Similarities between the Th/U map of the western US crystalline basement and the seismic properties of the underlying lithosphere

Bouchet, Romain A.; Blichert‐Toft, Janne; Reid, M. R.; Levander, A.; Albarède, Francis

doi:10.1016/j.epsl.2014.02.004

Cited by 9 publications

(7 citation statements)

References 110 publications

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“…The unique distribution of Pb isotopes provides a good foundation for sourcing exploited ores. Similar geochemical zoning and boundaries have been broadly established in other continents for the same purpose [94–96].…”

Section: Introductionmentioning

confidence: 77%

A geochemical characterization of lead ores in China: An isotope database for provenancing archaeological materials

Hsu¹,

Sabatini²

2019

PLoS ONE

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A well reasoned lead (Pb) isotope-driven provenance study lies in concert with a comprehensively evaluated database of geological ore sources and accompanying archaeological and contextual information. In this paper we have compiled and evaluated all currently available Pb isotope data for galena and K-feldspars in China, and provided geological interpretations for how their ore-forming substances evolved across relevant tectonic terrains. We pay particular attention to the geological settings of host ore deposits that were likely exploited in ancient and historic China, detailing the heterogeneity and homogeneity of their ore formation across different metallogenic provinces and belts. Using the isotope database, and supportive geological and archaeological background information, three case studies are presented that detail the provenancing of Chinese cultural materials. The isotope data themselves are presented in ternary diagrams that allow for their concise and accurate comparison.

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Section: Introductionmentioning

confidence: 77%

A geochemical characterization of lead ores in China: An isotope database for provenancing archaeological materials

Hsu¹,

Sabatini²

2019

PLoS ONE

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“…3 and 4) can be shown by converting the Pb isotope compositions into Pb model ages T mod , 238 U/ 204 Pb (μ), and 232 Th/ 238 U (κ) ratios (Table S3) using the equations given by Albarède et al (16). The advantages of this representation over that based on raw Pb isotope ratios have been shown in a number of geological and (geo)archeological contexts (2)(3)(4)(16)(17)(18)(19). In the present case, Peninsular Italy is a geologically young mountain range (T mod < 30 Ma); the presence of Hercynian Pb (T mod > 200 Ma) in Ostia sediments, therefore, unambiguously signals contamination of local waters by foreign Pb, likely lead artifacts ( Figs.…”

Section: Significancementioning

confidence: 99%

Rome’s urban history inferred from Pb-contaminated waters trapped in its ancient harbor basins

Delile

Keenan‐Jones

Blichert‐Toft

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Heavy metals from urban runoff preserved in sedimentary deposits record long-term economic and industrial development via the expansion and contraction of a city's infrastructure. Lead concentrations and isotopic compositions measured in the sediments of the harbor of Ostia-Rome's first harbor-show that lead pipes used in the water supply networks of Rome and Ostia were the only source of radiogenic Pb, which, in geologically young central Italy, is the hallmark of urban pollution. High-resolution geochemical, isotopic, and C analyses of a sedimentary core from Ostia harbor have allowed us to date the commissioning of Rome's lead pipe water distribution system to around the second century BC, considerably later than Rome's first aqueduct built in the late fourth century BC. Even more significantly, the isotopic record of Pb pollution proves to be an unparalleled proxy for tracking the urban development of ancient Rome over more than a millennium, providing a semiquantitative record of the water system's initial expansion, its later neglect, probably during the civil wars of the first century BC, and its peaking in extent during the relative stability of the early high Imperial period. This core record fills the gap in the system's history before the appearance of more detailed literary and inscriptional evidence from the late first century BC onward. It also preserves evidence of the changes in the dynamics of the Tiber River that accompanied the construction of Rome's artificial port,, during the first and second centuries AD.

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“…The efficacy of U-Th-Pb systematics in mapping out compositional evolution of the crust is borne out by the remarkable geochemical provinciality of continents as displayed by the Pb isotope compositions of ore sulfide deposits. In particular, there have been some suggestions that Pb model ages and model U/Pb and Th/U ratios derived from Pb isotope data correlate with regional tectonic history in Europe [Kober and Lippolt, 1985;Michard-Vitrac et al, 1981], Peru [Albarede et al, 2012], and the Western USA [Bouchet et al, 2014]. Although a high-resolution continentwide seismic database as comprehensive and coherent as that produced by the US Array project remains to be completed for Europe and the Mediterranean, databases of ore Pb isotope compositions across Europe are already in use which allows archeological artifacts such as Greek and Roman coins, tools, weapons, and statues to be associated with specific mining districts [Stos-Gale and Gale, 2009].…”

Section: Introductionmentioning

confidence: 99%

Large‐scale tectonic cycles in Europe revealed by distinct Pb isotope provinces

Blichert‐Toft

Delile

Lee

et al. 2016

Geochem Geophys Geosyst

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Significance statements We have compiled and mapped out ~6800 Pb isotope measurements of lead ores and Kfeldspars across Europe and the circum-Mediterranean  Lead model ages define spatially distinct age provinces consistent with major tectonic events ranging from the Paleozoic to the Archean  Time-integrated U/Pb and Th/Pb ratios are decoupled from the age provinces and suggest foundering of the lower crust in southern Europe Abstract Lead isotopic systematics of U-poor minerals, such as sulfides and feldspars, can provide unique insights into the origin and evolution of continents because these minerals 'freeze in' the Pb isotopic composition of the crust during major tectonothermal events, allowing the history of a continent to be told through Pb isotopes. Lead model ages constrain the timing of crust formation while time-integrated U/Pb, Th/Pb, and Th/U ratios shed light onto key geochemical processes associated with continent formation. Using ~6800 Pb isotope measurements of primarily lead ores and minor K-feldspar, we mapped out the Pb isotope systematics across Europe and the Mediterranean. Lead model ages define spatially distinct age provinces, consistent with major tectonic events ranging from the Paleozoic to the Proterozoic and latest Archean. However, the regions defined by time-integrated U/Pb and Th/Pb ratios cut across the boundaries of age provinces, with high U/Pb systematics characterizing most of southern Europe. Magmatic influx, followed by segregation of densesulfide-rich mafic cumulates, resulted in foundering of U-and Th-poor lower crust, thereby changing the bulk composition of the continental crust and leading to distinct time-integrated U-Th/Pb provinces. We show that the tectonic assembly of small crustal fragments leaves the crust largely undifferentiated, whereas the formation of supercontinents results in fundamental changes in the composition of the crust, identifiable in time and space by means of Pb isotope systematics. Observations based on Pb isotopes open up a new perspective on possible relationships between crustal thickness and geodynamic processes, in particular the role of crustal foundering into the mantle and the mechanisms responsible for the existence of cratons.

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Similarities between the Th/U map of the western US crystalline basement and the seismic properties of the underlying lithosphere

Cited by 9 publications

References 110 publications

A geochemical characterization of lead ores in China: An isotope database for provenancing archaeological materials

A geochemical characterization of lead ores in China: An isotope database for provenancing archaeological materials

Rome’s urban history inferred from Pb-contaminated waters trapped in its ancient harbor basins

Large‐scale tectonic cycles in Europe revealed by distinct Pb isotope provinces

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