Geology and geochronology of the Paleoproterozoic Hart Dolerite, Western Australia

R. R. Ramsay, A. E. Eves, S. W. Denyszyn, M. T.D. Wingate, M. Fiorentini, L. G. Gwalani, K. A. Rogers

Research output: Contribution to journalArticle

Abstract

The Hart Dolerite is the intrusive component of the Hart–Carson Large Igneous Province, which extends over an area of >160,000 km2 in the Speewah and Kimberley Basins in the western part of the North Australian Craton. In the core of the Speewah Dome, a ca. 500 m thick composite sill of Hart Dolerite intruded metasedimentary rocks of the Speewah Group, which have a maximum depositional age of 1814 ± 10 Ma. Referred to here as the Speewah sill, it comprises four discrete gabbroic units and two later-stage dyke and sill units of potassic granophyre. The gabbros locally contain sulfide-poor, Stella-type platinum-group element enrichment and vanadiferous titanomagnetite mineralisation. New ID-TIMS U-Pb geochronology of baddeleyite from gabbro units in the Speewah sill yield upper-intercept ages (all 2σ) of 1792.7 ± 1.3 Ma and 1791.7 ± 4.1 Ma. These results are complemented by a SHRIMP age of 1792.1 ± 5.9 Ma (2σ) for baddeleyite in a late-stage pigeonite vein in Hart Dolerite 120 km south of the Speewah Dome. These new data are consistent with previous regional geochronology of late-stage quartz–feldspar granophyres, and with a model of rapid emplacement of the Hart Dolerite at 1792.6 ± 1.2 Ma in an intracratonic extensional setting. Globally, the period around ca. 1793 Ma includes several large igneous provinces, suggesting that this interval was characterised by high mantle heat flow, continental extension, and voluminous mafic magmatism over large areas.

Original languageEnglish
Article number105482
JournalPrecambrian Research
Volume335
DOIs
Publication statusPublished - 1 Dec 2019

Fingerprint

Geochronology
Domes
Geology
diabase
sill
geochronology
geology
baddeleyite
large igneous province
Sulfides
Platinum
dome
Rocks
granophyre
Heat transfer
pigeonite
titanomagnetite
Composite materials
platinum group element
metasedimentary rock

Cite this

@article{11b45ef55d1a4f2d8d88aaf233c4beaa,
title = "Geology and geochronology of the Paleoproterozoic Hart Dolerite, Western Australia",
abstract = "The Hart Dolerite is the intrusive component of the Hart–Carson Large Igneous Province, which extends over an area of >160,000 km2 in the Speewah and Kimberley Basins in the western part of the North Australian Craton. In the core of the Speewah Dome, a ca. 500 m thick composite sill of Hart Dolerite intruded metasedimentary rocks of the Speewah Group, which have a maximum depositional age of 1814 ± 10 Ma. Referred to here as the Speewah sill, it comprises four discrete gabbroic units and two later-stage dyke and sill units of potassic granophyre. The gabbros locally contain sulfide-poor, Stella-type platinum-group element enrichment and vanadiferous titanomagnetite mineralisation. New ID-TIMS U-Pb geochronology of baddeleyite from gabbro units in the Speewah sill yield upper-intercept ages (all 2σ) of 1792.7 ± 1.3 Ma and 1791.7 ± 4.1 Ma. These results are complemented by a SHRIMP age of 1792.1 ± 5.9 Ma (2σ) for baddeleyite in a late-stage pigeonite vein in Hart Dolerite 120 km south of the Speewah Dome. These new data are consistent with previous regional geochronology of late-stage quartz–feldspar granophyres, and with a model of rapid emplacement of the Hart Dolerite at 1792.6 ± 1.2 Ma in an intracratonic extensional setting. Globally, the period around ca. 1793 Ma includes several large igneous provinces, suggesting that this interval was characterised by high mantle heat flow, continental extension, and voluminous mafic magmatism over large areas.",
keywords = "Baddeleyite, Large igneous province, Mafic igneous rocks, Petrography, U-Pb geochronology",
author = "Ramsay, {R. R.} and Eves, {A. E.} and Denyszyn, {S. W.} and Wingate, {M. T.D.} and M. Fiorentini and Gwalani, {L. G.} and Rogers, {K. A.}",
year = "2019",
month = "12",
day = "1",
doi = "10.1016/j.precamres.2019.105482",
language = "English",
volume = "335",
journal = "Precambrian Research",
issn = "0301-9268",
publisher = "Pergamon",

}

Geology and geochronology of the Paleoproterozoic Hart Dolerite, Western Australia. / Ramsay, R. R.; Eves, A. E.; Denyszyn, S. W.; Wingate, M. T.D.; Fiorentini, M.; Gwalani, L. G.; Rogers, K. A.

