Gravity and structure of an active margin—British Columbia and Washington

1979 ◽  
Vol 16 (2) ◽  
pp. 350-363 ◽  
Author(s):  
Robin P. Riddihough
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Subduction Zones ◽  
Gravity Data ◽  
Puget Sound ◽  
Granulite Facies ◽  
Vancouver Island ◽  
Positive Anomaly ◽  
Active Margin ◽  
The Pacific

Active subduction zones around the world have a gravity expression characterized by a linear negative gravity anomaly over the trench and a parallel, linear positive anomaly some 100km inland. Although there are local modifications, the same pattern is present in the Pacific northwest across the zone of interaction between the Juan de Fuca and American plates.Previous geophysical interpretations of this region have not specifically used a subduction model but have exposed an apparent conflict between seismic and gravity interpretations of the thickness of the crust under Vancouver Island. The position of Vancouver Island in the arc-trench gap of an active margin suggests that a compromise can be achieved by considering the wedge of material overlying the down-going plate to be of high density and low compressional velocity. Such materials have been documented in the laboratory and are typically amphibolite to granulite facies mafic rocks.Proceeding on this assumption, four structural sections across the margin in southern British Columbia and northern Washington show that both seismic and gravity data can be simply incorporated into models fulfilling the main criteria of a subduction zone. Among the features suggested by the construction of these sections are (1) the density of the material of the down-going slab need not increase beyond that of normal lithosphere to satisfy the gravity observations and (2) the down-going slab may increase in dip approximately beneath Georgia Strait and Puget Sound

scholarly journals Settler Anxiety and State Support for Missionary Schooling in Colonial British Columbia, 1849 –1871

2017 ◽  
Author(s):  
Sean Carleton
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Indigenous Peoples ◽  
Puget Sound ◽  
The State ◽  
State Support ◽  
Indigenous Resistance ◽  
The Pacific ◽  
Settler Colonization ◽  
Peuples Autochtones

Indigenous peoples and settlers engaged in innumerable conflicts in the colonies of Vancouver Island and British Columbia between 1849 and 1871. The constant threat of violent Indigenous resistance to settler colonization in the Pacific Northwest—both real and imagined—produced feelings of anxiety for settlers, especially state officials, that shaped colonial strategy and statecraft. To buttress colonial security, the nascent state partnered with Christian missionaries in the hope that missionaries could use education to cultivate the goodwill of Indigenous peoples and train them to accept colonization. The state’s support for early missionary schooling in colonial British Columbia is examined in the context of settler anxieties regarding three instances of Indigenous resistance: a Lekwungen convergence at Fort Victoria in 1851, the Puget Sound War of 1855–56, and the 1864 Tsilhqot'in War. In different ways, settler anxiety over these conflicts acted as a catalyst, prodding the state to support missionary schooling as a financially expeditious way of trying to contain Indigenous resistance and safeguard colonial security. RÉSUMÉ Entre 1849 et 1871, les colonies de l’île de Vancouver et de la Colombie-Britannique sont le lieu d’innombrables con its entre les peuples autochtones et les colons. La menace constante — réelle et imaginaire — d’une résistance violente des Autochtones à la colonisation dans le nord-ouest du Pacifique a engendré un sentiment d’anxiété chez les colons, et en particulier chez les fonctionnaires de l’État, ce qui a façonné la stratégie et la gestion coloniale. Afin de renforcer la sécurité coloniale, l’État naissant s’est associé avec les missionnaires chrétiens dans l’espoir qu’ils utilisent l’éducation afin d’assurer la bienveillance des peuples autochtones et de les amener à accepter la colonisation. Cet article examine le soutien apporté par l’État aux premiers efforts d’enseignement missionnaire en Colombie-Britannique coloniale, dans le contexte des inquiétudes des colons par rapport à trois actes de résistance autochtone : un rassemblement Lekwungen au Fort Victoria en 1851, la guerre du Puget Sound de 1855–1856 et la guerre des Tsilhqot'in de 1864. À maints égards, l’inquiétude des colons alimentée par ces conflits a agi comme un catalyseur, poussant l’État à soutenir l’enseignement missionnaire dans l’espoir d’arriver à contenir la résistance autochtone et à assurer la sécurité coloniale à peu de frais. 

Hydrographic Charting and Oceanography on the West Coast of Canada from the Eighteenth Century to the Present Day

1972 ◽  
Vol 73 ◽  
pp. 75-83
Author(s):  
Robert W. Sandilands
Keyword(s):  
British Columbia ◽  
Eighteenth Century ◽  
Pacific Northwest ◽  
West Coast ◽  
Vancouver Island ◽  
The West ◽  
Special Place ◽  
The Pacific ◽  
Short Period ◽  
Formative Years

Those participating in this Congress are aware of the leadership of Rear-Admiral George Henry Richards in mounting the Challenger Expedition, which he himself regarded as the crowning achievement of his career. However, he also has a very special place in the history and development of British Columbia and it can fairly be said that his work in the Pacific Northwest was the major achievement of his sea-going career. His service on the coast covered the short period 1857 to 1863, but these were formative years in the development of the west coast colonies of Vancouver Island and British Columbia.

