The release of Pb and REE from granitoids by the dissolution of accessory phases

Harlavan, Yehudit; Erel, Yigal

doi:10.1016/s0016-7037(01)00806-7

Cited by 126 publications

(80 citation statements)

References 26 publications

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“…Lead-bearing ores usually have a deviating composition in comparison with the common bedrock because the ore lead was separated from the uranium and thorium in the initial rock material, and therefore the isotopic composition of these ores does not appreciably alter over time, whereas lead isotope ratios continue to evolve in the original bedrock (Brown 1962;Faure 1986). However, although we can specifically characterize the lead isotopic composition of many anthropogenic lead sources (e.g., Hopper et al 1991;Stos-Gale et al 1995;Farmer et al 1999) as well as geogenic lead (Erel et al 1994;Harlavan et al 1998;Harlavan and Erel 2002;Klaminder et al 2005), both of these sources are in fact quite heterogeneous. The mineralogy of soils can be quite complex and weathering processes and their potential influence on lead isotopic composition are generally well understood, but cannot be well quantified in all regards.…”

Section: Introductionmentioning

confidence: 99%

Contaminated lead environments of man: reviewing the lead isotopic evidence in sediments, peat, and soils for the temporal and spatial patterns of atmospheric lead pollution in Sweden

Bindler

2011

Environ Geochem Health

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Clair Patterson and colleagues demonstrated already four decades ago that the lead cycle was greatly altered on a global scale by humans. Moreover, this change occurred long before the implementation of monitoring programs designed to study lead and other trace metals. Patterson and colleagues also developed stable lead isotope analyses as a tool to differentiate between natural and pollution-derived lead. Since then, stable isotope analyses of sediment, peat, herbaria collections, soils, and forest plants have given us new insights into lead biogeochemical cycling in space and time. Three important conclusions from our studies of lead in the Swedish environment conducted over the past 15 years, which are well supported by extensive results from elsewhere in Europe and in North America, are: (1) lead deposition rates at sites removed from major point sources during the twentieth century were about 1,000 times higher than natural background deposition rates a few thousand years ago (~10 mg Pb m(-2) year(-1) vs. 0.01 mg Pb m(-2) year(-1)), and even today (~1 mg Pb m(-2) year(-1)) are still almost 100 times greater than natural rates. This increase from natural background to maximum fluxes is similar to estimated changes in body burdens of lead from ancient times to the twentieth century. (2) Stable lead isotopes ((206)Pb/(207)Pb ratios shown in this paper) are an effective tool to distinguish anthropogenic lead from the natural lead present in sediments, peat, and soils for both the majority of sites receiving diffuse inputs from long range and regional sources and for sites in close proximity to point sources. In sediments >3,500 years and in the parent soil material of the C-horizon, (206)Pb/(207)Pb ratios are higher, 1.3 to >2.0, whereas pollution sources and surface soils and peat have lower ratios that have been in the range 1.14-1.18. (3) Using stable lead isotopes, we have estimated that in southern Sweden the cumulative anthropogenic burden of atmospherically deposited lead is ~2-5 g Pb m(-2) and ~1 g Pb m(-2) in the "pristine" north. Half of this cumulative total was deposited before industrialization. (4) In the vicinity of the Rönnskär smelter in northern Sweden, a major point source during the twentieth century, there is an isotopic pattern that deviates from the general trends elsewhere, reflecting the particular history of ore usage at Rönnskär, which further demonstrates the chronological record of lead loading recorded in peat and in soil mor horizons.

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Section: Introductionmentioning

confidence: 99%

Contaminated lead environments of man: reviewing the lead isotopic evidence in sediments, peat, and soils for the temporal and spatial patterns of atmospheric lead pollution in Sweden

Bindler

2011

Environ Geochem Health

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“…The specific incongruent chemical weathering behaviour that is responsible for a weathering signal in the Pb isotope system has been the focus of a number of studies in the past decade (Harlavan et al, 1998;Harlavan and Erel, 2002;Erel et al, 2004;Foster and Vance, 2006). Those studies focusing on Pb-specific chemical weathering trends noted systematic differences in the released solute Pb isotope signal in soil chronosequences.…”

Section: Introductionmentioning

confidence: 99%

Retreat of the Laurentide ice sheet tracked by the isotopic composition of Pb in western North Atlantic seawater during termination 1

