Phanerozoic Tectonic Phanerozoic Tectonic Evolution of the Evolution of the
Chukotka-Arctic Alaska Chukotka-Arctic Alaska Block: Problems of the Block: Problems of the
Rotational ModelRotational ModelBoris A. Natal’inBoris A. Natal’in
Istanbul Technical UniversityIstanbul Technical University
Components of the Components of the Chukotka-Arctic Alaska Chukotka-Arctic Alaska
blockblock
Arctic Alaska Arctic Alaska superterranesuperterrane
Seward TerraneSeward Terrane York Mountains York Mountains
terraneterrane
Bennett-Barrovia Bennett-Barrovia blockblock
Chukotka fold beltChukotka fold belt Nutesyn arcNutesyn arc
The Bennett-Barrovia block continues to The Bennett-Barrovia block continues to Alaska as the Hammond subterrane, York Alaska as the Hammond subterrane, York Mountains terrane, and Nixon Fork terraneMountains terrane, and Nixon Fork terrane
AlaskaAlaska ChukotkaChukotka
Late Jurassic, Late Jurassic, 150 Ma150 Ma
Lawver et al. Lawver et al. 20022002
1000 1000 kmkm
KotelnKotelnyiyi
SevernSevernayaaya
ZemlyaZemlya
KotelnKotelnyiyi
Bol. LyakhovskyBol. Lyakhovsky
122±7 K-122±7 K-ArAr
Younger than late Younger than late JurassicJurassic
291±62 Sm-291±62 Sm-NdNd133-139 Ma 133-139 Ma K-ArK-Ar
Geophysical dataGeophysical dataFranke et al. Franke et al. (2004): (2004): - Blagoveschensk - Blagoveschensk basin is absentbasin is absent- the shelf of the - the shelf of the East Siberian Sea East Siberian Sea is epicontinental is epicontinental platformplatformPuskarev et al. Puskarev et al. (1999):(1999):- Low standing - Low standing basementbasement- Densities are - Densities are characteristic for characteristic for consolidated crustconsolidated crust
Puskarev et al., 1999Puskarev et al., 1999
SS NN
Bennett-Barrovia block: Bennett-Barrovia block: BasementBasement
Granites 750 MaGranites 750 MaMetamorphism 655-Metamorphism 655-594 Ma594 Ma
GraniteGranitess
699 Ma699 Ma
GranitGraniteses
705 705 MaMa
OrthogneissOrthogneiss681 and 676 681 and 676
MaMa
OrthogneisOrthogneisss
650 Ma650 Ma
Correlation with TaimyrCorrelation with Taimyr Bennett-BarroviaBennett-Barrovia
pre-collision pre-collision volcanics – 633±25 volcanics – 633±25 MaMasyncollisional granites syncollisional granites – 750-699 (650?) Ma – 750-699 (650?) Ma metamorphism – 630 metamorphism – 630 MaMaassimilated crust – assimilated crust – 1.3-1.5 Ga (Nelson et 1.3-1.5 Ga (Nelson et al., 1989) and 0,8-1.0 al., 1989) and 0,8-1.0 (Karl et al., 1989)(Karl et al., 1989)Devonian granites – Devonian granites – 0.7-1.6 Ga0.7-1.6 Ga
TaimyrTaimyrpre-collision pre-collision volcanics – 630-615 volcanics – 630-615 MaMasyncollisional syncollisional granites – 630 Magranites – 630 Mametamorphism – metamorphism – 655-594655-594assimilated crust – assimilated crust – 0.84-1.1 Ga0.84-1.1 Ga
Taimyr and Severnaya Zemlya Taimyr and Severnaya Zemlya (Russia)(Russia)
Thick pile of the Thick pile of the upper Proterozoic-upper Proterozoic-Cambrian flyschCambrian flysch
Evaporites in the Evaporites in the Ordovician and Ordovician and Upper Silurian and Upper Silurian and DevonianDevonian
Early Paleozoic Early Paleozoic fossils are differentfossils are different
Franklinian structuresFranklinian structures
sandstone, sandstone, tuffaceous tuffaceous sandstone, sandstone, shale, shale, conglomerate, conglomerate, lavas and dikes lavas and dikes of basalt, of basalt, andesite, and andesite, and diabase diabase
Ordovician Ordovician to Silurian to Silurian oceanic oceanic and and magmatic magmatic arc rock arc rock assemblageassemblagess
Margin of N. America
Deformed Deformed Ordovician Ordovician and Silurian and Silurian slatesslates
Pre-late Devonian subduction Pre-late Devonian subduction related magmatic arc at the related magmatic arc at the
eastern edge of BBeastern edge of BBgravitgravityy
magnemagnetictic
Herman and Herman and Zerwick, 1998Zerwick, 1998
The late Silurian-early The late Silurian-early Devonian collision of the Devonian collision of the Bennett-Barrovia block Bennett-Barrovia block
Devonian-early Carboniferous Devonian-early Carboniferous subduction zone along the southern subduction zone along the southern
margin of the Bennett-Barrovia blockmargin of the Bennett-Barrovia block
398-383 398-383 MaMaeuhedraeuhedral zircons l zircons of 370-of 370-360 Ma360 Ma
381 381 MaMa 375 ± 11 375 ± 11
MaMa376 ± 37 376 ± 37 MaMa
εεNdNd is is +0.2 and +0.2 and -0.3-0.3
360 360 Ma Ma
ViseaViseann
Back arc basin of the Back arc basin of the Devonian arcDevonian arc
Tanatap basin- deep water shale and fine grained turbidite- high-K andesitic tuffs with εεNdNd -7 -7
Alyarmaut Alyarmaut - Calc-silicates, quartzite, mafic tuffs- Calc-silicates, quartzite, mafic tuffs
Belkovskyi-Nerpalakh Trough Belkovskyi-Nerpalakh Trough - Upper Devonian to Lower Carboniferous - Upper Devonian to Lower Carboniferous limestone, shale, sandstone, limestone, shale, sandstone, conglomerate, mafic dikes and sills conglomerate, mafic dikes and sills
Brooks RangeBrooks Range- Devonian extensional basin (the - Devonian extensional basin (the Beaucoup F.) Beaucoup F.)
Position of continents is Position of continents is after Lawver et al. (2002); 390 Maafter Lawver et al. (2002); 390 Ma
Carboniferous-PermianCarboniferous-Permian
Wrangel IslandWrangel Island- shallow marine Carboniferous limestones - shallow marine Carboniferous limestones grading up into Permian slates grading up into Permian slates (~2100 m)- basin slopes to the south
Chukotka- Lower Carboniferous conglomerates grading up into arkose sandstones, shale, and limestones (4500 m)- Permian rocks are unknown- Source area is expected in the south- Source area have to be rich in granites
Modified after Grantz et al. (1991)
4.5 4.5 kmkm
molasmolassese
orogeorogenyny
Many kmMany kmlithic lithic turbiditeturbiditemafic mafic magmatismagmatismmriftingrifting
0.1-0.2 km0.1-0.2 kmshale, shale, chert, chert, sandstonesandstonestable stable shelfshelf
Carboniferous collision?Carboniferous collision?Position of continents Position of continents is after Lawver et al. is after Lawver et al. (2002); 330 Ma(2002); 330 Ma
Opening of Opening of the South the South
Anyui Anyui oceanocean
Position of continents is after Lawver et al. (2002)