scholarly journals Landslides in weakly cemented glaciolacustrine sediments, Morkill River valley, British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 889-900 ◽  
Author(s):  
Corey R Froese ◽  
David M Cruden

Slopes in weakly cemented glaciolacustrine sediments in the Morkill River valley in the Canadian Rocky Mountains stand at up to 70°. Based on field and laboratory observations it appears that a contributing factor to instability is the softening of the soils by frost action and the leaching of calcite cement. Field density profiles demonstrated increased density and carbonate content with an increase in depth. Laboratory tests of carbonate content indicated a positive correlation between calcium carbonate and density in the glaciolacustrine sediments. The relationship was strongest in sands, in which leaching and dissolution were important components of softening. In clays, frost action was the dominant component of softening. Freeze-thaw tests showed a 50% decrease in strength after one cycle of freeze and thaw in the silts and clays.Key words: landslide, cemented, glaciolacustrine sediments, British Columbia.

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.


1986 ◽  
Vol 43 (8) ◽  
pp. 1643-1655 ◽  
Author(s):  
J. I. Manzer ◽  
I. Miki

The fecundity and egg retention of anadromous female sockeye salmon (Oncorhynchus nerka) collected during 1971–82 from several stocks in British Columbia undergoing controlled fertilization to enhance adult sockeye production were examined. The relationship between egg number and postorbital–hypural length based on 863 females representing 14 stocks was not consistent between all age-types, stocks, and years, probably because of inadequate sample size in some instances. Combined samples, however, revealed a significant positive relationship between postorbital–hypural length and egg number for age 1.2, 1.3, and 2.2 females. Mean absolute fecundity for the respective age-types was 3218, 4125, and 3544 eggs. For samples of 10 or more females, significant stock and annual differences were detected when individual mean absolute fecundity was adjusted to a postorbital–hypural length of 447 mm, but not for females of different age. A comparison of mean fecundities for coastal stocks with historical data for interior British Columbia stocks suggests that coastal stocks are 18% more fecund than interior stocks. Possible causal mechanisms for this regional difference are hypothesized. Examination of 796 carcasses (representing five stocks) for egg retention revealed a range from totally spawned to totally unspawned females, with 56% of the carcasses containing 20 eggs or less and 68% containing 50 eggs or less. The mean egg retention based on all samples combined was estimated to be 6.5% of the mean individual fecundity. This value was reduced to 3.9% when stock means were averaged.


2018 ◽  
Vol 48 (7) ◽  
pp. 809-820 ◽  
Author(s):  
Neil P. Thompson ◽  
Kathy J. Lewis ◽  
Lisa M. Poirier

Drought tolerance of trees may be affected by competition, but most studies quantifying the relationship do not consider the effect of stem clustering. Trees are often clustered in interior Douglas-fir (Pseudotsuga menziesii var. glauca (Mayr) Franco) forests near the grassland interface in central British Columbia due to past harvesting practices or habitat management for mule deer (Odocoileus hemionus hemionus (Rafinesque, 1817)). Climate change projections indicate continued increases in temperature, an outcome that would stress trees growing in dry environments. Trees placed in different states of competition by mechanical harvesting in the 1970s were sampled to provide a 40-year comparison of three levels of competition during 1–2 year droughts. Tree-ring analysis was used to assess the reduction in growth during drought years and resumption of growth in subsequent years. A clear separation of growth rates was evident between open-growing trees, trees on the edge of harvesting trails, and trees within the unharvested interior. Edge trees had intermediate growth rates but no differences were found in the long-term climate–growth relationship compared with open-growing trees. Both Edge and Open classes showed less relative growth reduction during droughts than Interior trees growing between harvest trails. Precipitation throughfall rates and competition for resources are likely driving short-term drought tolerance in combination with other factors.


