasniano medio. La fauna fósil constituye la primera evidencia devónica en Venezuela, de los tres grandes grupos de peces (antiárquidos, placodermos y dipnoos), con elementos endémicos de afinidad gondwánica. El conjunto paleofloral, dominado por licofitas, tanto en número de especies como en abundancia, es el más diverso reportado para el Devónico en Gondwana y es muy similar al encontrado en el estado de Nueva York, al este de Norteamérica (Euroamérica). Ubicando la localización geográfica de las ocurrencias florales de la Sierra de Perijá y Nueva York en las últimas reconstrucciones paleocontinentales del Devónico, las dos localidades están ubicadas en un cinturón de temperaturas cálidas entre Gondwana y Euroamérica. Una estrecha barrera marina se postula, separando ambas masas, para el tiempo de sedimentación de la Formación Campo Chico.

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.)

Following a synthesis of published archaeological investigations in the territory of Sezze by the team of the University of Groningen within the Pontine Region Project (PRP), this paper discusses the methodology and first results of two more recent fieldwork projects within the framework of the PRP, both funded by the Netherlands Organisation for Scientific Research (NWO): 1) the Avellino Event Project (AVP) of the universities of Groningen and Leiden that studies the distal effects of the great Bronze Age eruption of mount Vesuvius on the human environment of the Fondi and Pontine plains. 2) the Minor Centres project that studies the development of the settlements of Forum Appi and Ad Medias along the Via Appia in relation with the development of the Roman countryside. Both projects add significantly to the long term reconstruction of the human landscape in the plain south of Sezze as well as open up perspectives on further interdisciplinary work.

En la corta historia geológica y geomorfológica de la llanura de inundación, canal y delta del Dique, localizada en la costa Caribe colombiana, se han presentado, en los últimos 500 años, notables cambios por procesos naturales y antrópicos que han modificado la geometría del canal y la morfología del delta, que han repercutido notablemente en la alta sedimentación de las bahías de Barbacoas y de Cartagena en el mar Caribe colombiano, pasando de una bahía a un delta, lo que ha causado problemas ambientales. En este artículo se presenta una reconstrucción de la paleogeografía y sedimentología del canal y delta del Dique a partir de elementos químicos que evidencian la presencia del mar en la zona continental. Se utilizaron métodos de análisis de documentos, mapas históricos, procesamiento e interpretación digital de imágenes de satélite, exploraciones directas del subsuelo, levantamientos geológicos y geomorfológicos detallados de campo, muestreo y análisis geoquímicos de sedimentos y rocas por métodos de fluorescencia de rayos X.

The delta of Dique, flood plain and channel, located in the Colombian Caribbean coast displays natural and anthropic changes in its geologic and geomorphologic history during the last 500 years. The changes are evident in the channel geometry, the delta morphology, the high sedimentation in the Barbacoas and Cartagena bay that configured a delta in a previous bay, causing environmental problems. In this article, we present a paleogeographical and sedimological reconstruction of the Dique's channel and delta, using elemental chemistry that demonstrate the previous presence of sea water in the continental zone. Conclusions are additionally supported by other methodologies such as historic documents and maps, consultation, processing and interpretation of satellite images, the exploration of the subsoil, a detailed geologic and geomorphic survey, sediment and rock sampling, and elemental chemical composition measured by a portable xrf equipment. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia 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 sureste de la Cordillera Ibérica (España) existen una serie de afloramientos de rocas volcánicas origi­nadas por erupciones submarinas, principalmente de tipo volcanoclástico, interestratificadas en las sucesiones carbonatadas del Jurásico Inferior y Medio. La cartografía geológica de los afloramientos de rocas volcánicas revela que se encuentran alineados a lo largo de tres elementos de debilidad cortical bien definidos (zonas de falla de Teruel, de Caudiel y de Alcublas), originados probablemente por fracturas relacionadas con la apertura y expansión del Tethys Ligur y del Tethys Alpino. En este trabajo se presentan los resultados del estudio de la evolución tectonosedimentaria de un ambiente submarino somero afectado por la presencia de una acumulación volcánica que tuvo lugar en el Jurásico Medio (límite Aaleniense‒Bajociense). Se trata del afloramiento volcánico de Caudiel, que es el más suroriental de todos los afloramientos localizados en uno de los tres elementos de debilidad estructural mencionados: la Zona de Falla de Caudiel. La presencia de un relieve positivo en el fondo de la plataforma, ya de por sí bastante somera, condiciona la sedimentación carbonatada, muy sensible a la pro­fundidad, hasta el punto de llegar a inducir cambios significativos de facies con respecto a otras áreas cercanas o de impedir la sedimentación. Los movimientos episódicos del substrato generaron una topografía irregular y cambiante a lo largo del tiempo, con tasas variables de hundimiento y levantamiento en diferentes áreas. El aflo­ramiento de Caudiel constituye un buen ejemplo fósil de interacción entre varios factores (vulcanismo, tectónica y sedimentación) en plataformas carbonatadas someras, en las que los cambios de acomodación y las tasas de sedimentación parecen estar subordinadas a perturbaciones tectónicas de carácter local.

