U-Pb zircon (SHRIMP) ages for the Lebombo rhyolites, South Africa: Refining the duration of Karoo volcanism

T. R. Riley; I. L. Millar; M. K. Watkeys; M. L. Curtis; P. T. Leat; M. B. Klausen; C. M. Fanning

doi:10.1144/0016-764903-181

U-Pb zircon (SHRIMP) ages for the Lebombo rhyolites, South Africa: Refining the duration of Karoo volcanism

T. R. Riley^*, I. L. Millar, M. K. Watkeys, M. L. Curtis, P. T. Leat, M. B. Klausen, C. M. Fanning

^*Corresponding author for this work

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

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Abstract

U-Pb SHRIMP ages are reported for three rhyolite flows from the Lebombo rift region of the Karoo volcanic province. Two flows are interbedded with the Sabic River Basalt Formation and a third sample is from the overlying rhyolitic Jozini Formation. The interbedded rhyolites yield ages of 182.0 ± 2.1 and 179.9 ± 1.8 Ma, whilst the overlying Jozini Formation rhyolite yields an age of 182.1 ± 2.9 Ma. Combined with existing ⁴⁰Ar/³⁹ Ar geochronology, the new SHRIMP data fine-tunes the chronology of the Karoo volcanic province and indicates the 12 km succession of volcanic rocks in the Lebombo rift were erupted in 1-2 million years and lends considerable support to the links between the Pleinsbachian-Toarcian extinction event and the global environmental impact of Karoo volcanism.

Original language	English
Pages (from-to)	547-550
Number of pages	4
Journal	Journal of the Geological Society
Volume	161
Issue number	4
DOIs	https://doi.org/10.1144/0016-764903-181
Publication status	Published - Jul 2004

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title = "U-Pb zircon (SHRIMP) ages for the Lebombo rhyolites, South Africa: Refining the duration of Karoo volcanism",

abstract = "U-Pb SHRIMP ages are reported for three rhyolite flows from the Lebombo rift region of the Karoo volcanic province. Two flows are interbedded with the Sabic River Basalt Formation and a third sample is from the overlying rhyolitic Jozini Formation. The interbedded rhyolites yield ages of 182.0 ± 2.1 and 179.9 ± 1.8 Ma, whilst the overlying Jozini Formation rhyolite yields an age of 182.1 ± 2.9 Ma. Combined with existing 40Ar/39 Ar geochronology, the new SHRIMP data fine-tunes the chronology of the Karoo volcanic province and indicates the 12 km succession of volcanic rocks in the Lebombo rift were erupted in 1-2 million years and lends considerable support to the links between the Pleinsbachian-Toarcian extinction event and the global environmental impact of Karoo volcanism.",

keywords = "Flood basalts, Karoo, Lemombo rhyolites, Rhyolites, U-Pb",

author = "Riley, {T. R.} and Millar, {I. L.} and Watkeys, {M. K.} and Curtis, {M. L.} and Leat, {P. T.} and Klausen, {M. B.} and Fanning, {C. M.}",

year = "2004",

month = jul,

doi = "10.1144/0016-764903-181",

language = "English",

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pages = "547--550",

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T1 - U-Pb zircon (SHRIMP) ages for the Lebombo rhyolites, South Africa

T2 - Refining the duration of Karoo volcanism

AU - Riley, T. R.

AU - Millar, I. L.

AU - Watkeys, M. K.

AU - Curtis, M. L.

AU - Leat, P. T.

AU - Klausen, M. B.

AU - Fanning, C. M.

PY - 2004/7

Y1 - 2004/7

N2 - U-Pb SHRIMP ages are reported for three rhyolite flows from the Lebombo rift region of the Karoo volcanic province. Two flows are interbedded with the Sabic River Basalt Formation and a third sample is from the overlying rhyolitic Jozini Formation. The interbedded rhyolites yield ages of 182.0 ± 2.1 and 179.9 ± 1.8 Ma, whilst the overlying Jozini Formation rhyolite yields an age of 182.1 ± 2.9 Ma. Combined with existing 40Ar/39 Ar geochronology, the new SHRIMP data fine-tunes the chronology of the Karoo volcanic province and indicates the 12 km succession of volcanic rocks in the Lebombo rift were erupted in 1-2 million years and lends considerable support to the links between the Pleinsbachian-Toarcian extinction event and the global environmental impact of Karoo volcanism.

AB - U-Pb SHRIMP ages are reported for three rhyolite flows from the Lebombo rift region of the Karoo volcanic province. Two flows are interbedded with the Sabic River Basalt Formation and a third sample is from the overlying rhyolitic Jozini Formation. The interbedded rhyolites yield ages of 182.0 ± 2.1 and 179.9 ± 1.8 Ma, whilst the overlying Jozini Formation rhyolite yields an age of 182.1 ± 2.9 Ma. Combined with existing 40Ar/39 Ar geochronology, the new SHRIMP data fine-tunes the chronology of the Karoo volcanic province and indicates the 12 km succession of volcanic rocks in the Lebombo rift were erupted in 1-2 million years and lends considerable support to the links between the Pleinsbachian-Toarcian extinction event and the global environmental impact of Karoo volcanism.

KW - Flood basalts

KW - Karoo

KW - Lemombo rhyolites

KW - Rhyolites

KW - U-Pb

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DO - 10.1144/0016-764903-181

M3 - Article

SN - 0016-7649

VL - 161

SP - 547

EP - 550

JO - Journal of the Geological Society

JF - Journal of the Geological Society

IS - 4

ER -

U-Pb zircon (SHRIMP) ages for the Lebombo rhyolites, South Africa: Refining the duration of Karoo volcanism

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