2021 ◽  
Vol 12 (1) ◽  
pp. 37-76
Author(s):  
Sanja Škifić ◽  
Antonia Strika

This paper focuses on sociocultural and language-related issues among Croatian immigrants in Canada. It presents the results of thestudy conducted from November 2018 to February 2019 among Croatian immigrants of different generations in Ontario and British Columbia. Questions included in the questionnaire refer to different aspects of participants’ identity and their (families’) immigration, as well as issues related to their attitudes towards the homeland and engagement in Croatian associations in Canada. Participants were asked to provide feedback on their language acquisition, competence and use, as well as evaluations of the importance of the Croatian language for their identity. The questionnaire also contained questions related to participants’ language use from emotional and cognitive perspectives. Conclusions drawn on the basis of the collected data provide an insight into Croatian immigrants’ language use, the extent of cultural integration and language maintenance, and their attitudes towards the relationship between identity and language.


2021 ◽  
Vol 21 (2) ◽  
pp. 90-101
Author(s):  
V. Constanza Ocampo-Raeder

In this article I present the social life of camarones, a Peruvian river crustacean used in some of the region’s favorite dishes, and the liminal space they occupy in the geography, minds, and ecosystem of Peru and its people. I situate the relationship between these crawfish and the folks who capture them, known as camaroneros, within insights of environmental anthropologists and food scholars who also explore the connections between cultural and biological diversity and the entangled socio-ecological histories that inform the manner in which nature is mediated and understood by local societies. In this article, however, I expand this understanding to reveal unexpected spaces of engagement, especially those that emerge while eating, which tend to be overlooked by bounded notions of culture and nature and limit the ways we can imagine human-nature relationships. Via the story of camarones and camaroneros of one river valley of Peru, I argue that eating is a socio-ecological act that is imbued with profound cultural meanings involving a wide range of participants—not just farmers or producers—each with their own ecological identities yet still implicitly linked to one another through the process of producing, preparing, and consuming food.


1979 ◽  
Vol 16 (3) ◽  
pp. 488-496 ◽  
Author(s):  
N. H. Wade ◽  
H. Taylor

Deep test bleeder wells were installed in an artesian aquifer underlying the Bridge River No. 1 hydroelectric generating station in southern British Columbia to determine whether seasonal peak artesian pressures could be controlled.The Bridge River complex, built in the early 1950's, consists of two powerhouses located about a kilometre apart on the shore of Seton Lake, a system of power tunnels, and surface penstocks, which conduct water from the Carpenter Lake reservoir in Bridge River valley to the powerhouses. The No. 1 powerhouse is founded on consolidated deposits of clayey silt, underlain by sand and gravel. Shortly after the powerhouse was constructed, ground and powerhouse movements occurred. It was later determined that such movement was caused by high artesian pressures in the sand and gravel aquifer under the powerhouse.Attempts to install bleeder wells in 1952 were unsuccessful and an offshore fill was constructed as a toe weight, which functioned adequately until 1974 when additional ground cracking was observed. After further study and additional drilling at the site, test bleeder wells and piezometers were installed in 1976.Tests conducted to assess the effect of the bleeder wells indicated that control of excessive artesian pressures by a system of bleeder wells was feasible.


1982 ◽  
Vol 114 (7) ◽  
pp. 643-645 ◽  
Author(s):  
J. W. E. Harris ◽  
A. F. Dawson

Western spruce budworm, Choristoneura occidentalis Freeman, periodically attacks Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) in British Columbia, causing mortality, deformity, and growth loss. Insect populations are assessed annually by the Canadian Forestry Service's Forest Insect and Disease Survey, by branch sampling for egg mass densities; predictions of population trends and damage are based on these assessments. Eggs, laid in rows in masses affixed to needles, are a preferred stage to sample because they are easily collected, remain fixed in numbers for an extended period, and precede damage by sufficient time to plan suppression or other programs. Numbers of masses alone, however, may not show population trends accurately as egg numbers per mass varies. Thus it is sometimes necessary to count eggs (Miller 1957), which is a formidable task. Fortunately egg numbers can be estimated from the dimensions of egg masses (Washburn and Brickell 1973). In this study, we determined the relationship between egg numbers and egg mass length and number of rows for samples from Douglas-fir stands frequently affected by spruce budworm throughout British Columbia. Data were collected over 3 years, 1977-79, during which time budworm populations were in a period of decline.


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