Paleoclimate traits are highly varied at the diverse paleoflora of the Río Genoa Formation in Patagonia. They are thoroughly analyzed in order to define macroclimate parameters that ruled the terrestrial vegetational growth during the early Permian. Plant-climate relationships have been historically used for understanding the distribution of present/past vegetation since they represent a continuous feedback along the terrestrial environments on Earth. Most of the indicators found in Patagonia clearly suggest warm and humid conditions during the entire deposition of the studied unit. Such conditions, related to subtropical climates, cannot be correlated with paleoclimate approaches originated from other proxies. This is due to several imprecisions that affect the interpretation of the paleogeographic position of Patagonia. different hypotheses are erected in order to explain the paleofloristic and paleoclimatic anomaly present in southern South America, which should encourage new efforts to better understanding the geological dynamics of southwestern Gondwana. [ABSTRACT FROM AUTHOR]

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.)

Copyright of Comunicaçõe Geológicas is the property of Laboratorio Nacional de Energia e Geologia, I.P. 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.)

The Amazonian ichthyofauna is one of the most diverse in the world, yet fishes from the adjacent coastal basins of Maranhão State in Northeastern Brazil remain poorly known. We use phylogeographic, community phylogenetic and phylogenetic beta diversity methods to study the biogeographic history of fishes from the coastal basins of Maranhão State. We report a total of 160 fish species from the basins of the Maranhão region, representing a 93% increase over results of previous studies. All the fish species assemblages from Maranhão are polyphyletic, with only a few putative sister species pairs inhabiting the region. The modern watershed divides among Maranhão basins do not form substantial barriers to dispersal for freshwater fish species, and are more effectively modelled as biogeographic islands than as biogeographic provinces. In combination these results suggest that the Maranhão ichthyofauna was assembled under the influence of several macroevolutionary (extinction, dispersal) and landscape evolution processes, during the Miocene and Pliocene, as well as by the modern ecological characteristics of the region. The results indicate that the distinctive geological and climatic conditions and history of Northeastern Brazil strongly constrained the formation of aquatic faunas in coastal basins of Maranhão State. [ABSTRACT FROM AUTHOR]

Copyright of Geominas is the property of FUNDA-GEOMINAS. (Fundacion de Egresados d Amigos de la Escuela de Ingenieria Geologica y de Minas) 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 Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia 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.)

The paper summarises and discusses a set of 120 radiocarbon dates of Holocene aeolian, slope, fluvial and peatbog sediments from Central Poland that were deposited under human impact. Based on both the Holocene chronostratigraphic division and archaeological chronology, events that led to the formation of these sediments are presented. A link is made connecting events in aeolian, slope, fluvial and peatbog geosystems to the activity of prehistoric cultures and to settlement development in modern times in Central Poland. Special attention is paid to periods in which the responses of different systems were synchronous to each other. [ABSTRACT FROM AUTHOR]

The paper presents environmental factors that influenced the location of four selected early medieval strongholds in central Western Poland. The following objects were examined: a stronghold at Bobrowniki, on the border between the Warta-Odra Pradolina and Zielona Góra Hillocks, a stronghold at Bytom Odrzański in the Odra River valley within the Głogów Pradolina, and strongholds at Solniki and Popęszyce in the Dalków Hills. Geomorphic and Quaternary research was carried out during fieldworks, while other environmental factors were analysed from literature and cartographic sources. The relief was considered the dominant factor; it was very important to provide a defensive location for the strongholds at Bobrowniki, Solniki and Popęszyce. In two cases (Solniki and Bobrowniki), finding suitable geomorphological forms, such as intervalley rims and high erosional edges, enabled the stronghold to be settled almost without building ramparts. Besides relief, hydrology was also important (the course of river channels and the distribution of wetlands and marshes at the bottom of a large river valley), which ensured the defensive location at Bytom Odrzański. Other natural factors had an ambiguous and generally smaller impact on the settlement of strongholds in the early Middle Ages in central Western Poland. [ABSTRACT FROM AUTHOR]

Copyright of Acta Geologica Lilloana is the property of Fundacion Miguel Lillo 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.)

