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

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.

1987 ◽  
Vol 24 (8) ◽  
pp. 1688-1704 ◽  
Author(s):  
Russell L. Hall

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.


1987 ◽  
Vol 24 (8) ◽  
pp. 1634-1642 ◽  
Author(s):  
Daniel J. Smith

Solifluction lobes are tongue-shaped accumulations of sediment resulting from localized periglacial mass wasting. Radiocarbon records from beneath two turf-banked lobes in the Mount Rae area of the southern Canadian Rockies indicate that solifluction processes have been continuously active for at least the last 2000 years. The long-term rates of frontal movement at both sites average 0.49 cm/year, but vary in magnitude from 0.35 to 1.50 cm/year.Both lobes terminate above soil pedons progressively overridden by their advance. Estimates of the apparent mean residence time of the contemporary soil ranges from 962 ± 100 years in one case to 1600 ± 100 years in the other. This information was used to reconstruct a chronology of lobe activity. Collectively, the radiocarbon records indicate that solifluction lobes in this area were advancing quite rapidly between 1900–1750 years BP but declined to a much slower, but relatively constant, pace up until the present.


2006 ◽  
Vol 43 (11) ◽  
pp. 1673-1684 ◽  
Author(s):  
Kyle P Larson ◽  
Raymond A Price ◽  
Douglas A Archibald

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.


1902 ◽  
Vol 9 (11) ◽  
pp. 502-505 ◽  
Author(s):  
Henry Woodward

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.


1984 ◽  
Vol 21 (4) ◽  
pp. 500-501 ◽  
Author(s):  
Bernard L. Mamet ◽  
Samuel J. Nelson

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.


1993 ◽  
Vol 67 (5) ◽  
pp. 856-868 ◽  
Author(s):  
W. H. Fritz

The genus Cirquella is erected for small, smooth nevadiid trilobites that lack genal spines. The type species, C. nummularia, is associated with taxa in the Dogtooth Mountains, British Columbia, that belong to the Nevadella Zone. A second species, C. espinata, is described from the southern Canadian Rocky Mountains, where it is associated with the new archaeaspid genus Geraldinella. Strata in the latter locality can be physically correlated to documented strata of the Nevadella Zone. The same zone in Nevada contains C. nummularia?.


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