Kristoffer Szilas

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Below you can read a summary of the main findings for each of my publications, and also get access to the supporting data

[19]  Szilas et al. (2017). Highly refractory Archaean peridotite cumulates: Petrology and geochemistry of the Seqi Ultramafic Complex, SW Greenland. Geoscience Frontiers (in press). Download PDF of the paper


Summary: Cumulate peridotites with olivine-Mg# of 91 to 93 formed from a highly magnesian melt. Such melt extraction would have resulted in a highly depleted mantle residue similar to observed SCLM xenoliths in the region. Further studies of these peridotite cumulates may therefore yield new insights into the formation of the cratonic mantle of SW Greenland.


Data:

Table S1 - Bulk-rock geochemical data

Table S2 - Bulk-rock PGE data

Table S3 - Electron microprobe data

Table S4 - LA-ICP trace element data

Table S5 - U-Pb zircon data

Table S6 - Mossbauer data

Appendix A - Supplementary field observations

Appendix B - Supplementary microphotographs

Appendix C - Supplementary BSE microprobe images

Appendix D - Supplementary geochemical diagrams

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[18]  Rollinson et al. (2017). Archaean chromitites show constant Fe3+/ΣFe in Earth´s asthenospheric mantle since 3.8 Ga. Lithos 282, 316-325. Download PDF of the paper


Summary: Chromite Fe3+/ΣFe measured by Mössbauer spectroscopy shows a constant ratio of around 0.2 through time demonstrating no change in the oxygen fugacity of Earth´s mantle since at least 3800 million years ago.


Data:

Table S1 - Mineral data

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[17]  Szilas et al. (2017). Hafnium isotope constraints on the origin of Mesoarchaean andesites in southern West Greenland, North Atlantic craton. In: Halla, J., Whitehouse, M.J., Ahmad, T. & Bagai, Z. (Eds.) Crust-Mantle Interactions and Granitoid Diversification: Insights from Archaean Cratons. Geological Society, London, Special Publications 449, 19-38. Download PDF of the paper


Summary: Modelling of the initial Hf-isotope evolution of Archaean andesites from SW Greenland demonstrates that such volcanic rocks formed either by (1) high-degree partial melting of mafic proto-crust with chondritic Hf-isotope composition, or by (2) magma mixing between a felsic chondritic component and juvenile mafic melts.


Data:

Table 1 - Bulk-rock data

Table 2 - Lu-Hf isotope data

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[16]  Szilas et al. (2016). Combined bulk-rock Hf- and Nd-isotope compositions of Mesoarchaean metavolcanic rocks from the Ivisaartoq Supracrustal Belt, SW Greenland: Deviations from the mantle array caused by crustal recycling. Chemie der Erde 76, 543-554. Download PDF of the paper


Summary: Lack of isotope and trace element correlations for metavolcanic rocks from the Ivisaartoq supracrustal belt suggests incomplete equilibration, despite clear evidence for crustal assimilation in the form of inherited xenocrystic zircon. However, high-degree melts (picrites) samples chondritic components in the source region.


Data:

Table 1 - Major and trace element data

Table 2 - Isotope data

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[15]  Szilas et al. (2016). Aluminous gneiss derived by weathering of basaltic source rocks in the Neoarchean Storø Supracrustal Belt, southern West Greenland. Chemical Geology 441, 63-80.  Download PDF of the paper


Summary: It is debated whether sillimanite-garnet-biotite-plagioclase paragneisses associated with amphibolites, represent weathering products or hydrothermal leaches of the latter. We show that fractionation/redistribution of components such as Th, Cr and Ni are incompatible with an in situ process and that mechanical reworking is required. Thus, such paragneisses likely represent weathering products of a mix mafic-ultramafic source.


Data:

Table 1 - Geochronology overview

Table S1 - Bulk-rock geochemical data

Table S2 - Mass-balance calculations

Appendix A - Isocon mass-balance modeling

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[14]  Szilas et al. (2015). Sm-Nd and Lu-Hf isotope and trace-element systematics of Mesoarchaean amphibolites, inner Ameralik fjord, southern West Greenland. Mineralogical Magazine 79, 857-876. Download PDF of the paper


Summary: The studied amphibolites which are apparently most evolved and incompatible element-rich  also happen to have the most depleted Hf-isotope compositions. This apparent paradox may be explained by the sampling of a local mantle source region with ancient previous melt depletion, which was re-enriched by a fluid component during subduction zone volcanism or alternatively by preferential melting of an  ancient pyroxenite component in the mantle source of the enriched rocks.


