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| Titel |
LA-ICP-MS trace element mapping and its application to geochemical transport in garnet |
| VerfasserIn |
Tom Raimondo, Ben Wade, Justin Payne, Martin Hand, Chris Clark, Robert Anczkiewicz, Anthony Reid |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250090362
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| Publikation (Nr.) |
 EGU/EGU2014-4596.pdf |
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| Zusammenfassung |
| Existing instrumentation used to interrogate trace element distributions in geological samples
includes EPMA, TEM, SEM, SIMS and synchrotron XRF/XRD analysis. Each technique has
its inherent strengths and limitations, whether they relate to detection limits, analytical
volumes, sample preparation, and/or instrumentation cost and accessibility. Traditionally,
LA-ICP-MS has been used to quantify trace element (wt%–ppb) content in a wide
variety of materials via spot analysis. However, its utility as an imaging tool has
recently emerged to allow 2D mapping with excellent detection limits (ppb) over
a wide isotopic range (7Li to 238U), with minimal sample preparation required.
This is achieved by rastering of the focused laser beam in linear transects, which
are then stitched together by post-acquisition processing to form a quantified or
semi-quantified image of the trace element distribution. Large suites of isotopes are able to be
collected simultaneously, allowing access to substantially increased geochemical
information from analysed samples. We demonstrate the use of the LA-ICP-MS imaging
technique to reveal complex trace element zonation patterns in a variety of garnets
affected by fluid–rock interaction, including those from metasomatised mid-crustal
shear zones and a calcsilicate skarn deposit. Such detailed geochemical records
shed light on trace element behaviour during metasomatic processes, including
their impact on Sm-Nd and Lu-Hf garnet geochronology. Ultimately, this allows
for the construction of coupled P –T –t–fluid histories from individual samples. |
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