3000 Ma large mafic magmatic events

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261 Sargur event

Location: India (Western Dharwar Block)

Size: 10,000 sq. km.

Age: ca. 3.0 Ga

Rating: B (7)

VOLCANIC ROCKS: Greenstone belts: Sargur basalts & komatiites Rogers and Giral, 1997[644].

LAYERED INTRUSIONS: Rogers and Giral, 1997[644].


262 Murchison-1 events

Location: W. Australia (Murchison terrane, Yilgarn Craton)

Size: 100,000 sq. km.

Age: 3.0 Ga

Rating: B (4v)

VOLCANIC ROCKS: Luke Creek Group, 3000 Ma (p. 643 in Myers and Swagers, 1997[584]).

COMMENT: Early flood basalts at 3.0 Ga (this event) overlain by local volcanic centers at 2.8 Ga (Murchison-2 event) (p. 644 in Myers and Swagers, 1997[584]). See event 238.


263 Olondo oceanic flood basalt(O) event

Location: S. Siberia (W. Aldan Shield)

Size: 3000 sq. km.

Age: 3.0 Ga

Rating: B (7)

VOLCANIC ROCKS: Olondo greenstone belt (includes 15% komatiites), U & S ca. 3000 Ma Dobretsov et al., 1997[673].


264 Dominion Group event

Location: S. Africa (Kaapvaal Craton)

Age: 3.07 Ga

Rating: C (possibly 9v)

VOLCANIC ROCKS: Dominion Group (Uz 3074±6 Ma Armstrong et al., 1991[591].


265 Ruth Well oceanic flood basalt(O) event Arndt et al., this volume[578]

Location: NW. Australia (Pilbara Craton)

Age: ca. 3.2 Ga

Rating: B (7)

VOLCANIC ROCKS: Ruth Well (in Regal sequence) (includes komatiites) Arndt et al., this volume[578] Barley, 1997[645] (3200 Ma Arndt et al., this volume[578]).


266 Tungurcha oceanic flood basalt(O) event

Location: S. Siberia (W. Aldan Shield)

Size: 4500 sq. km.

Age: 3.3-3.2 Ga

Rating: B (7)

VOLCANIC ROCKS: Tungurcha Group greenstone belt (includes komatiites), S 3300-3200 Ma Dobretsov et al., 1997[673] Tomlinson and Condie, this volume[582].


267 Verkhovtsevo event

Location: SE. Europe (Ukranian Shield)

Size: 720 sq. km.

Age: 3.3-3.2 Ga

Rating: B (7)

VOLCANIC ROCKS: Verkhovtsevo greenstone belt (Sura, Chertomlyk) (includes <7% komatiites), S 3340 M, U 3250 Ma Kushev and Kornilov, 1997[674].


268 Upper Warrawoona-lower Gorge Creek event Arndt et al., this volume[578]

Location: NW. Australia (Pilbara Craton)

Age: 3.33 Ga

Rating: B (4v)

VOLCANIC ROCKS: Upper Warrawoona: top of Talga Talga (Duffer formation Uz 3464±3 & ca. 3330 Ma); Kelly formation (Uz 3324±4 Ma McNaughton et al., 1993[675]), Gorge Creek Group: basal Wyman formation (Uz 3325±4 Ma McNaughton et al., 1993[675]) McNaughton et al., 1993[675] Arndt et al., this volume[578] Barley, 1993[667].


269 Sebakwian events

Location: S. Africa (Zimbabwe Craton)

Age: =3.35 Ga

Rating: C (possibly 7)

VOLCANIC ROCKS: Ultramafites and amphibolites in Shurugwi, Masvingo, & other greenstone belts Blenkinsop et al., 1997[581].