Data:

Table S1 - Major and trace element data

Table S2 - Nd and Hf isotope data

Table S3 - Zircon U-Pb isotope data

Appendix A - Zircon images

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[13]  Szilas et al. (2015). The petrogenesis of ultramafic rocks in the >3.7 Ga Isua supracrustal belt, southern West Greenland: Geochemical evidence for two distinct magmatic cumulate trends. Gondwana Research 28, 565-580. Download PDF of the paper


Summary: Dunites at Isua have previously been postulated to represent the remnants of highly depleted fore-arc mantle wedge. In this study we used thermodynamic modelling of the melt evolution to show that such dunites represent cumulate rocks that form as a natural consequence of fractional crystallisation of the associated volcanic sequences.


Data:

Table S1 - ACMELabs Data

Table S2 - Lamont Data

Table S3 - Normative mineralogy

Table S4 - PGE Data

Table S5 - Electron microprobe data

Appendix A - Detailed analytical procedures

Appendix B - Supplementary Figures

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[12]  Szilas et al. (2015). Peridotite enclaves hosted by Mesoarchaean TTG-suite orthogneisses in the Fiskefjord region of southern West Greenland. GeoResJ 7, 22-34. Download PDF of the paper


Summary: This study presents preliminary geochemical data for enigmatic peridotite bodies that are found as inclusions within TTG gneiss in SW Greenland. Our data suggest that these ultramafic rocks represent fragments of layered complexes that predate the continental crust of the region.


Data:

Table S1 - AcmeLabs major and trace element data

Table S2 - LDEO trace element data

Table S3 - GEUS major and trace element data

Table S4 - UQAC PGE data

Table S5 - AMNH and GIC microprobe data

Appendix A - Field photographs

Appendix B - Methods description

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[11]  Keulen et al. (2014). Meso- and Neoarchaean geological history of the Bjørnesund and Ravns Storø Supracrustal Belts, southern West Greenland: settings for gold enrichment and corundum formation. Precambrian Research 254, 36-58. Download PDF of the paper


Summary: This study describes the regional geological evolution of supracrustal components of the Fiskenæsset Anorthosite Complex, which are relevant for local ruby and gold deposits.


Data:

Table S1 - Zircon U-Pb isotope data

Appendix A - Electronic supplement

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[10]  Szilas et al. (2014). The Neoarchaean Storø Supracrustal Belt, Nuuk region, southern West Greenland: An arc-related basin with continent-derived sedimentation. Precambrian Research 247, 208-222. Download PDF of the paper


Summary: A reinterpretation of the supracrustal rocks on Storø Island with implications for the local gold mineralisation, and the geodynamic setting of the metavolcanic sequence. We find that the gabbro-anorthosite complex predates the Storø Supracrustal Belt (sensu stricto) and may have formed the basement on which the latter erupted.


Data:

Table S1 - WR data

Table S2 - Sm-Nd data

Table S3 - U-Pb data

Appendix A - Previous work on Storø

Appendix B - Lithological units

Appendix C - Additional figures

Appendix D - Analytical methods description

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[9]  Szilas et al. (2014). The geochemical composition of serpentinites in the Mesoarchaean Tartoq Group, SW Greenland: Harzburgitic cumulates or melt-modified mantle? Lithos 198, 103-116. Download PDF of the paper


Summary: The studied serpentinites have bulk-rock compositions that points to a harzburgitic protolith, yet PGEs show both mantle-like and cumulate-late patterns.


Data:

Table 1 - Major and trace element data

Table 2 - PGE Data

Table 3 - Electron microprobe data

Table 4 - LA-ICP-MS data

Table 5 - Re-Os isotope data

Appendix A - Detailed methods description

Appendix B - Supplementary diagrams

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[8]  Szilas et al. (2013). Archaean andesite petrogenesis: Insights from the Grædefjord Supracrustal Belt, southern West Greenland. Precambrian Research 236, 1-15. Download PDF of the paper


Summary: Binary mixing between felsic and mafic end-members are proposed for andesites based of geochemical modelling and Hf-isotopes, which indicates processes similar to those operating in modern subduction zones.


