Provenance of Albian–Cenomanian rocks of the Methow and Tyaughton basins, southern British Columbia: a mid-Cretaceous link between North America and the Insular terrane

1992 ◽  
Vol 29 (6) ◽  
pp. 1274-1295 ◽  
Author(s):  
John Irwin Garver
Keyword(s):  
British Columbia ◽  
North America ◽  
Volcanic Rock ◽  
Basin Analysis ◽  
The West ◽  
Dominant Source ◽  
Rock Fragments ◽  
Metasedimentary Rocks ◽  
Taylor Creek ◽  
Topographic High

Basin analysis of Albian–Cenomanian rocks of the Tyaughton and Methow basins suggests that the two basins were filled by three principle petrofacies during a regionally significant contractional event. The Volcanic petrofacies, which occurs only in the Tyaughton basin, comprises west-derived volcaniclastic strata. This petrofacies is dominated by intermediate volcanic clasts and minor metavolcanic, sedimentary, and plutonic clasts. This petrofacies and correlatives to the west (Taylor Creek volcanics and the Gambier Group) are inferred to have been a volcanic cover and volcaniclastic apron to the Insular terrane.The Cherry petrofacies occurs in both the Tyaughton and the Methow basins. Paleocurrents suggest that these chert-rich sediments were shed both east and west off a topographic high that separated the two basins. The Cherry petrofacies is dominated by chert-lithic detritus with subordinate sedimentary and volcanic rock fragments. Locally, the petrofacies is characterized by clasts of chert, greenstone, serpentinite, and blueschist; all these lithologies are common in the unconformably underlying Bridge River terrane, which is inferred to have been the dominant source terrane.Rocks that contain the Arkosic petrofacies are 3–8 km thick in the Methow basin, but only a thin unit is present in the Tyaughton basin. This petrofacies is rich in quartz and feldspar, with lesser quantities of volcanic lithic and metamorphic lithic fragments. Detrital muscovite, which is the hallmark of this petrofacies, is interpreted to have been derived from granitic and metasedimentary rocks to the east. This petrofacies is interpreted to have been largely derived from the Omineca Crystalline Belt, which was rapidly uplifting during this time. The three petrofacies in the two basins provide the first provenance link between the Insular terrane to the west to what was then North America (Omineca Crystalline Belt and the Intermontane Belt) to the east; juxtaposition is inferred to have occurred in a contractional setting.

The Lower Jurassic phosphorites of southeastern British Columbia and terrane accretion to western North America

1989 ◽  
Vol 26 (8) ◽  
pp. 1612-1616 ◽  
Author(s):  
T. P. Poulton ◽  
J. D. Aitken
Keyword(s):  
British Columbia ◽  
North America ◽  
Oceanic Crust ◽  
West Coast ◽  
Cold Water ◽  
Lower Jurassic ◽  
Depositional Model ◽  
Western North America ◽  
The West ◽  
Terrane Accretion

Sinemurian phosphorites in southeastern British Columbia and southwestern Alberta conform with the "West Coast type" phosphorite depositional model. The model indicates that they were deposited on or near the Early Jurassic western cratonic margin, next to a sea or trough from which cold water upwelled. This suggests that the allochthonous terrane Quesnellia lay well offshore in Sinemurian time. The sea separating Quesnellia from North America was partly floored by oceanic crust ("Eastern Terrane") and partly by a thick sequence of rifted, continental terrace wedge rocks comprising the Purcell Supergroup and overlying Paleozoic sequence. This sequence must have been depressed sufficiently that access of upwelling deep currents to the phosphorite depositional area was not impeded.

RECORDS OF SOME SPECIES OF POLYCHAETA NEW TO BRITISH COLUMBIA AND OF EXTENSIONS IN DISTRIBUTION OF SOME OTHERS

1966 ◽  
Vol 44 (5) ◽  
pp. 839-849 ◽  
Author(s):  
C. Berkeley
Keyword(s):  
British Columbia ◽  
North America ◽  
West Coast ◽  
Vancouver Island ◽  
The Other ◽  
The West ◽  
New Subspecies ◽  
Northeast Pacific ◽  
Considerable Depth ◽  
Geographical Locations

