Imbricated terranes of the Cariboo gold belt with correlations and implications for tectonics in southeastern British Columbia

1986 ◽  
Vol 23 (8) ◽  
pp. 1047-1061 ◽  
Author(s):  
L. C. Struik
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Rocky Mountains ◽  
Rocky Mountain ◽  
East Central ◽  
Pillow Basalt ◽  
Shelf Sediments ◽  
Kootenay Lake ◽  
Southern Rocky Mountain ◽  
Bounded Sequences

The Cariboo gold belt of east-central British Columbia is divided into four fault-bounded sequences of distinct stratigraphy. They are, from east to west, the Cariboo (continental-shelf sediments), Barkerville (continental-shelf sediments and intercalated volcanics), Slide Mountain (rift-related submarine pillow basalt, chert, and diorite) and Quesnel (island-arc sediments and subaqueous volcanics) terranes. Each is separated from others by thrust faults. Grit, phyllite, limestone, and volcanics of the Barkerville terrane may be correlative with the Eagle Bay Formation near Adams Lake and the Lardeau Group near Kootenay Lake. Barkerville terrane may be part of a more regional rock package, Selkirk terrane, which is defined to include Kootenay terrane, Badshot Formation, and Horsethief Creek and Hamill groups. Selkirk terrane is (i) separated everywhere by a low-angle fault from the overlying age-equivalent but stratigraphically and structurally different Cariboo terrane and (ii) separated by a system of faults in the general location of the Southern Rocky Mountain Trench from the age-equivalent but stratigraphically and structurally different North American terrane of the Rocky Mountains.

THE ATHABASCA VALLEY ERRATICS TRAIN, ALBERTA AND PLEISTOCENE ICE MOVEMENTS ACROSS THE CONTINENTAL DIVIDE

1967 ◽  
Vol 4 (4) ◽  
pp. 625-632 ◽  
Author(s):  
M. A. Roed ◽  
E. W. Mountjoy ◽  
N. W. Rutter
Keyword(s):  
British Columbia ◽  
Rocky Mountains ◽  
Late Stage ◽  
National Park ◽  
Rocky Mountain ◽  
Metamorphic Rocks ◽  
Jasper National Park ◽  
Continental Divide ◽  
Park Area

The Athabasca Valley Erratics Train contains a variety of low- to medium- grade metamorphic rocks, the most abundant of which is talcose schist, with lesser amounts of garnet schist and biotite–quartz schist. This erratics train occurs in and west of the Athabasca Valley west of Edson, Alberta. It is probably a late stage deposit of the same glacier that carried and deposited the Erratics Train, Foothills of Alberta. The metamorphic erratics were incorporated into a glacier that originated in the northern part of the Monashee Mountains and Premier Range of British Columbia. This ice movement is also recorded by numerous U-shaped valleys, which extend across the Continental Divide. Thus, during a brief period in late(?) Wisconsin time, the Cordilleran ice in the Rocky Mountains of the Jasper National Park area was partly derived from west of the Continental Divide and the Rocky Mountain Trench. These data agree with the inferred ice movements shown on the 1958 Glacial Map of Canada.

Archaeocyathids and the Lower Cambrian Continental Shelf of the Canadian Cordillera

1975 ◽  
Vol 12 (12) ◽  
pp. 2014-2020 ◽  
Author(s):  
C. R. Stelck ◽  
A. S. Hedinger
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Lower Cambrian ◽  
Rocky Mountain ◽  
Canadian Cordillera ◽  
Western Canada ◽  
Early Cambrian ◽  
Structural Trend ◽  
East And West

The geographic occurrences of archaeocyathids are plotted for the Cordilleran region of western Canada. The archaeocyathids are found both east and west of, and within the Rocky Mountain Trench in British Columbia and are found east and west of the Tintina Trench in the southern Yukon. The overall pattern of the occurrences indicates that the shallow neritic portion of the continental shelf in Early Cambrian time traces a pattern widely diverse from that of the later, superimposed, Laramide structural trend. Portions of the continental shelf were already in existence west of the Rocky Mountain Trench by Early Cambrian time.

