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2500 Ma large mafic magmatic events

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211 Rampur-Garhwal events

Location: India (Himalayas)

Plume head center: ~31 N, 79 E Bhat et al., 1998[565]

Age: 2.5 Ga or 1.8 Ga

Rating: B (4v)

VOLCANIC ROCKS: Garhwal & Bhowali volcanic rocks (S 2510±80 Ma Bhat et al., 1998[565]) Ahmad and Tarney, 1991[566]; ? Rampur-Mandi volcanic rocks; ? Aravalli region volcanic rocks (S 2486±69 Ma for combined volcanic rocks, G, B, R, M) Bhat et al., 1998[565]).

DIKES: Garhwal dikes Ahmad and Tarney, 1991[566].

COMMENT: Associated rift identified Bhat et al., 1998[565]. Recent (lead evaporation) date on Rampur metabasalts, Uz 1800±13 Ma Miller et al., 2000[565a], suggests that the "previously published whole rock Sm-Nd age of 2510±90 Ma... may be geologically meaningless and... may have resulted from mixing" and implies a younger age for at least part of the event Miller et al., 2000[565a].


212 Lapland event

Location: N. Finland (Fennoscandian Shield)

Size: >50,000 sq. km.

Age: 2.53 Ga

Rating: B (7)

VOLCANIC ROCKS: Lapland greenstone belt (includes 20%-30% komatiites) Sorjonen-Ward et al., 1997[459].

COMMENT: Felsic pyroclastic dated at 2530 Ma Peltonen et al., 1988[567].


213 Great Dyke of Zimbabwe continental flood basalt(C) event

Location: Zimbabwe, (Zimbabwe Craton)

Size: 60,000 sq. km. Ernst et al., 1996[117]

Age: 2.574 Ga

Rating: B (5)

DIKES: satellite dikes (including the East and Umvimeela dikes).

FUNNEL DIKE: Great Dyke of Zimbabwe and its southern extension, NNE trending, (S 2586±16, Ur 2587±8, P 2596±14 Ma Mukasa et al., 1998[568] Mukasa et al., 1996[569]) Wilson, 1996[570] Wilson and Prendergast, 1989[571] Prendergast and Wilson, 1989[572] Podmore and Wilson, 1987[573]; (Uz 2581±11 Ma Wingate, 2000[574]).

COMMENT: U-Pb baddeleyite ages of Great Dyke, East and Umvimeela dikes are indistinguishable and give a pooled age of 2574±2 Ma Wingate, 2000[574].


214 Suomussalmi event

Location: E. Finland (Fennoscandian Shield)

Age: 2.65 Ga

Rating: B (7)

VOLCANIC ROCKS: greenstone belts: Vidal et al., 1980[575] Suomussalmi (includes komatiites) (P, R ca. 2650 Ma Vidal et al., 1980[575]), Kuhmo, Tipasjarvi.


215 Bohai Bay event

Location: E. China (E. Sino-Korean Craton)

Age: 2.66 Ga

Rating: C (possibly 7)

VOLCANIC ROCKS: Bohai Bay greenstone belt (includes meta-komatiites) (S 2660±75 Ma Jahn and Ernst, 1990[576]).


216 "Protobasinal" Transvaal event

Location: S. Africa (Kaapvaal Craton)

Age: 2.66 Ga

Rating: C (9v, possibly 8)

VOLCANIC ROCKS: Buffelsfontein Group U 2657-2659 Ma Eriksson and Reczko, 1995[577].

COMMENT: Plume origin advocated in Eriksson et al., 1999[522].


217 Maddina continental flood basalt(C) event

Location: Australia (Pilbara block)

Age: 2.69 Ga

Rating: B (6, 4v)

VOLCANIC ROCKS: Maddina, 2690 Ma Arndt et al., this volume[578] (between 2715 - 2684 Ma Arndt et al., 1991[579]) Nelson et al., 1992[580]; Nymerina Arndt et al., 1991[579]; Pearana Arndt et al., 1991[579]; Mount Jope Arndt et al., this volume[578].

COMMENT: Maddina basalt is upper part of Fortescue Group. Mount Jope volcanic rocks may alternatively be correlated with Kylena basalt Arndt et al., this volume[578]; see event 225.


