Geology, subsurface and surface data, lower and middle Devonian Strata, Slave-redstone map areas, Yukon and Northwest Territories

1981 ◽  
Author(s):  
G K Williams
Keyword(s):  
Northwest Territories ◽  
Middle Devonian ◽  
Surface Data

Deformation associated with gypsum karst in the Salt River Escarpment, northeastern Alberta

1984 ◽  
Vol 21 (8) ◽  
pp. 949-959 ◽  
Author(s):  
Po C. Tsui ◽  
David M. Cruden
Keyword(s):  
Groundwater Flow ◽  
Northwest Territories ◽  
Middle Devonian ◽  
Normal Faults ◽  
Gypsum Karst ◽  
Salt River ◽  
Fort Smith ◽  
Devonian Age ◽  
Northeastern Alberta ◽  
Subsurface Cavities

An escarpment formed by the carbonate Keg River and evaporitic Chinchaga formations of Middle Devonian age extends southwards from the Slave River 30 km west of Fort Smith, Northwest Territories. Newly described folds in the bedrock are due to hydration of the anhydrite to gypsum in the Chinchaga Formation underlying the escarpment. Local groundwater flow has also dissolved subsurface cavities in the Chinchaga Formation. As these openings grew, the carbonates of the Keg River Formation subsided along stepped normal faults. Depressions within the fault blocks occurred where subsidence was concentrated along joints.

An enigmatic blastozoan echinoderm fauna from central kentucky

2009 ◽  
Vol 83 (5) ◽  
pp. 739-749 ◽  
Author(s):  
Colin D. Sumrall ◽  
Carlton E. Brett ◽  
Troy A. Dexter ◽  
Alexander Bartholomew
Keyword(s):  
North America ◽  
Northwest Territories ◽  
Middle Devonian ◽  
Fossil Record ◽  
Foreland Basin ◽  
Late Ordovician ◽  
Upper Devonian ◽  
Range Extension ◽  
First Report ◽  
Appalachian Foreland

A series of small road cuts of lower Boyle Formation (Middle Devonian: Givetian) near Waco, Kentucky, has produced numerous specimens of three blastozoan clades, including both “anachronistic” diploporan and rhombiferan “cystoids” and relatively advanced Granatocrinid blastoids. This unusual assemblage occurs within a basal grainstone unit of the Boyle Limestone, apparently recording a local shoal deposit. Diploporans, the most abundant articulated echinoderms, are represented by a new protocrinitid species, Tristomiocystis globosus n. gen. and sp. Glyptocystitoid rhombiferans are represented by isolated thecal plates assignable to Callocystitidae. Three species of blastoids, all previously undescribed, include numerous thecae of the schizoblastid Hydroblastus hendyi n. gen. and sp., the rare nucleocrinid Nucleocrinus bosei n. sp., and an enigmatic troosticrinid radial. The blastoid Nucleocrinus is typical for the age; however, the callocystitid, schizoblastid, and protocrinitid are not. Hydroblastus is the oldest known schizoblastid. Middle and Upper Devonian callocystitids have been previously reported only from Iowa and Michigan USA with unpublished reports from Missouri USA and the Northwest Territories, Canada. This occurrence is thus the first report of a Middle Devonian rhombiferan from the Appalachian foreland basin. Tristomiocystis is the first known protocrinitid in North America and the only protocrinitid younger than Late Ordovician. This occurrence thus represents a range extension of nearly 50 million years for protocrinids. This extraordinary sample of echinoderms in a Middle Devonian limestone from a well-studied area of North America highlights the incompleteness of the known fossil record, at least in fragile organisms such as echinoderms.

