Hercynian/Alleghanian overprinting of an acadian terrane: 40Ar/39Ar studies in the Meguma zone, Nova Scotia, Canada

Muecke, G. K.; Elias, P.; Reynolds, P. H.

doi:10.1016/0168-9622(88)90013-9

Cited by 50 publications

(18 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hornblende MMhb-1, with an assumed age of 520G2 Ma (Samson and Alexander, 1987), was used as a standard for all analyses. Experimental procedures follow those described by Muecke et al (1988).…”

Section: Ar/ 40 Ar Analysesmentioning

confidence: 99%

Structural and geochronological constraints on the tectonic evolution of the Dulong-Song Chay tectonic dome in Yunnan province, SW China

Yan

Zhou

Wang

et al. 2006

Journal of Asian Earth Sciences

120

106

View full text Add to dashboard Cite

Section: Ar/ 40 Ar Analysesmentioning

confidence: 99%

Structural and geochronological constraints on the tectonic evolution of the Dulong-Song Chay tectonic dome in Yunnan province, SW China

Yan

Zhou

Wang

et al. 2006

Journal of Asian Earth Sciences

120

106

View full text Add to dashboard Cite

“…The Meguma Group represents a turbidite fan deposited on the continental margin of Gondwana (Schenk, 1991). The entire sequence, including the overlying Silurian and Early Devonian volcanic and sedimentary rocks (White Rock to Torbrook formations), was deformed and metamorphosed in the Acadian orogeny (Keppie and Dallmeyer, 1987;Muecke et al, 1988).…”

Section: General Regional Geology Of the Meguma Zonementioning

confidence: 99%

“…Their lithological classification follows Streckeisen (Clarke et al, 1993b). Meguma Group regional metamorphism 405-390 Ma (Ar-Ar) (Muecke et al, 1988). Meguma Group depositional age 500 Ma.…”

Section: Mineralogy and Petrologymentioning

confidence: 99%

Late Devonian mafic-felsic magmatism in the Meguma Zone, Nova Scotia

Clarke¹,

MacDonald²,

Tate³

1997

The Nature of Magmatism in the Appalachian Orogen

View full text Add to dashboard Cite

The Meguma Zone of southern Nova Scotia docked with North America in the mid-Late Devonian. Associated magmatic activity involved small calc-alkaline lamprophyric mafic bodies and large peraluminous granitoid plutons.The mafic bodies include ten dikes and one sheet cutting the Meguma Group metasedimentary rocks, two plugs in the Liscomb Complex, and four synplutonic bodies in some of the smaller granitoid plutons. They are generally coarse-grained hornblende-biotite gabbronorites, diorites, and spessartites, and all have highly fractionated rare earth element patterns and negligible Eu/Eu* anomalies.The granitoid plutons fall into two spatial-chemical-genetic types: 1. The central plutons, including the South Mountain Batholith, are ca. 372 Ma, late-tectonic to posttectonic, predominantly unfoliated, emplaced into low-grade metamorphic host rocks, generally not spatially associated with mafic intrusions, and exclusively peraluminous with Sn-W-Mo-U greisen-and vein-dominated mineral deposits; 2. The peripheral plutons, at the northeastern and southwestern extremities of the Meguma Zone, may be slightly older (376 Ma); they are late-tectonic, moderately foliated, emplaced into higher grade metamorphic host rocks, invariably spatially associated with Late Devonian mafic intrusions, and mostly peraluminous with only limited Be-pegmatite mineralization. The central plutons are apparently entirely crustally derived (sub-Meguma Group source rocks and Meguma Group contamination), and probably owe their origin to crustal thickening associated with the collision of the Meguma terrane against the Avalon terrane. The peripheral plutons are of mixed derivation (sub-Meguma Group source rocks and mantle-derived mafic magmas), and probably owe their origin to the lower to mid-crustal intrusion of subduction-related mafic magmas prior to the final emplacement of the Meguma terrane.

show abstract

“…390 Ma (Keppie and Dallmeyer 1987;Muecke et al 1988), prior to the intrusion of many peraluminous granitoid bodies at ca. 370 Ma, including the South Mountain Batholith (Clarke et al 1993).…”

Section: Introductionmentioning

confidence: 98%

Petrochemistry, tectonic history, and Sr–Nd systematics of the Liscomb Complex, Meguma Lithotectonic Zone, Nova Scotia

Clarke¹,

Chatterjee²,

Giles³

1993

Can. J. Earth Sci.

