Contributions to the tectonic history of the Innuitian Province, Arctic Canada

1979 ◽  
Vol 16 (3) ◽  
pp. 748-769 ◽  
Author(s):  
H. P. Trettin ◽  
H. R. Balkwill

The Innuitian Tectonic Province contains the record of a Phanerozoic mobile belt in northern Greenland and the Canadian Arctic Archipelago. Two fundamentally different phases in its development were separated by the Devonian–Carboniferous Ellesmerian Orogeny. The first contribution focuses on the early Paleozoic history of a key area, the second summarizes the Carboniferous to Cenozoic history of most of the Canadian part of the province.(1) The early Paleozoic architecture of the mobile belt is apparent only in Ellesmere Island, where exposures extend from the Canadian Shield through Arctic Platform and Franklinian basin into the Pearya orogenic welt. The Franklinian basin comprised the deep but ensulic Hazen Trough and two unstable shelves bordering it on the northwest and southeast. The northwestern shelf was a site of felsic to intermediate volcanism, mainly in the Ordovician Period. Pearya, a site of granitic plutonism in the Devonian Period, supplied much of the clastic basin fill. Its core consisted of a metamorphic complex, about 1.0 Ga old, exposed in basement uplifts in nor thernmost Ellesmere Island. Both basin and welt essentially formed part of the North American Plate, although rifting, evident from mafic and ultramafic intrusions, probably occurred in Early Devonian (or latest Silurian) time. The history of this part of the province is tentatively interpreted as response to the opening and closure of an ocean, connected with lapetus, that separated northern Ellesmere Island and Greenland from the sialic crust of the present Lomonosov Ridge and Barents Shelf. The Lomonosov Ridge still seems to be attached to the shelf off northeasternmost Ellesmere Island.(2) Deep subsidence and filling of Sverdrup Basin dominated the Innuitian region from Early Carboniferous through Late Cretaceous time. Large halokinetic diapirs and mafic dikes and sills intruded axial parts of the basin succession through Mesozoic time. Steep faults along the northwestern margin of the basin are Middle Cretaceous and older. Part of the northwestern rim of Sverdrup Basin sagged in latest Cretaceous time, becomingpart of the Arctic continental terrace. In the Late Cretaceous and early Tertiary a system of large grabens developed through the southern part of the Innuitian region, linking Canada Basin with Baffin Bay; about the same time, uplift formed some large arches in the northeastern part of the region. Middle Eocene and older rocks were laterally compressed by a phase of pre-Miocene folding and faulting. Some uplift took place in Oligocene or Miocene time on Axel Heiberg Island. The distribution of recent earth quakes does not indicate the presence of modern active plate margins.

2009 ◽  
Vol 24 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
J. D. Gleason ◽  
D. J. Thomas ◽  
T. C. Moore ◽  
J. D. Blum ◽  
R. M. Owen ◽  
...  

2021 ◽  
Author(s):  
Michael Pointon ◽  
Michael Flowerdew ◽  
Peter Hülse ◽  
Simon Schneider ◽  
Ian Millar ◽  
...  

<p>During Late Cretaceous times the Sverdrup Basin, Arctic Canada, received considerable air-fall volcanic material. This is manifested as numerous centimetre- to decimetre-thick diagenetically altered volcanic ash layers (bentonites) that occur interbedded with mudstones of the Kanguk Formation. Previous research on bentonite samples from an outcrop section in the east of the basin (Sawtooth Range, Ellesmere Island) revealed two distinct volcanic sources for the bentonites: most of the bentonites analysed (n=9) are relatively thick (0.1 to 5 m), were originally alkaline felsic ashes, and were likely sourced from local volcanic centres on northern Ellesmere Island or the Alpha Ridge that were associated with the High Arctic Large Igneous Province (HALIP). Two thinner (<5 cm) bentonites with contrasting subalkaline geochemistry were also identified. These were inferred to have been derived from further afield, from volcanic centres within the Okhotsk-Chukotka Volcanic Belt, Russia.</p><p>To better understand volcanism within the vicinity of the Sverdrup Basin during Late Cretaceous times, and further test the above interpretations, a larger suite of bentonite samples was investigated, drawing on samples from outcrop sections in the central and eastern Sverdrup Basin. Whole-rock geochemical analyses and combined zircon U-Pb age and Hf isotope analyses were undertaken. The vast majority of bentonites analysed to date have alkaline geochemistry and were likely sourced from proximal volcanic centres related to the HALIP. The combined U-Pb and Hf isotope data from these bentonites show a progression from evolved (-2 to 0) to moderately juvenile (+9 to +10) εHf<sub>(t)</sub> values between late Cenomanian and early Campanian times (<em>c</em>. 97–81 Ma). This is interpreted to record compositional change through time within the local HALIP magmatic system.</p>