The first U-Pb and Hf-Lu isotopic data of detrital zircons from Devonian strata of the Malvinas (Falkland) Islands allow re-evaluation of different hypotheses regarding their location before the breakup of Gondwana. Of the various published hypotheses there are only two that have gained support. Adie's hypothesis involves a rotation of 180 degrees of the islands and a large displacement of Patagonia, independently of South America, whereas Borrello's hypothesis assumes a relative fixed position of the islands with respect to South America over time. The first hypothesis has traditionally been evaluated by highlighting the similarities of the geology of the Malvinas Islands with similar rocks cropping out in South Africa. In this paper we test those hypotheses that led to correlate the islands with the Cape System, based on geological, paleomagnetic and geochronological data. However, new isotopic data compared with contemporaneous Patagonian rocks, together with the present knowledge of offshore features of the Malvinas Plateau, suggest that its correlation with South Africa is not as compelling. Although there is no conclusive evidence, the simplest hypothesis based on the present available datasets, favors a closer relationship with Patagonia. No doubt that more research is needed in order to elucidate the paleogeography of the Malvinas Islands before the opening of the South Atlantic Ocean. [ABSTRACT FROM AUTHOR]

Copyright of Geologické Práce Správy is the property of State Geological Institute of Dionyz Stur 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.)

Se revisan los efectos de la evolución del clima y los cambios de uso del suelo / cubierta vegetal en el Pirineo Central español a diferentes escalas espaciales y temporales. Los estudios paleoclimáticos, basados en análisis multiproxy de sedimentos lacustres, glaciares, espeleotémicos y registros dendrológicos, entre otros, han demostrado la ocurrencia de importantes fluctuaciones climáticas durante la deglaciación de finales del Pleistoceno Superior y durante el Holoceno, afectando a la distribución de la vegetación, la generación de escorrentía, la frecuencia de avenidas y las formas de organización del espacio por parte de las sociedades humanas, en particular durante el evento 8.2, la Edad del Bronce, la Anomalía Climática Medieval y la Pequeña Edad del Hielo. El estudio del impacto de las actividades humanas sobre la dinámica del paisaje en el último siglo y medio ha revelado cambios espectaculares en la estructura y distribución de la vegetación, tanto en el piso montano como en el subalpino y, consecuentemente, cambios en la generación de escorrentía, la intensidad de la erosión del suelo y las fuentes de sedimento, cualquiera que sea la escala espacial a la que se contempla el problema. De forma general puede afirmarse que a mediados del siglo XIX se alcanza la máxima presión sobre el territorio, cultivándose todas las laderas posibles hasta una altitud aproximada de 1650 m s.n.m. y empleando frecuentemente el fuego para limitar la expansión de matorrales en zonas de pastos, lo que dio lugar a intensos procesos de erosión y degradación del suelo, y al desarrollo de ríos trenzados con una elevada torrencialidad. Posteriormente, el abandono de tierras de cultivo desde comienzos del siglo XX (y, en especial, desde la década de 1960) y el descenso de la presión ganadera han favorecido la revegetación de las antiguas áreas de cultivo y pastos bien por avance de formaciones naturales de matorral y bosque, bien por la reforestación artificial de extensas laderas, ascendiendo el treeline en el piso subalpino, en este último caso ayudado además por el incremento de la temperatura. Las consecuencias más destacadas de esta evolución han sido: (i) el descenso sostenido del caudal de los ríos pirenaicos desde la década de 1970 debido al aumento de la evapotranspiración; (ii) la contracción espacial de las áreas fuente de sedimento; (iii) la creciente desconexión entre laderas y cauces; (iv) el peso decreciente de la nieve en el régimen de los ríos pirenaicos, con un adelanto en la ocurrencia del momento de aguas altas primaverales; (v) los cambios en la dinámica de llenado de los embalses que han obligado a introducir nuevos patrones de gestión de los embalses; y (vi) la incisión de los cauces fluviales en su propia llanura aluvial. Los estudios llevados a cabo en el Pirineo Central durante las tres últimas décadas sobre el Cambio Global y sus consecuencias confirman la complejidad de las interacciones que se producen en los sistemas naturales y la rápida respuesta de la vegetación, la generación de escorrentía y la erosión frente a variaciones del clima y las actividades humanas.