Twenty-five species of Polychaeta recently collected off the coast of British Columbia are discussed. Most were taken in waters of considerable depth off the west coast of Vancouver Island. Sixteen are new to British Columbia. Most of these are known from farther south on the west coast of North America, but some from much shallower depths than those from which they are now recorded; two of them are new to the northeast Pacific; one is a new subspecies. The other nine have been previously known from British Columbia, but they are now recorded from much greater depths than hitherto, or in new geographical locations.

scholarly journals II.—Sketch of the Geology of British Columbia

1881 ◽  
Vol 8 (4) ◽  
pp. 156-162
Author(s):  
George M. Dawson
Keyword(s):  
British Columbia ◽  
North America ◽  
West Coast ◽  
Geological Survey ◽  
Personal Knowledge ◽  
Territorial Disputes ◽  
The West ◽  
Coast Line ◽  
Geological Features

Twenty years ago the region now included in the Province of British Columbia was—with the exception of the coast-line— little known geographically, and quite unknown geologically. From the days of Cook and Vancouver, and the old territorial disputes with the Spaniards, this part of the west coast of North America attracted little attention till the discovery of gold in 1858. As among the first in the field geologically may be mentioned Dr. Hector and Messrs. H. Bauerman and G. Gibbs. The observations of these gentlemen, though bringing to light many facts of interest, were confined to a comparatively small part of the area of the province, and it was not till the inclusion of British Columbia in the Dominion of Canada in 1871 that the systematic operations of the Geological Survey of Canada were extended to this region. Since this date a number of reports treating of the geology of British Columbia have been published, and on these, together with a personal knowledge of the country, obtained during five seasons' work in it in connexion with the Survey, I shall chiefly depend in giving a brief account of the main geological features so far developed.

POLYCHAETA FROM BRITISH COLUMBIA; WITH A NOTE ON SOME WESTERN CANADIAN ARCTIC FORMS

1962 ◽  
Vol 40 (4) ◽  
pp. 571-577 ◽  
Author(s):  
E. Berkeley ◽  
C. Berkeley
Keyword(s):  
British Columbia ◽  
North America ◽  
West Coast ◽  
Canadian Arctic ◽  
The West

Nine species of Polychaeta collected off the coast of British Columbia are recorded. Two of these (Micromaldane ornithochaeta and Notomastus lineatus var. balanoglossi) have not been reported previously outside Europe, one (Asychis biceps) is new to the west coast of North America, and four are new to British Columbia. Six species are recorded from the neighborhood of Herschell Island in the western Canadian Arctic. All are new to that region, though known from further western seas, and, in three cases (Melaenis loveni, Antinoella sarsi, and Nephthys malmgreni) from the western Canadian Arctic further east.

Magnetism and age of the Porteau Pluton, southern Coast Belt, British Columbia: evidence for tilt and translation

1995 ◽  
Vol 32 (4) ◽  
pp. 380-392 ◽  
Author(s):  
E. Irving ◽  
J. Baker ◽  
N. Wright ◽  
C. J. Yorath ◽  
R. J. Enkin ◽  
...  
Keyword(s):  
British Columbia ◽  
North America ◽  
Coercive Force ◽  
The Body ◽  
Canadian Cordillera ◽  
Southern Coast ◽  
The South ◽  
The West ◽  
Zircon Age ◽  
Minimum Estimate

The Porteau Pluton is a variably foliated quartz diorite to granodiorite intrusion in the southern Coast Belt of the Canadian Cordillera (49.6°N, 123.2°W). 40Ar/39Ar ages are 95 ± 5 Ma from biotite and 101.5 ± 0.7 Ma from hornblende, which, together with an earlier U–Pb zircon age of 100 ± 2 Ma, indicate that the body was emplaced, uplifted, and cooled rapidly in mid-Cretaceous time. The rocks contain high coercive force (hard) remanent magnetizations with unblocking temperatures between 500 and 600 °C, close to those of Ar in hornblende, indicating that remanence was acquired at or close to the hornblende plateau age. The hard remanence directions have an elongate distribution, in agreement with the predictions of M.E. Beck regarding magnetization acquired during tilting, uplift, and cooling of plutons. No part of the distribution agrees with the direction expected from observations from rocks of mid-Cretaceous age from cratonic North America. The elongate distribution defines the axis of tilt (347° east of north) but not its direction; tilt could have been down toward the east or down toward the west. The former yields an inclination that is 29.0 ± 4.9° shallower than expected from cratonic observations, corresponding to a displacement from the south of 3200 ± 500 km. The latter reconstruction yields an inclination that is anomalously shallow by 14.8 ± 3.9°, corresponding to a displacement from the south of 1600 ± 400 km, which is a minimum estimate. It is argued, therefore, that the Porteau Pluton has undergone both tilt and displacement from the south by distances substantially in excess of 1000 km.

