STRUCTURAL GEOLOGY OF NORTH AMERICA 



Island, between the west half of the north shore of Prince Albert Sound and the 

 North shore of Walker Bay. Thence it crosses Victoria Island to its northeastern 

 part, where it probably stretches from Richard Collinson Inlet to the west part 

 of Goldsmith Channel, from which it trends southerly, being possibly within 

 40 miles of the east coast at Greely Haven. Magnetic data suggest that the 

 Precambrian extends, at shallow depth beneath a thin cover of Paleozoic strata, 

 from the latter locality to the Precambrian of eastern Prince of Wales Island. 

 The rocks of the Minto Arch appear to be entirely Proterozoic and include 

 sedimentary strata in part intercalated with lava and sills. The strata trend 

 northeasterly to northerly and, over most of the belt, form undulatory folds with 

 gende dips, although in some areas the beds are practically flat lying. In the 

 south half of Wollaston Peninsula unmapped rocks of reddish colour, as ob- 

 served from aircraft, form many ridges of uniform elevation and oriented east 

 to northeast. Possibly these are Proterozoic formations similar to those of the 

 Minto Arch. 



Basins 



The basins may be divided into two kinds, those of the miogeosynclinal 

 sedimentary province, and those in the shield (intercratonic). Those con- 

 sidered miogeosynclinal are the Jones-Lancaster and Melville basins, and 

 those of the intercratonic type are the Wollaston, Victoria Strait, and 

 Foxe basins. See Figs. 39.13 and 40.2. In a version of the sedimentary 

 provinces by A. H. McNair these basins are considered mostly inter- 

 cratonic, with the miogeosyncline being restricted to the fold belts (map 

 supplied writer by McNair). 



The Jones-Lancaster and Melville basins are separated by the Boothia 

 arch. According to Fortier (1957): 



They extend from Banks Island to Bache Peninsula, midway along the east 

 coast of Ellesmere Island and accordingly, lie mainly between the outer areas 

 of the Shield and the Innuitian Region. Most of the strata of the Jones-Lan- 

 caster Basin Range in age from Cambrian to Devonian but may include rocks 

 of Tertiary age. Although normal faults and a few folds are present, the strata 

 throughout most of the basin dip gently away from the Shield areas and towards 

 the Innuitian Region. Thus, in the northern part of the basin on Ellesmere 

 Island, the regional dip is northerly, farther south it is westerly, and near the 

 south coast of the island it is northwesterly. On Devon Island the dip is westerly 

 and on Brodeur Peninsula of Baffin Island it is northwesterly. Near the In- 

 nuitian Region, however, at least some of the beds are flexed into folds which 

 are probably related to the orogenies that affected that region, but are on a 

 smaller scale. Such folds are found, for instance, on Somerset Island. In the 

 northwestern and south central parts of Somerset Island and in the northeastern 



part of Prince of Wales Island, that is, on each side of the Boothia Arch, a late 

 Silurian or early Devonian conglomerate is made of detritus derived from the 

 Precambrian rocks of the arch. However, the arch is presendy separated from 

 the conglomerate by a wide exposure of earlier Paleozoic strata, the gende 

 flexure of which, at least in the east, may have been contemporaneous with 

 the uplift and denudation of the arch and with the deposition of the conglom- 

 erate. Litde is known of the Melville Basin, except for the above conglomerate, 

 but Silurian strata are apparendy widespread in its eastern part and Devonian 

 strata occur in its western part. North of the Minto Arch, the strata on north- 

 western Victoria Island regionally dip gendy to the northwest; on northern Banks 

 Island they are flexed in gentle, southerly trending folds; and on southwestern 

 Melville Island they are flat lying to gently flexed. 



FOLD BELTS-THE INNUITIAN REGION 



Nature and Distribution 



A belt of strong deformation extends from North Greenland south- 

 westerly through the Arctic Archipelago to the Parry Islands. It consists 

 of folds of mid- and late Paleozoic age (pre-Middle Pennsylvanian ) 

 developed in eugeosynclinal and miogeosynclinal strata, and structures 

 of late Mesozoic and Tertiary age in basin beds laid down on the older 

 orogenic complex. The fold belt in the miogeosynclinal strata ( Fig. 40.2 ) 

 is divided into a western segment, the Parry Islands fold belt, and an 

 eastern, the Ellesmere-Greenland fold belt, by a transverse zone of 

 structures, the Cornwallis fold belt. The Cornwallis fold belt is a northern 

 continuation of the Boothia arch. 



The Northern Ellesmere Island fold belt is regarded as deformed and 

 metamorphosed eugeosynclinal strata. 



The Eureka fold belt is the northeastern part of the Sverdrup basin 

 which is composed of Late Pennsylvanian and younger beds laid down 

 on the deformed eugeosyncline and miogeosyncline. 



Parry Islands Fold Belt 



The Parry Islands Fold Belt includes, in its eastern part, at least 1,800 feet 

 of calcareous and dolomite mudstone and shale, in part silty, overlain bv 3,000 

 feet of further Silurian graptolitic, argillaceous and calcareous, fine-grain sand- 

 stone. These are conformably overlain by 1,200 feet of Silurian or Lower 

 Devonian calcareous and argillaceous sandstone, 800 feet of Lower Devonian 

 shale and these are followed by a Middle and Upper Devonian sequence similar 