The Bramble Leaf hopper, Typhlocyba tenerrima H.-S. (Homoptera: Cicadellidae), A Destructive European Insect New to the Pacific Northwest

1950 ◽  
Vol 82 (3) ◽  
pp. 68-70 ◽  
Author(s):  
Harry Andison
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Coastal Area ◽  
Vancouver Island ◽  
Economic Damage ◽  
Leaf Hopper ◽  
The Pacific ◽  
Lower Fraser Valley ◽  
Serious Injury ◽  
Fraser Valley

In July, 1947, a leafhopper was found causing serious injury to the foliage of loganberries in the Brentwood area of Vancouver Island, B.C. A survey made at that time in southern Vancouver Island showed that this species was widely distributed, and that it occurred also on raspberries and blackberries. In 1948 it was again found injuring loganberries on Vancouver Island and was found also in the lower Fraser Valley; and in 1949 it was observed 40 miles north of Victoria, at Cowichan Bay, feeding on wild blackberry. It is probable that this species had been present in the coastal area of British Columbia for some time before it was first observed in 1947 causing economic damage.

Middle Wisconsin Stratigraphy and Climatic Reconstruction, Southern Vancouver Island, British Columbia

1979 ◽  
Vol 11 (2) ◽  
pp. 213-237 ◽  
Author(s):  
Neville F. Alley
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Vancouver Island ◽  
Olympic Peninsula ◽  
Radiocarbon Dates ◽  
Modern Pollen ◽  
The Pacific ◽  
Vegetation And Climate ◽  
Coastal British Columbia ◽  
Almost Continuous

Interbedded, organic-rich terrestrial and marine sediments exposed along the eastern coastal lowland of Vancouver Island contain an almost continuous record of middle Wisconsin vegetation and climate. The record has been interpreted largely from palynostratigraphic studies at three sites and supported by a study of modern pollen spectra from the three major biogeoclimatic zones of the extant vegetation. Radiocarbon dates from a variety of organic materials in the middle Wisconsin beds reveal that the fossil pollen spectra span an interval ranging from approximately 21,000 yr B.P. to more than 51,000 yr B.P. The spectra are divided into eight major pollen zones encompassing the Olympia Interglaciation and early Fraser Glaciation geologicclimate units of the Pacific Northwest. The Olympia Interglaciation extended from before 51,000 yr B.P. to ca. 29,000 yr B.P. and was characterized by a climate similar to present. During the early Fraser Glaciation, from 29,000 years ago to approximately 21,000 yr B.P., climate deteriorated until tundra like conditions prevailed. These pollen sequences are correlative with those of coastal British Columbia and partly with those from Olympic Peninsula, but apparently are not comparable with events in the Puget Lowland.

scholarly journals Fault locking, block rotation and crustal deformation in the Pacific Northwest

2007 ◽  
Vol 169 (3) ◽  
pp. 1315-1340 ◽  
Author(s):  
Robert McCaffrey ◽  
Anthony I. Qamar ◽  
Robert W. King ◽  
Ray Wells ◽  
Giorgi Khazaradze ◽  
...  
Keyword(s):  
North America ◽  
Shear Deformation ◽  
Pacific Northwest ◽  
Puget Sound ◽  
Vancouver Island ◽  
Block Rotation ◽  
The Pacific ◽  
Juan De Fuca ◽  
Gps Velocities ◽  
Relative Motions