1993 ◽  
Vol 40 ◽  
pp. 9-32
Author(s):  
E. Håkansson ◽  
C. Heinberg ◽  
C. Hjort ◽  
P. Mølgaard ◽  
S. A. S. Pedersen

The 1985 expedition constitutes the first comprehensive investigation of the isolated, hyperarctic semi­nunatak Kilen in eastern North Greenland. Well over 3 km of generally marine, elastic sediments are preserved from the Late Jurassic to Late Cretaceous period. While half this amount accumulated in ·a comparatively stable tectonic regime prevailing during Late Jurassic and Early Cretaceous time, the Late Cretaceous (Turonian-Coniacian) sediments are characterized by their deposition in a local pull-apart basin developed in the regional Wandel Hav Strike-Slip Mobile Belt. Subsequent, localized compression along this belt has deformed the entire sequence rather severely in a complex series of en echelon domal folding and thrusting, most likely during the later part of the Cretaceous. Quaternary marine sediments of probable interglacial origin (> 100.000 years old) have been found to contain a mollusc fauna requiring temperatures above the present level. Flade lsblink, the largest local icecap in Greenland, is composed of several semi-independant ice domes, and there is evidence that the history of this icecap deviates significantly from that of the Inland Ice. A total of 34 species of higher plants, 29 species of birds, and 11 species of mammals have been recorded from Kilen; vegetation studies indicate a July mean temperature of around 2.5°C.


2013 ◽  
Vol 330 ◽  
pp. 1067-1070
Author(s):  
Hui Xiao ◽  
Wei Han ◽  
Feng Guo

This study uses the application of zircon fission track (ZFT) and apatite fission track (AFT) thermochronometry technique to investigate the tectonic and uplift history of the Kuruketage area, north-east edge of the Tarim Basin. Based on measured ZFT, AFT and equivalent vitrinite reflectance measurements of samples in sedimentary rocks in Kuruketage area, the temperature time evolution history from early Paleozoic strata was modeled. The results show that the youngest peaks of ZFT at 371-392Ma and 328 - 305.7Ma record Hercynian tectonic and uplift event; the AFT peaks at 134.5 - 164Ma, 73 - 100Ma and 35.4Ma mainly represent the Late-Cretaceous tectonic and uplift event in Kuruketage area. The AFT thermal modeling results from the early Paleozoic strata indicate that the maximum paleo-temperature (at 140 215°C) experienced in late Silurian to early Devonian, and the strata temperature decreased to about 120°C before the Late-Cretaceous.


Paleobiology ◽  
1987 ◽  
Vol 13 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Robert A. Spicer ◽  
Jack A. Wolfe ◽  
Douglas J. Nichols

Cretaceous floras in Alaska, when compared to those at mid-latitudes, generally indicate later appearances in Alaska of major clades and major leaf morphologies. Compared to mid-latitude floras, Alaskan Late Cretaceous floras contain few major clades. The Alaskan clades diversified but at a low taxonomic level. Migrational pathways into high latitudes were probably along streams. Similar patterns characterized the Alaskan Tertiary, although some southward migrations of lineages occurred during the Neogene.Review of other Arctic paleontological data from Ellesmere Island, previously used to suggest that the Arctic was a major center of origin during the Late Cretaceous, indicates that the ages of supposedly substantiating dinoflagellate floras were misinterpreted. When the dinoflagellate data are interpreted according to standard methodology, first occurrences of genera and species groups on Ellesmere are, like the Alaskan occurrences, later than first occurrences at middle latitudes.


1988 ◽  
Vol 25 (8) ◽  
pp. 1220-1239 ◽  
Author(s):  
P. J. Wynne ◽  
E. Irving ◽  
K. G. Osadetz

