scholarly journals Surficial geology of the Vancouver Island continental shelf, Scott Islands to Nootka Sound, offshore British Columbia

1992 ◽  
Author(s):  
K W Conway ◽  
J V Barrie ◽  
B D Bornhold
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Vancouver Island ◽  
Surficial Geology

Late Pleistocene history and geomorphology, southwestern Vancouver Island, British Columbia

1979 ◽  
Vol 16 (9) ◽  
pp. 1645-1657 ◽  
Author(s):  
Neville F. Alley ◽  
Steven C. Chatwin
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Late Pleistocene ◽  
Vancouver Island ◽  
Glacial Lakes ◽  
Small Lakes ◽  
Strait Of Georgia ◽  
Coast Mountains ◽  
Juan De Fuca ◽  
Juan De Fuca Strait

The major Pleistocene deposits and landforms on southwestern Vancouver Island are the result of the Late Wisconsin (Fraser) Glaciation. Cordilleran glaciers formed in the Vancouver Island Mountains and in the Coast Mountains had advanced down Strait of Georgia to southeastern Vancouver Island after 19 000 years BP. The ice split into the Puget and Juan de Fuca lobes, the latter damming small lakes along the southwestern coastal slope of the island. During the maximum of the glaciation (Vashon Stade), southern Vancouver Island lay completely under the cover of an ice-sheet which flowed in a south-southwesterly direction across Juan de Fuca Strait, eventually terminating on the edge of the continental shelf. Deglaciation was by downwasting during which ice thinned into major valleys and the strait. Most upland areas were free of ice down to an elevation of 400 m by before 13 000 years BP. A possible glacier standstill and (or) resurgence occurred along Juan de Fuca Strait and in some interior upland valleys before deglaciation was complete. Glacial lakes occupied major valleys during later stages of deglaciation.

Distribution of Nitzschia pungens in Coastal Waters of British Columbia

1991 ◽  
Vol 48 (6) ◽  
pp. 960-967 ◽  
Author(s):  
J. R. Forbes ◽  
K. L. Denman
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Coastal Waters ◽  
Domoic Acid ◽  
Pacific Coast ◽  
Minor Component ◽  
Vancouver Island ◽  
Large Diatom ◽  
A Minor ◽  
Nitzschia Pungens

Concern about the potential for contamination of Pacific coast molluscan shellfish by domoic acid prompted us to review the distribution of Nitzschia pungens in coastal waters of British Columbia. From 1980 to 1988, N. pungens occurred throughout waters of the continental shelf, most frequently as a minor component of the large diatom aggregations observed off southwest Vancouver Island during July and August. The species was less common in the Strait of Georgia and north of Vancouver Island, but interannual variability in distribution and abundance was considerable. Maximum concentrations recorded were 106 cells∙L−1 in Hecate Strait in July 1983 and 5 × 105 cells∙L−1 off southwest Vancouver Island in August 1986. Discrimination of presence or absence on the basis of existing environmental variables produced mixed results, but has potential. Scanning electron microscopy showed that both N. pungens f. pungens and N. pungens f. multiseries (the latter being implicated in the contamination of shellfish in Atlantic Canada) occur in British Columbia. It remains to be shown whether N. pungens produces domoic acid in Pacific coast waters and whether the high abundances observed over the continental shelf also occur near shore.

Surficial geology of Hecate Strait, British Columbia continental shelf

1989 ◽  
Vol 26 (6) ◽  
pp. 1241-1254 ◽  
Author(s):  
J. V. Barrie ◽  
B. D. Bornhold
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Glacial Till ◽  
Hydrodynamic Conditions ◽  
Surficial Geology ◽  
Sand Ridges ◽  
Late Tertiary ◽  
Drainage Channels ◽  
Late Wisconsinan ◽  
Geological Units

Four surficial geological units are defined geophysically for Hecate Strait on the northern British Columbia continental shelf. They consist of Tertiary bedrock (unit 1) unconformably overlain in much of the strait of glacial till (unit 2), which is in turn overlain below 200 m water depth by thick silts (unit 4) and above 200 m by Quaternary sands and gravels (unit 3), except in areas where till or Tertiary bedrock is at or near surface.Glacial ice covered most of the strait at some time in the Pleistocene, but evidence for a Late Wisconsinan advance is more prevalent in the principal troughs of the strait. Sea level was as low as the present-day 180 m isobath during the late Tertiary or early Quaternary and possibly as low as 100 m at the end of the Pleistocene, based on the presence of drainage channels, wave-cut terraces, and both shore-oblique and shore-parallel sand ridges. Sedimentary bedforms found ubiquitously above 100 m appear to be in equilibrium with the present hydrodynamic conditions, and their presence suggests that significant seabed erosion and transport occur within the strait.

Biological and Hydrographical Evidence for Pacific Equatorial Water on the Continental Shelf North of Vancouver Island, British Columbia

1982 ◽  
Vol 39 (5) ◽  
pp. 660-667 ◽  
Author(s):  
Grant A. Gardner
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Deep Water ◽  
Water Mass ◽  
Fish Communities ◽  
Vancouver Island ◽  
Zooplankton Species ◽  
Regular Event

Data from two cruises in April and November 1977 indicate the presence of Pacific equatorial water on the continental shelf north of Vancouver Island. Water with the general temperature/salinity characteristics of the California Undercurrent was found on the shelf at both times. Equatorial water formed ~30% of this deep-water mass, with Pacific subarctic water making up the remainder. Evidence for the presence of equatorial water was supported by the occurrence in the study area of six normally subtropical zooplankton species: Mesocalanus tenuicornis, Lophothrix frontalis, Candacia bipinnata, Lucicutia flavicornis, Heterostylites longicornis, and Pleuromamma xiphias. An increase in the proportion of equatorial water on the shelf, and a concomitant extension of the limits of distribution of oceanic zooplankters in the study area, both infer an intrustion of deep water onto the shelf during the period between the two cruises. This intrusion is probably a regular event with important ramifications for the zooplankton and fish communities of the area.Key words: continental shelf, British Columbia, hydrography, California Undercurrent, zooplankton

Sign in / Sign up

Export Citation Format

Share Document