This paper shows the paleogeographic evolution of the Jaguaruna and Lagoa de Garopaba do Sul charts, located in the Southern littoral of the Santa Catarina State. The paleogeographic model of the study area can be resumed in five evolution stages, following this order: I – lower Pleistocene regression with alluvial fan formation associated to semi-arid climate; II – upper Pleistocene transgression and barrier-lagoon formation; III – upper Pleistocene regression after the maximum transgression with erosion of the Pleistocene deposits and development of the eolian system; IV - Holocene transgression with Pleistocene valley erosion and development of a new barrier-lagoon system; V – Holocene regression, coastline progradation with strand plains beyond the development of the Tubarão river intralagoon delta.

The upper Pleistocene deposits (± 120 ky BP) outcrop in several coastal plains throughout the Brazilian coast. The occurrences in Santa Catarina State - Northern coast, where São Francisco do Sul Island is located are included in this context. The Pleistocene deposits which have marine and lagoon origin on the base and eolic origin on the top, characterize typical barrier island confined to crystalline basement elevations. The deposits outcrop on the central sector of São Francisco do Sul Island, close to the coastline, reaching up to 6 km of width and have variable heights from 12 to 17 m in elevations and 10 to 12 m in depressions. The geologic contact with the others coastal plain unities are interdigited and/or abrupt through scarps well defined that reach up to 4 m of vertical fall. The geomorphologic features consist in terraces exhibiting horizontal and undulated surface, dominating sandy sediments, fine to medium, well sorted, constituted by quartz and heavy minerals. These deposits were formed in higher sea level (8±2 m), between 18 to 120 ky BP, during regressive phase of the Sangamonian - Yarmoutian maximum transgression/regression, which is correlated to the interglacial Riss/Wurm, corresponding in Brazil to Cananéia transgression (SP), Penultimate transgression (BA) or barrier III (RS).Os depósitos do Pleistoceno superior (±120 ka AP) afloram em diversas planícies costeiras ao longo do litoral brasileiro, incluindo as ocorrências no setor Norte do litoral do Estado de Santa Catarina, onde se encontra localizada a ilha de São Francisco do Sul. Os sedimentos do Pleistoceno superior, de origem marinho praial e lagunar na base e eólica no topo, representam típicas ilhas - barreiras confinadas às elevações do embasamento cristalino. Os depósitos afloram no setor central da ilha de São Francisco do Sul, próximos à linha de costa atingindo até 6 km de largura e altitudes variáveis de 12 a 17 m nas elevações e 10 a 12 m nas depressões. O contato geológico com as demais unidades da planície costeira é interdigitado e/ou brusco através de falésias bem definidas que alcançam até 4 m de desnível vertical. As formas dominantes dos depósitos são terraços de superfície plana a levemente ondulada, predominando grãos arenosos, finos a médios, selecionados, constituídos de quartzo e minerais pesados. Os depósitos foram formados em um nível marinho mais elevado que o atual (8±2m), entre 18 e 120 ka AP, durante a fase regressiva do máximo da transgressão/regressão Sangamoniana - Yarmoutiana, correlacionada ao período interglacial Riss/Wurm, correspondendo no Brasil à transgressão Cananéia (SP), Penúltima transgressão (BA) ou barreira III (RS).

