Universität zu Köln

Ibanez-Mejia, Mauricio ORCID: 0000-0002-7839-2425, Pullen, Alex, Pepper, Martin, Urbani, Franco, Ghoshal, Gourab ORCID: 0000-0001-7593-5626 and Ibanez-Mejia, Juan C. (2018). Use and abuse of detrital zircon U-Pb geochronology-A case from the Rio Orinoco delta, eastern Venezuela. Geology, 46 (11). S. 1019 - 1023. BOULDER: GEOLOGICAL SOC AMER, INC. ISSN 1943-2682

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Abstract

Advancements in mass spectrometry methods over the past two decades have allowed for rapid measurement of (U-Th)/Pb isotopes for geochronologic applications, a tool that has deeply influenced the way sediment provenance and paleo-tectonic reconstructions are approached. Geochronology-based studies of sediment provenance typically rely on dating n approximate to 100-150 single detrital zircon crystals from individual samples, where the sample age distributions are used to make inferences about the parent age distributions, make qualitative geologic interpretations, and/or perform quantitative intersample comparisons. Most efforts to quantitatively compare detrital zircon age spectra make use of non-parametric dissimilarity statistics. Here, we use laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb detrital zircon moderate-n (n approximate to 100) and large-n (n approximate to 1000) results from unconsolidated fluvial sediments of the Rio Orinoco delta, eastern Venezuela, to highlight the concealed pitfalls of making geological interpretations based on quantitative comparisons of U-Pb age distributions alone. Three samples analyzed at large n, selected from contrastingly different mean sediment grain sizes along the active channel of the Rio Orinoco, yield large dissimilarities amongst their age spectra, resulting in the misleading conclusion that these were likely not sourced from the same parent distribution. We demonstrate that statistically significant differences amongst detrital zircon samples derived from the same (integrated) source region can be introduced by the dynamics of sediment transport, which may in turn lead to erroneous geologic interpretations arising from the inaccurate assumptions that, at present, condition the quantitative treatment of detrital zircon data.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ibanez-Mejia, Mauricio UNSPECIFIED orcid.org/0000-0002-7839-2425 UNSPECIFIED Pullen, Alex UNSPECIFIED UNSPECIFIED UNSPECIFIED Pepper, Martin UNSPECIFIED UNSPECIFIED UNSPECIFIED Urbani, Franco UNSPECIFIED UNSPECIFIED UNSPECIFIED Ghoshal, Gourab UNSPECIFIED orcid.org/0000-0001-7593-5626 UNSPECIFIED Ibanez-Mejia, Juan C. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-166935
DOI:	10.1130/G45596.1
Journal or Publication Title:	Geology
Volume:	46
Number:	11
Page Range:	S. 1019 - 1023
Date:	2018
Publisher:	GEOLOGICAL SOC AMER, INC
Place of Publication:	BOULDER
ISSN:	1943-2682
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language PROVENANCE; SEDIMENT; GRAINS; BIAS Multiple languages Geology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/16693