Precambrian geology northwestern Baffin Island, District of Franklin

Blackadar, R G

doi:10.4095/100785

Cited by 10 publications

(8 citation statements)

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“…These are the dominant rock types and primary minerals derived from bedrock and supplied by glaciers to the sedimentary system. The data also illustrate that rock types contributing to the Guys Bight sediments are representative of the Aphebian bedrock throughout north-eastern Baffin Island (Blackadar, 1970;Jackson et a]., 1975;Jackson & Morgan, 1978). Furthermore, the proportions of local bedrock types, and mineral proportions, are consistent with observations of Aphebian bedrock on a regional scale (Blackadar, 1970;Jackson et al, 1975;Jackson & Morgan, 1978).…”

Section: Bedrock Geology and Mineralogysupporting

confidence: 73%

“…The geology and mineralogy of the rocks of the source area have been reported elsewhere (Blackadar, 1970;Jackson et al, 1975;Jackson & Morgan, 1978). According to these authors, the bedrock of the study area consists predominantly of upper amphibolite and granulite facies gneisses and migmatites, and plutonic rocks.…”

Section: Bedrock Geology and Mineralogymentioning

confidence: 84%

“…Another important criterion for selection was the availability of a reliable estimate of the bedrock bulk composition. The dominant rock types and their major mineralogy are known for north-eastern Baffin Island (Daniels, 1956;Blackadar, 1970;Jackson e f al., 1975;Jackson & Morgan, 1978), and the average bedrock composition for northern Baffin Island is well documented (Shaw et al, 1967).…”

Section: The Guys Bight Sedimentary Basinmentioning

confidence: 99%

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Petrogenesis of sediments in the absence of chemical weathering: effects of abrasion and sorting on bulk composition and mineralogy

1996

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Comminution in the glaciers that debouch into Guys Bight Basin, followed by selective sorting in the fluvial system, has had little effect on the bulk composition, or on the mineralogy, of the basin sands and muds. Most striking are the feldspar contents, and the feldspar‐quartz ratios in sands and muds, both of which remain similar to those of average bedrock. The feldspar contents of sands and muds range from 48 to 52% feldspar whereas average bedrock contains 51·7% feldspar. Feldspar‐quartz ratios average 1·58:1 in bedrock and 1·54:1, 1·66:1 and 1·69:1 in the medium to coarse sands, fine sands and muds, respectively, indicating minimal feldspar enrichment in the fine‐grained sediments. In the absence of appreciable chemical weathering, extreme abrasion followed by hydraulic sorting has not produced mature sediments such as quartz arenites and clay‐mineral‐rich muds. There is, however, some chemical differentiation. Preferential accumulation of mafic minerals in fine sands and muds is reflected in bulk compositions by higher abundances of MgO, FeO and TiO2, and in the mineralogy by enrichment of biotite in the fine grades. Bulk compositional studies focused solely on muds and mudstones will result in an overestimate of the mafic contribution from source rocks. This work shows that bulk compositional studies of sediments and sedimentary rocks should include all available granulometric grades.

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Section: Bedrock Geology and Mineralogysupporting

confidence: 73%

Section: Bedrock Geology and Mineralogymentioning

confidence: 84%

Section: The Guys Bight Sedimentary Basinmentioning

confidence: 99%

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Petrogenesis of sediments in the absence of chemical weathering: effects of abrasion and sorting on bulk composition and mineralogy

1996

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“…In the Adams and Strathcona sounds of Borden Peninsula (Admiralty Inlet), red to purple quartz arenites of the Nauyat Formation (Jackson & Ianelli ) and red shales of the Society Cliffs Formation (Lemon & Blackadar , b) form prominent exposures. Southwest near Agu Bay (Gulf of Boothia/Prince Regent Inlet), red sandstones of the Nyeboe and Agu Bay formations (Blackader , ; Chandler ) represent another potential source, as do outcrops of the Mary River Iron Formation (Jackson ; Johns & Young ) in central northern Baffin Island. Klassen (, ) noted that erratic clasts in tills (Eclipse drift) on northern Bylot Island are derived entirely of material originating on northern Baffin Island and potentially Foxe Basin, with an absence of lithologies from sources to the north or west of Bylot Island.…”

Section: Discussionmentioning

confidence: 99%

Deglaciation and ice shelf development at the northeast margin of the Laurentide Ice Sheet during the Younger Dryas chronozone