Summary We interpret Global Positioning System (GPS) measurements in the northwestern United States and adjacent parts of western Canada to describe relative motions of crustal blocks, locking on faults and permanent deformation associated with convergence between the Juan de Fuca and North American plates. To estimate angular velocities of the oceanic Juan de Fuca and Explorer plates and several continental crustal blocks, we invert the GPS velocities together with seafloor spreading rates, earthquake slip vector azimuths and fault slip azimuths and rates. We also determine the degree to which faults are either creeping aseismically or, alternatively, locked on the block-bounding faults. The Cascadia subduction thrust is locked mainly offshore, except in central Oregon, where locking extends inland. Most of Oregon and southwest Washington rotate clockwise relative to North America at rates of 0.4–1.0 ° Myr−1. No shear or extension along the Cascades volcanic arc has occurred at the mm/yr level during the past decade, suggesting that the shear deformation extending northward from the Walker Lane and eastern California shear zone south of Oregon is largely accommodated by block rotation in Oregon. The general agreement of vertical axis rotation rates derived from GPS velocities with those estimated from palaeomagnetic declination anomalies suggests that the rotations have been relatively steady for 10–15 Ma. Additional permanent dextral shear is indicated within the Oregon Coast Range near the coast. Block rotations in the Pacific Northwest do not result in net westward flux of crustal material—the crust is simply spinning and not escaping. On Vancouver Island, where the convergence obliquity is less than in Oregon and Washington, the contractional strain at the coast is more aligned with Juan de Fuca—North America motion. GPS velocities are fit significantly better when Vancouver Island and the southern Coast Mountains move relative to North America in a block-like fashion. The relative motions of the Oregon, western Washington and Vancouver Island crustal blocks indicate that the rate of permanent shortening, the type that causes upper plate earthquakes, across the Puget Sound region is 4.4 ± 0.3 mm yr−1. This shortening is likely distributed over several faults but GPS data alone cannot determine the partitioning of slip on them. The transition from predominantly shear deformation within the continent south of the Mendocino Triple Junction to predominantly block rotations north of it is similar to changes in tectonic style at other transitions from shear to subduction. This similarity suggests that crustal block rotations are enhanced in the vicinity of subduction zones possibly due to lower resisting stress.

Lag of the Fraser glacial maximum in the Pacific Northwest: pollen and macrofossil evidence from western Fraser Lowland, British Columbia

1982 ◽  
Vol 19 (12) ◽  
pp. 2288-2296 ◽  
Author(s):  
Stephen R. Hicock ◽  
Richard J. Hebda ◽  
John E. Armstrong
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Vancouver Island ◽  
Glacial Maximum ◽  
Mean Annual Temperature ◽  
Abies Lasiocarpa ◽  
Taxus Brevifolia ◽  
Weather Patterns ◽  
Plant Assemblage ◽  
The Pacific

Pollen and macrofossil evidence from two sites in northwestern Fraser Lowland reveals that Abies lasiocarpa – Picea cf. engelmannii forest and parkland grew there about 18 000 years ago under cold humid continental conditions. Taxus brevifolia was also a significant constituent of this forest. This plant assemblage resembles the ESSF Biogeoclimatic Zone of subalpine elevations in the northern interior of British Columbia (900–2250 m). Climate was probably cold with low to moderate rainfall and characterized by long, cold, wet winters and very short, probably dry, frost-free summers. Mean annual temperature was depressed about 8 °C and the tree line was probably 1200–1500 m lower than today.Fraser Lowland was probably removed from Pacific oceanic influence because the land–sea interface was located on the continental shelf to the west of Vancouver Island and Washington about the time of the last global glacial maximum, global depression of sea level, and Quadra Sand aggradation in the Pacific Northwest. Lowland glaciation was probably delayed because of insufficient precipitation in the drier macroclimate and the precipitation shadow created behind mountains on Vancouver Island and Olympic Peninsula. We speculate that, as Laurentide ice decayed, there was a northward shift of zonal weather patterns over the eastern Pacific, bringing very wet winters to the Fraser Lowland and providing moisture for rapid, extensive, Vashon glaciation, which culminated about 14 500 BP, lagging at least 3000 years behind the Laurentide glacial maximum.

Experiments on Oral Secretion of the Rocky Mountain Wood Tick, Dermacentor andersoni Stiles (Acarina: Ixodidae)

1957 ◽  
Vol 89 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. D. Gregson
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Rocky Mountain ◽  
Dermacentor Variabilis ◽  
Oral Secretion ◽  
Amblyomma Maculatum ◽  
Dermacentor Andersoni ◽  
The Pacific ◽  
Tick Paralysis ◽  
Rocky Mountain Wood Tick

Tick paralysis continues to be one of the most baffling and fascinating tickborne diseases in Canada. It was first reported in this country by Todd in 1912. Since then about 250 human cases, including 28 deaths, have been recorded from British Columbia. Outbreaks in cattle have affected up to 400 animals at a time, with losses in a herd as high as 65 head. Although the disease is most common in the Pacific northwest, where it is caused by the Rocky Mountain wood tick, Dermacentor andersoni Stiles, it has lately been reported as far south as Florida and has been produced by Dermacentor variabilis Say, Amblyomma maculatum Koch, and A. americanum (L.) (Gregson, 1953). The symptoms include a gradual ascending symmetrical flaccid paralysis. Apparently only man, sheep, cattle, dogs, and buffalo (one known instance) are susceptible, but even these may not necessarily be paralysed.

