Tectonic implications of 40Ar/39Ar muscovite dates from the Mt. Haley stock and Lussier River stock, near Fort Steele, British Columbia

2006 ◽  
Vol 43 (11) ◽  
pp. 1673-1684 ◽  
Author(s):  
Kyle P Larson ◽  
Raymond A Price ◽  
Douglas A Archibald
Keyword(s):  
British Columbia ◽  
Single Crystal ◽  
Rocky Mountains ◽  
Potassium Feldspar ◽  
Canadian Rocky Mountains ◽  
The West ◽  
Lower Paleozoic ◽  
Tectonic Implications ◽  
West Limb ◽  
Step Heating

The Mt. Haley and Lussier River stocks are located northeast of Cranbrook, B.C. near the south end of the Western Main Ranges of the Southern Canadian Rocky Mountains. Both are multiphase, potassium-feldspar porphyritic monzonite plutons that intrude lower Paleozoic miogeoclinal strata. They crosscut and thermally overprint the Lussier River fault and the thrust and fold structures in the east flank of the Purcell anticlinorium and the west limb of the Porcupine Creek anticlinorial fan structure. Muscovite from the Mt. Haley stock yielded a 40Ar/39Ar plateau age of 108.2 ± 0.7 Ma (2σ), and a single-crystal, step-heating analysis of muscovite from a skarn in the metamorphic aureole adjacent to the Lussier River stock gave a plateau date of 108.7 ± 0.6 Ma (2σ). These dates constrain the timing of thrusting and folding in this portion of the western Rocky Mountains and of the displacement along the Lussier River – St. Mary fault to pre-middle Albian.

New Lower Jurassic ammonite faunas from the Fernie Formation, southern Canadian Rocky Mountains

1987 ◽  
Vol 24 (8) ◽  
pp. 1688-1704 ◽  
Author(s):  
Russell L. Hall
Keyword(s):  
British Columbia ◽  
North American ◽  
Rocky Mountains ◽  
Red Deer ◽  
First Record ◽  
Lower Jurassic ◽  
Canadian Rocky Mountains ◽  
Poker Chip

New ammonite faunas are described from sections along Bighorn and Scalp creeks in central-western Alberta where Lower Jurassic parts of the Fernie Formation are exposed. The first record of the upper Sinemurian Obtusum Zone from the Fernie is based on the occurrence of Asteroceras cf. stellare and Epophioceras cf. breoni in the basal pebbly coquina on Bighorn Creek. The overlying Red Deer Member has yielded Amaltheus cf. stokesi, representing the upper Pliensbachian Margaritatus Zone; in immediately superjacent strata the first North American examples of ?Amauroceras occur together with Protogrammoceras and ?Aveyroniceras. In the basal parts of the overlying Poker Chip Shale a fauna including Harpoceras cf. falciferum, Harpoceratoides, Polyplectus cf. subplanatus, Hildaites cf. serpentiniformis, and Dactylioceras cf. athleticum is correlated with the lower Toarcian Falciferum Zone.The upper parts of the Poker Chip Shale on Fording River in southeastern British Columbia contain a fauna representing some part of the upper Toarcian, but owing to poor preservation, generic identifications are only tentatively made.

THE ROCKY MOUNTAIN TRENCH: A PROBLEM

1964 ◽  
Vol 1 (3) ◽  
pp. 184-205 ◽  
Author(s):  
C. H. Crickmay
Keyword(s):  
Rocky Mountains ◽  
Rocky Mountain ◽  
Canadian Rocky Mountains ◽  
The West ◽  
West Side ◽  
Combined Action ◽  
Headward Erosion

The Rocky Mountain Trench is defined as the 1 000-mile valley which marks the west side of the Canadian Rocky Mountains. The background of the Trench as a problem is examined, and descriptions, geographical and geological, are given. Previous work on Trench origin is reviewed and note is taken of the seeming inapplicability of accepted erosion theories to the making of the erosion-made Trench. An hypothesis is offered in which the combined action of drainage hemmed in by bordering uplifts, guided headward erosion, lateral corrasion, and streams repeatedly reversed by continuing diastrophism is suggested as the excavator of the Trench, a valley characterized by the puzzling peculiarity of continuous depth without a consistent gradient.

Nucleation during primary succession in the Canadian Rockies

1993 ◽  
Vol 71 (8) ◽  
pp. 1093-1096 ◽  
Author(s):  
D. J. Blundon ◽  
D. A. MacIsaac ◽  
M. R. T. Dale
Keyword(s):  
British Columbia ◽  
Nitrogen Fixation ◽  
Key Words ◽  
Rocky Mountains ◽  
Primary Succession ◽  
The Other ◽  
Pioneer Species ◽  
Canadian Rocky Mountains ◽  
Successional Species ◽  
Key Words Colonization

A study of nucleation during primary succession was carried out on age sequences of communities at two sites in the Canadian Rocky Mountains: one at the Mount Robson moraines, British Columbia, the other at Southeast Lyell Glacier, Alberta. The study concentrated on the associations of species with the nitrogen-fixing plants Hedysarum boreale var. mackenzii at Mount Robson moraines and Dryas drummondii at Southeast Lyell Glacier because those plants might serve as nuclei for colonization by other species, thus facilitating succession. The data show that recruitment of later successional species is greater in patches of the two pioneer species, but the fact that recruitment takes place away from the plants also suggests that although there is nucleation, it is not necessary for succession at these sites. Key words: colonization, nitrogen fixation, nucleation, succession.