The principal magnetization of lavas of the Isachsen and Strand Fiord formations on Axel Heiberg Island is shown to predate the Eocene Eurekan Orogeny. Basalt flows of the Strand Fiord Formation, volcanigenic sandstone from the Christopher Formation, and the uppermost flows of the Isachsen Formation are normally magnetized. Reversed magnetizations are found only in the Isachsen Formation, occurring at two horizons, which, we suggest, correspond to M0 and M1 of the M sequence of marine magnetic anomalies (118–123 Ma). It is possible, therefore, that we have located, at least approximately, the base of the Cretaceous normal polarity superchron in these sections. Because inclinations are steep, the analysis of directions of magnetization is not straightforward and has been done by two methods. Method I assumes that no relative rotations have occurred amongst sample localities, and calculations on this basis show a 33 ± 24 °(P = 0.05) counterclockwise rotation with no paleolatitudinal displacement relative to North America. The rotation is in agreement with the rotation of 36 ± 8 °(P = 0.05) determined earlier from the Permian Esayoo Formation on Ellesmere Island. Analysis by method I assumes that the Esayoo and the Isachsen – Strand Fiord sampling localities on Axel Heiberg and Ellesmere Island are contained within what is essentially one large structural domain. The agreement (using method I) of paleolatitude with that of North America is consistent with standard plate reconstructions in which there is a gap of about 300 km between Greenland and Ellesmere Island. However, the dispersion of site-mean directions is greater than that expected for paleosecular variation during the Cretaceous, and therefore some of the dispersion may be attributable to relative motions amongst collecting localities. Therefore, by method II, relative rotations amongst localities are assumed to have occurred, and inclinations and declinations are analysed separately. As with method I, declinations are predominantly counterclockwise from that expected, but by method II the mean inclination (74 ± 2 °standard error) is significantly shallower than that expected (79 ± 1 °standard error). This apparent flattening is consistent with the idea that the Arctic Islands were close to Greenland in the Cretaceous and that there was no gap along Nares Strait. Hence both methods of calculation yield similar counter clockwise rotation, but each gives slightly different paleolatitudes. The latter difference cannot at present be resolved.


Since middle Proterozoic time, two long-lasting phases affected the Canadian Arctic Archipelago, each forming a different sedimentary basin. The Franklinian Basin, which was floored by continental or quasi-continental crust, received 10 km or more of clastic, carbonate and volcanic rocks from the mid-Proterozoic to Devonian. Internal parts of the basin were deformed, intruded and metamorphosed locally, and external parts were folded and thrust cratonward by compressional episodes of the Ellesmerian Orogeny, which culminated in the late Devonian. This marked the end of a phase, at which time the entire region may have been emergent. The nature of plate interactions that produced Ellesmerian deformation are unknown. The second phase began in the early Carboniferous, when plate movements of the Boreal Rifting Episode created the proto-Canada Basin by left-hand transform motion of a plate along the modern continental margin and the location of the Kaltag Fault of northern Alaska. As a marginal side effect of that motion, the Sverdrup Basin developed as a peri-cratonic incipient rift. From the Carboniferous to late Cretaceous the basin received about 13 km of cratonic-derived clastic detritus. From late Cretaceous to early Tertiary time, the Arctic Archipelago was disrupted by the interference of two plate movements originating in the Arctic and North Atlantic regions. Those events had three main effects: the craton was extended and a graben-filled depression formed in the southeastern part of the archipelago; the eastern and central parts of the Sverdrup Basin were compressed and uplifted (Eurekan Orogeny); and resultant elastics prograded northwestward toward the Canada Basin, to form the Arctic continental terrace wedge.


1986 ◽  
Vol 23 (3) ◽  
pp. 350-358 ◽  
Author(s):  
A. V. Okulitch ◽  
J. J. Packard ◽  
A. I. Zolnai

The Boothia Uplift extends 1000 km northward from the northern Canadian Shield into the Arctic Archipelago. Consisting of a core of Archean(?) to Aphebian gneissic units and a cover of Proterozoic to Devonian strata of the Arctic Platform and Franklinian Miogeocline, it formed during several minor pulses of uplift in the late Proterozoic and early Paleozoic and a major episode of tectonism during the Siluro-Devonian. Although it has long been regarded as a "horst" or vertical block uplift, compilation of new and previous data suggests that the uplift can be interpreted as a major, west-directed, imbricate mass of crystalline basement mantled by faulted and drape-folded cover. Details of the vertical component of movement have been provided by sedimentological and stratrigraphic studies. Uplift increases northward from the craton to a maximum of 5 km. Estimates of horizontal movement, predicated on assumed fault dips, could be as much as 30 km.Major tectonism of the Boothia Uplift was approximately coeval with uplift on southeastern Ellesmere Island and on northern Axel Heiberg Island, folding and low-grade metamorphism on northernmost Ellesmere Island, and west-directed thrusting and folding on Greenland. The plate tectonic interactions responsible for these events remain obscure; a general regime of west-directed compressive stresses associated with late stages of the Caledonian Orogeny may have been present.


Author(s):  
Michael D. Gordin

Dmitrii Mendeleev (1834–1907) is a name we recognize, but perhaps only as the creator of the periodic table of elements. Generally, little else has been known about him. This book is an authoritative biography of Mendeleev that draws a multifaceted portrait of his life for the first time. As the book reveals, Mendeleev was not only a luminary in the history of science, he was also an astonishingly wide-ranging political and cultural figure. From his attack on Spiritualism to his failed voyage to the Arctic and his near-mythical hot-air balloon trip, this is the story of an extraordinary maverick. The ideals that shaped his work outside science also led Mendeleev to order the elements and, eventually, to engineer one of the most fascinating scientific developments of the nineteenth century. This book is a classic work that tells the story of one of the world's most important minds.


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