In: Precambrian Research, Vol. 335, 105482, 01.12.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Geology and geochronology of the Paleoproterozoic Hart Dolerite, Western Australia

AU - Ramsay, R. R.

AU - Eves, A. E.

AU - Denyszyn, S. W.

AU - Wingate, M. T.D.

AU - Fiorentini, M.

AU - Gwalani, L. G.

AU - Rogers, K. A.

PY - 2019/12/1

Y1 - 2019/12/1

N2 - The Hart Dolerite is the intrusive component of the Hart–Carson Large Igneous Province, which extends over an area of >160,000 km2 in the Speewah and Kimberley Basins in the western part of the North Australian Craton. In the core of the Speewah Dome, a ca. 500 m thick composite sill of Hart Dolerite intruded metasedimentary rocks of the Speewah Group, which have a maximum depositional age of 1814 ± 10 Ma. Referred to here as the Speewah sill, it comprises four discrete gabbroic units and two later-stage dyke and sill units of potassic granophyre. The gabbros locally contain sulfide-poor, Stella-type platinum-group element enrichment and vanadiferous titanomagnetite mineralisation. New ID-TIMS U-Pb geochronology of baddeleyite from gabbro units in the Speewah sill yield upper-intercept ages (all 2σ) of 1792.7 ± 1.3 Ma and 1791.7 ± 4.1 Ma. These results are complemented by a SHRIMP age of 1792.1 ± 5.9 Ma (2σ) for baddeleyite in a late-stage pigeonite vein in Hart Dolerite 120 km south of the Speewah Dome. These new data are consistent with previous regional geochronology of late-stage quartz–feldspar granophyres, and with a model of rapid emplacement of the Hart Dolerite at 1792.6 ± 1.2 Ma in an intracratonic extensional setting. Globally, the period around ca. 1793 Ma includes several large igneous provinces, suggesting that this interval was characterised by high mantle heat flow, continental extension, and voluminous mafic magmatism over large areas.

AB - The Hart Dolerite is the intrusive component of the Hart–Carson Large Igneous Province, which extends over an area of >160,000 km2 in the Speewah and Kimberley Basins in the western part of the North Australian Craton. In the core of the Speewah Dome, a ca. 500 m thick composite sill of Hart Dolerite intruded metasedimentary rocks of the Speewah Group, which have a maximum depositional age of 1814 ± 10 Ma. Referred to here as the Speewah sill, it comprises four discrete gabbroic units and two later-stage dyke and sill units of potassic granophyre. The gabbros locally contain sulfide-poor, Stella-type platinum-group element enrichment and vanadiferous titanomagnetite mineralisation. New ID-TIMS U-Pb geochronology of baddeleyite from gabbro units in the Speewah sill yield upper-intercept ages (all 2σ) of 1792.7 ± 1.3 Ma and 1791.7 ± 4.1 Ma. These results are complemented by a SHRIMP age of 1792.1 ± 5.9 Ma (2σ) for baddeleyite in a late-stage pigeonite vein in Hart Dolerite 120 km south of the Speewah Dome. These new data are consistent with previous regional geochronology of late-stage quartz–feldspar granophyres, and with a model of rapid emplacement of the Hart Dolerite at 1792.6 ± 1.2 Ma in an intracratonic extensional setting. Globally, the period around ca. 1793 Ma includes several large igneous provinces, suggesting that this interval was characterised by high mantle heat flow, continental extension, and voluminous mafic magmatism over large areas.

KW - Baddeleyite

KW - Large igneous province

KW - Mafic igneous rocks

KW - Petrography

KW - U-Pb geochronology

UR - http://www.scopus.com/inward/record.url?scp=85073724725&partnerID=8YFLogxK

U2 - 10.1016/j.precamres.2019.105482

DO - 10.1016/j.precamres.2019.105482

M3 - Article

VL - 335

JO - Precambrian Research

JF - Precambrian Research

SN - 0301-9268

M1 - 105482

ER -