scholarly journals VII.—The Canadian Rockies. Part I : On a Collection of Middle Cambrian Fossils obtained by Edward Whymper, Esq., F.R.G.S., from Mount Stephen, British Columbia

1902 ◽  
Vol 9 (11) ◽  
pp. 502-505 ◽  
Author(s):  
Henry Woodward
Keyword(s):  
British Columbia ◽  
Rocky Mountains ◽  
Canadian Rocky Mountains ◽  
Canadian Rockies ◽  
Middle Cambrian ◽  
Pacific Railroad ◽  
Northern Side

In the Summer of 1901 my friend Mr. Edward Whymper, the well-known traveller, mountain explorer, and writer, paid a visit to the watershed of the Canadian Rocky Mountains, and during a stay at Field, the highest pass reached on the Canadian and Pacific Railroad, he examined the slopes of Mount Stephen, and at a height of 6,000 feet on its northern side found numerous Trilobites, and brought home a considerable collection.

Stratigraphic position of Carboniferous Macgowanella and Sinopora? pascuali, Canadian Cordillera

1984 ◽  
Vol 21 (4) ◽  
pp. 500-501 ◽  
Author(s):  
Bernard L. Mamet ◽  
Samuel J. Nelson
Keyword(s):  
British Columbia ◽  
Rocky Mountains ◽  
Canadian Cordillera ◽  
Canadian Rocky Mountains ◽  
Lower Upper ◽  
Head Formation ◽  
Stratigraphic Position ◽  
Age Determinations

Microfossils associated with Carboniferous Macgowanella and Sinopora? pascuali allow more precise age determinations than previously determined. Macgowanella, a possible bryozoan holdfast, is represented by two species, M. tenuiradiata (Warren) and M. stellata (Warren), both from the Viséan (Upper Mississippian, Meramecian) Mount Head Formation of the southern Canadian Rocky Mountains. Microfossils indicate a correlation with upper Viséan Zone 14, equivalent to the lower upper Meramecian Marston/lower Opal members of the Mount Head Formation.The syringoporid coral Sinopora? pascuali is from near Kamloops, British Columbia. Microfossils support the Early Pennsylvanian date earlier assigned, correlating it with Zones 20 or 21, Bashkirian = Morrowan to basal Atokan.

An 40Ar/39Ar geochronological study of the Elzevir batholith and its bearing on the tectonothermal history of the southwestern Grenville Province, Canada

1988 ◽  
Vol 25 (11) ◽  
pp. 1834-1845 ◽  
Author(s):  
J. A. Hanes ◽  
S. J. Clark ◽  
D. A. Archibald
Keyword(s):  
Potassium Feldspar ◽  
Age Difference ◽  
The West ◽  
Slow Cooling ◽  
Grenville Province ◽  
Cooling Path ◽  
Time Period ◽  
Step Heating ◽  
Geochronological Study ◽  
History Of

Results of 40Ar/39Ar step heating for muscovite, potassium feldspar, and plagioclase from the ca. 1240 Ma Elzevir trondhjemite in the Central Metasedimentary Belt of the Canadian Grenville Province have been combined with earlier data and used to deduce a thermal history for the eastern Elzevir terrane following the Ottawan orogeny (1050–950 Ma). Muscovite yielded precise plateau dates of ca. 900 Ma, whereas the potassium feldspar displayed disturbed age spectra with ca. 730–760 Ma dates for broad "plateau" regions. This age difference could be explained by slow cooling or by thermal overprinting at 760–800 Ma that has updated the microcline. The plagioclase spectra provide evidence for a low-temperature hydrothermal event ca. 380 Ma ago that has generated sericite in saussurite and has caused partial argon loss from the microcline. This result agrees with the other plagioclase thermochronometry and paleomagnetism on the Cordova gabbro 25 km to the west but provides a lower estimate for the upper age bracket of this event. It is suggested that earlier models of protracted, post-700 Ma cooling of this part of the Grenville orogen may be a consequence of variable updating of plagioclase by this Devonian alteration event.Results of 40Ar/39Ar step heating for muscovite and microcline from the Bark Lake diorite in the Bancroft terrane are in agreement with earlier work in this area, and the cooling path of the Elzevir trondhjemite is seen to be indistinguishable, within the limitations of the method, from that of the Bark Lake diorite in the time period 1050–750 Ma.

173 Ma U–Pb age of felsite sills (Kaslo River intrusives) west of Kootenay Lake, southeastern British Columbia

1992 ◽  
Vol 29 (3) ◽  
pp. 531-534 ◽  
Author(s):  
Moira T. Smith ◽  
George E. Gehrels ◽  
David W. Klepacki
Keyword(s):  
British Columbia ◽  
Second Phase ◽  
The West ◽  
West Side ◽  
Lower Paleozoic ◽  
Upper Proterozoic ◽  
Third Phase ◽  
Phase Deformation ◽  
Kootenay Lake ◽  
Middle Proterozoic

U–Pb geochronological analyses of five zircon fractions from a lineated and foliated monzonite sill on the west side of Kootenay Lake are discordant and yield a lower intercept age of 173 ± 5 Ma, interpreted as the minimum crystallization age. An upper intercept of 1710 ± 180 Ma is interpreted as the average age of inherited components, and is consistent with contamination by Middle Proterozoic detritus in Upper Proterozoic to lower Paleozoic strata. The sills are interpreted as pre- to syn-kinematic with respect to regional second-phase or possibly third-phase deformation, thus further constraining the timing of Mesozoic orogeny in the Kootenay Arc, and may represent an early, foliated phase of the Nelson Batholith.

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