Sedimentary Environments and Late Quaternary History of a 'Low-Energy' Mountain Delta

1975 ◽  
Vol 12 (12) ◽  
pp. 2004-2013 ◽  
Author(s):  
Norman D. Smith
Keyword(s):  
Late Quaternary ◽  
Coarse Sand ◽  
Alluvial Fan ◽  
High Mountain ◽  
Fine Grained ◽  
Sedimentary Environments ◽  
Coarse Sediment ◽  
History Of ◽  
Quaternary History ◽  
Time Of Origin

Due to its low input of coarse sediment, Upper Waterfowl Lake, in Banff Park, Alberta, has developed a delta atypical of lacustrine deltas in this high mountain region: lack of foresets, vertically aggrading stable distributary channels, and a surface composed of mostly fine-grained floodplain materials. Deltaic progradation has outrun the supply of coarse sediment, resulting in entrapment of all gravel and coarse sand in proximal channels.Data provided by auger samples, including stratigraphic positions of Mazama and Bridge River volcanic ashes, suggest the lake was formed about 8800 years ago when deposition of a large alluvial fan blocked the Mistaya River at the upper end of Lower Waterfowl Lake. The delta has undergone two progradations, one beginning at the lake's time of origin, the other following a renewed lake level rise some 2300 years ago. Mean aggradation rates since Mazama time (6600 y BP) have been approximately steady at about.05 cm/y. Pre-Mazama lake sediments, however, were deposited more than twice as fast as a result of accelerated sedimentation rates that accompanied deglaciation.

Late Quaternary sediments and geomorphic history of northern Vancouver Island, British Columbia

1983 ◽  
Vol 20 (1) ◽  
pp. 57-65 ◽  
Author(s):  
D. E. Howes
Keyword(s):  
British Columbia ◽  
Late Quaternary ◽  
Mass Movement ◽  
Vancouver Island ◽  
Alluvial Fan ◽  
Eastern Coast ◽  
Sedimentary Environments ◽  
History Of ◽  
Floodplain Deposits ◽  
Organic Deposits

Materials from two glacial intervals and one nonglacial interval have been identified on northern Vancouver Island, British Columbia. The oldest Pleistocene unit, termed "older drift," consists of glaciomarine silt and clay >38 000 years BP in age that overlie a till that has only been recorded in well logs. "Older drift" is tentatively correlated with Dashwood drift of the Semiahmoo Glaciation (early Wisconsin or older). No sediments of the succeeding Olympia nonglacial interval (mid-Wisconsin) have been found in the area. It is thought that this interval was characterized by a period of degradation in which Olympia-age sediments were deposited in transient sedimentary environments and subsequently eroded, in part during the Fraser Glaciation (late Wisconsin). The youngest Pleistocene unit, termed Port McNeill drift, includes advance deposits, till, and deglacial sediments, all deposited during Fraser Glaciation. Ice of this glaciation did not cover most of northern Vancouver Island until after 20 600 ± 330 years BP. At the maximum, which probably occurred about 15 000 years ago, Coast Mountain ice coalesced with and overrode Vancouver Island ice, and flowed in a westerly to northwesterly direction across northern Vancouver Island. Deglaciation commenced prior to 12 930 ± 160 years BP and possibly as early as 13 630 years ago on the eastern coast. Maximum sea level during and immediately following deglaciation was about 92 and 20 m elevation on the east and west coasts, respectively. This suggests that ice thickness at the Fraser maximum decreased westward across the study area. Deposits of Recent time include colluvial sediments formed by weathering and mass movement processes, alluvial fan and floodplain deposits, eolian sands associated with active beaches on the west coast, and organic deposits.

Late Quaternary history of colluvial deposition and erosion in hollows, central California Coast Ranges

1990 ◽  
Vol 102 (7) ◽  
pp. 969-982 ◽  
Author(s):  
STEVEN L. RENEAU ◽  
WILLIAM E. DIETRICH ◽  
DOUGLAS J. DONAHUE ◽  
A. J. TIMOTHY JULL ◽  
MEYER RUBIN
Keyword(s):  
Late Quaternary ◽  
California Coast ◽  
Central California ◽  
History Of ◽  
Quaternary History ◽  
Coast Ranges ◽  
California Coast Ranges

Late Quaternary glacial and interglacial environments of the Nechako River - Cheslatta Lake area, central British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 719-731 ◽  
Author(s):  
A Plouffe ◽  
V M Levson
Keyword(s):  
British Columbia ◽  
Late Quaternary ◽  
Late Glacial ◽  
Lake Area ◽  
Glacial Lakes ◽  
Ice Flow ◽  
Coast Mountains ◽  
Quaternary Stratigraphy ◽  
History Of ◽  
Quaternary History

The Quaternary stratigraphy of the Nechako River – Cheslatta Lake area of central British Columbia is described and interpreted to reconstruct the late Quaternary history of the region. Exposures of glacial and nonglacial sediments deposited prior to the last glaciation (Fraser) are limited to three sites. Pollen assemblages from pre-Fraser nonglacial sediments at two of these sites reveal forested conditions around 39 000 BP. During the advance phase of the Fraser Glaciation, glacial lakes were ponded when trunk glaciers blocked some tributary valleys. Early in the glaciation, the drainage was free in easterly draining valleys. Subsequently, the easterly drainage was blocked either locally by sediments and ice or as a result of impoundment of the Fraser River and its tributaries east of the study area. Ice generally moved east and northeast from accumulation zones in the Coast Mountains. Ice flow was influenced by topography. Major late-glacial lakes developed in the Nechako River valley and the Knewstubb Lake region because potential drainage routes were blocked by ice.

The physical geography and geology of the estuary and Firth of Forth, Scotland

1987 ◽  
Vol 93 (3-4) ◽  
pp. 235-244 ◽  
Author(s):  
Michael A. E. Browne
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Physical Geography ◽  
Glacial Till ◽  
Estuarine Sediments ◽  
Volcanic Origin ◽  
Quaternary Glaciation ◽  
History Of ◽  
Quaternary History ◽  
Firth Of Forth

SynopsisThe Upper Palaeozoic bedrock, which is of sedimentary and volcanic origin, is briefly described. The origin of the Forth as a series of depressions in the bedrock surface probably owes much to erosion of a pre-existing Tertiary landscape during phases of Quaternary glaciation. The late Quaternary history of the area is described, relating the distribution of the sediments deposited in the Forth to climatic events and changes in relative sea-level. Since the acme of the last main glaciation about 20,000 years ago, late Devensian marine and estuarine sediments have been deposited on the underlying glacial till sheet at altitudes ranging from more than 120 m below O.D. to at least 46 m above O.D. Similarly, raised and buried beaches and their deposits occur at altitudes from 40 m above O.D. down to around 10 m below O.D. in the estuary. During the Flandrian, sea-level has fluctuated, reaching its maximum (about 11 to 15 m above O.D.) about 6500 years ago. The typical deposit of this period is the carse clay which forms a series of extensive, fertile raised mudflats around the estuary. The calcareous marine faunas of the carse clay and older deposits are outlined.

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