As exposições do Grupo Santa Bárbara (Ediacarano) na Sub-bacia Camaquã Central são representadas por uma sucessãode depósitos arenosos e rítmicos marinhos/transicionais e depósitos conglomeráticos de leques aluviais, que compõem ciclosprogradacionais-retrogradacionais. Nesta sub-bacia, o Grupo Santa Bárbara apresenta mais de 2.000 m de espessura, comexcelentes exposições nas regiões das Minas do Camaquã e de Bom Jardim. Estudos estratigráficos de paleoambientes,paleocorrentes e de proveniência realizados nestas regiões possibilitaram a seguinte subdivisão do Grupo Santa Bárbara naSub-bacia Camaquã Central, a partir da base: 1. Formação Passo da Capela: unidade areno-siltítica subdividida em turbiditosdistais de leque subaquoso (Outer-fan), e turbiditos proximais a distais de leque subaquoso (Inner-Fan a Outer-fan) etempestitos de costa-afora (offshore); 2. Formação Seival: arenitos e siltitos de depósitos litorâneos e de planície de marés;3. Formação Rincão do Mouras: unidade areno-conglomerática formada por depósitos de leques aluviais e de sistemas fluviaisentrelaçados e 4. Formação João Dias: composta principalmente por arenitos interpretados como depósitos litorâneos deantepraia e de face litorânea e tempestitos de face litorânea. Estes estudos permitiram ainda o reconhecimento de uma notávelcorrelação entre as unidades encontradas nestas regiões legitimando, desta forma, a proposta de englobar os depósitos daregião das Minas do Camaquã, classicamente relacionadas à Formação Arroio dos Nobres, no redefinido Grupo Santa Bárbara.

The Late Paleozoic Ice Age is recorded in the Paraná Basin as glacial deposits, deformational features and ice-related erosional landforms of the Itararé Group. Erosional landforms are often employed to build paleogeographic models that depict the location of ice masses and paleo ice-flow directions. This paper provides a review of the literature and new data on micro- to meso- scale ice-related, erosional landforms of the Paraná Basin. Examined landforms can be placed into four broad categories based on their mode of origin. Subglacial landforms on rigid substrates occur on the Precambrian basement or on older units in the Paraná Basin. They include streamlined landforms and striated pavements formed by abrasion and/or plucking beneath advancing glaciers. Subglacial landforms on soft beds are intraformational surfaces generated by erosion and deformation of unconsolidated deposits when overridden by glaciers. Ice-keel scour marks are soft- sediment striated/grooved landforms developed by the scouring of free-floating ice masses on underlying sediments. Striated clast pavements are horizons containing aligned clasts that are abraded subglacially due to the advance of glaciers on unconsolidated deposits. Only those erosional landforms formed subglacially can be used as reliable paleo ice-flow indicators. Based on these data, the paleogeography of the Paraná Basin during the Late Paleozoic Ice Age fits into a model of several glacial lobes derived from topographically- controlled ice spreading centers located around the basin instead of a single continental ice sheet. [ABSTRACT FROM AUTHOR]

The Marajó Basin area presents geologic and geomorphologic features chiefly due to the Mesozoic extension and post-Miocene neotectonics. The extension event with an Early and a Late Cretaceous phases originated four sub-basins that constitutes the Marajó Basin, with a thick continental clastic sequence showing marine influence. NW and NNW normal faults and NE and ENE strike-slip faults controlled the basin geometry. The extension, related to the Equatorial Atlantic opening, propagated into the continent along crustal weakness zones of the Precambrian Tumucumaque, Amapá and Araguaia orogenic belts. The neotectonic event is a strike-slip regime which developed transtensional basins filled in by Upper Tertiary shallow marine (Pirabas Formation) and transitional sequences (Barreiras Group), followed by Quaternary fluvial deposits and transitional sequences derived from the Amazon and Tocantins rivers and the Marajoara estuary. The current landscape has a typical estuarine morphology. The coast morphology presents sea-cliffs on transitional Upper Tertiary sequences, while inwards dominate hills sustained by Mid-Pleistocene lateritic crust, with a flat erosive surface at 70 m. In the eastern Marajó Island several generations of paleochannels associated with fluvial-estuarine sequences are recognized, while a fluvial-marine plain is widespread on its western side.A área da Bacia do Marajó apresenta feições geológicas e geomorfológicas devidas principamente à distensão Mesozóica e à neotectônica pós-miocênica. O evento de distensão, com fases do Cretáceo Inferior e Superior, originou quatro sub-bacias que contituem a Bacia do Marajó, com uma espessa seqüência clástica continental mostrando influência marinha. Falhas normais NW e NNW e direcionais NE e ENE controlaram a geometria da bacia. A distensão, relacionada com a abertura do Atlântico Equatorial, propagou-se continente adentro ao longo de zonas de fraqueza crustal dos cinturões orogênicos pré-cambrianos Tumucumaque, Amapá e Araguaia. O evento neotectônico é um regime transcorrente que desenvolveu bacias transtensivas preenchidas por sedimentos marinhos rasos (Formação Pirabas) e seqüências transicionais (Grupo Barreiras) do Terciário Superior, seguidos por depósitos fluviais e seqüências transicionais do Quaternário, derivadas dos rios Amazoans e Tocantins e do estuário do Marajó. A paisagem atual tem morfologia tipicamente estuarina. A morfologia costeira apresenta escarpas em seqüências transicionais do Terciário Superior, enquanto no interior dominam elevações sustentadas por crosta laterítica do Pleistoceno Médio, aparadas por superfície erosiva a 70 m. No leste da Ilha do Marajó são reconhecidas várias gerações de paleocanais com seqüências estuarinas associadas, enquanto no lado oeste predomina uma planície flúvio-marinha.

