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Bernhard Bühn
University of Brasília
22Publications
9H-index
339Citations
Publications 22
Newest
2018 in Mineralium DepositaIF: 3.37
Wendell Fabricio-Silva1
Estimated H-index: 1
(Universidade Federal de Minas Gerais),
Carlos Alberto Rosière15
Estimated H-index: 15
(Universidade Federal de Minas Gerais),
Bernhard Bühn9
Estimated H-index: 9
(University of Brasília)
Turmalina is an important orogenic gold deposit located in the NW region of the Quadrilatero Ferrifero. The deposit is hosted in an Archean greenstone belt composed of ortho-amphibolites and pelites with interleaved tuffs metamorphosed under amphibolite facies conditions and intruded by a granite stock. The orebodies are controlled by WNW-ESE-trending shear zones, associated with hydrothermal alteration. Three deformation events are recognized in the Turmalina gold deposit: D1 and D2 are the res...
1 Citations Source Cite
2018 in Polar ScienceIF: 1.03
Ravikant Vadlamani3
Estimated H-index: 3
(Indian Institute of Technology Kharagpur),
Bernhard Bühn9
Estimated H-index: 9
(University of Brasília),
Márcio Martins Pimentel35
Estimated H-index: 35
(University of Brasília)
Abstract Schirmacher Oasis, central Dronning Maud Land, East Antarctica, a dispersed fragment of the 660-610 Ma East African Orogen (EAO), exposes platformal-facies high-grade metasedimentary rocks. Here we constrain the depositional age of these sedimentary rocks to test models relating to timing of the closure of the Mozambique Ocean, the southern segment of the EAO, since Tonian time. Zircon, a proxy for detritus, was dated by LA-MC-ICPMS ( 206 Pb/ 238 U ages) that includes both magmatic and ...
Source Cite
Alexandre Raphael Cabral15
Estimated H-index: 15
,
Bernhard Bühn9
Estimated H-index: 9
(University of Brasília)
+ 3 AuthorsStefan Halder1
Estimated H-index: 1
Abstract In-situ laser ablation and multicollector–inductively coupled plasma–mass spectrometry were combined to analyse for sulfur isotopes in sulfide minerals that occur in the 2.7-billion-year-old black shale of Serra Sul, Carajas mineral province, Brazil. The black shale is part of a banded-iron-formation unit – the Carajas Formation – that hosts world-class iron-ore deposits. An obvious signal of mass-independent fractionation of sulfur isotopes (MIF-S) is not present in the black-shale sul...
1 Citations Source Cite
2016 in Ore Geology ReviewsIF: 3.99
Claudinei Gouveia de Oliveira10
Estimated H-index: 10
(University of Brasília),
Frederico Bedran de Oliveira1
Estimated H-index: 1
+ 4 AuthorsBernhard Bühn9
Estimated H-index: 9
(University of Brasília)
Abstract The large Chapada Cu–Au deposit is situated in Goias Magmatic Arc, Central Brazil, which is part of an accretionary orogen with tectonic evolution between ca. 900 and 600 Ma during the Brasiliano Orogeny. With a current reserve (proven and probable) of 420.94 Mt Cu (0.29%) and 479.84 Mt Au (0.25 g/t) or 3.83 Moz Au, the Chapada Cu–Au deposit is an important example of a large-tonnage, low-grade porphyry copper–gold deposit of Precambrian age, in which the mineralization is disseminated ...
9 Citations Source Cite
2016 in Precambrian ResearchIF: 3.91
Sebastian Viehmann7
Estimated H-index: 7
(Jacobs University Bremen),
Michael Bau41
Estimated H-index: 41
(Jacobs University Bremen)
+ 3 AuthorsDetlef H.G. Walde8
Estimated H-index: 8
(University of Brasília)
Abstract The Urucum iron and manganese formation (IF and MnF) in the Neoproterozoic Santa Cruz Formation, Brazil, provides unique insights into Neoproterozoic seawater and the habitat for the evolution of the Ediacaran fauna. Pure Urucum IF drill core samples, i.e. chemical sediments that are devoid of any syn- or post-depositional alteration, are reliable and robust archives of Neoproterozoic seawater proxies. They display low concentrations of rather immobile elements and shale-normalized r ar...