scholarly journals A Hybrid Precipitation Index Inspired by the SPI, PDSI, and MCDI. Part II: Application to Investigate Precipitation Variability along the West Coast of North America

2020 ◽  
Vol 21 (9) ◽  
pp. 1977-2002 ◽  
Author(s):  
Dudley B. Chelton ◽  
Craig M. Risien
Keyword(s):  
British Columbia ◽  
North America ◽  
Time Scales ◽  
West Coast ◽  
Time Scale ◽  
Opposite Sign ◽  
Precipitation Variability ◽  
The West ◽  
Southeast Alaska ◽  
Precipitation Anomalies

AbstractThe hybrid precipitation index developed in Part I of this study is applied to investigate precipitation variability along the west coast of North America during the wet season November–March on monthly-to-interannual time scales. The variability in each of six regions considered in this study is negatively correlated with nearby 500-hPa geopotential height anomalies. Except in Southeast Alaska, these correlation patterns indicate that precipitation variability in each region is predominantly influenced by local atmospheric forcing analogous to the ridging of the westerly flow that has been studied extensively with regard to California drought variability. The first empirical orthogonal function (EOF) accounts for nearly all of the Southeast Alaska precipitation variability, which is controlled by the strength of the onshore flow rather than ridging. In association with this mode of variability, precipitation anomalies of opposite sign account for about 40% of the precipitation variance in Northern California and Oregon on all time scales. On short time scales, the second and third EOFs account primarily for precipitation variability in British Columbia/Washington and California, respectively. With increasing time scale, the third EOF diminishes in importance and the second EOF evolves into a pattern of synchronous precipitation anomalies of the same sign from British Columbia to Northern California. Precipitation variability in Southern California is only modestly related to precipitation elsewhere. With increasing time scale, Southern California precipitation variability becomes increasingly related to precipitation anomalies of opposite sign in Washington.

New and interesting seaweed records from the Hakai area of the central coast of British Columbia, Canada: Chlorophyta

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sandra C. Lindstrom ◽  
Matthew A. Lemay ◽  
Samuel Starko ◽  
Katharine R. Hind ◽  
Patrick T. Martone
Keyword(s):  
British Columbia ◽  
North America ◽  
Dna Sequences ◽  
West Coast ◽  
Undescribed Species ◽  
The West ◽  
Central Coast ◽  
Japanese Species ◽  
Green Macroalgae ◽  
Northeast Pacific

Abstract Since 2011 we have been documenting seaweed diversity and abundance along a poorly studied area of the central coast of British Columbia, Canada. This first installment focuses on the Chlorophyta. To date, 42 species have been recorded, and we have obtained DNA sequences for most. Although most of these species reportedly have wide distributions along the west coast of North America, others appear to represent new northern or southern records or possible introductions, and a number have yet to be described. New southern limits are recorded for Acrosiphonia sonderi, Acrosiphonia sp., Protomonostroma undulatum, and Ulva pouliotii sp. nov., and new northern records are documented for Ulva expansa, U. stenophylla, and another undescribed species of Ulva. Among species of Cladophoraceae, we obtained a sequence only for Cladophora opaca, a Japanese species not previously recorded from North America, and an undetermined species of Rhizoclonium. We sequenced three species of Derbesia, none of which is D. marina, the currently recognized species for this area; all three require taxonomic treatment. A sequence for a shell-boring species, which is tentatively identified as Eugomontia sacculata, was also obtained. These findings extend our understanding of the diversity and biogeography of green macroalgae in the northeast Pacific.