Data:

Table 1 - WR Data

Table 2 - PGE data

Table 3 - Sm-Nd Lu-Hf Data

Table 4 - U-Pb Data

Appendix A - Methods description

Appendix B - Supplementary diagrams

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[7]  Szilas & Garde (2013). Mesoarchaean aluminous rocks at Storø, southern West Greenland: New age data and evidence of premetamorphic seafloor weathering of basalts. Chemical Geology 354, 124-138. Download PDF of the paper


Summary: Preliminary geochemical data are used to perform isocon modelling of aluminous paragneisses with a proposed mafic precursor. This study supports an in situ formation of the paragneisses by leaching. However, the study was severely limited by lack of a coherent sample profile (see Szilas et al. 2016 Chemical Geology issue 441 for a reinterpretation based on better constrained drill-core samples).


Data:

Table 1 - WR data

Table 2 - Zircon U-Pb isotope data

Table 3 - Isocon results

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[6]  Bernstein et al. (2013). Highly depleted cratonic mantle in West Greenland extending into diamond stability field in the Proterozoic. Lithos 168, 160-172. Download PDF of the paper


Summary: Garnet within peridotite xenoliths from the Qeqertaa dyke suggests the depth of the xenolith suite to be near the diamond stability-field, which is substantiated by the finding of diamonds in bulk samples. This indicates the presence of a lithospheric mantle domain dominated by high-Mg# dunite to this depth in Palaeoproterozoic time.


Data:

Table S1 - Microprobe data

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[5]  Szilas et al. (2013). Remnants of arc-related Mesoarchaean oceanic crust in the Tartoq Group, SW Greenland. Gondwana Research 23, 436-451. Download PDF of the paper


Summary: Bulk-rock trace element compositions of metabasalts at Tartoq in SW Greenland are compatible with them having formed in an arc-related environment. The lithological association furthermore indicates these rocks having formed as oceanic crust and may thus essentially represent a fragmented Archaean ophiolite sequence.


Data:

Table 1 - Geochemical data

Table 2 - Disko-1 standard

Table 3 - Isotope data

Table 4 - Zircon U-Pb isotope data for sample 510772

Table 5 - Zircon U-Pb isotope data for sample 510657

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[4]  Kisters et al. (2012). Geology of an Archaean accretionary complex - The structural record of burial and return flow in the Tartoq Group of South West Greenland. Precambrian Research 220, 107-122. Download PDF of the paper


Summary: Structural interpretation of the Tartoq supracrustal rocks support formation in an accretionary environment.


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[3]  Szilas et al. (2012). Complex calc-alkaline volcanism recorded in Mesoarchaean supracrustal belts north of Frederikshåb Isblink, southern West Greenland: Implications for subduction zone processes in the early Earth. Precambrian Research 208, 90-123. Download PDF of the paper


Summary: Geochemical evidence for magma mixing processes in the formation of Archaean andesites, which may be similar to modern subduction zone environments.


Data:

Table 1 - WR Geochemistry

Table 2 - Disko-1 standard

Table 3 - Isotope Data

Table 4 - U-Pb Zircon Data

Appendix A - Methods

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[2]  Szilas et al. (2012). Origin of Mesoarchaean arc related rocks with boninite/komatiite affinities from southern West Greenland. Lithos 144, 24-39. Download PDF of the paper


Summary: Ultramafic rocks with arc-like geochemical signatures, which may either represent crustal contamination or metasomatism of mantle source by subduction-like processes.


Data:

Table S1 - Major and trace element data

Table S2 - PGE Data

Table S3 - Disko-1 standard

Table S4 Sm-Nd isotope data

Table S5 - Zircon U-Pb data

Table S6 - Zircon U-Pb-Hf data

Table S7 - Zircon oxygen data

Table S8 - Tourmaline data

Appendix A - Methods

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[1]  Scherstén et al. (2012). Re-Os and U-Pb constraints on gold mineralisation events in the Meso- to Neoarchaean Storø greenstone belt, Storø, southern West Greenland. Precambrian Research 200, 149-162. Download PDF of the paper


Summary: Isotope constraints on the geochronology of sulfides associated with gold mineralisation at Storø, which support two distinct events although a prolonged metamorphic event cannot be excluded.


Data:

Appendix A - LA-SF-ICP-MS U-Th-Pb dating

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Figure: Geological map of SW Greenland showing the areas that I done research on. Numbers match the publication list above.