270 Nondweni continental flood basalt(C) events

Location: S. Africa (Kaapvaal Craton)

Age: 3.41 & 3.33 Ga

Rating: B (7)

VOLCANIC ROCKS: Greenstone belts: Nondweni (includes 17% komatiites) Brandl and de Wit, 1997[676] Wilson and Versfeld, 1994[677], (Uz 3406±4 Ma Wilson and Versfeld, 1994[677]), Assegaai Brandl and de Wit, 1997[676], De Kraalen Brandl and de Wit, 1997[676], Commondale Brandl and de Wit, 1997[676] (S 3334±18 Ma Wilson and Carlson, 1989[678]).

COMMENT: Setting proposed as ensialic backarc basin Brandl and de Wit, 1997[676] Wilson and Versfeld, 1994[677]. But the presence of komatiites suggests plume involvement.


271 Lower Warrawoona oceanic flood basalt(O) event Arndt et al., this volume[578]

Location: NW. Australia (Pilbara Craton)

Age: 3.46 Ga

Rating: B (6)

VOLCANIC ROCKS: Lower part of Warrawoona Group (komatiitic and tholeiitic basalts) 3460 Ma McNaughton et al., 1993[675] Arndt et al., this volume[578] Barley, 1993[667].

COMMENT: Upper part of Warrawoona Group yields younger ages of Uz 3324±4 Ma and 3330 Ma and implies a hiatus in the group Arndt et al., this volume[578] McNaughton et al., 1993[675]. See event 268.


272 Upper Onverwacht Group events

Location: South Africa (Barberton belt, Kaapvaal Craton)

Age: 3.45 -3.30 Ga

Rating: B (7)

VOLCANIC ROCKS: VOLCANIC & INTRUSIVE ROCKS: greenstone belts: Hooggenoeg (includes komatiites) (Uz 3445± 8 Ma Armstrong et al., 1990[679]) (=3472±5 Ma & =3445±3 Ma Brandl and de Wit, 1997[676] (Uz 3452±3 Byerly et al., 1996[680]; Kromberg (includes minor komatiites) (Uz <3416±5 >3334±3 Ma Byerly et al., 1996[680]; Mendon (includes komatiites) (Uz 3298±3 Ma Byerly et al., 1996[680]); Weltevreden (includes komatiites) Byerly et al., 1996[680] Lahaye et al., 1995[681].

INTRUSION: Komati formation Gabbro (Uz 3482±5 Ma & 3351±6 Ma Armstrong et al., 1990[679] (Ub ca. 3350 Ma, Ubz 3352±6 Ma Kamo and Davis, 1994[682].


273 Lower Onverwacht oceanic flood basalt(O) events

Location: South Africa (Barberton belt, Kaapvaal Craton)

Age: 3.47 Ga

Rating: B (7)

VOLCANIC ROCKS: VOLCANIC & INTRUSIVE ROCKS: greenstone belts: Lower Onverwacht Group, includes: Komati Tomlinson and Condie, this volume[582] (Uz 3472±5 Ma Armstrong et al., 1990[679]), (Uz =3458±8 Ma (on crosscutting felsic dike) Brandl and de Wit, 1997[676].

COMMENT: Volcanic rocks include 5%-10% komatiites Brandl and de Wit, 1997[676].


274 Pietersburg-Giyani oceanic flood basalt(O) event

Location: S. Africa (N. Kaapvaal Craton)

Age: 3.5-3.2 Ga

Rating: B (7)

VOLCANIC ROCKS: VOLCANIC & INTRUSIVE ROCKS: greenstone belts: Pietersburg (includes 15% komatiites) 3400-3500 Ma Brandl and de Wit, 1997[676]; Giyani 3200 Ma Brandl and de Wit, 1997[676].


275 Dwalile event

Location: S. Africa (Kaapvaal Craton)

Age: 3.5-3.4 Ga

Rating: B (7)

VOLCANIC ROCKS: Dwalile greenstone belt (includes komatiites) Kröner and Tegtmeyer, 1994[683].

COMMENT: Age constrained between 3436±5 and 3521±23 Ma Kröner and Tegtmeyer, 1994[683]. Geochemical similarities suggest link with Onverwacht Kröner and Tegtmeyer, 1994[683]. See event 273.