Sebastian Viehmann

Sebastian Viehmann
Leibniz Universität Hannover · Institute of Mineralogy

Dr.

About

42
Publications
7,273
Reads
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470
Citations
Citations since 2016
30 Research Items
444 Citations
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
Additional affiliations
April 2017 - present
University of Vienna
Position
  • PostDoc Position
Description
  • • Preparation, acquisition, management and coordination of research projects • Reconstruction of marine habitats on Early Earth • Teaching & supervision of BSc. theses
August 2016 - March 2017
University of Vienna
Position
  • Researcher
Description
  • • Preparation of interdisciplinary research fellowships • Preparation and review of scientific manuscripts • Presentation and organisation of geology and geobiology-sedimentology seminars • Fieldwork and sampling in the Dolomites (Alps)
May 2011 - August 2016
Jacobs University
Position
  • PhD Student
Description
  • • Geochemical characterisation (major & trace element and radiogenic isotope analyses) of Precambrian chemical and clastic sediments • Investigation of the environmental conditions of the atmosphere-hydrosphere systems between 4 Ga and 500 Ma ago
Education
October 2004 - April 2011
University of Bonn
Field of study
  • Geology/ Palaeontology

Publications

Publications (42)
Article
The geodynamic reorganization of major cratonic blocks during the assembly of Gondwana in the late Neoproterozoic caused a (bio)geochemical evolution of marine habitats that witnessed fluctuating seawater oxygenation and nutrient fluxes. Previous studies of carbonates deposited on the Yangtze Platform (South China) have shown their use as reliable...
Article
Unique deposits that formed in the Precambrian oceans are the Banded Iron-Formations (BIFs) which are chemical sediments comprised of alternating layers of iron- and silica-dominated precipitates. The origin of this enigmatic banding is still debated, with most favoring a primary sedimentary and a few others arguing for a secondary diagenetic origi...
Article
Full-text available
Radiogenic isotope systems are important geochemical tools to unravel geodynamic processes on Earth. Applied to ancient marine chemical sediments such as banded iron formations , the short-lived 182 Hf-182 W isotope system can serve as key instrument to decipher Earth's geodynamic evolution. Here we show high-precision 182 W isotope data of the 2.7...
Preprint
Radiogenic isotope systems are important geochemical tools to unravel geodynamic processes on Earth1. Applied to ancient marine chemical sediments such as banded iron formations (BIFs), the short-lived 182Hf-182W isotope system can serve as key instrument to decipher Earth’s geodynamic evolution. High-precision 182W isotope data of the 2.7 Ga old B...
Preprint
Unique deposits that formed in the Precambrian oceans are the Banded Iron-Formations (BIFs) which are chemical sediments comprised of alternating layers of iron- and silica-dominated precipitates. The origin of this enigmatic banding is still debated, with most favoring a primary sedimentary and a few others arguing for a secondary diagenetic origi...
Article
Full-text available
Understanding the delayed rise of eukaryotic life on Earth is one of the most fundamental questions about biological evolution. Numerous studies have presented evidence for oxygen and nutrient limitations in seawater during the Mesoproterozoic era, indicating that open marine settings may not have been able to sustain a eukaryotic biosphere with co...
Article
Banded iron formations (BIFs) were deposited before and concurrent with the Great Oxidation Event at ∼2.33 Ga. They provide useful archives that document the transformation of the Precambrian hydrosphere from anoxic to progressively oxygenated conditions. Their formation involves removal of oceanic Fe by either inorganic or biologically promoted Fe...
Article
The Urucum area of Brazil hosts a series of Cryogenian ironstones intercalated by oxide-dominated manganese layers. The Urucum iron and manganese formations (IF-MnF) are among the largest sedimentary iron and associated manganese deposits of the Neoproterozoic, however, the depositional model and the source of metals for the IF-MnF in this area are...
Article
Full-text available
Understanding the origin and evolution of life on Earth and potentially other planets in our solar system is of fundamental interest for humanity. For the longest time in Earth's history, life evolved in microbial communities. It is, however, still incompletely understood how, when and where such habitable environments formed and how microbial comm...
Article
Drill core and outcrop samples of pure marine chemical sediments (banded iron formation (BIF), manganese formation (MnF), jaspilites, lutites, and cherts) from the transition of the ~2426 Ma old Ongeluk Formation into the 2413 Ma old Hotazel Formation, Transvaal Supergroup, South Africa, reveal remarkable changes of seawater chemistry in the Transv...
Article
Carbonates and cherts in the 3.35 billion-year-old Strelley Pool Formation (Fm.; Australia) host stromatolites that are among the oldest remnants of life on Earth. However, it is still not entirely clear whether these mineral phases are authigenic precipitates, and whether they represent reliable geochemical archives of early Earth environments. He...
Article
Full-text available
The behaviour of bioavailable trace metals and their stable isotopes in the modern oceans is controlled by uptake into phototrophic organisms and adsorption on and incorporation into marine authigenic minerals. Among other bioessential metals, Cd and its stable isotopes have recently been used in carbonate lithologies as novel tracer for changes in...
Article
