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Coupling of in-situ Sm-Nd Systematics and U-Pb dating of monazite and allanite with applications to crustal evolution studies

McFarlane, Christopher; McCulloch, Malcolm

Description

Here we demonstrate the capabilities of LA-MC-ICPMS Sm-Nd-isotope measurements applied to two of the most common LREE-enriched minerals in the Earth's crust: monazite and allanite. We show that high precision measurements of143Nd/144Nd comparable to solution-based MC-ICPMS measurements (< 0.5 epsilon units) can be achieved for laser spot sizes ranging from 16 to 50 μm. At this scale, sub-grain domains previously dated using in-situ U-Th-Pb geochronology (e.g., ion-microprobe) can be...[Show more]

dc.contributor.authorMcFarlane, Christopher
dc.contributor.authorMcCulloch, Malcolm
dc.date.accessioned2015-12-07T22:44:03Z
dc.identifier.issn0009-2541
dc.identifier.urihttp://hdl.handle.net/1885/25044
dc.description.abstractHere we demonstrate the capabilities of LA-MC-ICPMS Sm-Nd-isotope measurements applied to two of the most common LREE-enriched minerals in the Earth's crust: monazite and allanite. We show that high precision measurements of143Nd/144Nd comparable to solution-based MC-ICPMS measurements (< 0.5 epsilon units) can be achieved for laser spot sizes ranging from 16 to 50 μm. At this scale, sub-grain domains previously dated using in-situ U-Th-Pb geochronology (e.g., ion-microprobe) can be characterized with in-situ Nd-isotopic and Sm/Nd elemental measurement to determine robust initial143Nd/144Nd ratios and investigate grain-scale isotopic heterogeneities. In addition, the LREE-enriched pattern and Eu* anomaly can be simultaneously determined from in-situ Ce, Nd Sm, Eu, and Gd concentration measurements. This approach is applied here to granulite-facies metamorphic rocks previously dated in-situ using an ion-microprobe. It is shown that precise initial143Nd/144Nd ratios and LREE concentrations measured in monazite and allanite grains by LA-MC-ICPMS on grain mounts and in-situ in polished thin sections can provide constraints on isotopic inheritance, and an understanding of the origin of compositional domains (e.g., core-overgrowth features) within a textural context. Differences between monazite U-Pb and garnet-whole-rock Sm-Nd isochron ages can also be used to estimate crustal cooling rates, thereby elucidating the timescales of crustal residence of high-grade terrains.
dc.publisherElsevier
dc.sourceChemical Geology
dc.subjectKeywords: allanite; crustal evolution; geochronology; granulite facies; inductively coupled plasma method; monazite; samarium-neodymium dating; uranium-lead dating Allanite; LA-MC-ICPMS; Monazite; Sm--Nd; U--Pb geochronology
dc.titleCoupling of in-situ Sm-Nd Systematics and U-Pb dating of monazite and allanite with applications to crustal evolution studies
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume245
dc.date.issued2007
local.identifier.absfor040203 - Isotope Geochemistry
local.identifier.ariespublicationu3533991xPUB36
local.type.statusPublished Version
local.contributor.affiliationMcFarlane, Christopher, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationMcCulloch, Malcolm, College of Physical and Mathematical Sciences, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.issue2007
local.bibliographicCitation.startpage45
local.bibliographicCitation.lastpage60
local.identifier.doi10.1016/j.chemgeo.2007.07.020
dc.date.updated2015-12-07T11:20:46Z
local.identifier.scopusID2-s2.0-34748849265
CollectionsANU Research Publications

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