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Skip to Search Results- 2Iron formations
- 2Precambrian
- 2Stratigraphy
- 2Uruguay
- 1Archipelago Los Roques, Venezuela
- 1Banded Iron Formation
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Fall 2018
Banded iron formations (BIF) are a key chemical sedimentary record for examining the evolution of the early oceans, atmosphere, and biosphere. While the classic model suggests that BIF were deposited by either anoxygenic photoferrotrophs or oxygen producing cyanobacteria, recent studies have...
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Chemostratigraphy of the Boolgeeda Iron Formation and Turee Creek Group, Hamersley Basin, Western Australia
DownloadFall 2018
In the most general sense, the Great Oxygenation Event (GOE) refers to the transition from oxygen poor to oxygen rich conditions on ancient Earth (Holland, 2002; Holland, 2006). It has traditionally been defined as the sedimentary intervals in which the isotopic signature for mass independent...
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Spring 2020
Clay minerals are ubiquitous at the Earth’s surface and they impart a significant influence on numerous geochemical cycles due to their high surface reactivity. Aqueous pH and ionic strength (hereafter IS) are two major factors that affect clay surface reactivity and subsequently govern trace...
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Ediacaran iron formations and carbonates from Uruguay: palaeoceanographic, palaeoclimatic and palaeobiologic implications
DownloadFall 2010
The Ediacaran in Uruguay preserves a unique record of deposits generated during the assembly of the palaeocontinent Gondwana and concurrent with major changes in the atmosphere and oceans, and the rise of animal life. Recent studies have suggested that the deep oceans remained anoxic and highly...
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Spring 2022
Cyanobacteria are among the most abundant primary producers in the oceans and are present in nearly every environment on the planet. They were one of the first organisms to evolve nearly 3.8 billion years ago, making them excellent analogs for the investigation of ancient ocean chemistry. The...
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Paleoceanographic significance of the Neoproterozoic Polanco Limestones Formation (Uruguay): stratigraphy, isotopic geochemistry and age
DownloadSpring 2016
Carbon and Strontium isotope data for marine carbonates can provide a detailed record of isotopic variations in seawater through time and have proven to be a valuable tool for interpreting biogeochemical events and correlating Neoproterozoic sedimentary successions worldwide. The Neoproterozoic...
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Fall 2018
Trace metals have been estimated to be required in one-quarter to one-third of all proteins as cofactors in metalloenzymes which code for numerous crucial biological processes such as respiration, photosynthesis, DNA and RNA synthesis, nitrogen fixation, and electron transfer reactions. However,...
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The trace metal content of modern and ancient peritidal and shallow subtidal dolomites: significance and systematics
DownloadSpring 2016
Dolomitization has traditionally been regarded as being related to the interaction of thermally active Mg-rich fluids with poorly ordered carbonate precursors of elusive origin. Our ideas on how such precursors form have evolved rapidly since the late 1990s, and microbes are now considered key...
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Using a novel approach to precisely measure the sedimentation velocity of a (bio)chemical sediment: cyanobacteria-ferrihydrite aggregates
DownloadFall 2020
Banded iron formations (BIF) are iron-rich (~20-40% Fe), siliceous (~40-50% SiO2), and organic-lean (<0.5 wt.%) sedimentary deposits that precipitated widely during the late Archean (2.7-2.5 Ga) and Paleoproterozoic (2.5-1.8 Ga). As cyanobacteria evolved, the reaction between dissolved Fe(II) and...
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Zinc in Precambrian iron formations: The record, partitioning, diagenetic effects and implications for eukaryotic metallome evolution
DownloadFall 2013
Zinc is amongst the most important trace elements for eukaryotes. Previous work has suggested it to have been at biolimiting concentrations for much of the Precambrian, thereby limiting eukaryotic evolution. Yet, the iron formation (IF) record, a critical proxy for paleomarine conditions, has...