10 Citations Source Cite
Gila Merschel4
Estimated H-index: 4
(University of Brasília),
Michael Bau41
Estimated H-index: 41
(Jacobs University Bremen)
+ 3 AuthorsBernhard Bühn9
Estimated H-index: 9
(University of Brasília)
Abstract Total and dissolved rare earth element (REEs) and U concentrations were determined for waters from Lake Paranoa (Brasilia, Brazil) sampled in the dry (November 2012) and wet seasons (July 2013). Shale-normalized REE patterns of all samples display the M-type lanthanide tetrad effect and large positive Gd anomalies, but only the total REE pool shows a positive Ce anomaly, possibly reflecting aeolian and/or fluvial input from surrounding laterites. The positive Gd anomaly increased strong...
21 Citations Source Cite
Sebastian Viehmann7
Estimated H-index: 7
(Jacobs University Bremen),
Michael Bau41
Estimated H-index: 41
(Jacobs University Bremen)
+ 3 AuthorsBernhard Bühn9
Estimated H-index: 9
(University of Brasília)
Abstract Pure marine chemical sediments, such as (Banded) Iron Formations, (B)IFs, are archives of geochemical proxies for the composition of Precambrian seawater and may provide information about the ancient hydrosphere-atmosphere system. We here present rare earths and yttrium (REY) and high precision Sm–Nd isotope data of ∼2.90 Ga old Superior-type BIFs from the Witwatersrand Supergroup, South Africa, and compare those with data for near-contemporaneous BIFs from the correlative Pongola Super...
12 Citations Source Cite
2013 in Chemical GeologyIF: 3.57
Caroline Siqueira Gomide2
Estimated H-index: 2
(Universidade Federal de Goiás),
José Affonso Brod2
Estimated H-index: 2
(Universidade Federal de Goiás)
+ 7 AuthorsMurilo Gomes Torres1
Estimated H-index: 1
(Universidade Católica de Brasília)
Abstract This work presents the first sulfur isotope data for the Tapira, Araxa, Salitre, Serra Negra, Catalao I and Catalao II alkaline–carbonatite complexes of the Alto Paranaiba Igneous Province (APIP) and the Jacupiranga complex of the Ponta Grossa Province, in central and southeast Brazil, respectively. The APIP complexes are composed of alkaline silicate rocks (bebedourite, alkali clinopyroxenite, minor syenite), phoscorites, nelsonites, and carbonatites. The Jacupiranga complex is compose...
8 Citations Source Cite
2012 in Chemical GeologyIF: 3.57
Bernhard Bühn9
Estimated H-index: 9
(University of Brasília),
Roberto Ventura Santos18
Estimated H-index: 18
(University of Brasília)
+ 1 AuthorsClaudinei Gouveia de Oliveira10
Estimated H-index: 10
(University of Brasília)
Abstract Mass-independent sulfur isotope fractionation (MIF) has been observed in rocks of the geological record older than about 2.45 Ga, a characteristic which is thought to be related to processes in the Neoarchean atmosphere. Samples recording a MIF effect therefore have to contain sulfur of the exogenic sulfur cycle, while endogenic sulfur should not show this effect. The sulfides analysed from six Brazilian deposits represent either exogenic or endogenic sulfur sources, with supposed ages ...
25 Citations Source Cite
2012 in Gondwana ResearchIF: 5.66
Joseneusa Brilhante Rodrigues5
Estimated H-index: 5
(University of Brasília),
Márcio Martins Pimentel35
Estimated H-index: 35
(Universidade Federal do Rio Grande do Sul)
+ 4 AuthorsRichard Armstrong51
Estimated H-index: 51
(Australian National University)
Abstract The Vazante Group show varied U–Pb provenance patterns along the basin. Zircon ages range from 936 to 3409 Ma, but Paleo- and Mesoproterozoic terrains constitute the main sources of the original sediments. The youngest population (~ 930 Ma) establishes the maximum depositional age of the group. Sm–Nd T DM data show the predominance of Paleoproterozoic ages (1.90–2.08 Ga) and also indicate some input from younger sources in rocks of the Lapa Formation (1.67 to 2.0 Ga) in the upper part o...
26 Citations Source Cite
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