218 Upper Bulawayan event

Location: Zimbabwe (Zimbabwe Craton)

Age: 2.69 Ga

Rating: B (7)

VOLCANIC ROCKS: Ngezi Group (in Belingwe greenstone belt) (includes 10% komatiites) Blenkinsop et al., 1997[581] Tomlinson and Condie, this volume[582], (P 2690±13 Ma, Chauvel et al., unpublished data cited in Nisbet et al., 1987[583]).


219 Pniel event

Location: South Africa (Kaapvaal craton)

Age: 2.71-2.69 Ga

Rating: B (6, 4v)

VOLCANIC ROCKS: Pniel group, <2709±4 Ma, >2687±2 Ma Cheney and de la R. Winter, 1995[583a] Cheney, 1998[583b].

COMMENT: Upper part of Ventersdorp Group.


220 Prince Albert continental flood basalt(C) event

Location: W. Canada (Prince Albert Group, Churchill province)

Age: >2.7 Ga

Rating: B (6)

VOLCANIC ROCKS: Greenstone belts: Prince Albert Group amphibolites, >2700 Ma Tomlinson and Condie, this volume[582].


221 Eastern Goldfields event

Location: W. Australia (Eastern Goldfields Superterrane, Yilgarn Craton)

Size: 100,000 sq. km.

Age: 2.71-2.69 Ga

Rating: B (7)

VOLCANIC ROCKS: Greenstone belts: Tomlinson and Condie, this volume[582] Myers and Swagers, 1997[584] Norseman-Wiluna (which includes the Kalgoorlie, Gindalbie and Jubilee terranes & the Kambalda (komatiite); (Uz 2708±7, 2705±4 Ma Nelson, 1997[585]), (Uz 2692±4 Ma Claoué-Long et al., 1988[586]).

COMMENT: Volcanic rocks in the southern part of Kalgoorlie terrane include 10%-15% komatiites Myers and Swagers, 1997[584].


222 Stillwater continental flood basalt(C) event

Location: NW. USA (Wyoming Province)

Size: 4500 sq. km., 6.5 km thick, 25,000 cu. km.

Age: 2.709-2.701 Ga

Rating: B (4i)

SILL-LIKE LAYERED INTRUSION: Stillwater complex (S 2701±8 Ma DePaolo and Wasserburg, 1979[587] Uzb 2705±4 Ma Premo et al., 1990[588]) (Uz 2713±3 Ma Nunes, 1981[589]) McCallum, 1996[590].


223 Klipriviersberg-Platberg continental flood basalt(C) event(s)

Location: South Africa (Kaapvaal craton)

Age: 2.717-2.701 Ga

Rating: B (6, 4v)

VOLCANIC ROCKS: Klipriviersberg (Uz 2714±16 Ma Armstrong et al., 1991[591] Marsh et al., 1992[591a] Cheney and de la R. Winter, 1995[583a]; Platberg group, Uz 2709±8 Ma Armstrong et al., 1991[591].

COMMENT: Part of Ventersdorp Group. See age discussion in event 234. Plume origin for Ventersdorp discussed in White, 1997[591b].


224 Abitibi oceanic flood basalt(O) event(s)

Location: Canada (Abitibi belt, Superior province)

Age: 2.720-2.700 Ga

Rating: B (7)

VOLCANIC ROCKS: Abitibi greenstone belts: Lower Tisdale Group volcanic rocks U 2714 Ma Tomlinson and Condie, this volume[582] Wyman, 1999[592]; Stoughton-Roquemaure Group volcanic rocks, U 2714±2 Ma U 2713+7/-5 Tomlinson and Condie, this volume[582] Wyman, 1999[592]; Boston Creek flow (peridotite to diorite), and associated Fe-tholeiite flows, ca. 2720 Ma Tomlinson and Condie, this volume[582]; Kinojevis Group U 2701 Ma Tomlinson and Condie, this volume[582] Xie, 1996[593]; Wabewawa (U 2747±2, 2720±2 Ma, Mortensen, 1993[593a] Corfu and Noble, 1992[593b], Isley and Abbott, 1999[594]); Larder Lake (U 2705±2 Ma Corfu et al., 1989[595]).

LAYERED INTRUSIONS: Kamiskotia Barrie et al., 1991[596] Barrie and Shirey, 1991[597] (Uz 2707±2 Ma Barrie and Davis, 1990[598]); Montcalm Barrie and Shirey, 1991[597] (Uz 2702±2 Ma Barrie and Naldrett, 1989[599]).

