40Ar/39Ar dating of exceptional concentration of metals by weathering of Precambrian rocks at the Precambrian–Cambrian boundary

John Parnell; Darren F. Mark; Robert Frei; Anthony E. Fallick; Rob M. Ellam

doi:10.1016/j.precamres.2014.02.012

⁴⁰Ar/³⁹Ar dating of exceptional concentration of metals by weathering of Precambrian rocks at the Precambrian–Cambrian boundary

John Parnell, Darren F. Mark, Robert Frei, Anthony E. Fallick, Rob M. Ellam

Geology

10 Citations (Scopus)

Abstract

The sub-Cambrian surface, including diverse metalliferous deposits, shows evidence of intense weathering of Precambrian rocks to form supergene-enriched ores and metalliferous placers, followed by widespread peneplanation. Much of the metal would have been flushed to the Cambrian ocean during peneplanation. An 40Ar/39Ar age of 542.62 ± 0.38 Ma (1 sigma, full external precision, Renne et al., 2011) for metalliferous alteration clays in Scotland shows that this event occurred immediately prior to the Precambrian–Cambrian boundary. A negative δ53Cr isotopic signature for the clay is consistent with mobilization on land of redox sensitive metals by oxidative terrestrial weathering. This unprecedented flushing of metals from the weathered Precambrian surface would have contributed to the chemistry of the earliest Cambrian ocean at a time of marked faunal evolution.

Original language	English
Journal	Precambrian Research
Volume	246
Pages (from-to)	54-63
Number of pages	10
ISSN	0301-9268
DOIs	https://doi.org/10.1016/j.precamres.2014.02.012
Publication status	Published - Jun 2014

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title = "40Ar/39Ar dating of exceptional concentration of metals by weathering of Precambrian rocks at the Precambrian–Cambrian boundary",

abstract = "The sub-Cambrian surface, including diverse metalliferous deposits, shows evidence of intense weathering of Precambrian rocks to form supergene-enriched ores and metalliferous placers, followed by widespread peneplanation. Much of the metal would have been flushed to the Cambrian ocean during peneplanation. An 40Ar/39Ar age of 542.62 ± 0.38 Ma (1 sigma, full external precision, Renne et al., 2011) for metalliferous alteration clays in Scotland shows that this event occurred immediately prior to the Precambrian–Cambrian boundary. A negative δ53Cr isotopic signature for the clay is consistent with mobilization on land of redox sensitive metals by oxidative terrestrial weathering. This unprecedented flushing of metals from the weathered Precambrian surface would have contributed to the chemistry of the earliest Cambrian ocean at a time of marked faunal evolution.",

author = "John Parnell and Mark, {Darren F.} and Robert Frei and Fallick, {Anthony E.} and Ellam, {Rob M.}",

year = "2014",

month = jun,

doi = "10.1016/j.precamres.2014.02.012",

language = "English",

volume = "246",

pages = "54--63",

journal = "Precambrian Research",

issn = "0301-9268",

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T1 - 40Ar/39Ar dating of exceptional concentration of metals by weathering of Precambrian rocks at the Precambrian–Cambrian boundary

AU - Parnell, John

AU - Mark, Darren F.

AU - Frei, Robert

AU - Fallick, Anthony E.

AU - Ellam, Rob M.

PY - 2014/6

Y1 - 2014/6

N2 - The sub-Cambrian surface, including diverse metalliferous deposits, shows evidence of intense weathering of Precambrian rocks to form supergene-enriched ores and metalliferous placers, followed by widespread peneplanation. Much of the metal would have been flushed to the Cambrian ocean during peneplanation. An 40Ar/39Ar age of 542.62 ± 0.38 Ma (1 sigma, full external precision, Renne et al., 2011) for metalliferous alteration clays in Scotland shows that this event occurred immediately prior to the Precambrian–Cambrian boundary. A negative δ53Cr isotopic signature for the clay is consistent with mobilization on land of redox sensitive metals by oxidative terrestrial weathering. This unprecedented flushing of metals from the weathered Precambrian surface would have contributed to the chemistry of the earliest Cambrian ocean at a time of marked faunal evolution.

AB - The sub-Cambrian surface, including diverse metalliferous deposits, shows evidence of intense weathering of Precambrian rocks to form supergene-enriched ores and metalliferous placers, followed by widespread peneplanation. Much of the metal would have been flushed to the Cambrian ocean during peneplanation. An 40Ar/39Ar age of 542.62 ± 0.38 Ma (1 sigma, full external precision, Renne et al., 2011) for metalliferous alteration clays in Scotland shows that this event occurred immediately prior to the Precambrian–Cambrian boundary. A negative δ53Cr isotopic signature for the clay is consistent with mobilization on land of redox sensitive metals by oxidative terrestrial weathering. This unprecedented flushing of metals from the weathered Precambrian surface would have contributed to the chemistry of the earliest Cambrian ocean at a time of marked faunal evolution.

U2 - 10.1016/j.precamres.2014.02.012

DO - 10.1016/j.precamres.2014.02.012

M3 - Journal article

SN - 0301-9268

VL - 246

SP - 54

EP - 63

JO - Precambrian Research

JF - Precambrian Research

ER -

40Ar/39Ar dating of exceptional concentration of metals by weathering of Precambrian rocks at the Precambrian–Cambrian boundary

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⁴⁰Ar/³⁹Ar dating of exceptional concentration of metals by weathering of Precambrian rocks at the Precambrian–Cambrian boundary