Geochemistry of the gneissic basement complex near Valemount, British Columbia: further evidence for a varied origin

1988 ◽  
Vol 25 (11) ◽  
pp. 1725-1739 ◽  
Author(s):  
V. E. Chamberlain ◽  
R. St J. Lambert ◽  
M. J. M. Duke ◽  
J. G. Holland
Keyword(s):  
British Columbia ◽  
Rocky Mountain ◽  
Small Scale ◽  
Basement Complex ◽  
X Ray ◽  
Low Magnesium ◽  
Upper Proterozoic ◽  
Four Blocks ◽  
Southern Rocky Mountain ◽  
Representative Samples

Rare-earth elements and other trace elements have been determined by activation analysis and X-ray fluorescence for representative samples from each of the four blocks of basement gneisses near Valemount, eastern British Columbia. Patterns in mafic and tonalitic gneisses are generally as expected, but the granite–gneisses have very large negative europium anomalies, up to Eu*/Eu = 18, indicating multistage histories involving plagioclase fractionation. Modelling shows that plagioclase fractionation alone is insufficient to account for these anomalies without intervention of other phases: apatite control is suggested, among other possibilities. The granite–gneisses also contain exceptionally low magnesium (0.1–0.2%), phosphorus (<300 ppm), scandium (<0.07 ppm), and cesium (<0.5 ppm). After partial melting is considered as a possible mode of origin, it is concluded that the granite–gneisses are final, small-scale fractionates from enriched tholeiite magmas. These might be associated with upper Proterozoic rifting processes. Previously published conclusions regarding the protolith of each subset of the gneisses are confirmed; likewise, the earlier conclusion that the gneisses cannot be correlated across the Southern Rocky Mountain Trench is substantiated in detail.

Geology, Paleoecology, and Palynology of some Oligocene Rocks in the Rocky Mountain Trench of British Columbia

1972 ◽  
Vol 9 (4) ◽  
pp. 460-470 ◽  
Author(s):  
W. S. Hopkins Jr. ◽  
N. W. Rutter ◽  
G. E. Rouse
Keyword(s):  
British Columbia ◽  
Rocky Mountains ◽  
Sedimentary Rocks ◽  
Rocky Mountain ◽  
Early Oligocene ◽  
Pollen Content

Mildly deformed sedimentary rocks of the Northern Rocky Mountain Trench were analyzed for their spore and pollen content. From these it was deduced that the rocks were of Early Oligocene (Chadronian) age. Two conclusions were reached: (1) at least mild deformation occurred in this portion of the Trench following the Early Oligocene and (2) Early Oligocene climate appears to have been essentially subtropical of a summer-wet, winter-dry type. These add further evidence to the theory that the Rocky Mountains were already of considerable elevation by Early Oligocene time.

Geochemistry, geochronology, and tectonic implications of two quartz monzonite intrusions, Purcell Mountains, southeastern British Columbia

1988 ◽  
Vol 25 (1) ◽  
pp. 106-115 ◽  
Author(s):  
Trygve Höy ◽  
P. van der Heyden
Keyword(s):  
British Columbia ◽  
Rocky Mountains ◽  
Tectonic Evolution ◽  
Rocky Mountain ◽  
Normal Fault ◽  
Thrust Faults ◽  
Quartz Monzonite ◽  
Reverse Thrust ◽  
Early Late ◽  
Middle Proterozoic

The Reade Lake and Kiakho stocks are posttectonic mesozonal quartz monzonite porphyries that intrude dominantly Middle Proterozoic Purcell Supergroup rocks in southeastern British Columbia. K–Ar dates of hornblende from the Reade Lake stock range from 103 to 143 Ma. However, a U–Pb date of 94 Ma from zircon concentrates is interpreted to be the age of emplacement of the stock, suggesting the range and older K–Ar dates are due to excess 40Ar. A K–Ar date of 122 Ma for the hornblende from the Kiakho stock is believed to be a more reliable intrusive age.Both stocks cut across and apparently seal two faults that have played roles in the tectonic evolution of the Purcell anticlinorium and Rocky Mountain thrust belt. The Reade Lake stock cuts the St. Mary fault, an east-trending reverse thrust that crosses the Rocky Mountain trench and links with thrusts in the Rocky Mountains; the Kiakho stock cuts the Cranbrook fault, an older east-trending normal fault. Hence, the 94 Ma date on the Reade Lake stock constrains the latest movement on the St. Mary fault to early Late Cretaceous; and the 122 Ma date on the Kiakho stock appears to limit latest movement on the Cranbrook fault to Early Cretaceous. These faults and the intrusions are part of an allochthonous package, displaced eastward by underlying thrust faults during formation of the Purcell anticlinorium and more eastern thrusts in the Rocky Mountains.