Investigation of redox variations in recent and paleo-oceans has been of particular scientific interest to elucidate the rise and variations of the atmospheric oxygen level by analyses of isotopic signatures of redox-sensitive elements like Fe, Mo, and U. Vanadium is another redox-sensitive metal that has become the target of stable isotope researc...
Article
Full-text available
Cadmium (Cd) isotopes are an emerging proxy for biological controlled metal and nutrient cycling in the modern oceans, but its potential as a geochemical proxy in ancient environments is still uncertain yet. Sequential leaching experiments of organic matter (OM)-rich shales from the early Cambrian Niutitang Formation (Fm.) were performed in order t...
Article
Chromium mobilization and isotope fractionation during water-rock interaction in presence of the biogenic siderophore desferrioxamine B (DFOB) was studied with batch leaching experiments on chromitite and other igneous oxide and silicate rocks. Siderophores are a group of organic ligands synthesized and excreted by bacteria, fungi and plants to enh...
Article
The Pennine Orefield is one of the most important ore fields for Pb-Zn-Ba-F mineralization in Great Britain. It is subdivided into the Northern Pennine Orefield (NPO), consisting of the Alston and Askrigg Blocks, and the Southern Pennine Orefield (SPO). The Alston Block is underlain by the early Devonian Weardale Granite and the Askrigg Block by th...
Article
Reconstructing the environmental conditions that supported early life on Earth relies on well-preserved geochemical archives in the rock record. However, many geochemical tracers either lack specificity or they are affected by post-depositional alteration. We present a data set of major and trace element abundances and Cd isotope compositions of do...
Article
Full-text available
The Hf-Nd isotope systems are coupled in magmatic systems, but incongruent Hf weathering (‘zircon effect’) of the continental crust leads to a decoupling of the Hf-Nd isotope systems in low-temperature environments during weathering and erosion processes. The Hf-Nd isotope record was recently dated back from the Cenozoic oceans until the Archean, s...
Article
Pure, stromatolitic limestones from the ∼2.44 to 2.43 Ga old Rooinekke Formation, Transvaal Supergroup (South Africa), provide unique insight into the geochemistry of Paleoproterozoic shallow seawater and, therefore, into the evolution of ambient redox-levels of the Earth's atmosphere-hydrosphere system. In contrast to the stromatolitic Klipput dol...
Article
Bulk-rock Lu-Hf and Sm-Nd isotope compositions, as well as major and trace element data are presented for metavolcanic rocks from the Mesoarchaean (ca. 3075 Ma) Ivisaartoq Supracrustal Belt in the Nuuk region of southern West Greenland. The Hf t calculated at 3075 Ma range from +0.8 to +3.1 and the corresponding Nd t values range from +0.7 to +3.6,...
Article
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...
Article
The ca. 3480-3430 Ma Tsawela Gneiss (TG) is a well-preserved coarse-grained diorite to tonalite suite within the Ancient Gneiss Complex of Swaziland, eastern Kaapvaal craton. These gneisses are texturally and compositionally distinct from the hosting oldest components of the ca. 3200-3660 Ma TTG-type Ngwane Gneisses (NG). Major and trace elements,...
Article
Full-text available
Fragmented supracrustal rocks are typical components of Archaean high-grade gneiss terranes, such as those in the North Atlantic Craton. Here we present the first major, trace element and Nd-Hf isotope data for amphibolites collected in the yet poorly studied southern inner Ameralik fjord region of southern West Greenland. In addition, new U-Pb zir...
Research
Manuscript (in press) about the Nd- and Hf-isotopic compositions of Mesoarchaean amphibolites from the Ameralik region and the identification of new areas of Eoarchaean crust in SW Greenland
Article
Marine chemical sediments from the Temagami banded iron formation (BIF) in Canada exhibit nonchondritic Zr/Hf and Y/Ho ratios and seawater-like rare earth element patterns, indicating that their Hf and Nd are not detrital, but derived from seawater. This is confirmed by Sm-Nd and Lu-Hf isochron ages of 2605 ± 140 Ma (initial εNd +0.03 ± 4.1) and 27...
Conference Paper
Hf-Nd isotope decoupling in Early Precambrian seawater S.VIEHMANN1,3*,J.E. HOFFMANN1,2,C.MÜNKER2 AND M.BAU3 1Steinmann Institut, Universität Bonn, Germany 2Institut für Geologie und Mineralogie, Universität zu Köln, Germany 3Jacobs University Bremen,Earth and Space Science Program, Germany *present address, s.viehmann@jacobs-university.de Banded...
Article
Micro-computed tomography is a non-destructive technique that allows the study of 3D meteorite petrography. The tech-nique produces a unique and instructive visualisation of the meteorite for quantifying its components. We studied the overall petrography of the two CV chondrites Allende and Mokoia to constrain their formation histories. A set of mo...

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Projects

Projects (3)
Project
Stromatolites, i.e., lithified microbial mats that occur in sedimentary successions from at least 3.4 billion years ago until today, hold the geochemical key to our understanding of the evolution of microbial life on Earth and may also provide a blueprint for planetary studies. This review targets the potential and pitfalls of emerging and established isotope applications to stromatolites based on improved and newly developed analytical and technical capabilities in the last decades.
Project
A petrological and geochemical investigation of Mesoarchaean metavolcanic andesitic rocks from West Greenland. Existing data points to large degrees of magma mixing between mafic and felsic endmembers or alternatively the introduction of a felsic contaminant into the mantle source of these high-Mg andesites. The aim of this project is to determine the petrogenesis of the metaandesites from West Greenland and test if they represent an early analogue similar to andesites from modern subduction zone environments.