Furze

Pieńkowski

McNeely

et al. 2017

Boreas

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Core 2011804-0010 from easternmost Lancaster Sound provides important insights into deglacial timing and style at the marine margin of the NE Laurentide Ice Sheet (LIS). Spanning 13.2-11.0 cal. ka BP and investigated for ice-rafted debris (IRD), foraminifera, biogenic silica and total organic carbon, the stratigraphy comprises a lithofacies progression from proximal grounding line and sub-ice shelf environments to open glaciomarine deposition; a sequence similar to deposits from Antarctic ice shelves. These results are the first marine evidence of a former ice shelf in the eastern Northwest Passage and are consistent with a preceding phase of ice streaming in eastern Lancaster Sound. Initial glacial float-off and retreat occurred >13.2 cal. ka BP, followed by formation of an extensive deglacial ice shelf during the Younger Dryas, which acted to stabilize the retreating margin of the NE LIS until 12.5 cal. ka BP. IRD analyses of sub-ice shelf facies indicate initial high input from source areas on northern Baffin Island delivered to Lancaster Sound by a tributary ice stream in Admiralty Inlet. After ice shelf break-up, Bylot Island became the dominant source area. Foraminifera are dominated by characteristic ice-proximal glaciomarine benthics (Cassidulina reniforme, Elphidium excavatum f. clavata), complemented by advected Atlantic water (Cassidulina neoteretis, Neogloboquadrina pachyderma) and enhanced current indicators (Lobatula lobatula). The biostratigraphy further supports the ice shelf model, with advection of sparse faunas beneath the ice shelf, followed by increased productivity underopen water glaciomarine conditions. The absence of Holocene sediments in the core suggests that the uppermost deposits were removed, most likely due to mass transport resulting from the site's proximity to modern tidewater glacier margins. Collectively, this study presents important new constraints on the deglacial behaviour of the NE Laurentide Ice Sheet, with implications for past ice sheet stability, ice-rafted sediment delivery, and iceÀocean interactions in this complex archipelago setting.

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“…Borden Basin is a 250-km-long graben that contains a 10-km-thick succession of virtually unmetamorphosed and undeformed strata ranging in age from Proterozoic to Tertiary (Jackson & Sangster, 1987). The Proterozoic geology has been summarized by Lemon & Blackadar (1963), Blackadar (1970), Geldsetzer (1973), Jackson & Ianelli (1981 and Knight & Jackson (1994) ; Hofmann & Jackson (1991 have described the microfossils. Proterozoic strata comprise the Bylot Supergroup, which can be subdivided into three groups that reflect different tectonic regimes: the Eqalulik Group comprises volcanics and siliciclastic sediments deposited during early stages of rifting, the Uluksan Group contains carbonates deposited during a period of relative tectonic stability and the Nunatsiaq Group comprises mainly siliciclastic deposits that reflect renewed tectonic activity (Fig.…”

Section: Geological Setting and Agementioning

confidence: 99%

Mesoproterozoic deep‐water reefs from Borden Peninsula, Arctic Canada

Narbonne

James

1996

Sedimentology

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A superbly exposed stromatolite reef complex occurs in the Victor Bay Formation near Strathcona River on northern Baffin Island. Individual reefs are up to 130 m thick and nearly 1 km in length, and their development was clearly related to their position in the facies spectrum and to sea-level dynamics. In the first sea-level cycle, metre-scale reefs grew amongst mid-ramp calcarenites and outer-ramp shales during slow sea-level rise; a 25-m-thick oblate reef tract, separating mid-ramp and outer-ramp facies, formed during the highstand. The greatest period of reef growth was during the second sea-level cycle. Pinnacle reefs nucleated on the karsted upper surface of the oblate reef tract and aggraded rapidly in response to rising sea-level, producing structures with more than 75 m of depositional relief. A gradual symmetrical succession of stromatolite growth forms, from stratiform to cylindrical columns to conical columns and then back through cylindrical columns to stratiform, is mirrored by evidence in offreef deposits for deepening to a maximum flooding surface and then shallowing. The tops of these high-standing reefs were karsted during the following regression, while dolomite 'cryptodomes' grew as sheets on their submerged flanks and as progradational tongues extending basinward of the reefs. Continued sea-level fall resulted in subaerial exposure of the entire reef complex and the extensive formation of surface and subsurface karst.These Proterozoic slope buildups are similar to Phanerozoic deep-water reefs in size, shape, prevalence of synsedimentary lithification, presence of Neptunian dykes and in their well-developed vertical zonation of reefbuilders. However, they differ in being constructed exclusively by stromatolites rather than being mud mounds with small skeletal elements, and in lacking halos of perireefal sand-and gravel-sized calcareous debris. Their responses to changes in sea-level were strikingly similar to those shown by their younger counterparts, and suggest that sequence-stratigraphic concepts derived from studies of Phanerozoic reefs can also be applied to the Proterozoic.

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Precambrian geology northwestern Baffin Island, District of Franklin

Cited by 10 publications

References 0 publications

Petrogenesis of sediments in the absence of chemical weathering: effects of abrasion and sorting on bulk composition and mineralogy

Petrogenesis of sediments in the absence of chemical weathering: effects of abrasion and sorting on bulk composition and mineralogy

Deglaciation and ice shelf development at the northeast margin of the Laurentide Ice Sheet during the Younger Dryas chronozone

Mesoproterozoic deep‐water reefs from Borden Peninsula, Arctic Canada

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