COMMENT: Komatiites present Tomlinson and Condie, this volume[582] Isley and Abbott, 1999[594]. Some komatiites interpreted to represent partial melting in the majorite garnet stability field Tomlinson and Condie, this volume[582].


225 Kylena continental flood basalt(C) event

Location: Australia (Pilbara block)

Age: ca. 2.72 Ga

Rating: B (6, 4v)

VOLCANIC ROCKS: Kylena ca. 2720 Ma Blake, 1993[600] Williams and Trendall, 1998[601] Arndt et al., 1991[579] Arndt et al., this volume[578] Nelson et al., 1992[580]; Mount Jope Blake, 1993[600].

SILLS: Cooya Pooya Blake, 1993[600], (p. 16 in Hoatson et al., 1992[602]).

COMMENT: Kylena basalt is middle part of Fortescue Group. Petrography of Cooya Pooya sills match that of Kylena units (p. 227 in Blake, 1993[600]). Mount Jope volcanic rocks may alternatively be correlated with Maddina event Arndt et al., this volume[578]; see event 217.


226 Mulcahy Lake event

Location: W. Canada (Central Wabigoon, Superior province)

Age: 2.73 Ga

Rating: C (possibly 9isv)

VOLCANIC ROCKS: Mg-Fe rich tholeiitic basalts (p. 342 in Blackburn et al., 1991[603a].

SILLS: (p. 348 in Blackburn et al., 1991[603a]): Katimiagamak Lake (U 2732+4/-3 Ma Davis and Edwards, 1986[603b]); Kakagi Lake (U2728±2 Ma Davis and Edwards, 1986[603b]).

LAYERED INTRUSIONS: Mulcahy Lake intrusion U 2732+1.0/-0.9 Ma Morrison et al., 1985[603] and related intrusions Morrison et al., 1986[604] Davies, 1966[605] Davis et al., 1982[606] Davis and Edwards, 1982[607], Nabish Lake intrusion, Mile Lake-Trapp Lake intrusion, Denmark Lake intrusion.

COMMENT: Arc origin suggested (p. 360 in Blackburn et al., 1991[603a]).


227 Kam Group continental flood basalt(C) event(s)

Location: NW. Canada (Slave Province)

Size: possibly >100,000 sq. km.

Age: 2.73-2.70 Ga

Rating: B (4v)

DIKES: Uz 2734±2 Ma Bleeker et al., 1999b[611].

BASALTS: Kam Group Cousens, 2000[609] Bleeker et al., 1999a[610] Bleeker et al., 1999b[611] (U 2729+8/-7 Ma rhyolite porphyry cutting basal basalts Villeneuve, 1993[612]; U2722-2701 Ma upper Kam Group Bleeker et al., 1999a[610]).

COMMENT: Cousens, 2000[609] favors a continental rift, or backarc setting. Plume origin is favored by W. Bleeker (Bleeker et al., 1999a[610] & 2000, personal communication).


228 Olenegorsk continental flood basalt(C) event

Location: Russia, Kola Peninsula (N. Baltic Shield, Olenegorsk district)

Age: 2.74 Ga

Rating: C (possibly 5)

DIKES: Olenegorsk, NNW trending, Uz 2738±6, 2739±11 Ma Yegorov and Bayanova, 1999[613] Bayanova et al., 1998[614].

COMMENT: Dikes interpreted to be related to continental rifting Yegorov and Bayanova, 1999[613].


229 Southern Onaman-Tashota oceanic flood basalt(O) event

Location: Canada (eastern Wabigoon Subprovince, Superior Province)

Age: ?>2.740 Ga

Rating: B (7)

VOLCANIC ROCKS: Southern Onaman-Tashota terrane greenstone belts (includes komatiites, ?>2740 Ma Tomlinson and Condie, this volume[582] Tomlinson, 1996[615].

SILLS: Tomlinson and Condie, this volume[582].


230 Wawa oceanic flood basalt(O) event

Location: C. Canada (Wawa subprovince, SW. Superior Province)

Age: mainly 2.75-2.73 Ga

Rating: B (7)

VOLCANIC ROCKS: Greenstone belts: Tomlinson and Condie, this volume[582] Polat et al., 1999[616] Polat et al., 1998[617] Schreiber-Hemlo belt (includes komatiites); White River-Dayohessarah belt (includes komatiites); (U 2749±2, 2744±10 Ma Turek et al., 1982[618]).


