RESUMEN El estudio de los materiales calcareos (de rocas y venas) de las Formaciones sedimentarias Cretacicas Rosablanca, Paja yTablazo, aflorantes al sur del Departamento de Santander (Colombia), permitio establecer la presencia de dos grupos decarbonatos, segun su afinidad isotopica (δ18O y δ13C): a) Los carbonatos de Tipo I: con valores de δ18O entre 20.15‰ y22.28‰ y valores de δ13C relativamente homogeneos -1.1‰<δ13C<0.9‰ y; b) Los carbonatos de Tipo II: con valores de δ18Oentre 20.31‰ y 21.60‰, y valores isotopicos de carbono 1.8‰ <δ13C< 5.8‰. Algunas diferencias entre la signatura isotopicade los carbonatos de rocas y venas, parecen indicar incorporacion de aguas aloctonas. El analisis de los datos geoquimicos deREE en las rocas Cretacicas de las Formaciones Paja y Rosablanca, corroboran el caracter marino de estas dos unidades, talcomo lo indican las anomalias negativas de Eu y Ce. La ausencia de una anomalia negativa en Eu en los agregados de micaspotasicas de relleno de venas, se interpreta como relacionada con las condiciones oxidantes en el que tuvo lugar la formacionde este producto hidrotermal. La geoquimica del Sr (87Sr/86Sr) en las muestras analizadas, indica que su fuente es de caractermixta: continental y marina. Por otro lado, su participacion en los fluidos que circularon por las fracturas de las rocas, pareceser derivado exclusivamente de las rocas encajantes. Palabras clave: Departamento de Santander, carbonatos, isotopos estables, fluidos, geoquimica de REE y Sr. C, O, Sr ISOTOPE AND RARE EARTH ELEMENTS (REE) STUDY IN SEDIMENTARY CRETACEOUSROCKS FROM THE EAST CORDILLERA (DPTO. DE SANTANDER, COLOMBIA):PALEOHYDROGEOLOGICAL IMPLICATIONS ABSTRACT The study of calcareous materials (from rocks and veins) of the Cretaceous Rosablanca, Paja and Tablazo Formationsoutcropping to the South of the Dpto. Santander allowed the distinction of two carbonates groups on the basis of theirisotopic (δ18O y δ13C) signature: a) Carbonates type I: with a range of δ18O values between 20.15‰ and 22.28‰ and relativityhomogeneous δ13C values -1.1‰<δ13C<0.9‰; b) Carbonates type II: with δ18O values between 20.31‰ and 21.60‰, and1.8‰ <δ13C< 5.8‰ values. Some differences in the isotopic signature of calcareous rocks and veins could indicate theinfluence of aloctonous waters. Geochemical data analysis of REE of the Cretaceous Paja and Rosablanca Formations, provethe marine features of these two units, as indicated by the negative Eu and Ce anomalies. The absence of a negative anomalyin Eu of the K-mica agregates from veins, is the result of the oxic conditions at the time of the hydrothermal event. The Srgeochemistry (87Sr/86Sr) in the studied samples, indicates a mixed source derived from both: continental and marine. On theother hand, the Sr of circulating waters through fractured rocks, show that it was derived exclusively from theses host rocks. Key words: Departamento de Santander, carbonates, stable isotopes, fluids, REE and Sr geochemistry.

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Variabilidad del Monzón sudamericano durante los últimos 1000 años inferidos a partir de estudios isotópicos en espeleotemas recolectados en los andes orientales del Perú y Bolivia

Anais (2012)

James Apaéstegui Francisco William da Cruz Júnior Jean‐Loup Guyot Abdel Siffedine R. V. Santos

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Relationships of stable isotopes, water-rock interaction and salinization in fractured aquifers, Petrolina region, Pernambuco State, Brazil

REM - International Engineering Journal (2018)

Priscila Sousa Silva José Elói Guimarães Campos Luciano Soares da Cunha Luís Henrique Mancini

The Petrolina County, Pernambuco State, Brazil, presents specificities that make it unique from a hydrogeological point of view. Water resource scarcity is both a quantitative and qualitative issue. The climate is classified as semiarid, having low precipitation, along with high temperatures and evapotranspiration rates. Aquifer zones are related to low connected fractures resulting in a restricted water flow in the aquifer. The recharge is limited and the groundwater salinity is high. Stable isotope analyses of H and O were developed in groundwater samples (with different electrical conductivity) and surface water collected in a bypass channel flowing from the São Francisco River. The results were plotted in a dD ‰ versus δ18O ‰ graph along with the curves of the global and local meteoric water line. Groundwater samples showed unexpected results showing a lighter sign pattern when compared to the meteoric waters. More negative dD and δ18O values indicate an enrichment in light isotopes, which show that this process is not influenced by surface processes, where the enrichment occurs in heavy isotopes due to evaporation. The isotopic signature observed is interpreted either as resulting from the water-rock interaction, or as resulting from recharge from paleo rains. The waters are old and show restricted flow. So the water-rock contact time is extended. In the rock weathering processes, through the hydration of feldspars, there is preferential assimilation of heavy isotopes at the expense of the lighter ones that remain in the water. Analyses of the 87Sr/86Sr ratio and isotopic groundwater dating assist in the interpretations.

δ18O

Environmental isotopes

10.1590/0370-44672016710178

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Meso-Neoproterozoic isotope stratigraphy on carbonates platforms in the Brasilia Belt of Brazil

Precambrian Research (2014)

Carlos José Souza de Alvarenga Roberto Ventura Santos Lucieth Cruz Vieira Bárbara Lima Luís Henrique Mancini

Diamictite

Siltstone

Carbonate platform

Chemostratigraphy

Snowball Earth

Dolostone

10.1016/j.precamres.2014.06.011

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PADRÕES DE RECARGA DO SISTEMA AQUÍFERO CRISTALINO A PARTIR DE ISÓTOPOS ESTÁVEIS 18O E 2H DE ÁGUAS PLUVIAIS E SUBTERRÂNEAS

Águas Subterrâneas (2019)

Matheus Serri Moulin de Oliveira Mirna Aparecida Neves Fabrício de Andrade Caxito Luís Henrique Mancini Fabririca Benda de Oliveira

Apresenta-se aqui a Linha Meteorica Local e as variacoes ligadas aos efeitos de pluviosidade, continentalidade e altitude na Bacia Hidrografica do Rio Itapemirim (BHRI), Sul do Estado do Espirito Santo, Sudeste do Brasil. A assinatura isotopica da agua da chuva e diferenciada nas porcoes da Alta, Media e Baixa BHRI devido as diferencas de precipitacao media em cada setor. A assinatura isotopica das aguas subterrâneas e similar a das aguas meteoricas, indicando alta velocidade de recarga, porem, com taxas variadas ao longo da bacia. Maiores elucidacoes a respeito do tempo de renovacao da agua subterrânea poderao ser feitas com base nas analises de Tritio (³H) que estao sendo conduzidas na agua subterrânea do aquifero fraturado.

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