View full text Add to dashboard Cite

The Liscomb Complex (area ca. 240 km2), located in the Meguma Lithotectonic Zone of the Canadian Appalachians, consists of three main lithological components: high-grade gneisses, mafic plutons, and peraluminous granitoid bodies. Field relations and 40Ar139Ar dating (369-377 Ma) embracing all three lithological groups show that the complex is postAcadian. The gneisses occur as a domal uplift and represent a mixed volcano-sedimentary package that is structurally, metamorphically, and chemically distinct from the surrounding low-grade metawackes and metapelites of the Meguma Group. The mafic intrusions (quartz gabbro to quartz diorite) have major and trace element compositions (e.g., Ti -Zr -Y, Nb-Zr -Y, ThIYb -TaIYb, rare earth elements) typical of within-plate or volcanic arc materials. The peraluminous granitoid rocks range from two-mica granodiorites to leucomonzogranites, and are mineralogically and chemically very similar to granitic rocks elsewhere in the Meguma Zone. Neodymium and strontium isotopic analyses show that (i) the gneisses have a wide range of e, , and initial Sr isotopic ratios, with Nd model ages that are generally younger than those of the Meguma Group;(ii) the mafic intrusive rocks represent magmas derived from slightly depleted mantle sources (eNd +3.3 to + 1.4), in part modified by crustal contamination (E,, +0.5 to -5.0); and (iii) the granitoid rocks isotopically overlap both the South Mountain Batholith and the intermediate gneisses of the Liscomb Complex. The combined field, petrological, and chemical evidence suggests that underplating by mafic magmas, followed by thermal doming of the gneisses, diapirism through the Meguma Group, anatexis, and multiple intrusion of both mafic and felsic magmas best explain the observed relationships in the Liscomb Complex. This mechanical model may also apply to granite generation throughout the Meguma Zone. Le Complexe de Liscomb (superficie d'environ 240 km2), IocalisC dans la Zone lithotectonique de Meguma, dans les Appalaches canadiennes, est form6 de trois unitCs lithologiques: des gneiss intensement mCtamorphisCs, des plutons mafiques, et des corps de granitoides peralumineux. Les relations sur le terrain, et les datations 40Ar/39Ar (369-377 Ma) englobant les trois groupes lithologiques demontrent que le complexe est post-Acadien. Les gneiss apparaissent comme un sulbvement en forme de dBme, et ils sont reprksentks par un assemblage volcano-~Cdimentaire melange, qui du point de vue structural, mktamorphique et chimique se distingue nettement des mttawackes et des mCtapClites de faiblement metamorphises du Groupe de Meguma. Les intrusions mafiques (gabbro quartzique 2 diorite quartzique) possbdent des compositions en ClCments majeurs et traces (c.-a-d., Ti-Zr -Y, Nb -Zr-Y, ThIYb -TalYb, terres rares) typiques de materiaux intra-plaques ou d'arc volcanique. Les roches granitoides peralumineuses varient de granodiorites a deux micas a des leucomonzogranites, elles sont minCralogiquement et chimiquement trbs semblables aux roches granitiques trouve...

show abstract

Hercynian/Alleghanian overprinting of an acadian terrane: 40Ar/39Ar studies in the Meguma zone, Nova Scotia, Canada

Cited by 50 publications

References 34 publications

Structural and geochronological constraints on the tectonic evolution of the Dulong-Song Chay tectonic dome in Yunnan province, SW China

Structural and geochronological constraints on the tectonic evolution of the Dulong-Song Chay tectonic dome in Yunnan province, SW China

Late Devonian mafic-felsic magmatism in the Meguma Zone, Nova Scotia

Petrochemistry, tectonic history, and Sr–Nd systematics of the Liscomb Complex, Meguma Lithotectonic Zone, Nova Scotia

Contact Info

Product

Resources

About