Status of Glacial Lake Columbia during the Last Floods from Glacial Lake Missoula

1987 ◽  
Vol 27 (2) ◽  
pp. 182-201 ◽  
Author(s):  
Brian F. Atwater
Keyword(s):  
Columbia River ◽  
River Valley ◽  
Glacial Lake ◽  
Grand Coulee

AbstractThe last floods from glacial Lake Missoula, Montana, probably ran into glacial Lake Columbia, in northeastern Washington. In or near Lake Columbia's Sanpoil arm, Lake Missoula floods dating from late in the Fraser glaciation produced normally graded silt beds that become thinner upsection and which alternate with intervals of progressively fewer varves. The highest three interflood intervals each contain only one or two varves, and about 200–400 successive varves conformably overlie the highest flood bed. This sequence suggests that jökulhlaup frequency progressively increased until Lake Missoula ended, and that Lake Columbia outlasted Lake Missoula. The upper Grand Coulee, Lake Columbia's late Fraser-age outlet, contains a section of 13 graded beds, most of them sandy and separated by varves, that may correlate with the highest Missoula-flood beds of the Sanpoil River valley. The upper Grand Coulee also contains probable correlatives of many of the approximately 200–400 succeeding varves, as do nearby parts of the Columbia River valley. This collective evidence casts doubt on a prevailing hypothesis according to which one or more late Fraser-age floods from Lake Missoula descended the Columbia River valley with little or no interference from Lake Columbia's Okanogan-lobe dam.

The late Wisconsinan olistostrome of the lower Coppermine River valley, Northwest Territories

1986 ◽  
Vol 23 (11) ◽  
pp. 1700-1708 ◽  
Author(s):  
Denis A. St-Onge ◽  
Jean Lajoie
Keyword(s):  
Debris Flows ◽  
Late Quaternary ◽  
Fine Sand ◽  
Coarse Sand ◽  
Coarse Fraction ◽  
River Valley ◽  
Glacial Lake ◽  
The North ◽  
Geologic Record ◽  
Coppermine River

The late Quaternary olistostrome exposed in the lower Coppermine River valley fills a paleovalley that ranges in apparent width from 150 to 400 m and was cut into Precambrian bedrock before the last glaciation. The olistostrome is here named the Sleigh Creek Formation. The coarse fraction of the formation is matrix supported; beds are massive or reversely graded and have sharp, nonerosive contacts. These characteristics suggest deposition of the coarse fraction by debris flows. The olistostrome sequence is bracketed by, and wedged into, a marine rhythmite sequence, which indicates that deposition occurred in a marine environment.About 10 500 years BP glacier ice in the Coronation Gulf lowland dammed the valley to the south, which was occupied by glacial Lake Coppermine. Sediments accumulated in this lake in a 30 m thick, coarsening upward sequence ranging from glaciolacustrine rhythmites of silt and fine sand at the base to coarse sand alluvium, and deltaic gravels at the top. As the Coronation Gulf lowlands became ice free, the Coppermine River reoccupied its former drainage course to the north. The steep south to north gradient and rapid downcutting by the river through the glacial lake sediments produced unstable slope conditions. The resulting debris flows filled a bedrock valley network below the postglacial sea level, forming the diamicton sequence.The interpretation of the Sleigh Creek Formation raises questions concerning silimar diamicton deposits usually defined as "flowtills." More generally, the results of this study indicate that care must be used when attempting paleogeographic reconstructions of "glaciogenic" deposits in marine sequences in any part of the geologic record.

Slope and Valley Winds in the Columbia River Valley *

1950 ◽  
Vol 31 (3) ◽  
pp. 79-84 ◽  
Author(s):  
C. M. Cross
Keyword(s):  
Columbia River ◽  
River Valley ◽  
Wind Pattern ◽  
Slope Winds ◽  
Wind Velocities ◽  
The Alps ◽  
Diurnal Wind ◽  
The Town ◽  
Made In ◽  
The Ideal

The behavior of slope and valley winds near the town of Trail in the Columbia River valley system in southern British Columbia was studied, and the results compared with those obtained from similar studies made in the Alps. The hourly wind velocities for two stations—one in the main valley, the other in a side valley—were resolved into components parallel to and at right angles to the valley. This procedure gives the valley and slope winds respectively. The usual diurnal wind pattern was found to prevail in most instances, with up-slope and up-valley winds during the day, and down-slope and down-valley winds at night. These systems were much better developed during the summer than in winter, and approximated the ideal pattern more closely on sunny days when the overall pressure gradient was weak.