The otarionine trilobites Harpidella and Maurotarion, with species from northwestern Canada, the United States, and Australia

1995 ◽  
Vol 69 (2) ◽  
pp. 307-326 ◽  
Author(s):  
Jonathan M. Adrain ◽  
Brian D. E. Chatterton
Keyword(s):  
United States ◽  
New Species ◽  
Northwest Territories ◽  
Middle Devonian ◽  
The United States ◽  
Upper Ordovician ◽  
Mackenzie Mountains ◽  
New Diagnosis

Maurotarion Alberti, 1969, is a diverse otarionine clade that can be readily distinguished from Harpidella M'Coy, 1849. Both genera appear in the Upper Ordovician and range until the Middle Devonian. A new diagnosis for each taxon is given. New species of the genera from the Ordovician and Silurian of the central Mackenzie Mountains, Northwest Territories, Canada, include Harpidella kurrii (Ashgill), H. tikkaneni (Llandovery), H. greggi (Wenlock), and Maurotarion messieri (Llandovery). Harpidella megalops (M'Coy, 1846), H. triloba (Hu, 1975), H. spinafrons (Williams in Cooper and Williams, 1935), Maurotarion struszi (Chatterton, 1971), and M. instita (Whittington and Campbell, 1967) are revised.

scholarly journals Reassessment of Middle Devonian dolomite, Presqu'ile barrier, Northwest Territories

2006 ◽  
Author(s):  
M Coniglio ◽  
D W Morrow ◽  
N Wilson
Keyword(s):  
Northwest Territories ◽  
Middle Devonian

Provenance of Paleozoic sedimentary rocks in the Canadian Cordilleran miogeocline: a Nd isotopic study

1997 ◽  
Vol 34 (12) ◽  
pp. 1603-1618 ◽  
Author(s):  
Carmala N. Garzione ◽  
P. Jonathan Patchett ◽  
Gerald M. Ross ◽  
JoAnne Nelson
Keyword(s):  
British Columbia ◽  
Northwest Territories ◽  
Middle Devonian ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Canadian Shield ◽  
Isotopic Study ◽  
Middle Ordovician ◽  
Southern Alberta ◽  
T Values

Nd isotopes and trace elements in sedimentary rocks of the Yukon, the Northwest Territories, and northern British Columbia are used to examine the source of sediments in the Canadian Cordilleran miogeocline. Previous Nd isotope studies in southern Alberta demonstrated that strata of Neoproterozoic to Late Ordovician age were derived from Archean and Proterozoic Canadian Shield sources, whereas by the Late Devonian, a shift of 6 εNd units to younger crustal sources (εNd (T) = −6 to −9) had occurred. In this study, we found that the shift to younger crustal Nd isotopic signatures in the Yukon and Northwest Territories occurred much earlier than in southern Alberta. Cambrian and older strata have εNd(T) values of −10.0 to −21.1, consistent with derivation from Canadian Shield sources. Lower Ordovician through Permian strata in the Yukon and Northwest Territories, including the Innuitian-derived Imperial Assemblage, have εNd(T) values of −5 to −11.4. In northern British Columbia, the shift to a younger source reflects a wider range of εNd(T) values, from -−8.7 to −14.6 in Middle Ordovician through Middle Devonian strata, suggesting continued input from Canadian Shield sources. By the Middle Devonian, a complete shift to younger crustal signatures (εNd(T) = −5.9 to −10.5) had occurred in northern British Columbia. Several sources for the more juvenile sediments include (1) a mixture of locally erupted volcanic rocks with Canadian Shield sources, (2) a Grenville source, and (3) an Innuitian source. We propose that Ordovician to Lower Devonian strata were derived from a mixture of locally erupted, juvenile volcanics and pre-Cambrian Canadian Shield sources, and post-Middle Devonian strata were sourced from the Innuitian orogen in the Canadian Arctic.

Nadiastrophia from the Headless Formation (Eifelian), Mackenzie Mountains, District of Mackenzie, Northwest Territories

1973 ◽  
Vol 10 (9) ◽  
pp. 1460-1464 ◽  
Author(s):  
A. C. Lenz
Keyword(s):  
New Species ◽  
Northwest Territories ◽  
Middle Devonian ◽  
Southeastern Pacific ◽  
Mackenzie Mountains ◽  
A New Species

The genus Nadiastrophia previously recorded only from Australia and China, is described from the Headless Formation of the Mackenzie Mountains. This discovery further emphasizes the early Middle Devonian faunal affinities between the Cordilleran and southeastern Pacific regions. The Mackenzie Mountains Nadiastrophia is assigned to a new species, N. mackenziensis.

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