Sponge spicules as proxy in Upper Quaternary lake deposits near Cianorte (PR): a tentative correlation with lakes of Central-Southern Brazil (NW Paraná and SE Mato Grosso do Sul

Researchers recognize the use of bio-proxy in Quaternary paleo environment reconstruction for more than 50 years. Among the bio-indicators, pollens and spores are, by far, the most used palynomorphs, followed by diatoms. However, oxidizing conditions can destroy and leach organic material. In such cases, sponge spicules, with siliceous skeleton, resist geochemist weathering and diagenesis, preserving in the sediment. This paper proposes an experimental correlation between sponge analyses obtained from lakes sediment in the NW Paraná and SE Mato Grosso do Sul States, Brazil, in a pioneering attempt of paleoclimatic data integration for the south-central Brazil. The structures used to identify the sponges were megascleres, microscleres and gemmoscleres. Both short- and long-distance correlations were satisfactory. Although a temporal and genetic correlation between lakes of NW Paraná and SE Mato Grosso do Sul lakes has been observed, their hydrological functioning was different

ANÁLISE COMPARATIVA ENTRE ASPECTOS FÍSICOECONÔMICOS E VULNERABILIDADE AMBIENTAL: MUNICÍPIO DE IVATÉ, NW DO PARANÁ

A área de pesquisa se localiza no município de Ivaté, localidade em que foram identificados, mapeados e interpretados atributos físico-econômicos da paisagem no intuito de correlacioná-los com o uso e ocupação do solo tendo em vista a organização de informações que possam contribuir com projetos de planejamento, gestão ambiental e manejo adequado do solo. Para tanto, foram levantadas características do meio físico e econômico deste município, atribuindo a influência que o conjunto dessas características tem na formação e no desenvolvimento do município. O artigo foi elaborado seguindo como parâmetros, dados municipais obtidos pelo IBGE, Embrapa, ITCG e bibliografia específica. A análise integrada permitiu constatar que o município é propenso a processos de erosão, principalmente pela interrelação de fatores como solo e declividade. Deste modo, técnicas de manejo do solo (cobertura vegetal e terraceamento) que minimizem os efeitos da erosão provocados pelo escoamento superficial devem ser aplicadas no município, a fim de se conservar o solo e suas características pertinentes

Evolução geomorfológica e palaeoambiental dos terraços da margem esquerda do alto rio Paraná

Terraces levels and sedimentary deposits of different ages and characteristics in the upper Paraná River has been associated as a paleohydrological and paleoenvironmental record by Quaternary paleoclimatic changes. The study area is located in northwest of Paraná State (Brazil), near to Querência do Norte city, left bank of upper Paraná river. Based on remote sensing data and fieldworks, including vibro-core drilling and outcrops description, was held the study área geomorphological subdivision and caracterization, with recognition of terraces associated of Parana and Ivaí rivers, current plains of both rivers, various formats ponds and inactive alluvial fans formed by streams that drain high land. Geomorphology, geology, absolute dating (OSL and 14C) and interpretation of proxy records data as continental sponges spicules, diatoms frustules and phytoliths allowed to reconstruct paleoenvironmental and paleoclimatic conditions. Dating showed ages of 150,900 ± 32,400 and 50,300 ± 7900 years BP to terraces; 26,900 ± 5,000 and 20,600 ± 4800 years BP to ponds; and 7,540 years BP to aluvial fan. The terraces of the study area were correlated with the geomorphological units Taquaruçu and Fazenda Boa Vista, in southeastern Mato Grosso do Sul State (Brazil), and Ivaí Terrace on the right bank of the lower Ivaí river. The terraces were interpreted as extensions of these units and products of the same Quaternary paleoenvironmental / paleoclimatic changes events. The presence of sponge spicules in lake sediments show that lotic environments were not associated with the ponds genesis and evolution. Gemmoscleres were identified corresponding to four sponges species: a) Dosilia pydanieli; b) Radiospongilla amazonensis c) Metania spinata; and d) Uruguaya corallioides, as well two genus of diatoms frustules: a) Pinnularia sp. and b) Eunotia sp., which enabled the interpretation of paleoenvironmental change. The terraces degradation and ...A presença de vários níveis de terraços e depósitos sedimentares de idades e características distintas no alto rio Paraná sempre foi associada como registro de mudanças paleohidrológicas e paleoambientais em resposta às variações paleoclimáticas quaternárias. A área estudada está localizada no noroeste do Paraná, próximo a cidade de Querência do Norte, na margem esquerda do rio Paraná. Com base em dados de sensores remotos e de campo, que incluíram sondagens vibratórias e descrição de afloramentos, foi realizada a compartimentação e caracterização geomorfológica da área estudada com reconhecimento de terraços associados aos rios Paraná e Ivaí, planícies atuais de ambos os rios, lagoas de variados formatos e leques aluviais inativos formados por riachos que drenam terrenos situados a leste. Dados geomorfológicos, geológicos, datações absolutas (LOE e 14C) e interpretação de dados proxy como espículas de esponjas continentais, frústulas de diatomáceas e fitólitos permitiram reconstituir condições paleoambientais e paleoclimáticas. Datações revelaram idades de 150.900±32.400 e 50.300±7.900 anos AP para os terraços; 26.900±5.000 e 20.600±4.800 anos AP para as lagoas; e 7.540 anos AP para o leque aluvial. Os terraços da área estudada foram correlacionados com as unidades geomorfológicas Taquaruçu e Fazenda Boa Vista, no sudeste do Mato Grosso do Sul, e Terraço Ivaí, na margem direita do rio Ivaí, interpretados como extensões dessas unidades e produtos dos mesmos eventos paleoambientais/paleoclimáticos quaternários. A presença de espículas de esponjas em sedimentos lacustres descartou a contribuição de ambientes lóticos na gênese e evolução das lagoas. Foram identificadas gemoscleras correspondentes a quatro espécies de esponjas: a) Dosilia pydanieli; b) Radiospongilla amazonensis; c) Metania spinata, e d) Uruguaya corallioides; e frústulas de diatomáceas dos gêneros: a)...Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Late Pleistocene and Holocene paleoenvironments in ponds and alluvial sediments of Upper Paraná River, Brazil

