Source to sink zircon grain shape: Constraints on selective preservation and significance for Western Australian Proterozoic basin provenance
The effect of selective preservation during transportation of zircon grains on the detrital age spectrum is difficult to quantify and could potentially lead to systematic bias in provenance analysis. Here we investigate whether the shape of detrital zircon grains holds provenance information and if...
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| Format: | Article |
| Language: | English |
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Elsevier
2018-03-01
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| Series: | Geoscience Frontiers |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674987117300567 |
| _version_ | 1797713415495483392 |
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| author | V. Markwitz C.L. Kirkland |
| author_facet | V. Markwitz C.L. Kirkland |
| author_sort | V. Markwitz |
| collection | DOAJ |
| description | The effect of selective preservation during transportation of zircon grains on the detrital age spectrum is difficult to quantify and could potentially lead to systematic bias in provenance analysis. Here we investigate whether the shape of detrital zircon grains holds provenance information and if the grain shape can assist in understanding preservation. We applied multiple linear regression analysis to identify significant shape properties in detrital zircons from Proterozoic metasediments of the Capricorn and Amadeus basins and their Archean and Proterozoic sources in the Yilgarn Craton and the Musgrave Province in Western Australia. Digital images and isotopic data from 819 SIMS U–Pb dated zircons were examined for correlation between grain shape, age, U and Th content. Out of twelve shape descriptors measured, Minor Axis, the width of zircon grains perpendicular to the crystallographic c-axis, consistently shows the most significant correlation with isotopic age. In the studied population Archean grains are narrower than Proterozoic grains: the probability that grains wider than 75 μm are Archean is less than 30%.
Calculations of the proportions of source material in sedimentary rocks relative to the proportions of source material in the overall catchment area (erosion parameter ‘K’ calculated based on age spectra) produced values typical for mature river systems, with K = 6 for the Yilgarn-Capricorn and K = 5.5 for the Musgrave-Amadeus source-sink system. For the Yilgarn-Capricorn system, we also calculated ‘K’ based on Minor Axis, to determine whether grain width can be linked to age populations. Results of the shape-based K of 5.3 suggest a similarity between age-based and shape-based ‘K’ values, demonstrating that zircon grain width may be a useful discriminator of provenance. Contrary to commonly applied qualitative shape classifications, we found no consistent correlations between shape descriptors of magmatic zircons and the composition of their host rock. While metamict zircons were preferentially removed during transport, the similarities in grain shape and age distribution of magmatic and detrital populations suggest that hydraulic sorting did not have a significant effect. We conclude that transport of zircon grains from magmatic source to sedimentary sink affects their width less than their length. |
| first_indexed | 2024-03-12T07:36:08Z |
| format | Article |
| id | doaj.art-578876587d4d4119bd4f011fc6ac011b |
| institution | Directory Open Access Journal |
| issn | 1674-9871 |
| language | English |
| last_indexed | 2024-03-12T07:36:08Z |
| publishDate | 2018-03-01 |
| publisher | Elsevier |
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| series | Geoscience Frontiers |
| spelling | doaj.art-578876587d4d4119bd4f011fc6ac011b2023-09-02T21:30:48ZengElsevierGeoscience Frontiers1674-98712018-03-019241543010.1016/j.gsf.2017.04.004Source to sink zircon grain shape: Constraints on selective preservation and significance for Western Australian Proterozoic basin provenanceV. Markwitz0C.L. Kirkland1School of Earth & Environment, The University of Western Australia, Crawley, WA 6009, AustraliaDepartment of Applied Geology, Centre for Exploration Targeting – Curtin Node, John de Laeter Centre, Institute of Geoscience Research (TIGeR), Curtin University, WA 6045, AustraliaThe effect of selective preservation during transportation of zircon grains on the detrital age spectrum is difficult to quantify and could potentially lead to systematic bias in provenance analysis. Here we investigate whether the shape of detrital zircon grains holds provenance information and if the grain shape can assist in understanding preservation. We applied multiple linear regression analysis to identify significant shape properties in detrital zircons from Proterozoic metasediments of the Capricorn and Amadeus basins and their Archean and Proterozoic sources in the Yilgarn Craton and the Musgrave Province in Western Australia. Digital images and isotopic data from 819 SIMS U–Pb dated zircons were examined for correlation between grain shape, age, U and Th content. Out of twelve shape descriptors measured, Minor Axis, the width of zircon grains perpendicular to the crystallographic c-axis, consistently shows the most significant correlation with isotopic age. In the studied population Archean grains are narrower than Proterozoic grains: the probability that grains wider than 75 μm are Archean is less than 30%. Calculations of the proportions of source material in sedimentary rocks relative to the proportions of source material in the overall catchment area (erosion parameter ‘K’ calculated based on age spectra) produced values typical for mature river systems, with K = 6 for the Yilgarn-Capricorn and K = 5.5 for the Musgrave-Amadeus source-sink system. For the Yilgarn-Capricorn system, we also calculated ‘K’ based on Minor Axis, to determine whether grain width can be linked to age populations. Results of the shape-based K of 5.3 suggest a similarity between age-based and shape-based ‘K’ values, demonstrating that zircon grain width may be a useful discriminator of provenance. Contrary to commonly applied qualitative shape classifications, we found no consistent correlations between shape descriptors of magmatic zircons and the composition of their host rock. While metamict zircons were preferentially removed during transport, the similarities in grain shape and age distribution of magmatic and detrital populations suggest that hydraulic sorting did not have a significant effect. We conclude that transport of zircon grains from magmatic source to sedimentary sink affects their width less than their length.http://www.sciencedirect.com/science/article/pii/S1674987117300567Zircon grain shapeU–Pb geochronologyDetritalWhole rock geochemistryPrecambrian |
| spellingShingle | V. Markwitz C.L. Kirkland Source to sink zircon grain shape: Constraints on selective preservation and significance for Western Australian Proterozoic basin provenance Geoscience Frontiers Zircon grain shape U–Pb geochronology Detrital Whole rock geochemistry Precambrian |
| title | Source to sink zircon grain shape: Constraints on selective preservation and significance for Western Australian Proterozoic basin provenance |
| title_full | Source to sink zircon grain shape: Constraints on selective preservation and significance for Western Australian Proterozoic basin provenance |
| title_fullStr | Source to sink zircon grain shape: Constraints on selective preservation and significance for Western Australian Proterozoic basin provenance |
| title_full_unstemmed | Source to sink zircon grain shape: Constraints on selective preservation and significance for Western Australian Proterozoic basin provenance |
| title_short | Source to sink zircon grain shape: Constraints on selective preservation and significance for Western Australian Proterozoic basin provenance |
| title_sort | source to sink zircon grain shape constraints on selective preservation and significance for western australian proterozoic basin provenance |
| topic | Zircon grain shape U–Pb geochronology Detrital Whole rock geochemistry Precambrian |
| url | http://www.sciencedirect.com/science/article/pii/S1674987117300567 |
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