Gutjahr¹,

Halliday²,

Keigwin³

2009

Earth and Planetary Science Letters

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“…The whole rock geochemical results from this study demonstrate that there was preferential inclusion of a K-Rb-Ba bearing phase(s) and preferential exclusion of a Ca-Na-Sr-Eu bearing phase(s) during pseudotachylyte formation. The depletion of Sr and Eu strongly suggest that the phase depleted from the pseudotachylyte is plagioclase, and not another Ca-bearing phase (i.e., epidote, which may have a negative Eu anomaly; Harlavan & Erel 2002). …”

Section: Pseudotachylyte Geochemistrymentioning

confidence: 99%

Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand

Barker

Sibson

Palin

et al. 2010

New Zealand Journal of Geology and Geophysics

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At Tucker Hill, in Central Otago, New Zealand, a series of pseudotachylyte veins are hosted in quartzofeldspathic schist. Chilled margins, microlites, flow banding, and the crystallisation of mineral phases absent from the host rock provide unequivocal evidence for melting during pseudotachylyte formation. Whole rock analyses of pseudotachylyte reveal c. 3 ) enrichment of K 2 O, Ba, and Rb, and similar depletion of Na 2 O, CaO, Sr, and Eu, as compared to host schist. Formation age of pseudotachylyte is 95.991.8 Ma as measured by total fusion 40 Ar/ 39 Ar analyses. Stepwise heating of pseudotachylyte matrix yields an excellently defined 40 Ar/ 39 Ar plateau age of 96.090.3 Ma. These well-defined ages are attributed to the presence of potassium feldspar, low abundance of inherited lithic material from the host rock, and few fluid inclusions containing extraneous Ar. We propose that formation of these pseudotachylyte veins was related to Cretaceous extensional uplift and exhumation of the Otago Schist.Keywords: pseudotachylyte; schist; Otago; Ar-Ar; geochronology; friction melting IntroductionThe presence of pseudotachylyte (former friction melt) in a fault zone is commonly attributed to frictional melting of rock during seismic slip (Sibson 1975). As such, pseudotachylytes are valuable indicators that an exhumed fault zone was seismically active. Pseudotachylytes have been described from inactive, ancient fault zones (e.g., Outer Hebrides Fault Zone: Sibson 1975;Maddock 1983;Kelley et al. 1994) and present day seismically active fault zones (e.g., the Alpine Fault: Sibson et al. 1981;Bossiere 1991;Warr et al. 2003). Determining the formation age of pseudotachylyte can reveal when a fault was seismically active, and provide information on the significance of a pseudotachylytebearing fault zone relative to the timing of other regional deformation events (Kelley et al. 1994;Magloughlin et al. 2001;Sherlock & Hetzel 2001;Mueller et al. 2002;Warr et al. 2003).In Central Otago, New Zealand, a series of pseudotachylyte veins are found in schist outcropping on Tucker Hill (1698 24?23??E; 458 15?16?S), near the township of Alexandra (Fig. 1). The pseudotachylyte veins are hosted in the garnet-biotite-albite zone of the greenschist facies of the Otago Schist, which forms the basement rocks of much of the Otago region (Mortimer 1993a, b). Tucker Hill is approximately 15 km to the east of the Cromwell Gorge Shear Zone and approximately 20 km to the south of the Rise and Shine Shear Zone, which are two Cretaceous age extensional shear zones (Deckert et al. 2002).Previous studies that have attempted to determine the age of pseudotachylyte utilising 40 Ar/ 39 Ar geochronology in various localities have met with varying degrees of success. In particular, accurate and geologically meaningful 40 Ar/ 39 Ar age determinations are negatively influenced by the presence of variable amounts of inherited crystals (i.e., incompletely melted) from host rocks (Magloughlin et al. 2001;Warr et al. 2007), argon loss by diffusion or alteration ...

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The release of Pb and REE from granitoids by the dissolution of accessory phases

Cited by 126 publications

References 26 publications

Contaminated lead environments of man: reviewing the lead isotopic evidence in sediments, peat, and soils for the temporal and spatial patterns of atmospheric lead pollution in Sweden

Contaminated lead environments of man: reviewing the lead isotopic evidence in sediments, peat, and soils for the temporal and spatial patterns of atmospheric lead pollution in Sweden

Retreat of the Laurentide ice sheet tracked by the isotopic composition of Pb in western North Atlantic seawater during termination 1

Cretaceous age, composition, and microstructure of pseudotachylyte in the Otago Schist, New Zealand

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