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TitleEpisodic Paleoproterozoic crustal growth preserved in the Aillik Domain, Makkovik Province, Labrador
AuthorHinchey, A M; Rayner, NORCID logo; Davis, W JORCID logo
SourcePrecambrian Research vol. 337, 105526, 2019 p. 1-20,
Alt SeriesNatural Resources Canada, Contribution Series 20190287
Mediapaper; on-line; digital
File formatpdf; html
ProvinceNewfoundland and Labrador
NTS13I/05; 13I/12; 13I/13; 13J/05; 13J/06; 13J/07; 13J/08; 13J/09; 13J/10; 13J/11; 13J/12; 13J/13; 13J/14; 13J/15; 13J/16; 13K/07; 13K/08; 13K/09; 13K/10; 13K/15; 13K/16; 13N/01; 13N/02; 13N/07; 13N/08; 13O/02; 13O/03; 13O/04; 13O/05; 13O/06
AreaLabrador; Benedict Mountains; Cape Harrison; Cape Makkovik; Cape Aillik; Kaipokok Bay; Adlavik Bay; Labrador Sea
Lat/Long WENS -60.9000 -57.7167 55.4000 54.4000
Subjectstectonics; geochronology; regional geology; Science and Technology; Nature and Environment; tectonic history; tectonic evolution; crustal evolution; plate margins; continental crust; accretion; terranes; orogenies; magmatism; volcanism; metamorphism; faulting; deformation; intrusions; plutons; dykes; sills; sedimentation; subduction; radiometric dating; uranium lead dating; zircon dates; lead lead dates; fabric analyses; crustal models; tectonic models; mobile belts; craton; bedrock geology; lithology; igneous rocks; intrusive rocks; gabbros; granites; monzodiorites; leucogabbros; leucogranites; monzonites; aplites; volcanic rocks; tuffs; volcano-sedimentary strata; sedimentary rocks; metamorphic rocks; metavolcanic rocks; metarhyolites; metabasalts; metasedimentary rocks; iron formations; semipelites; quartzites; gneisses; metagabbros; amphibolites; schists; granitic rocks; structural features; shear zones; faults; faults, thrust; faults, transcurrent; fault zones; Archean; Paleoproterozoic; Makkovik Province; Aillik Domain; Laurentia; Great Proterozoic Accretionary Orogen; Makkovik Orogen; Aillik Group; Neoarchean; Churchill Province; Canadian Shield; Baltic Shield; North Atlantic Craton; Ketilidian Mobile Belt; Kaipokok Bay Domain; Post Hill Group; Moran Lake Group; Cape Harrison Domain; Kaipokok Bay Shear Zone; Island Harboour Bay Plutonic Suite; Adlavik Brook Fault Zone; Adlavik Intrusive Suite; Little Monkey Hill Granite; Cape Strawberry Granite; Strawberry Intrusive Suite; Pistol Lake Granite; Lanceground Intrusive Suite; Kennedy Mountain Intrusive Suite; Long Island Quartz Monzonite; Aillik Basin; Cape Harrison Metamorphic Complex; Kanartok Shear Zone; Ketilidian Orogen; Precambrian; Proterozoic
Illustrationsgeoscientific sketch maps; tables; photographs; photomicrographs; Concordia diagrams; plots; histograms; models; geochronological charts
ProgramGEM2: Geo-mapping for Energy and Minerals Hudson/Ungava Saglek Block: Canada-Greenland connection and metallogeny
Released2019 11 06
AbstractThe convergent margin of southeastern Laurentia consists of reworked continental crust as well as accretion of continental ribbons and juvenile arc terranes forming part of the Great Proterozoic Accretionary Orogen. The Makkovik orogen, in Labrador, preserves evidence of the timing, duration and complexities of these accretionary events during the interval 1.88-1.78 Ma.
New regional bedrock geological mapping combined with new U-Pb zircon SHRIMP ages constrain the Paleoproterozoic felsic magmatism in the Aillik Group of the Makkovik orogen. Nine samples from the Aillik Group yield magmatic 207Pb/206Pb ages between 1883 ± 7 Ma and 1858 ± 3 Ma. The ages extend the previously documented ages of felsic volcanism, providing evidence for periodic volcanism spanning 35 m.y. with the most prolific volcanic activity occurring ca. 1860 Ma. Combined with previous studies, the Aillik Group is now constrained between 1883 ± 7 and 1848 ± 2.7 Ma. Development of a pervasive planar fabric associated with the northwestward thrusting of the Aillik Group (D3) occurred after 1848 Ma.
Lithotectonic evolution in the Makkovik Province comprised significant crustal reworking, magmatism, and minor preserved juvenile crustal growth between ca. 1883 and 1848 Ma. The revised model for formation of the Aillik Group proposed herein suggests that the Aillik Group formed in a continental back-arc setting. These new ages further refine the timing of the accretionary events as well as characterizing the age of the crustal root of the arc, which could be a juvenile substrate (Neoarchean/Paleoproterozoic) or reworked Archean crust, possibly the 2.3-2.6 Ma Mistinibi-Raude crust of the Southeast Churchill Province.
Summary(Plain Language Summary, not published)
This report summarizes new U-Pb ages of volcanic rocks in southern Labrador that further light on the complex tectonic history of the eastern margin of the Canadian Shield.

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