Deciphering superimposed Ellesmerian and Eurekan deformation, Piper Pass area, northern Ellesmere Island (Nunavut)

2007 ◽  
Vol 44 (10) ◽  
pp. 1439-1452 ◽  
Author(s):  
Karsten Piepjohn ◽  
Werner von Gosen ◽  
Solveig Estrada ◽  
Franz Tessensohn
Keyword(s):  
Fault Zone ◽  
Tectonic Evolution ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
Thrust Faults ◽  
Fold Belt ◽  
Sverdrup Basin

The tectonic evolution in the Piper Pass area in northern Ellesmere Island (Canadian Arctic) is characterized by the superimposition of two major deformational events: the Paleozoic Ellesmerian Orogeny and the Tertiary Eurekan deformation. It is difficult to separate the structures formed during each deformation in the parts of the Canadian Arctic in which the post-Ellesmerian and pre-Eurekan Sverdrup Basin is not preserved (Hazen Fold Belt, Central Ellesmere Fold Belt). In the vicinity of the Lake Hazen Fault Zone in the Piper Pass area, kilometre-scale kink folds, cleavage planes and SSE-directed thrust faults are unconformably overlain by Permian through Tertiary rocks of the Sverdrup Basin, which clearly indicates that they are related to the Ellesmerian Orogeny. However, the steep faults of the Lake Hazen Fault Zone are characterized by possible lateral movements and by NNW–SSE compression that cut through or affect both the pre-Ellesmerian Franklinian strata, as well as the post-Ellesmerian Sverdrup Basin deposits. These structures can clearly be assigned to post-mid Cretaceous movements of the Eurekan deformation. The Piper Pass area is a key area in which it is possible to recognize and distinguish Ellesmerian from Eurekan structures.

Whole-Rock Rb/Sr Ages of Metamorphic Rocks from Northern Ellesmere Island, Canadian Arctic Archipelago. I. The Gneiss Terrain between Ayles Fiord and Yelverton Inlet

1975 ◽  
Vol 12 (1) ◽  
pp. 90-94 ◽  
Author(s):  
A. K. Sinha ◽  
Thomas Frisch
Keyword(s):  
Regional Metamorphism ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
Metamorphic Rocks ◽  
Canadian Arctic Archipelago ◽  
Fold Belt ◽  
Late Precambrian

The first Precambrian ages from the Northern Ellesmere Fold Belt are reported. Six rocks from the largest gneiss terrain in northern Ellesmere Island yield a Late Precambrian age (minimum 742 ± 12 m.y.) of regional metamorphism. Relatively high initial 87Sr/86Sr suggests that the rocks were derived from crustal materials.

Paleozoic metamorphism across the boundary between the Clements Markham fold belt and the Pearya terrane in northern Ellesmere Island, Canadian Arctic Archipelago

1993 ◽  
Vol 30 (4) ◽  
pp. 867-880 ◽  
Author(s):  
Eva M. Klaper ◽  
Yoshihide Ohta
Keyword(s):  
Invariant Point ◽  
Sedimentary Rocks ◽  
Canadian Arctic ◽  
Boundary Region ◽  
Ellesmere Island ◽  
Canadian Arctic Archipelago ◽  
Fold Belt ◽  
Garnet Porphyroblasts ◽  
Single Episode ◽  
Differential Uplift

Microstructural and petrological data suggest that a single episode of syn- to post-tectonic metamorphism affected the boundary region between the Clements Markham fold belt and Pearya, a postulated Caledonian terrane, during a mid-Paleozoic orogenic event in northern Ellesmere Island. The sedimentary rocks of the Clements Markham fold belt pass from chlorite to biotite to garnet grade over a distance of about 10 km as the contact with the Mitchell Point belt gneisses of Pearya is approached from the south. Foliation development and chevron-style folding was followed by the growth of the index minerals chlorite, biotite, chloritoid, garnet, staurolite, and kyanite in semipelitic rocks in four metamorphic zones. Thermobarometry of garnet porphyroblasts indicates peak metamorphic conditions of about 600 °C and 600 MPa in the highest grade rocks. Chloritoid-involving phase relations define an invariant point at 540 °C and 500 MPa only 2 km away from the highest grade zone. It may be concluded from the calculated pressure and temperature differences over this short distance that the isogradic surfaces of the post-chevron-folding metamorphism are steeply oriented. Much of the observed metamorphic pattern can, therefore, be explained as the result of a significant post-chevron-folding differential uplift (overthrusting) of the hot Mitchell Point belt gneisses relative to the Clements Markham fold belt. This indicates that the Mitchell Point belt forms a thrust sheet which overlies the Clements Markham fold belt and that the accretion of Pearya predates the Late Silurian.

