Project

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Trace elements in authigenic quartz

Applicant Ramseyer Karl
Number 121742
Funding scheme Project funding (Div. I-III)
Research institution Institut für Geologie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Geology
Start/End 01.11.2008 - 30.11.2009
Approved amount 58'532.00
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Keywords (8)

Trace elements; Syntaxial quartz cement; LA-ICPMS; SIMS; FTIR; Pore water characteristics; Diagenesis; EMPA

Lay Summary (English)

Lead
Lay summary
Authigenic quartz cement is one of the most abundant non-reversible pore-occluding diagenetic phases in sandstones of terrestrial and marine origin. Despite its common occurrence, important factors of quartz precipitation such as driving cause(s), source(s) of silica and significance of trace elements are insufficiently known.The project is a continuation of research on parameters controlling syntaxial quartz precipitation in sandstones. Focusing points are the quantification of trace elements and their significance for quartz precipitation at diagenetic conditions.The research is based on state-of-the-art in-situ quantification of trace elements, such as H, Li, Na, Al, and Ti, in syntaxial quartz by laser-ablation inductively-coupled-plasma-mass-spectrometry (LA-ICPMS), secondary ion mass spectrometry (SIMS), electron microprobe analyzer (EMPA) and fourier-transform infrared spectroscopy (FTIR). Samples are from the siliciclastic Haushi Group, Sultanate of Oman, which cover today’s depths ranging from surface outcrop to almost 5000 m. Previous studies unraveled a basin-wide onset of quartz precipitation mainly sourced from pressure solution concurrent with the obduction of the Oman Mountains, irrespective of burial depth or temperature. The aim is to unravel the relationship between the trace element concentration and distribution in syntaxial quartz cement and growth conditions during precipitation. To quantify element concentrations on a micron-scale with the SIMS technology we anticipate to develop appropriate synthetic quartz standarts.The findings of this study will greatly enhance the understanding of trace element uptake and distribution in quartz precipitated from an aqueous solution. It will be the first time that hydrogen is quantified in quartz on a micron scale together with other trace elements.The results will document relationships between the incorporated trace elements in authigenic quartz and its controlling parameters such as cogenetic reactions and pH buffering reactions.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

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Associated projects

Number Title Start Funding scheme
107482 Trace elements in authigenic quartz 01.11.2005 Project funding (Div. I-III)

Abstract

The proposed project is a 4th year continuation of research on parameters controlling syntaxial quartz precipitation in sandstones. Focusing points are the quantification of trace elements and their significance for quartz precipitation at diagenetic conditions.The research is based on state-of-the-art in-situ quantification of trace elements, such as H, Li, Na, Al, and Ti, in syntaxial quartz by LA-ICPMS, SIMS, and FTIR methods. Samples are from the siliciclastic Haushi Group, Sultanate of Oman, which cover today’s depths ranging from surface outcrop to almost 5000 m. Previous studies unraveled a basin-wide onset of quartz precipitation mainly sourced from pressure solution concurrent with the obduction of the Oman Mountains, irrespective of burial depth or temperature. The trace element composition and variability in syntaxial quartz cement shall be used to deduce controlling mechanisms for their uptake and thus also for quartz precipitation. Thermodynamic calculations of the pore water chemistry based on cogenetic equilibrium reactions, temperature and pH shall be performed to interpret the measured trace element composition and variability in authigenic quartz, assuming equilibrium processes for the incorporation of these elements.
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