Anomalous early 20th century sedimentation in proglacial Green Lake, British Columbia, Canada

2006 ◽  
Vol 43 (6) ◽  
pp. 671-678 ◽  
Author(s):  
Brian Menounos
Keyword(s):  
British Columbia ◽  
Air Temperature ◽  
Laminated Sediments ◽  
Annual Maximum ◽  
Coast Mountains ◽  
Varve Thickness ◽  
Green Lake ◽  
Daily Discharge ◽  
Temperature Records ◽  
Temperature Proxy

Annually laminated sediments were recovered from Green Lake, a proglacial lake in the southern Coast Mountains in British Columbia, to examine their potential as a temperature proxy. Varve thickness is moderately correlated with temperature anomalies (A.D. 1900–1994) and annual maximum mean daily discharge of Lillooet River (A.D. 1930–1999), but these relations are not stable through time. Following A.D. 1977, the relation between varve thickness and annual maximum mean daily discharge is stronger. Prior to A.D. 1977, varve thickness is correlated with March to October air temperature, which controls the intensity and duration of glacier runoff. Varve thickness is weakly correlated with reconstructed air temperature records for North America and the Northern Hemisphere for the period A.D. 1600–1976. Less extensive glacier cover may explain the lack of a clear temperature signal in the varved sediment record prior to A.D. 1600 and following A.D. 1977. The period of highest lake sedimentation, from A.D. 1920 to 1945, coincides with rapid retreat of glaciers in the watershed. The lack of a similar level of sedimentation in the varve chronology suggests that glacier recession during the period 1920–1945 was higher than at any time in the past 600 years.

Linking Atmospheric Rivers to Annual and Extreme River Runoff in British Columbia and Southeastern Alaska

2020 ◽  
Vol 21 (11) ◽  
pp. 2457-2472
Author(s):  
Aseem R. Sharma ◽  
Stephen J. Déry
Keyword(s):  
British Columbia ◽  
River Runoff ◽  
Annual Maximum ◽  
Flood Risk Assessment ◽  
Atmospheric Rivers ◽  
Coast Mountains ◽  
Topographic Characteristics ◽  
Peak Runoff ◽  
Northwestern North America ◽  
Maximum Runoff

AbstractThis study quantifies the contribution of atmospheric rivers (ARs) to annual and extreme river runoff and evaluates the relationships between watershed characteristics and AR-related maximum river runoff across British Columbia and southeastern Alaska (BCSAK). Datasets used include gauged runoff from 168 unregulated watersheds, topographic characteristics of those watersheds, a regional AR catalog, and integrated vapor transport fields for water years (WYs) 1979–2016. ARs contribute ~22% of annual river runoff along the Coast and Insular Mountains watersheds, which decreases inland to ~11% in the watersheds of the Interior Mountains and Plateau. Average association between ARs and annual maximum river runoff attains >80%, >50%, and <50% along the watersheds of the western flanks of the Coast Mountains, the Interior Mountains, and Interior Plateau, respectively. There is no significant change in AR-related extreme annual maximum runoff across BCSAK during 1979–2016. AR conditions occur during 25 out of 32 of the flood-related natural disasters in British Columbia during WYs 1979–2016. AR-related annual maximum runoff magnitude is significantly higher than non-AR-related annual maximum runoff for 30% of the watersheds studied. Smaller and steeper watersheds closer to the coast are more susceptible to AR-related annual maximum runoff than their inland counterparts. These results illustrate the importance of AR activity as a major control for the distribution of peak runoff in BCSAK. This work provides insights on the hydrological response of watersheds of northwestern North America to landfalling ARs that may improve flood risk assessment and disaster management in this region.

Century-scale variability in late-summer rainfall events recorded over seven centuries in subannually laminated lacustrine sediments, White Pass, British Columbia

2007 ◽  
Vol 67 (2) ◽  
pp. 193-203 ◽  
Author(s):  
Jaclyn M.H. Cockburn ◽  
Scott F. Lamoureux
Keyword(s):  
British Columbia ◽  
Seventeenth Century ◽  
Lacustrine Sediments ◽  
Late Summer ◽  
Summer Rainfall ◽  
Laminated Sediments ◽  
Ice Age ◽  
Rainfall Events ◽  
Varve Thickness ◽  
Glacier Melt

