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Molecular and isotopic biogeochemistry of Neoproterozoic sediments from SW-Gondwana - insight into early palaeoclimatic changes and evolution of life

English title Molecular and isotopic biogeochemistry of Neoproterozoic sediments from SW-Gondwana - insight into early palaeoclimatic changes and evolution of life
Applicant Spangenberg Jorge
Number 121808
Funding scheme Project funding (Div. I-III)
Research institution Institut de Minéralogie et Géochimie Université de Lausanne
Institution of higher education University of Lausanne - LA
Main discipline Geochemistry
Start/End 01.11.2008 - 31.10.2009
Approved amount 71'226.00
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Keywords (12)

neoproterozoic; global changes; glaciations; metabolic evolution; acritarchs; stable isotopes; hydrocarbon biomarkers; carbonates; kerogen; GC-MSD; GC-C-IRMS; CSIA

Lay Summary (English)

Lead
Lay summary
The proposal requests 12 months funding for the termination of the doctoral study of Mariluz Velasquez on the biogeochemistry of Late Proterozoic to Early Cambrian (LPEC) sediments of SW-Gondwana. This study started on 1st November 2005 as a major part of the SNSF request #200021-10942. The main goal of the Ph.D. work is to link biogeochemical changes with known changes of the fossil record and occurence of glaciation lithologies in the Neoproterozoic to Cambrian sediments of the Corumbá Group (CG, SW-Brazil), the Arroyo del Soldado Group (ASG, Uruguay), and Sierras Bayas Group (SBG, Argentina), by using inorganic, organic and isotopic geochemistry. These LPEC sections are part of the Rio de la Plata Craton, SW-Gondwana. The biogeochemistry of these continuous sedimentary sequences with well-preserved fossil record in these three units provides new insight on changes in climate and chemistry of oceans, probably triggering the extraordinary life evolution, in the South-American part of SW-Gondwana. Ms. Velasquez performed two sampling campaigns and performed numerous geochemical analyses including isotopic data from carbonates (?13C and ?18O) and associated organic carbon (13C/12C and 15N/14N), concentrations of major, trace, and rare earth elements and distribution of hydrocarbons. She achieved important new results, which constrain the chemical and biological changes on the Ediacaran ocean in SW-Gondwana. The stable carbon isotope composition of carbonates and kerogen were used to trace changes in Neoproterozoic ocean chemistry, particularly in oxic/anoxic stages. The molecular composition of biomarker hydrocarbons allowed defining the microbial diversity participating at the evolution of early life. The scientific results of the first 27 months of the project are summarized in two manuscripts submitted for publication in reviewed journals and several abstracts (3 extended and 3 short). Further publications are in preparation.
Direct link to Lay Summary Last update: 21.02.2013

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Number Title Start Funding scheme
109421 Molecular and isotopic biogeochemistry of Neoproterozoic sediments from SW-Gondwana - insight into early palaeoclimatic changes and evolution of life 01.11.2005 Project funding (Div. I-III)

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