Freshwater sponge spicules were analyzed as a paleoenvironmental proxy indicator in five cores of ponds and alluvial fan sediments in the Upper Paraná River's left bank, near Querência do Norte town, northwestern of State of Paraná, southern Brazil. Two optically stimulated luminescence (OSL) dates were obtained from sediments of ponds and one radiocarbon (14C) date was obtained from the alluvial fan. Microscopic analysis of spicules preserved in the sediments allowed a determination of freshwater sponge species. The species assemblage provides evidence for dominantly dry conditions in the Upper Paraná River during the Late Pleistocene. A wetter climate phase was recognized at 14C 7,540 yrs BP, with alluvial fan formation commencing at the transition of the dry Pleistocene climate to the Early Holocene wet climate. This wet interval was characterized by a sponge assemblage marked by the presence of the Neotropical families and typically associated with lotic environments. Sponge spicules analysis from pond sediments reject the possibility that lotic environments contributed to pond genesis and evolution. © 2013 by the Sociedade Brasileira de Paleontologia

Holocene stratigraphic evolution of saline lakes in Nhecolandia, southern Pantanal wetlands (Brazil)

Nhecolandia is a fossil lobe of the Taquari River megafan and a prominent geomorphic subunit of the Pantanal wetlands because of the presence of >10,000 small lakes. We investigated the stratigraphic records of three saline lakes from Nhecolandia to explore their potential as Quaternary hydroclimate archives. Radiocarbon data indicate that accumulation at two lakes was approximately continuous in the late Holocene, and chemostratigraphic variability suggests sensitivity to environmental change with multicentennial resolution. A basal sandy unit and an upper muddy unit comprise the shallow stratigraphy of each lake. A pronounced change in depositional environment from freshwater wetlands to saline lakes at similar to 3300-3200 cal yr BP best explains the lithofacies transition. Ephemeral freshwater wetlands formed on the abandoned megafan lobe, which was molded by deflation in the arid early Holocene. Wind-scouring of the megafan lobe generated topographically closed depressions with complex marginal sand ridges, which allowed permanent lakes to evolve when rainfall increased in the late Holocene. The lakes became highly saline and alkaline after similar to 910 cal yr BP, which influences biogeochemistry and aquatic ecology. The results hold implications for understanding the response of the southern Pantanal to climate change, as well as the development of pans in tropical megafan settings.FAPESPUK-VPRCAPESCNPqUniv Kentucky, Dept Earth & Environm Sci, 106 Slone Res Bldg, Lexington, KY 40506 USAInst Fed Parana, Assis Chateaubriand Campus, BR-85935000 Assis Chateaubriand, Parana, BrazilUniv Estadual Paulista Rio Claro, Inst Geociencias & Ciencias Exatas, BR-13506900 Sao Paulo, BrazilEmbrapa Pantanal, Lab Biomass Convers, BR-79320900 Corumba, MS, BrazilUniv Fed Mato Grosso do Sul CPAN, Dept Geog, 1270 Ave Rio Branco, BR-79304902 Corumba, MS, BrazilUniv Fed Sao Paulo, Dept Environm Sci, BR-09913030 Diadema, SP, BrazilUniv Fed Sao Paulo, Dept Environm Sci, BR-09913030 Diadema, SP, BrazilFAPESP: 2014/06889-2FAPESP: 2014/23334-4CNPq: 312386/2014-1CNPq: 308563/2013-1Web of Scienc