scholarly journals A rifted margin origin for the crescent basalts and related rocks in the northern Coast Range Volcanic Province, Washington and British Columbia

1992 ◽  
Vol 97 (B5) ◽  
pp. 6799 ◽  
Author(s):  
R. S. Babcock ◽  
R. F. Burmester ◽  
D. C. Engebretson ◽  
A. Warnock ◽  
K. P. Clark
Keyword(s):  
British Columbia ◽  
Northern Coast ◽  
Coast Range ◽  
Volcanic Province ◽  
Rifted Margin

Holocene tephras in lake cores from northern British Columbia, Canada

2008 ◽  
Vol 45 (8) ◽  
pp. 935-947 ◽  
Author(s):  
Thomas R. Lakeman ◽  
John J. Clague ◽  
Brian Menounos ◽  
Gerald D. Osborn ◽  
Britta J.L. Jensen ◽  
...  
Keyword(s):  
British Columbia ◽  
Sediment Cores ◽  
Volcanic Field ◽  
Northern Coast ◽  
Lake Area ◽  
Volcanic Province ◽  
Coast Mountains ◽  
White River ◽  
Subalpine Lakes ◽  
Lake Cores

Sediment cores recovered from alpine and subalpine lakes up to 250 km apart in northern British Columbia contain five previously unrecognized tephras. Two black phonolitic tephras, each 5–10 mm thick, occur within 2–4 cm of each other in basal sediments from seven lakes in the Finlay River – Dease Lake area. The upper and lower Finlay tephras are slightly older than 10 220 – 10 560 cal year B.P. and likely originate from two closely spaced eruptions of one or two large volcanoes in the northern Cordilleran volcanic province. The Finlay tephras occur at the transition between deglacial sediments and organic-rich postglacial mud in the lake cores and, therefore, closely delimit the termination of the Fraser Glaciation in northern British Columbia. Sediments in Bob Quinn Lake, which lies on the east edge of the northern Coast Mountains, contain two black tephras that differ in age and composition from the Finlay tephras. The lower Bob Quinn tephra is 3–4 mm thick, basaltic in composition, and is derived from an eruption in the Iskut River volcanic field about 9400 cal years ago. The upper Bob Quinn tephra is 12 mm thick, trachytic in composition, and probably 7000–8000 cal years old. A fifth tephra occurs as a cryptotephra near the top of two cores from the Finlay River area and is correlated to the east lobe of the White River tephra (ca. 1150 cal year B.P.). Although present throughout southern Yukon, the White River tephra has not previously been documented this far south in British Columbia. The tephras are valuable new isochrons for future paleoenvironmental studies in northern British Columbia.

STRUCTURE, STRATIGRAPHY, AND PALEONTOLOGY OF AN UPPER TRIASSIC SECTION ON THE WEST COAST OF BRITISH COLUMBIA

1965 ◽  
Vol 2 (5) ◽  
pp. 442-484 ◽  
Author(s):  
Donald Carlisle ◽  
Takeo Susuki
Keyword(s):  
British Columbia ◽  
Structural Information ◽  
Pillow Lava ◽  
Middle Part ◽  
Upper Triassic ◽  
Coast Range ◽  
Thermal Alteration ◽  
The West ◽  
Coastal British Columbia ◽  
Sedimentary Unit

The highly deformed section at Open Bay is one of the few good exposures of a thick sedimentary unit within the prebatholithic rocks along coastal British Columbia. It provides new structural information relating to emplacement of a part of the Coast Range batholith and it contains an important Upper Triassic fauna unusually well represented. Structural and paleontological analyses are mutually supporting and are purposely combined in one paper.Thirteen ammonite genera from 14 localities clearly substantiate McLearn's tentative assignment to the Tropites subbullatus zone (Upper Karnian) and suggest a restriction to the T. dilleri subzone as defined in northern California.Contrary to an earlier view, the beds are lithologically similar across the whole bay except for variations in the intensity of deformation and thermal alteration. Their contact with slightly older relatively undeformed flows is apparently a zone of dislocation. Stratigraphic thicknesses cannot be measured with confidence, and subdivision into "Marble Bay Formation" and "Open Bay Group" cannot be accepted. Open Bay Formation is redefined to include all the folded marble and interbedded pillow lava at Open Bay. Lithologic and biostratigraphic correlation is suggested with the lower middle part of the Quatsino Formation on Iron River, 24 miles to the southwest. Basalt flows and pillowed volcanics west of Open Bay are correlated with the Texada Formation within the Karmutsen Group.The predominant folding is shown to precede, accompany, and follow intrusion of numerous andesitic pods and to precede emplacement of quartz diorite of the batholith. Structural asymmetry is shown to have originated through gentle cross-folding and emplacement of minor intrusives during deformation.

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.

scholarly journals VII.—Mesozoic Volcanic Rocks of British Columbia and Chile. Relation of Volcanic and Metamorphic Rocks

1877 ◽  
Vol 4 (7) ◽  
pp. 314-317
Author(s):  
George M. Dawson
Keyword(s):  
British Columbia ◽  
South America ◽  
Volcanic Rocks ◽  
Geological Survey ◽  
Metamorphic Rocks ◽  
Coast Range ◽  
Similar Relation

In Chile and adjacent regions of South America, Mr. Darwin, in his “Geological Observations,” has described a great series of Mesozoic rocks, which he calls the “porphyritic formation,” and which shows an interesting resemblance to certain rocks in British Columbia. These I had provisionally designated in my report in connexion with the Geological Survey of Canada for 1875, as the Porphyrite series, without at the time remembering Mr. Darwin's name for the Chilian rocks. Many of Mr. Darwin's descriptions of the rocks of Chile would apply word for word to those of British Columbia, where the formation would also appear to bear a somewhat similar relation to the Cascade or Coast Range, which that of Chile does to the Cordillera.

THE NYMPH OF CINYGMA INTEGRUM AND DESCRIPTION OF A NEW HEPTAGENINE GENUS

1933 ◽  
Vol 65 (4) ◽  
pp. 73-77 ◽  
Author(s):  
J. McDunnough
Keyword(s):  
British Columbia ◽  
Coast Range ◽  
Female Adult ◽  
Structural Details

The species, integrum Eaton, described from material collected in Washington and Oregon states, was designated by Eaton as the genotype of Cinygma. I have already (1926, Can. Ent. LVIII, 302) recorded the capture of adults of this species in the Coast range of British Columbia and at the time expressed some doubt as to whether all the species at present included in this genus were strictly congeneric. Since nymphal structures have been recognized by a number of recent workers as of great importance in furnishing distinguishing characters in the Heptagenine genera it was with considerable interest that I discovered among material collected in the Hope Mts., B. C. in 1932 by my assistant, Mr. A. N. Gartrell, a bred female adult of integrum, together with its nymphal exuvia, preserved in alcohol. A study of this exuvia soon convinced me that in the nymphal gills and mouth-parts there are excellent and in part unique structural details which should at once establish not only the validity of the genus but also its limitations and position in the group of allied genera.

Sign in / Sign up

Export Citation Format

Share Document