The age of the Mesoproterozoic Stoer Group sedimentary and impact deposits, NW Scotland

John Parnell; Darren Mark; Anthony E. Fallick; Adrian Boyce; Scott Thackrey

doi:10.1144/0016-76492010-099

The age of the Mesoproterozoic Stoer Group sedimentary and impact deposits, NW Scotland

John Parnell, Darren Mark, Anthony E. Fallick, Adrian Boyce, Scott Thackrey

Geology and Geophysics

Scottish Universities Environmental Research Centre (SUERC)

Research output: Contribution to journal › Article › peer-review

52 Citations (Scopus)

Abstract

The Mesoproterozoic Stoer Group of the 'Torridonian' has been dated at 1177 +/- 5 Ma (2 sigma), based on Ar-40/Ar-39 dating of authigenic K-feldspars precipitated in degassing structures within the Stac Fada Member, interpreted previously as an impact ejecta deposit. Fluid inclusion analysis of the K-feldspar shows that it precipitated from hot fluids, and so must immediately post-date emplacement of the ejecta blanket. The oxygen isotopic composition of K-feldspar is remarkably constant at 9.7 +/- 0.2 parts per thousand (V-SMOW) and is consistent with derivation from evaporated lake water. The new age supports previous determinations of 1199 +/- 70 Ma from Pb-Pb dating of limestone and 1180 Ma from palaeomagnetic data, but provides much higher precision.

Original language	English
Pages (from-to)	349-358
Number of pages	10
Journal	Journal of the Geological Society
Volume	168
Issue number	2
DOIs	https://doi.org/10.1144/0016-76492010-099
Publication status	Published - Mar 2011

Keywords

moine thrust zone
Northwest Scotland
fluid-flow
geochronology
pseudotachylite
geochemistry
provenance
seawater
events
origin

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10.1144/0016-76492010-099

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title = "The age of the Mesoproterozoic Stoer Group sedimentary and impact deposits, NW Scotland",

abstract = "The Mesoproterozoic Stoer Group of the 'Torridonian' has been dated at 1177 +/- 5 Ma (2 sigma), based on Ar-40/Ar-39 dating of authigenic K-feldspars precipitated in degassing structures within the Stac Fada Member, interpreted previously as an impact ejecta deposit. Fluid inclusion analysis of the K-feldspar shows that it precipitated from hot fluids, and so must immediately post-date emplacement of the ejecta blanket. The oxygen isotopic composition of K-feldspar is remarkably constant at 9.7 +/- 0.2 parts per thousand (V-SMOW) and is consistent with derivation from evaporated lake water. The new age supports previous determinations of 1199 +/- 70 Ma from Pb-Pb dating of limestone and 1180 Ma from palaeomagnetic data, but provides much higher precision.",

keywords = "moine thrust zone, Northwest Scotland, fluid-flow, geochronology, pseudotachylite, geochemistry, provenance, seawater, events, origin",

author = "John Parnell and Darren Mark and Fallick, {Anthony E.} and Adrian Boyce and Scott Thackrey",

year = "2011",

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doi = "10.1144/0016-76492010-099",

language = "English",

volume = "168",

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T1 - The age of the Mesoproterozoic Stoer Group sedimentary and impact deposits, NW Scotland

AU - Parnell, John

AU - Mark, Darren

AU - Fallick, Anthony E.

AU - Boyce, Adrian

AU - Thackrey, Scott

PY - 2011/3

Y1 - 2011/3

N2 - The Mesoproterozoic Stoer Group of the 'Torridonian' has been dated at 1177 +/- 5 Ma (2 sigma), based on Ar-40/Ar-39 dating of authigenic K-feldspars precipitated in degassing structures within the Stac Fada Member, interpreted previously as an impact ejecta deposit. Fluid inclusion analysis of the K-feldspar shows that it precipitated from hot fluids, and so must immediately post-date emplacement of the ejecta blanket. The oxygen isotopic composition of K-feldspar is remarkably constant at 9.7 +/- 0.2 parts per thousand (V-SMOW) and is consistent with derivation from evaporated lake water. The new age supports previous determinations of 1199 +/- 70 Ma from Pb-Pb dating of limestone and 1180 Ma from palaeomagnetic data, but provides much higher precision.

AB - The Mesoproterozoic Stoer Group of the 'Torridonian' has been dated at 1177 +/- 5 Ma (2 sigma), based on Ar-40/Ar-39 dating of authigenic K-feldspars precipitated in degassing structures within the Stac Fada Member, interpreted previously as an impact ejecta deposit. Fluid inclusion analysis of the K-feldspar shows that it precipitated from hot fluids, and so must immediately post-date emplacement of the ejecta blanket. The oxygen isotopic composition of K-feldspar is remarkably constant at 9.7 +/- 0.2 parts per thousand (V-SMOW) and is consistent with derivation from evaporated lake water. The new age supports previous determinations of 1199 +/- 70 Ma from Pb-Pb dating of limestone and 1180 Ma from palaeomagnetic data, but provides much higher precision.

KW - moine thrust zone

KW - Northwest Scotland

KW - fluid-flow

KW - geochronology

KW - pseudotachylite

KW - geochemistry

KW - provenance

KW - seawater

KW - events

KW - origin

U2 - 10.1144/0016-76492010-099

DO - 10.1144/0016-76492010-099

M3 - Article

SN - 0016-7649

VL - 168

SP - 349

EP - 358

JO - Journal of the Geological Society

JF - Journal of the Geological Society

IS - 2

ER -

The age of the Mesoproterozoic Stoer Group sedimentary and impact deposits, NW Scotland

Abstract

Keywords

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