231 Sylvania Inlier continental flood basalt(C) event

Location: western Australia (Sylvania Inlier)

Age: 2.751-2.743 Ga

Rating: C (possibly 5)

DIKES: Sylvania Inlier, NNE trending, Uz 2747±4 Ma Wingate, 1999[619].

COMMENT: possibly linked to Kylena event Wingate, 1999[619].


232 Ilomantsi event

Location: N. Finland (N. Fennoscandian Shield)

Size: 800 sq. km. (Hattu schist belt part)

Age: ca. 2.75 Ga

Rating: B (7)

VOLCANIC ROCKS: Hattu schist belt (includes <10% komatiites) Sorjonen-Ward et al., 1997[459].

COMMENT: Felsic pyroclastic rocks low in sequence dated at 2754±6 Ma and porphyry clasts in a conglomerate higher up in sequence dated at 2726± 15 Ma Sorjonen-Ward et al., 1997[459]. The komatiites are in upper part of succession Sorjonen-Ward et al., 1997[459].


233 Mount Roe continental flood basalt(C) events

Location: NW. Australia (Pilbara block)

Age: 2.771 Ga

Rating: B (6, 4v)

VOLCANIC ROCKS: Mount Roe Blake, 1993[600] Wingate, 1999[619] Arndt et al., this volume[578] Nelson et al., 1992[580] (Uz 2775±10, 2763±13 Ma, mean = 2771±7 Ma Arndt et al., 1991[579]), Koongaling Arndt et al., 1991[579] (Uz 2764±8 Ma Arndt et al., 1991[579]).

DIKES: Black Range, N-NNE trending, Ub 2772±2 Ma Wingate, 1999[619].

SILLS: ? Blake, 1993[600].

COMMENT: Mount Roe event is lower part of Fortescue Group.


234 Derdepoort continental flood basalt(C) event

Location: South Africa, SE. Botswana (Kaapvaal craton)

Size: 60,000 sq. km. (Fig. 7 in White, 1997[84])

Age: 2.78 Ga

Rating: B (6)

VOLCANIC ROCKS: Cheney and Winter, 1995[620]: Derdepoort, Uz 2782±5 Ma Wingate, 1998[621], Klipriviersberg (Uz 2714±16 Ma Armstrong et al., 1991[591]. However, this age may not be dating the time of emplacement Wingate, 1998[621]). See also event 223.

DIKES: NE trending dike swarm (200 km wide) not precisely dated Uken and Watkeys, 1997[88].

INTRUSION: Gaborone Complex, Uz ca. 2785 Ma Grobler and Walraven, 1993[623] Moores et al., 1993[624]; ? Modipe gabbro Wingate, 1998[621].

COMMENT: Part of Ventersdorp Group.


235 Rio das Velhas events

Location: Brazil (Quadrilátero Ferrifero, São Francisco Craton)

Size: 7000 sq. km.

Age: 2.78 & 2.71 Ga

Rating: B (7)

VOLCANIC ROCKS: Nova Lima group in Rio Das Velhas Supergroup of Quadrilátero Ferrifero greenstone belt (includes <15% komatiites) Baars, 1997[625] (2776+23/-10 M & 2772±6 Ma from felsic volcanic rocks Machado et al., 1992[626]).

DIKES: U 2706±9 Ma (Baars and Armstrong, unpublished data cited in Baars, 1997[625].


236 Vizien oceanic flood basalt(O) event

Location: Canada (Minto block, Superior province)

Age: 2.786 Ga

Rating: B (7)

VOLCANIC ROCKS: Vizien greenstone belt Skulski and Percival, 1996[627].

SILLS: Vizien (Uz 2786±1 Ma Skulski and Percival, 1996[627]).

COMMENT: Komatiities present Skulski and Percival, 1996[627] Tomlinson and Condie, this volume[582].


237 Kuhmo event

Location: N. Finland (N. Fennoscandian Shield)

Size: 450 sq. Km.

Age: 2.8 -2.7 Ga

Rating: B (7)

VOLCANIC ROCKS: Kuhmo greenstone belt (includes <5% komatiites) Sorjonen-Ward et al., 1997[459].

SILLS: Moisiovaara, 2790±12 Ma Sorjonen-Ward et al., 1997[459].

COMMENT: "2.8-2.7 Ga event interpreted as ensialic rifting induced by mantle plume" (p. 684 in Sorjonen-Ward et al., 1997[459]).