AbstractFormation of annually laminated sediments in Summit Lake, White Pass, British Columbia is controlled by runoff generated by snowpack and glacier melt and major rainfall events. The 700-yr varve record is divided into two subannual series (early and late) based on sedimentological criteria and sedimentary structures within each varve. A comparison of recent subannual laminae with nearby meteorological records supports the interpretation they are formed by river discharge events generated by major snow and glacier melt events and large late-summer rainfall events. A significant correlation exists between the late subannual thickness series and the size of the largest rainfall events in late summer. The long record indicates there was an abrupt increase in the thickness and frequency of major rainfall-induced sedimentary events at the end of the seventeenth century. In addition, the frequency of laminae generated by early runoff events also increased. However, early subannual varve thickness component remains statistically the same as the thickness prior to the end of the seventeenth century. This suggests the change in varve thickness at this time is due to increases in major late-summer rainfall frequency rather than increased sediment availability caused by regional Little Ice Age glacier advances.

scholarly journals Along‐Strike Variation in the Magmatic Tempo of the Coast Mountains Batholith, British Columbia, and Implications for Processes Controlling Episodicity in Arcs

2018 ◽  
Vol 19 (11) ◽  
pp. 4274-4289 ◽  
Author(s):  
M. R. Cecil ◽  
M. E. Rusmore ◽  
G. E. Gehrels ◽  
G. J. Woodsworth ◽  
H. H. Stowell ◽  
...  
Keyword(s):  
British Columbia ◽  
Coast Mountains

III.—Recent Observations on the Glaciation of British Columbia and Adjacent Regions

1888 ◽  
Vol 5 (8) ◽  
pp. 347-350 ◽  
Author(s):  
Geo. M. Dawson
Keyword(s):  
British Columbia ◽  
Glacial Period ◽  
Coast Range ◽  
Coast Mountains ◽  
One Stage ◽  
Queen Charlotte Islands ◽  
Glacier Ice ◽  
Inland Ice ◽  
Great Valley ◽  
The U.S

Previous observations in British Columbia have shown that at one stage in the Glacial period—that of maximum glaciation—a great confluent ice-mass has occupied the region which may be named the Interior Plateau, between the Coast Mountains and Gold and Eocky Mountain Kanges. From the 55th to the 49th parallel this great glacier has left traces of its general southward or southeastward movement, which are distinct from those of subsequent local glaciers. The southern extensions or terminations of this confluent glacier, in Washington and Idaho Territories, have quite recently been examined by Mr. Bailley Willis and Prof. T. C. Chamberlin, of the U.S. Geological Survey. There is, further, evidence to show that this inland-ice flowed also, by transverse valleys and gaps, across the Coast Range, and that the fiords of the coast were thus deeply filled with glacier-ice which, supplemented by that originating on the Coast Range itself, buried the entire great valley which separates Vancouver Island from the mainland and discharged seaward round both ends of the island. Further north, the glacier extending from the mainland coast touched the northern shores of the Queen Charlotte Islands.

Nd isotopic characteristics of metamorphic and plutonic rocks of the Coast Mountains near Prince Rupert, British Columbia

1998 ◽  
Vol 35 (5) ◽  
pp. 556-561 ◽  
Author(s):  
P J Patchett ◽  
G E Gehrels ◽  
C E Isachsen
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Metamorphic Rocks ◽  
Published Data ◽  
Isotopic Data ◽  
Crustal Component ◽  
Coast Mountains ◽  
Crustal Rocks ◽  
Metasedimentary Rocks ◽  
Plutonic Rocks

Nd isotopic data are presented for a suite of metamorphic and plutonic rocks from a traverse across the Coast Mountains between Terrace and Prince Rupert, British Columbia, and for three contrasting batholiths in the Omineca Belt of southern Yukon. A presumed metamorphic equivalent of Jurassic volcanic rocks of the Stikine terrane gives epsilon Nd = +6, and a number of other metaigneous and metasedimentary rocks in the core of the Coast Mountains give epsilon Nd values from +3 to +7. A single metasedimentary rock approximately 3 km east of the Work Channel shear zone gives a epsilon Nd value of -9. Coast Belt plutons in the traverse yield epsilon Nd from -1 to +2. The Omineca Belt plutons give epsilon Nd from -10 to -17. All results are consistent with published data in demonstrating that (i) juvenile origins for both igneous and metamorphic rocks are common in the Coast Belt; (ii) representatives of a continental-margin sedimentary sequence with Precambrian crustal Nd are tectonically interleaved in the Coast Mountains; (iii) Coast Mountains plutons can be interpreted as derived from a blend of metamorphic rocks like those seen at the surface, or as arc-type melts contaminated with the older crustal component; and (iv) Omineca Belt plutons are dominated by remelted Precambrian crustal rocks.

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