Structure and Dynamics of the Southern Rocky Mountain Trench near Valemount, British Columbia, Inferred from Local Seismicity

2021 ◽  
Author(s):  
Joshua C. S. Purba ◽  
Hersh Gilbert ◽  
Jan Dettmer
Keyword(s):  
British Columbia ◽  
Correlation Coefficients ◽  
Rocky Mountain ◽  
Earthquake Catalog ◽  
P Waves ◽  
Local Seismicity ◽  
Subsurface Structures ◽  
Level Of Activity ◽  
And Shifts ◽  
Southern Rocky Mountain

Abstract Stretching nearly the extent of the Canadian Cordillera, the Rocky Mountain trench (RMT) forms one of the longest valleys on Earth. Yet, the level of seismicity, and style of faulting, on the RMT remains poorly known. We assess earthquakes in the southern RMT using a temporary network of seismometers around Valemount, British Columbia, and identify active structures using a probabilistic earthquake catalog spanning from September 2017 to August 2018. Together with results from earlier geological and seismic studies, our new earthquake catalog provides a constraint on the geometry of subsurface faults and their level of activity during a year of recording. The tectonic analysis presented here benefits from the catalog of 47 earthquakes, including robust horizontal and vertical uncertainty quantification. The westward dip of the southern RMT fault is one of the prominent subsurface structures that we observe. The seismicity observed here occurs on smaller surrounding faults away from the RMT and shifts from the east to the west of the trench from north to south of Valemount. The change in distribution of earthquakes follows changes in the style of deformation along the length of the RMT. Focal mechanisms calculated for two earthquakes with particularly clear waveforms reveal northeast–southwest-oriented thrusting. The seismicity reveals a change in the pattern of deformation from narrowly focused transpression north of Valemount to more broadly distributed activity in an area characterized by normal faulting to the south. Six sets of repeating events detected here produce similar waveforms whose P waves exhibit correlation coefficients that exceed 0.7 and may result from the migration of fluids through the fractured crust.

Late Quaternary Sediments and Geomorphic History of the Southern Rocky Mountain Trench, British Columbia

1975 ◽  
Vol 12 (4) ◽  
pp. 595-605 ◽  
Author(s):  
John J. Clague
Keyword(s):  
British Columbia ◽  
Short Duration ◽  
Late Quaternary ◽  
Lacustrine Sediments ◽  
Rocky Mountain ◽  
Quaternary Sediments ◽  
Glacier Recession ◽  
History Of ◽  
Cordilleran Ice Sheet ◽  
Southern Rocky Mountain

The southern Rocky Mountain Trench was a major outlet valley of the Cordilleran Ice Sheet. Quaternary sediments underlying the floor of the trench in southeastern British Columbia consist mainly of glacial, glaciofluvial, and glaciolacustrine materials deposited during the Fraser (Pinedale) Glaciation, and fluvial and lacustrine sediments deposited during the preceding interglaciation.Deposits of three stades and two intervening nonglacial intervals are recognized. Interglacial sediments which contain wood dated at 26 800 ± 1000 y B.P. underlie drift of the early stade. During the interval between the early and middle stades, the Rocky Mountain Trench in southeastern British Columbia probably was completely deglaciated, and sediments were deposited in one or more lakes on the floor of the trench. In contrast, glacier recession between the middle and late stades was of short duration and extent; glaciolacustrine sediments were deposited only along the margins of the Rocky Mountain Trench, and apparently residual ice remained in the center of the valley. Final recession of the trunk glacier occurred prior to 10 000 y B.P. with no major halts and without significant stagnation of the terminus.

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