238 Murchison-2 event

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

Size: 17,000 sq. km. (intrusions), 80,000 sq. km. (greenstones)

Age: 2.8 Ga

Rating: C (9i)

VOLCANIC ROCKS: Mount Farmer Group, 2800 Ma (p. 643 in Myers and Swagers, 1997[584]).

LAYERED INTRUSIONS: (Fig. 2-125 Ahmat and Ruddock, 1990[629]) Hoatson et al., 1992[602] Mathison and Ahmat, 1996[630] Myers and Swagers, 1997[584]: Windimurra (S ca. 2800 Ma, >R 2700 Ma), Narndee, Youanmi, Barrambie, Atley, Gabanintha.

COMMENT: Early flood basalts at 3.0 Ga (Murchison-1 event) (event 262) overlain by local volcanic centers at 2.8 Ga (this event) (p. 644 in Myers and Swagers, 1997[584]). Link between volcanic rocks and intrusive rocks is supported by geographic proximity and age similarity.


239 Usushwana continental flood basalt(C) event

Location: NE. South Africa (Kaapvaal Craton)

Age: 2.87 Ga

Rating: C (possibly 5)

DIKES: ? Barberton-1, NW trending, >2800 <3200 Ma Hunter and Halls, 1992[631] Havenga, 1995[632], (could be older, i.e., Pongola age Uken and Watkeys, 1997[88] (event 253).

DIKE-SILL COMPLEX: Usushwana Intrusive Suite (two funnel dikes linked by a gently dipping sill) (S 2871±30 Ma Hegner et al., 1984[633]) Hatton and Von Gruenewaldt, 1990[436] Hunter and Reid, 1987[90] Hunter, 1970[634] (Fig. 2.30 Goodwin, 1991[180]).


240 Lavras event

Location: Brazil

Size: 50,000 sq. km.

Age: 2.83 Ga

Rating: B (5)

DIKES: Lavras-1, SE trending Quéméneur, 1991[635] Sial et al., 1987[113], (S 2833±65 Ma Pinese et al., 1995[636]).


241 Kostomuksha oceanic flood basalt(O) event Tomlinson and Condie, this volume[582]

Location: NW. Russia (NW. Fennoscandian Shield)

Size: 120 sq. km

Age: 2.84 Ga

Rating: B (7)

VOLCANIC ROCKS: Kostomuksha greenstone belt (includes 20-30% komatiites), U >2795 Ma, S 2840 Ma, P 2810 Ma Puchtel et al., 1998b[637] Tomlinson and Condie, this volume[582] Puchtel et al., 1997b[638].


242 Barlee-Yellowdine event

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

Size: 4500 sq. km. (Marda greenstone belt)

Age: 2.85 Ga

Rating: B (7)

VOLCANIC ROCKS: Barlee terrane (Marda greenstone belt) (includes 10% komatiites) Myers and Swagers, 1997[584] (S 2850±25 Ma Fletcher et al., 1984[639], Yellowdine terrane Myers and Swagers, 1997[584].


243 Fiskenaesset oceanic flood basalt(O) event Tomlinson and Condie, this volume[582]

Location: SW. Greenland (Greenland Shield)

Age: >2.8 Ga

Rating: B (6)

VOLCANIC ROCKS: Fiskenaesset greenstone belt, >2850 Ma Weaver et al., 1982[640] Tomlinson and Condie, this volume[582].

COMMENT: Metamorphosed to amphibolites.


244 Pickle Crow oceanic flood basalt(O) event

Location: Canada (Pickle Lake belt, Uchi subprovince, Superior province)

Age: 2.86 Ga

Rating: B (7)

VOLCANIC ROCKS: Pickle Crow assemblage (includes komatiites) ca. 2860 Ma Tomlinson and Condie, this volume[582] Hollings, 1998[641].


245 Otter Creek event

Location: C. USA

Age: 2.9 Ga

Rating: C (possibly 9i)

SILL-LIKE LAYERED INTRUSION: Otter Creek layered intrusion S 2890±90 Ma Windom et al., 1993[642]; delineated by magnetic anomaly pattern and by drill holes through cover rocks Windom et al., 1993[642].

COMMENT: Part of a line of magnetic anomalies extending for almost 300 km in a NE trend.


