scholarly journals Two Middle Holocene Marker Beds in Vertically Accreted Floodplain Deposits, Lower Fraser River, British Columbia

2007 ◽  
Vol 44 (1) ◽  
pp. 27-32 ◽  
Author(s):  
Harry F. L. Williams ◽  
Michael C. Roberts
Keyword(s):  
British Columbia ◽  
Fraser River ◽  
Middle Holocene ◽  
Floodplain Deposits ◽  
Forme Triangulaire ◽  
Marker Beds

RÉSUMÉ Des carottes recueillies dans la partie est du delta du Fraser et de la plaine d'inondation adjacente montrent deux lits repères datant du milieu de l'Holocène, un lit de tourbe datant d'à peu près 6000 BP et un lit de tephra, correspondant à l'éruption du mont Mazama (6800 BP). Ces lits repères, ainsi que les datations au radiocarbone obtenues dans les sédiments de crue, montrent que la plaine d'inondation du Fraser a progressé en réponse à une hausse du niveau marin survenue entre environ 8000 et 2250 BP et que l'aggradation suivait la hausse du niveau marin. L'accumulation de sédiments, de forme triangulaire, est composée principalement de limons riches en matière organique et de sables fins d'origine alluviale. Le triangle s'étend jusqu'à au moins 20 km dans la vallée inférieure du Fraser. La conservation des lits repères démontre la grande stabilité des biefs du Fraser inférieur depuis environ 7000 ans.

A Mazama tephra marker bed in the Fraser Lowland, British Columbia

1991 ◽  
Vol 28 (1) ◽  
pp. 150-153 ◽  
Author(s):  
Harry F. L. Williams ◽  
John D'Auria
Keyword(s):  
British Columbia ◽  
Spectroscopic Analysis ◽  
Chemical Compositions ◽  
Fraser River ◽  
River Floodplain ◽  
Future Studies ◽  
X Ray ◽  
Tephra Layers ◽  
Fraser River Delta ◽  
Floodplain Deposits

Drill cores from the Fraser River delta and western Fraser River floodplain, British Columbia, reveal a widespread tephra marker bed within silty floodplain deposits. Isolated tephra layers have been noted in previous studies in the Fraser Lowland and have been assumed to be Mazama tephra (ca. 6800 BP). This note presents the results of the first attempt to systematically identify a number of tephra samples from this area, based on X-ray energy spectroscopic analysis of their chemical compositions and bracketing radiocarbon ages. The results confirm that the tephra bed is Mazama, a finding of considerable utility to future studies in this area.

Bedforms, bed material, and bedload transport in a salt-wedge estuary: Fraser River, British Columbia

1989 ◽  
Vol 26 (7) ◽  
pp. 1440-1452 ◽  
Author(s):  
R. A. Kostaschuk ◽  
M. A. Church ◽  
J. L. Luternauer
Keyword(s):  
British Columbia ◽  
River Discharge ◽  
Bedload Transport ◽  
Fraser River ◽  
Seasonal Fluctuations ◽  
Salt Wedge ◽  
Migration Rates ◽  
Material Load ◽  
Bed Material

The lower main channel of the Fraser River, British Columbia, is a sand-bed, salt-wedge estuary in which variations in velocity, discharge, and bedform characteristics are contolled by river discharge and the tides. Bed-material composition remains consistent over the discharge season and in the long term. Changes in bedform height and length follow but lag behind seasonal fluctuations in river discharge. Migration rates of bedforms respond more directly to river discharge and tidal fall than do height and length. Bedform characteristics were utilized to estimate bedload transport in the estuary, and a strong, direct, but very sensitive relationship was found between bed load and river discharge. Annual bedload transport in the estuary is estimated to be of the order of 0.35 Mt in 1986. Bedload transport in the estuary appears to be higher than in reaches upstream, possibly because of an increase in sediment movement along the bed to compensate for a reduction in suspended bed-material load produced by tidal slack water and the salt wedge.

Breeding characteristics of Townsend's vole (Microtus townsendii) during population fluctuations

1980 ◽  
Vol 58 (4) ◽  
pp. 623-625 ◽  
Author(s):  
Terry D. Beacham
Keyword(s):  
British Columbia ◽  
Sexual Maturity ◽  
Fraser River ◽  
Population Fluctuations ◽  
Peak Density ◽  
Decline Phase ◽  
Early Maturing ◽  
Fraser River Delta ◽  
Peak Phase ◽  
Microtus Townsendii

A 2-year livetrapping study on Townsend's vole (Microtus townsendii) on Reifel Island in the Fraser River delta in British Columbia, Canada, showed that there was an early stop to summer breeding in the peak phase summer compared with the increasing phase summer. Selective dispersal and death of early-maturing voles may account for this result. A delay occurred in the onset of breeding in the decline phase. Voles in peak density populations had the highest median weights at sexual maturity, and males matured at heavier weights than did females.

The Influence of Climate on the Stock and Recruitment of Pink and Sockeye Salmon from the Fraser River, British Columbia, Canada

2004 ◽  
Vol 133 (6) ◽  
pp. 1396-1412 ◽  
Author(s):  
R. J. Beamish ◽  
J. T. Schnute ◽  
A. J. Cass ◽  
C. M. Neville ◽  
R. M. Sweeting
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Fraser River ◽  
Stock And Recruitment
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