El presente trabajo forma parte del estudio interdisciplinar llevado a cabo en el yacimiento prehistórico en cueva de Labeko Koba. El yacimiento arqueológico de Labeko Koba se encontraba ubicado en un conjunto cárstico del "complejo Urgoniano" perteneciente a la Unidad Murugain de edad imprecisa, Aptiense inferior - Albiense medio. En el presente estudio, se analiza la relación existente entre los Sedimentos de la Unidad Murugain con sus contemporáneos : Margas de Bilbao y Calizas de Udalaitz, siendo estas últimas las más relevantes ya que en la actualidad constituyen un relieve sobresaliente en el paisaje continental : el macizo calizo (biolitito) de peña Udalaitz, mientras que en el momento de su formación, en el Cretácico Inferior, constituían un banco carbonatado elevado sobre el fondo marino de la época (arrecife pináculo). En este sentido, las calizas de la unidad Murugain se han revelado como un paso lateral del arrecife principal, depositadas a mayor profundidad que las de aquel.

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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 Comunicaçõe Geológicas is the property of Laboratorio Nacional de Energia e Geologia, I.P. 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.)

O Supergrupo Camaquã, localizado na região centro-sul do Rio Grande do Sul, Brasil, constitui uma bacia sedimentar ­pós-orogênica do tipo rift, cuja deposição ocorreu em ambiente continental entre o Ediacarano e o Eocambriano. O topo da sucessão do Supergrupo Camaquã é representado pelo Grupo Guaritas, uma unidade formada por depósitos fluviais, eólicos e de leques aluviais que abriga importantes registros da sedimentação logo após o final das orogêneses neoproterozoicas que deram origem ao supercontinente Gondwana. O objetivo do presente trabalho foi aplicar a análise de proveniência sedimentar em arenitos conglomeráticos e conglomerados do Grupo Guaritas, a fim de explorar a história da evolução tectônica e climática dessa unidade. Com base nos dados composicionais de seixos, foram reconhecidas duas áreas fonte principais para os depósitos dessa unidade, uma mais distal e situada a norte, relacionada a um sistema de rio tronco paralelo ao eixo principal da bacia, e outra mais proximal e situada a leste, relacionada a sistemas fluviais transversais e de leques aluviais da borda da bacia. O confronto dos dados de proveniência com estudos anteriores de fácies e paleocorrentes sugere que, durante toda a evolução da borda leste da bacia, houve um mesmo sistema fluvial transversal, cuja área de captação sofreu reduções significativas devido à reativação da falha da borda leste durante a deposição das formações Varzinha e Pedra Pintada. Na Formação Serra do Apertado, unidade de topo do Grupo Guaritas, foi verificada uma alta correlação entre a variação dos seixos de composição quartzosa e não quartzosa, e isso foi atribuído a variações entre climas mais úmidos e mais áridos.

Multidisciplinary investigations carried out at Koźmin Las have been analysed in the aspect of recognition of fast natural climate changes in geosystems during the Vistulian Late Glacial. A series of short events, reconstructed for the extensive valley of a large lowland river in the old morainic area of Central Poland, has been related to global changes. Features in accordance with the scheme for Greenland ice core records and with the stratotypes of terrestrial palaeoenvironment of Central Poland have been highlighted. Properties of deposits which contributed to the knowledge of evolution of the Łódź Region have been pointed out. [ABSTRACT FROM AUTHOR]