246 Crixás event(s)

Location: Brazil (Goiás massif)

Age: 2.9 Ga

Rating: B (7)

VOLCANIC ROCKS: Baars, 1997[625] Crixás (includes komatiites) (S 2900 Ma Arndt et al., 1989[643]), Caiamar, Moquém, Pilar de Goiás greenstone belts.


247 Mtshingwe Group event

Location: Zimbabwe (Zimbabwe Craton)

Age: 2.9 Ga

Rating: B (6)

VOLCANIC ROCKS: Mtshingwe group (Belingwe greenstone belt), ca. 2900 Ma Tomlinson and Condie, this volume[582].


248 Eastern Dharwar event

Location: S. India (Eastern Dharwar block)

Size: 50,000 sq. km.

Age: 2.9 Ga

Rating: B (7)

VOLCANIC ROCKS: Eastern Dharwar greenstone belts includes Kolar schist (amphibolite) belt, ca. 2900 Ma Tomlinson and Condie, this volume[582] (includes 10% komatiites) Rogers and Giral, 1997[644] Tomlinson and Condie, this volume[582].

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


249 Mount Negri event(s) Arndt et al., this volume[578]

Location: NW. Australia (Pilbara Craton)

Age: 2.9 Ga

Rating: B (7)

VOLCANIC ROCKS: Louden (includes komatiites), Mount Negri (includes komatiites) Barley, 1997[645] Arndt et al., this volume[578] (2900 Ma Barley, 1997[645]).


250 Forrestania-Lake Johnston continental flood basalt(C) event Perring et al., 1996[646]

Location: W. Australia (S. Southern Cross province, Yilgarn Craton)

Age: 2.9 Ga

Rating: B (7)

VOLCANIC ROCKS: greenstone belts: Forrestania (includes komatiites) (ca. 2900 Ma) Perring et al., 1996[646] Tomlinson and Condie, this volume[582]; Lake Johnston (includes komatiites) Wang et al., 1996[647] (Uz >2903±5 Ma <2921±4 Ma Wang et al., 1996[647]; Penneshaw ca. 2900 Ma Wang et al., 1996[647], (p. 15 in Campbell and Hill, 1988[648]).


251 West Pilbara continental flood basalt(C) event

Location: W. Australia (Pilbara Craton)

Age: 2.94-2.91 Ga

Rating: B (4i)

DIKES: Cadgerina (NE-N trending feeder dike to Munni Munni intrusion) Barnes and Hoatson, 1994[649] Hoatson et al., 1992[602].

SILL-LIKE LAYERED INTRUSIONS: West Pilbara layered intrusions Fitton et al., 1975[650] Korsch and Gulson, 1986[651] Hickman, 1983[652] Ashwal, 1993[653] Hoatson et al., 1992[602]: Munni Munni (Uz 2925±16 Ma Arndt et al., 1991[579], (S 2927±13 Ma Sun and Hoatson, 1992[654]), Mount Sholl, Maitland, Radio Hill, Andover, Balla Balla, Dingo, Sherlock Bay, & Mount Hall-Carlow Castle intrusions.


252 Steep Rock continental flood basalt(C) event

Location: Canada (C. Wabigoon subprovince & N. Caribou terrane, Superior province)

Age: mainly 2.93-2.92 Ga

Rating: B (7)

VOLCANIC ROCKS: greenstone belts: Steep Rock (includes komatiites) ca. 2930 Ma Tomlinson and Condie, this volume[582]; D'Alton Lake-Toronto Lake (includes komatiites) ca. 2920 Ma Tomlinson and Condie, this volume[582]; Finlayson Tomlinson et al., 1999[655] (U 2932±2, Ma (on rhyolite), D.W. Davis cited in Tomlinson et al., 1999[655]); Lumby Lake (includes komatiites) <2963-2898 Ma Tomlinson et al., 1999[655] Tomlinson and Condie, this volume[582]; Heaven Lake (includes komatiites) 2954 Ma Tomlinson and Condie, this volume[582]; McGruer assemblage (includes komatiites) Hollings et al., 1999[657] Stott, 1997[658] Tomlinson and Condie, this volume[582] (North Rim unit, Uz 2932 Ma, D. Davis, unpublished data Hollings et al., 1999[657] Stott, 1997[658]).

COMMENT: McGruer assemblage is located in North Caribou terrane; the other greenstone units are in the Central Wabigoon Subprovince. The 20-my-older age for Heaven Lake greenstone belt may suggest a separate plume event.