Whole-rock Rb/Sr and zircon U/Pb ages of metamorphic rocks from northern Ellesmere Island, Canadian Arctic Archipelago. II. The Cape Columbia Complex

1976 ◽  
Vol 13 (6) ◽  
pp. 774-780 ◽  
Author(s):  
A. K. Sinha ◽  
Thomas Frisch
Keyword(s):  
North Atlantic ◽  
Age Groups ◽  
Canadian Arctic ◽  
Ellesmere Island ◽  
Metamorphic Rocks ◽  
Canadian Arctic Archipelago ◽  
Fold Belt ◽  
The North ◽  
The North Atlantic ◽  
North Atlantic Craton

Although not clearly separable on field and petrographic criteria, the gneisses of the Cape Columbia Complex, one of the two major crystalline terrains in the Northern Ellesmere Fold Belt, fall into two Rb/Sr age groups: nine samples define an isochron corresponding to an age of 1083 ± 18 m.y., Sr0 = 0.7057, while six samples show more scatter at 512 ± 90 m.y.,Sr0 = 0.7189. Zircons from two gneisses have 207Pb/206Pb, i.e. minimum, ages of 926 and 980 m.y. These data are interpreted as indicating that the rocks were recrystallized in the amphibolite facies about 1000 m.y. ago; little significance is attached to the younger Rb/Sr age. However, the possibility that the rocks are orthogneisses emplaced about 1000 m.y. ago and subsequently metamorphosed ~500–600 m.y. ago, cannot be excluded. In any event, the Cape Columbia Complex becomes the latest addition to the growing list of occurrences of 900–1200 m.y.-old ('Grenville-Sveco-Norwegian') rocks in the North Atlantic craton and environs.

Insights into the Phanerozoic tectonic evolution of the northern Laurentian margin: detrital apatite and zircon (U–Th)/He ages from Devonian strata of the Franklinian Basin, Canadian Arctic Islands

2013 ◽  
Vol 50 (7) ◽  
pp. 761-768 ◽  
Author(s):  
Owen A. Anfinson ◽  
Andrew L. Leier ◽  
Keith Dewing ◽  
Bernard Guest ◽  
Daniel F. Stockli ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Middle Devonian ◽  
Source Region ◽  
Canadian Arctic ◽  
Upper Devonian ◽  
Sediment Source ◽  
Western Margin ◽  
Source Regions ◽  
Sverdrup Basin ◽  
Single Grain

Middle to Upper Devonian strata of the Franklinian Basin in the Canadian Arctic contain a rich record of Phanerozoic tectonic events along the northern margin of Laurentia. We report detrital thermochronometric zircon (U–Th)/He ages (ZHe; number of aliquots, n = 72) and apatite (U–Th)/He ages (AHe; n = 38) from these Paleozoic strata in an effort to better understand the sediment source regions and the exhumation history of the basin. Detrital ZHe ages are older than corresponding stratigraphic ages and were not reset during subsequent burial, thus constraining both maximum burial depths (<7 km) within the basin and source terrane thermal–tectonic evolution. Paleocurrent data, sediment composition, εNd values and detrital zircon U–Pb ages from previous studies indicate Middle to Upper Devonian strata of the Franklinian Basin are derived from two principal sediment source regions, the East Greenland Caledonides and a northern continental landmass (referred to as Crockerland). However, ZHe ages indicate these two distinctly different source regions experienced coeval exhumation in the Silurian Period. ZHe ages from Crockerland-derived sediment provide evidence that this landmass, which collided with northern Laurentia during the Ellesmerian Orogeny, was associated with the Caledonian Orogen. AHe ages from Middle to Upper Devonian strata are younger than depositional ages, indicating the AHe ages are at least partially reset since deposition and hence record information about exhumation of the strata and not the sediment source region. Dispersion of AHe single-grain ages from Middle Devonian strata along the southeastern margin of the basin suggest complex initial single-grain characteristics and may indicate long residence time in the He partial retention zone. AHe ages from Upper Devonian samples from the western margin of the basin are also dispersed but indicate the region experienced protracted exhumation from 330 to 190 Ma during early stages of Sverdrup Basin development. AHe ages from Middle Devonian samples from the western margin of the basin suggest two potential periods of prolonged exhumation in Early Cretaceous (Valanginian to Aptian) and Late Cretaceous (Campanian) times. These ages partially coincide with regional erosional or nondepositional events followed by deposition of major clastic units in the adjacent Sverdrup Basin.

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