Monte Carlo simulation results of zircon depletion effects on Hf isotopic compositions of dust
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| Natura: | Dataset Open Access |
| Lingua: | en |
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PANGAEA
2017
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| author | Újvári, Gábor Wegner, Wencke Klötzli, Urs Horschinegg, Monika Hippler, Dorothee |
| author_facet | Újvári, Gábor Wegner, Wencke Klötzli, Urs Horschinegg, Monika Hippler, Dorothee |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Combined Sr-Nd-Hf isotopic data of two reference materials (AGV-1/BCR2) and 50, 10 and 5 mg aliquots of carbonate-free fine grain (<10 µm) separates of three loess samples (Central Europe/NUS, China/BEI, USA/JUD) are presented. Good agreement between measured and reference Sr-Nd-Hf isotopic compositions (ICs) demonstrate that robust isotopic ratios can be obtained from 5-10 mg size rock samples using the ion exchange/mass spectrometry techniques applied. While 87Sr/86Sr ratios of dust aluminosilicate fractions are affected by even small changes in pretreatments, Nd isotopic ratios are found to be insensitive to acid leaching, grain-size or weathering effects. However, the Nd isotopic tracer is sometimes inconclusive in dust source fingerprinting (BEI and NUS both close to epsilon-Nd(0) -10). Hafnium isotopic values (<10 µm fractions) are homogenous for NUS, while highly variable for BEI. This heterogeneity and vertical arrays of Hf isotopic data suggest zircon depletion effects towards the clay fractions (<2 µm). Monte Carlo simulations demonstrate that the Hf IC of the dust <10 µm fraction is influenced by both the abundance of zircons present and maturity of crustal rocks supplying this heavy mineral, while the <2 µm fraction is almost unaffected. Thus, epsilon-Hf(0) variations in the clay fraction are largely controlled by the Hf IC of clays/heavy minerals having high Lu/Hf and radiogenic 176Hf/177Hf IC. Future work should be focused on Hf IC of both the <10 and <2 µm fractions of dust from potential source areas to gain more insight into the origin of last glacial dust in Greenland ice cores. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_884461 |
| institution | PANGAEA |
| language | en |
| publishDate | 2017 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Monte Carlo simulation results of zircon depletion effects on Hf isotopic compositions of dust Újvári, Gábor Wegner, Wencke Klötzli, Urs Horschinegg, Monika Hippler, Dorothee Combined Sr-Nd-Hf isotopic data of two reference materials (AGV-1/BCR2) and 50, 10 and 5 mg aliquots of carbonate-free fine grain (<10 µm) separates of three loess samples (Central Europe/NUS, China/BEI, USA/JUD) are presented. Good agreement between measured and reference Sr-Nd-Hf isotopic compositions (ICs) demonstrate that robust isotopic ratios can be obtained from 5-10 mg size rock samples using the ion exchange/mass spectrometry techniques applied. While 87Sr/86Sr ratios of dust aluminosilicate fractions are affected by even small changes in pretreatments, Nd isotopic ratios are found to be insensitive to acid leaching, grain-size or weathering effects. However, the Nd isotopic tracer is sometimes inconclusive in dust source fingerprinting (BEI and NUS both close to epsilon-Nd(0) -10). Hafnium isotopic values (<10 µm fractions) are homogenous for NUS, while highly variable for BEI. This heterogeneity and vertical arrays of Hf isotopic data suggest zircon depletion effects towards the clay fractions (<2 µm). Monte Carlo simulations demonstrate that the Hf IC of the dust <10 µm fraction is influenced by both the abundance of zircons present and maturity of crustal rocks supplying this heavy mineral, while the <2 µm fraction is almost unaffected. Thus, epsilon-Hf(0) variations in the clay fraction are largely controlled by the Hf IC of clays/heavy minerals having high Lu/Hf and radiogenic 176Hf/177Hf IC. Future work should be focused on Hf IC of both the <10 and <2 µm fractions of dust from potential source areas to gain more insight into the origin of last glacial dust in Greenland ice cores. |
| title | Monte Carlo simulation results of zircon depletion effects on Hf isotopic compositions of dust |
| topic | |
| url | https://doi.org/10.1594/PANGAEA.884461 |