Un lac glaciaire dans la région du lac Minto—Nouveau-Québec

1983 ◽  
Vol 20 (9) ◽  
pp. 1488-1492 ◽  
Author(s):  
Bernard Lauriol ◽  
James T. Gray
Keyword(s):  
Main Part ◽  
River Valley ◽  
Glacial Lake ◽  
Glacial Ice ◽  
Isostatic Rebound ◽  
Raised Beaches

The presence of raised beaches around Lake Minto, northern Quebec, and the washing of till in the upper part of the Leaf River valley are attributed to the existence of a glacial lake. It drained westward into the Tyrrell Sea and was dammed in the east by glacial ice that occupied the main part of the Leaf River valley. The disappearance of this ice prior to 5200 years BP led to rapid drainage of the glacial lake into an arm of the D'Iberville Sea. Postglacial isostatic rebound has subsequently led to warping of the highest water plane associated with this glacial lake, as well as those of the postglacial seas.

Paleomagnetic Evidence for Repeated Glacial Lake Missoula Floods from Sediments of the Sanpoil River Valley, Northeastern Washington

1991 ◽  
Vol 35 (2) ◽  
pp. 197-207 ◽  
Author(s):  
William K. Steele
Keyword(s):  
Secular Variation ◽  
Geomagnetic Field ◽  
Remanent Magnetization ◽  
River Valley ◽  
Field Direction ◽  
Glacial Lake ◽  
Laboratory Measurements ◽  
Eastern Washington

AbstractRecent explanations of widespread rhythmically layered sediments in eastern Washington as the result of repeated great floods from glacial Lake Missoula implicitly suggest a paleomagnetic test for validity. If each conjectural flood layer is separated by years or decades, as hypothesized, a sequence of several such flood beds should record measurable secular variation in geomagnetic field direction. In the Sanpoil River valley where the rhythmite sequences are thought to have been deposited in glacial Lake Columbia, the paleomagnetic test consists of measuring remanent magnetization (RM) directions for thick, upwardly fining beds inferred to be sediments deposited by the influx of flood waters from glacial Lake Missoula into glacial Lake Columbia. Laboratory measurements of samples from three widely spaced sections along the Sanpoil River yield RM vectors with erratic inclinations, apparently affected by varying contributions of inclination error and (or) compaction shallowing, but with declinations that generally differ statistically from one flood to the next and that show the same west-to-east trend at all three locations. The rates of declination change inferred from these data are consistent with modern rates, thus providing the first geophysical evidence supporting the timing in the tens-of-floods theory.

Late Quaternary paleoenvironments and growth of intrusive ice in eastern Beringia (Eagle River valley, northern Yukon, Canada)

2010 ◽  
Vol 47 (7) ◽  
pp. 941-955 ◽  
Author(s):  
Bernard Lauriol ◽  
Denis Lacelle ◽  
Mélanie St-Jean ◽  
Ian D. Clark ◽  
Grant D. Zazula
Keyword(s):  
Late Quaternary ◽  
Maximum Level ◽  
River Valley ◽  
Bison Bison ◽  
Glacial Lake ◽  
Silty Clay ◽  
Uneven Surface ◽  
Ground Ice ◽  
Fluvial Terrace ◽  
Cut Marks

In this study, the sediments exposed in a fluvial terrace and in the headwall of a thaw slump in the Eagle River valley, northern Yukon, provide new data about the timing of flooding of glacial Lake Old Crow, the formation of massive ground ice bodies, and the vegetation and the fauna in eastern Beringia during the late Quaternary. The stratigraphy and radiocarbon ages establish the following chronology of events: (1) a gravel fluvial terrace was deposited by an overflow from glacial Lake Hughes into glacial Lake Old Crow; (2) a carbonate silty clay was deposited during the maximum level of glacial Lake Old Crow at 15 120 14C year BP; (3) permafrost and large intrusive ice bodies aggraded through the glaciolacustrine and underlying sediments following the drainage of glacial Lake Old Crow from the site; (4) at 11 290 14C year BP, a shrub–sedge tundra colonized an uneven surface deformed by the bodies of ground ice; (5) a thaw lake drained at 6730 14C year BP after flooding the site; (6) during the early Holocene and from the previous major event onwards, material from the slope nearby the site buried the previous organic and inorganic sediment and the ice bodies; and (7) a bison (Bison) vertebra with conspicuous cut marks was dated to 12 210 ± 70 14C year BP. The age from the bison bone is amongst the most recent of the late Pleistocene bison specimens yet found in eastern Beringia.

Sign in / Sign up

Export Citation Format

Share Document