Sedimentary Rocks
Mostrando 1-12 de 111 artigos, teses e dissertações.
-
1. Indicator kriging applied to RMR geomechanical modelling in a Pb-Zn deposit case study
Abstract The opening of a mining enterprise requires knowledge of the geomechanical characteristics of the mineral deposit, which will be worked according to the use of parameters of stability and/or resistance of the material, as well as the discontinuities present in the rock. In this study, the Rock Mass Rating methodology was used to propose a geomechani
REM, Int. Eng. J.. Publicado em: 2021-06
-
2. Radionuclídeos como marcadores de um novo tempo: o Antropoceno
On May 2019, the members of the Anthropocene Working Group completed a binding vote to affirm some of the key questions that have been agreed in 2016: the Anthropocene should be considered as a formal chronostratigraphic unit, defined by a Global Boundary Stratotype Section and Point (GSSP), using one of the stratigraphic signals around the mid-twentieth cen
Quím. Nova. Publicado em: 2020-04
-
3. White sand vegetation in an Amazonian lowland under the perspective of a young geological history
Abstract: What controls the formation of patchy substrates of white sand vegetation in the Amazonian lowlands is still unclear. This research integrated the geological history and plant inventories of a white sand vegetation patch confined to one large fan-shaped sandy substrate of northern Amazonia, which is related to a megafan environment. We examined flo
An. Acad. Bras. Ciênc.. Publicado em: 02/12/2019
-
4. The sedimentary record of wet and dry eolian systems in the Cretaceous of Southeast Brazil: stratigraphic and paleogeographic significance
Abstract Sedimentologic and stratigraphic studies of paleo-deserts from the Brazilian Cretaceous are of great potential to understand the paleoclimate and paleogeography of Gondwana during its final rifting stage. Herein, we describe and discuss two depositional units characterized by two distinct eolian systems that are bounded by a long-lived unconformity.
Braz. J. Geol.. Publicado em: 11/11/2019
-
5. Provenance of the Ediacaran Salinas Formation (Araçuaí Orogen, Brazil): Clues from lithochemical data and zircon U-Pb (SHRIMP) ages of volcanic clasts
Abstract Salinas Formation occurs in a large region of the Northern Araçuaí orogen, Southeastern Brazil. It includes turbiditic wackes (> 10% matrix) to arenites (< 10% matrix), pelites and clast-supported conglomerates, metamorphosed from the biotite zone of the greenschist facies to the sillimanite zone of the amphibolite facies. Salinas Formation lies u
Braz. J. Geol.. Publicado em: 01/07/2019
-
6. The Neostratotype of Itapecuru Formation (Lower-Middle Albian) and Its Impact for Mesozoic Stratigraphy of Parnaíba Basin
Abstract Abstract: This study defines the neostratotype of the Lower-Middle Albian Itapecuru Formation in the Parnaíba Basin, Northeast Brazil. In this sedimentary succession along the right bank of the Itapecuru River near the Itapecuru-Mirim City, Maranhão State, three lithofacies associations are recognized. The first is silty claystone with some very f
An. Acad. Bras. Ciênc.. Publicado em: 06/05/2019
-
7. Geochemistry, metamorphic evolution and tectonic significance of metabasites from Caçapava do Sul, southern Brazil
Abstract This paper proposes the generation and closure of a proto-ocean and formation of an island arc in the Neoproterozoic Passo Feio Metamorphic Complex (PFMC), Caçapava do Sul region, southern Brazil. The PFMC, São Gabriel Terrane, consists of a Neoproterozoic supracrustal metavolcano-sedimentary sequence intruded by the Caçapava Granite. The study u
Braz. J. Geol.. Publicado em: 29/04/2019
-
8. Petrography and detrital zircon U-Pb geochronology of sedimentary rocks of the Campo Alegre Basin, Southern Brazil: implications for Gondwana assembly
Abstract The Campo Alegre Basin is a volcano-sedimentary sequence covering an area of about 500 km 2 , located at the northeast portion of Santa Catarina state (Brazil), and formed during the late stages of the Neoproterozoic era. Three main stratigraphic units compose this basin, the lowermost of which is the Bateias Formation, corresponding to the pre-volc
Braz. J. Geol.. Publicado em: 15/04/2019
-
9. Genesis and Classification of Nitisols from Volcano-Sedimentary Lithology in Northeastern Brazil
ABSTRACT On the southern coast of Pernambuco State (PE), Brazil, lithotypes of the Cabo Basin (volcanic and sedimentary rocks), in association with the relief, allow the determination of the dynamics of the formation of Nitossolos Háplicos (Nitisols), including those with high levels of exchangeable aluminum. The objective of this study was to evaluate the
Rev. Bras. Ciênc. Solo. Publicado em: 14/02/2019
-
10. Evaluación reológica de fluidos de perforación base agua con nanosílice
ABSTRACT Generally, drilling fluids may be defined as fluids with a composition that can assist the generation and removal of cuttings from the borehole to the surface. They are classified according to their base as water based mud (WBM), oil based mud (OBM) or gas. Polymers, densifiers, brines, surfactants, among others are the primary components of drillin
Matéria (Rio J.). Publicado em: 19/07/2018
-
11. Geochemistry and Spatial Variability of Rare Earth Elements in Soils under Different Geological and Climate Patterns of the Brazilian Northeast
ABSTRACT Growth in the agricultural and industrial sectors has increased the demand for rare earth elements (REEs) in the production of technological devices and fertilizers. Thus, the accumulation of these elements in the soil has become an environmental concern. Here, we aim to determine the natural contents of REEs in soils derived from different parent m
Rev. Bras. Ciênc. Solo. Publicado em: 02/07/2018
-
12. Geochemistry of the Northern Paraná Continental Flood Basalt (PCFB) Province: implications for regional chemostratigraphy
ABSTRACT: The Paraná Continental Flood Basalt (PCFB) province is one of the largest igneous provinces on Earth, but little is known about the architecture and geochemical characteristics of the lava flows. In this context, a set of borehole samples arranged in an NEE-SWW profile - more than 600 km long - located in the northern PCFB was used to define its c
Braz. J. Geol.. Publicado em: 2018-06