Sedimentology of Archean Turbidites at Yellowknife, Northwest Territories

1972 ◽  
Vol 9 (7) ◽  
pp. 882-902 ◽  
Author(s):  
John B. Henderson
Keyword(s):  
Chemical Composition ◽  
Volcanic Rock ◽  
Sedimentary Basin ◽  
Granitic Rock ◽  
Considerable Extent ◽  
The West ◽  
Submarine Fan ◽  
Rock Fragments ◽  
Granitic Terrain ◽  
Silicic Volcanic

The Burwash Formation is a major formation of the Archean Yellowknife Supergroup at Yellowknife. It consists of about 15 000 ft (4572 m) of interbedded graywackes and mudstones and shows many of the features characteristic of turbidites. Analysis of the internal sedimentary structures and paleocurrent data on the sediments indicate that the sediments were derived from the west, possibly from an area now occupied by an extensive granitic terrain, and accumulated in depositional fan valleys on a submarine fan complex near the margin of a large Archean sedimentary basin that lies to the east of Yellowknife. The high proportion of volcanic rock fragments, particularly silicic–volcanic lithic clasts, along with abundant quartz and feldspar and the minor but ubiquitous granitic rock fragments in the graywackes, indicates a mixed silicic–volcanic and granitic provenance. The modal and chemical composition, and volumetric abundance, of these sediments denotes the presence, and considerable extent, of sialic crust prior to the deposition of the Burwash Formation.

Deformation of the western margin of the Omineca Belt near Crooked Lake, east-central British Columbia

1990 ◽  
Vol 27 (3) ◽  
pp. 414-425
Author(s):  
Jeffrey A. Fillipone ◽  
John V. Ross
Keyword(s):  
British Columbia ◽  
North America ◽  
Middle Jurassic ◽  
Phase 1 ◽  
Late Devonian ◽  
East Central ◽  
Western Margin ◽  
Metasedimentary Rocks ◽  
Narrow Zone ◽  
Minimum Age

The western margin of the Omineca Belt near Crooked Lake, British Columbia, consists of metasedimentary rocks (Snowshoe Group) and orthogneisses of the Barkerville terrane, structurally overlain by a mafic volcanic – sedimentary package of rocks belonging to the allochthonous Slide Mountain (Crooked Amphibolite) and Quesnel terranes (Triassic phyllite and Nicola Group). At least two episodes of regional deformational (phases 2 and 3) affected this composite package. Deformation and metamorphism (phase 1) in the Snowshow Group predate the formation of this package and are nowhere evident within the allochthonous terranes.Middle Jurassic metamorphism ranging from chlorite zone through sillimanite zone affected all units. Isograds are folded, together with the junction between the terranes, indicating that the metamorphic assemblages developed prior to folding of this boundary. Granitic orthogneiss (Boss Mountain, Quesnel Lake, and Perseus gneisses), having a minimum age of Late Devonian to Early Pennsylvanian, was intruded into and deformed with the Snowshoe Group during the earliest recognizable phase of deformation in the Barkerville terrane (phase 1). Slide Mountain terrane rocks occupy a narrow zone where large eastward displacement occurred during overthrusting of the Intermontane superterrane upon the western margin of North America in Middle Jurassic time.

Extreme Precipitation over the West Coast of North America: Is There a Trend?

2011 ◽  
Vol 12 (2) ◽  
pp. 310-318 ◽  
Author(s):  
Clifford Mass ◽  
Adam Skalenakis ◽  
Michael Warner
Keyword(s):  
British Columbia ◽  
North America ◽  
West Coast ◽  
Heavy Precipitation ◽  
Northern California ◽  
The West ◽  
Modest Increase ◽  
The Past ◽  
Daily Discharge ◽  
Precipitation Events

Abstract Heavy precipitation and the resulting flooding are the most serious weather-related hazards over the west coast of North America. This paper analyzes the trends in heavy precipitation for the period 1950–2009 by examining the decadal distributions of the top 60, 40, and 20 two-day precipitation events for a collection of stations along the coastal zone of the United States and British Columbia, as well as the decadal distribution of maximum daily discharge for unregulated rivers from northern California to Washington State. During the past 60 years there has been a modest increase in heavy precipitation events over southern and central coastal California, a decline in heavy events from northern California through the central Oregon coast, a substantial increase in major events over Washington, and a modest increase over coastal British Columbia. Most of these trends are not significantly different from zero at the 95% level. The trends in maximum daily discharge of unregulated rivers are consistent with the above pattern, with increasing discharges over the past three decades over Washington and northern Oregon and declines over the remainder of Oregon and northern California. Finally, the above trends in heavy rainfall and daily discharge are compared to the future patterns indicated by general circulation models under various global warming scenarios.

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