Evaluating the impact of Pb volatilization during 40Ar/39Ar CO2 laser fusion upon LA-ICP-MS measurement of Pb isotopic composition of detrital K-feldspar

Shulaker, Danielle Ziva; Hourigan, J. K.; Grove, Marty

doi:10.1016/j.chemgeo.2018.02.021

Cited by 2 publications

(1 citation statement)

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“…The advantage of reporting 204 Pb measurements is evaluation of thorogenic and uranogenic ingrowth. However, the accurate measurement of 204 Pb is challenging in high‐throughput LA‐ICP‐MS studies due to the interference of 204 Hg carrier gas (Shulaker et al, 2018), and thus, removing 204 Pb normalization generally decreases uncertainty on the other Pb‐isotopic ratio measurements. This normalization to 204 Pb amplifies the resulting Pb‐isotopic ratios in a way that is likely not needed except for distinguishing very small variations of Pb‐isotopes generated at mid‐oceanic basalts or in intra‐plate regions (Shulaker et al, 2019).…”

Section: Approach and Methodsmentioning

confidence: 99%

Light fractions can also be heavy hitters: Comparison of detrital zircon U–Pb and detrital K‐feldspar Pb–Pb as provenance indicators—A case study from Cretaceous strata of southern Utah, USA

Reat

Johnson

2023

Basin Research

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Comparison of detrital zircon U–Pb geochronology and detrital K‐feldspar Pb–Pb isotopic data from Upper Cretaceous sandstones of southern Utah reveals important provenance information that is unrecorded by more chemically and physically durable detrital minerals like zircons. To better understand these signals, we also present an updated database of Pb‐isotopic ratios in ores, whole rocks and feldspars, for potential sediment source terranes in North America. Detrital K‐feldspar Pb‐isotopes indicate sediment provenance of the Western Cordillera/Mojave, Yavapai‐Mazatzal and Wyoming terranes, with limited input from recycled Sevier fold‐thrust belt strata. The K‐feldspar data broadly support previous interpretations, largely based on detrital zircon datasets, of a Cretaceous palaeo‐river system transporting sediment from the southwest. However, the light‐fraction data also provide important, complementary and otherwise unrecognized perspectives as compared to detrital zircon datasets. For example, K‐feldspars indicate a stronger apparent influence of Western Cordillera/Mojave and Wyoming terrane sources than previously interpreted. We interpret the K‐feldspar Wyoming terrane signal as the result of south‐directed longshore drift, with preferential loss of zircons due to hydraulic sorting processes. As relatively new detrital K‐feldspar detrital methods continue to be developed, this multi‐proxy approach to provenance could be informative in other sedimentary basins where suitable source terranes can be identified.

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Section: Approach and Methodsmentioning

confidence: 99%