The magmatic affinities of some volcanic rocks from the Tweed Shield Volcano, S.E. Queensland — N.E. New South Wales

Wilkinson, J. F. G.

doi:10.1017/s0016756800052298

Cited by 15 publications

(4 citation statements)

References 23 publications

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“…In some cases, a structural regime involving compression and strike-slip was shown to predominate (Turner and Verhoogen 1960;Souther 1977), whereas other examples involve either extension or compression (Wilkinson 1968;Eaton 1982). In some cases, a structural regime involving compression and strike-slip was shown to predominate (Turner and Verhoogen 1960;Souther 1977), whereas other examples involve either extension or compression (Wilkinson 1968;Eaton 1982).…”

Section: Bmentioning

confidence: 99%

Late Devonian – Early Carboniferous volcanism in western Cape Breton Island, Nova Scotia

Blanchard¹,

Jamieson²,

More³

1984

Can. J. Earth Sci.

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The Fisset Brook Formation of western Cape Breton Island and its equivalents at MacMillan Mountain and the north Baddeck River are examples of Late Devonian and Early Carboniferous volcanic sequences associated with the formation of post-Acadian successor basins in the northeastern Appalachians. They consist of bimodal basalt-rhyolite suites interbedded with alluvial fan, lacustrine, and rare fluvial sediments. The earliest volcanic products are rhyolites and somewhat evolved basalts associated with coarse sediments, followed by tholeiitic to transitional basalt flows interlayered with lacustrine-type deposits. Geochemical studies on the Fisset Brook Formation indicate extensive remobilization of alkalies, Ca, Rb, and Sr, making these elements inappropriate for determining tectonic setting or magmatic affinity. Use of less mobile elements (Ti, Nb, Y, and Zr) suggests that the basalts are tholeiitic and that the apparent alkalinity of the type section lavas is a result of alteration. We conclude that volcanism in western Cape Breton Island started at MacMillan Mountain and migrated westwards, probably towards the centre of the deepening Magdalen Basin.La formation de Fisset Brook et les sequences volcano-skdimentaires de MacMillan Mountain et North Baddeck River dans I'ouest de l'ile du Cap Breton sont des exemples de volcanisme du DCvonien superieur -Carbonifkre inferieur reliC au stage anorogtnique post-Acadien dans le nord-ouest des Appalaches. Les roches sedimentaires associees aux coulees de basalte et rhyolite suggerent un environnement propice a la formation de c8nes de dejection et de dtp8ts de type lacustre ou fluvial. Les premikres sequences de laves contiennent surtout des rhyolites et andesites basaltiques associees a des faciks proximaux; les sequences plus jeunes sont formees de basaltes tholeiitiques ou de transition interstratifies avec des dCp8ts lacustres. Nos etudes gtochimiques revelent que I'alteration des laves de la formation de Fisset Brook mobilise de preference les elements alcalins, Ca, Rb et Sr. L'utilisation d' C1Cments relativement "immobiles" (Ti, Nb, Y et Zr) indique que les basaltes sont tholeiitiques et que leur caractkre apparemment alcalin est dQ aux processus secondaires. La gtochronologie et stratigraphie des laves suggkrent I'amorce du v~lcanisme~dans la region de MacMillan Mountain, suivie d'une migration des centres Cruptifs vers I'ouest ou le centre du bassin des Iles-de-la-Madeleine.

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Section: Bmentioning

confidence: 99%

Late Devonian – Early Carboniferous volcanism in western Cape Breton Island, Nova Scotia

Blanchard¹,

Jamieson²,

More³

1984

Can. J. Earth Sci.

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“…The lavas are moderately oversaturated tholeiites ranging from basalt to rhyolite, with minor transitional and possibly alkaline basaltic rocks and some alkaline trachyte and alkaline rhyolite (Richards, 1916;Wilkinson, 1968;Green, 1970). McTaggart (1961) has divided the volcanic sequence into formations using two very extensive rhyolite horizons as a basis for stratigraphy.…”

Section: Tweed Volcano (21)mentioning

confidence: 99%

Potassium‐argon ages on the Cainozoic volcanic rocks of New South Wales

Wellman

McDougall

1974

Journal of the Geological Society of Australia

198

101

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“…The analyses illustrate the essentially alkaline character of the rocks, most of which contain normative nepheline in contradistinction to the predominantly qz-normative tholeiitic suite comprising the Lismore and Blue Knob Basalts (Wilkinson, 1968;Duggan, in prep.). The appearance of minor hy in Nos 6 and 7 may be attributed to their degree of oxidation (Fe2O 3 = 5.43 and 7.57 wt% respectively).…”

Section: Northeastern New South Walesmentioning

confidence: 93%

“…The volcanics include both alkaline and tholeiitic types and the eruptive activity varied in nature from small lava-fields to large central type volcanoes (Wellman & McDougall, 1974a). Notable among the latter is the Tweed Shield Volcano* (Hill, 1951;Stephenson et al, 1960;Wilkinson, 1968;Stevens, 1970) which is located astride the state border separating northeastern New South Wales and southeastern Queensland (Fig. 1).…”

mentioning

confidence: 99%