253 Pongola event

Location: South Africa (Kaapvaal Craton)

Age: ca. 2.94 Ga

Rating: B (4v)

VOLCANIC ROCKS: Nsuze Group (Pongola supergroup) (mafic to felsic) Tankard et al., 1982[659] Smith, 1990[660] Uken and Watkeys, 1997[88] (Uz 2940±22 Hegner et al., 1984[633]).

DIKES: ? Barberton-1, NW trending, >2800 <3200 Ma Hunter and Halls, 1992[631] Havenga, 1995[632], could be older, i.e., Pongola age Uken and Watkeys, 1997[88].


254 Nandagao event

Location: India (Bastar Craton)

Age: ca. 2.95-2.6 Ga

Rating: B (4v)

VOLCANIC ROCKS: (p. 285-286 in Eriksson et al., 1999[522]).

COMMENT: An enormous thickness of volcanic rocks possibly related to a mantle plume Eriksson et al., 1999[522].


255 Sumozero-Kenozero event

Location: N. Europe (Fennoscandian Shield)

Age: ca. 2.96 Ga

Rating: B (7)

VOLCANIC ROCKS: Sumozero-Kenozero greenstone belt (includes <10% komatiites) Puchtel et al., 1997b[638] (S 2960±150 Ma Sochevanov et al., 1991[662]).


256 Balmer event

Location: Canada (S. North Caribou terrane, Superior province)

Age: 2.99 Ga

Rating: B (6)

VOLCANIC ROCKS: Balmer assemblage (Red Lake greenstone belt) Tomlinson and Condie, this volume[582] Hollings et al., 1999[657] (Uz 2992+20/-9 Ma Corfu and Wallace, 1986[663]) (Uz 2989±3 Ma Corfu and Andrews, 1987[664]).

SILLS: Balmer assemblage Tomlinson et al., 1998[665] Tomlinson and Condie, this volume[582].

COMMENT: Komatiites present Tomlinson et al., 1998[665] Tomlinson and Condie, this volume[582]. Dates are from felsic volcanic rocks. An additional date on the Balmer assemblage, Uz 2964+5/-1 has cores >2982 Ma, and the 2964 Ma age is considered "not totally reliable" (p. 39 in Corfu and Wallace, 1986[663]).


257 Whim Creek event

Location: NW. Australia (Pilbara Craton)

Age: 2.99 Ga

Rating: C (possibly 8)

VOLCANIC ROCKS: Krapez, 1993[666] Arndt et al., this volume[578]: Mons Cupri (Uz 2990±7 Ma on Mount Brown rhyolite at base Trendall et al., 1990[666a]) Barley, 1987[669]; Warambie.

COMMENT: Felsic volcanic rocks of Sholl sequence dated at Uz 3112±6 Ma Horwitz and Pidgeon, 1993[668]. Emplaced in pull-apart basins within continental crust Barley, 1987[669].


258 Bababudan continental flood basalt(C) event

Location: India (Western Dharwar block)

Size: 30,000 sq. km.

Age: 3.0 - 2.5 Ga

Rating: C (9v)

VOLCANIC ROCKS: Bababudan Group (lower part of Dharwar suite) Rogers and Giral, 1997[644] Chadwick et al., 1985[670]; Chitradurga Group (mainly sedimentary rocks but some volcanic rocks) may be correlative Rogers and Giral, 1997[644].

COMMENT: Volcanic rocks are bimodal and represent continental volcanism Eriksson et al., 1999[522].


259 Lower Bulawayan event

Location: Zimbabwe (Zimbabwe Craton)

Age: 3.0-2.8 Ga

Rating: B (7)

VOLCANIC ROCKS: Mtshingwe (in Belingwe greenstone belt) (includes 2% komatiites) Blenkinsop et al., 1997[581].


260 Carajas event(s)

Location: Brazil (Central Amazonian province, Amazonian Craton)

Size: 30,000 sq. km.

Age: 3.0-2.9 Ga

Rating: B (7)

VOLCANIC ROCKS: Carajas greenstone belt includes: Lagoa Seca Group (with komatiites) (>2874±10 Ma <2971±19 Ma Macambira and Lancelot, 1991[671] Tassinari, 1997[672]) & Serra do Inaja Group (with meta-ultramafic volcanic rocks) Tassinari, 1997[672].

COMMENT: Continental-rift setting Tassinari, 1997[672].