1999 Pacific Northwest Labor History Association Conference

2000 ◽  
Vol 57 ◽  
pp. 117-119 ◽  
Author(s):  
Daniel Jacoby
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Labor History ◽  
Definitive Answer ◽  
Preferable Alternative ◽  
The Pacific ◽  
The Moment ◽  
Academic Conferences

I cannot provide a definitive answer to those of us pondering what the best alternative to capitalism is, but after attending the Pacific Northwest Labor History Association (PNLHA) Conference in Westminster, British Columbia, over the weekend of May 28–30, 1999, I can tell you that this is certainly a preferable alternative to standard academic conferences. As usual, the PNLHA was able to produce a cadre of historians (from the trades as well as academia), active unionists, and old-timers whose memories are as tapable as a keg of beer. Although the association designates labor history as its subject, newly elected President Ross Rieder likes to say, “History ends the moment before now.”

Notes on Parathion-Resistant Strains of Two Phytophagous Mites and a Predacious Mite in British Columbia

1958 ◽  
Vol 90 (2) ◽  
pp. 92-97 ◽  
Author(s):  
C. V. G. Morgan ◽  
N. H. Anderson
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Predacious Mites ◽  
Predacious Mite ◽  
Phytophagous Mites ◽  
European Red Mite ◽  
The Pacific ◽  
Resistant Strains ◽  
Tetranychus Pacificus

The existence of strains of mites resistant to parathion has been well established (Garman, 1950; Lienk, Dean, & Chapman, 1952; Newcomer & Dean, 1952; Smith & Fulton, 1951). Resistant strains of the European red mite, Metatetranychus ulmi (Koch), first occurred in orchards of the Pacific northwest in 1950 (Newcomer, 1951; O'Neill & Hantsbarger, 1951), approximately three years after parathion was first used as an acaricide. Two other species of orchard mites, the Pacific mite, Tetranychus pacificus McG., and T. mcdanieli McG., were subsequently reported to have developed parathion-resistant strains in the same area (Newcomer & Dean, 1953). Though parathion is lethal to most predacious mites and insects, Huffaker and Kennett (1953) found a difference in tolerance between species of Typhlodromus in the field and in the laboratory: T. reticulatus Oudms. was very susceptible to parathion whereas T. occidentalis Nesbitt was not appreciably affected by it.

Ella Rhoads Higginson

2021 ◽  
Keyword(s):  
World War I ◽  
New England ◽  
Pacific Northwest ◽  
Private School ◽  
White Women ◽  
White Male ◽  
Puget Sound ◽  
Her Family ◽  
The Pacific ◽  
City Newspaper

Ella Rhoads Higginson (b. 1862?–d. 1940) was born in Council Grove, Kansas, a launching point for westward movement of settler colonialists. When she was a child, her family moved to Oregon, traveling in a wagon train following the old Oregon Trail. The family eventually settled in Oregon City, where she was educated in private school. Ella’s strong interests in reading and writing began early. Her parents possessed a substantial library that included books by Irving, Longfellow, Shakespeare, and Tennyson. Ella began writing when she was eight. Her first publication, the poem “Dreams of the Past,” appeared in The Oregon City newspaper when she was fourteen. The following year she began work on The Oregon City Enterprise newspaper, learning typesetting and editorial writing. She also started publishing fiction. In 1885, she married Russell Carden Higginson, a businessman who was a cousin to New England author Thomas Wentworth Higginson. The couple moved north to Whatcom (later Bellingham), Washington, where Higginson lived for fifty-two years until her death. There she devoted herself to writing. She soon became the first influential Pacific Northwest author. People around the world were introduced to the region when they read Higginson’s award-winning writing. Her descriptions of majestic mountains, vast forests, and the scenic waters of the Puget Sound presented the then-remote, unfamiliar Pacific Northwest to eager readers. Her characterizations of white women and men who inhabited the region revealed what life was like in this part of the nation as opposed to regions such as New England. Higginson’s celebrated writings were the first to place the Pacific Northwest on the literary map. Her talent was widely recognized. The prestigious Macmillan Company, which became her publisher, approached her seeking to print her work. She was awarded prizes from magazines such as Collier’s and McClure’s. Her poems were set to music and performed internationally. She published over eight hundred works in her lifetime. However, World War I altered the means of production, resulting in books going out of print and diminishing reputations of well-known authors, especially writers of color and women. Most of Higginson’s books went out of print. After the war, new editors, mostly white men, managed US newspapers, periodicals, and publishing companies. Largely uninterested in prewar authors, they sought writing from nascent literary movements such as Modernism while also promoting works by overlooked white male authors such as Melville. Higginson’s reputation faded in the last decades of her life. By the time she was chosen first Poet Laureate of Washington State in 1931, she and her work were largely remembered only in the Pacific Northwest. When she died in 1940, she was almost completely forgotten. In the 21st century, Higginson and her writings are returning to literary distinction.

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