Cyclic sedimentation in the Eocene Allenby Formation of south-central British Columbia and the origin of the Princeton Chert fossil beds

2011 ◽  
Vol 48 (1) ◽  
pp. 25-43 ◽  
Author(s):  
George E. Mustoe
Keyword(s):  
British Columbia ◽  
Bituminous Coal ◽  
Open Water ◽  
Carbonaceous Shale ◽  
Dissolved Silica ◽  
South Central ◽  
Metavolcanic Rocks ◽  
Half Graben ◽  
Volcanic Debris

Extensive deposits of Eocene conglomerate, sandstone, shale, and sub-bituminous coal occur within a half-graben at Princeton, British Columbia. These strata comprise ∼2000 m of fluvial sediment interbedded with tephra and volcanic flows. Near the southeast margin of the basin, ∼200 m of rhythmically bedded strata are exposed along the Similkameen River. Cyclic deposition resulted from repeated episodes of hydrologic and topographic change related to seismic activity along the Boundary Fault on the east flank of the Princeton Basin, where Allenby Formation sediments are juxtaposed against metamorphic and metavolcanic rocks of the Upper Triassic Nicola Group. Interbedded carbonaceous shale and tuffaceous sandstone record influxes of distal lahar deposits into a lowland swamp. Coal–breccia transitions originated when debris flows along the scarp carried volcanic debris into adjacent wetlands. Coal–chert rhythmites are inferred to be evidence of hydrologic changes associated with floodplain tilt events that caused lowland to repeatedly alternate between a stagnant pond (“fen”) and a stream-fed lake. During fen stages, peat was silicified in situ from percolation of groundwater carrying silica dissolved from underlying tuffaceous beds. Episodic influxes of stream flow reduced dissolved silica concentrations and caused increases in dissolved oxygen levels. These geochemical changes caused organic matter that accumulated during these conditions of open water circulation to remain unsilicified and susceptible to partial maceration. Diagenesis eventually converted these deposits to alternating beds of sub-bituminous coal intercalated with chert horizons.

An Early Pleistocene proglacial succession in south-central British Columbia

1986 ◽  
Vol 23 (11) ◽  
pp. 1796-1803 ◽  
Author(s):  
W. H. Mathews ◽  
G. E. Rouse
Keyword(s):  
British Columbia ◽  
Early Pleistocene ◽  
Fraser River ◽  
High Mountains ◽  
South Central ◽  
Metavolcanic Rocks ◽  
Glacial Stage ◽  
Sedimentary Succession ◽  
Basaltic Lavas

A succession of conglomerates, sandstones, siltstones, and tills, herein named the Dog Creek Formation, is sandwiched between flat-lying basalts along Dog Creek (lat. 51°36′N, long. 122°02′–122°12′W) for about 15 km east of Fraser River. The sedimentary succession rests disconformably on underlying basaltic lavas (herein referred to as the Harpers Creek Formation), which have yielded K–Ar dates of 1.3–2.9 Ma, and in one place, on a glaciated surface carved in metavolcanic rocks of Permian(?) age. The sedimentary succession is capped by basalt flows yielding K–Ar whole-rock ages of 1.1 Ma. The occurrence of proglacial beds and a glaciated surface in south-central British Columbia, 70 km away from any high mountains capable of supporting glaciers today, testifies to a major glacial stage in Early Pleistocene time. The record of sedimentation and volcanism sheds light on early incision of the nearby valley of Fraser River.

scholarly journals Post-glacial diatom-inferred aquatic changes in Sicamous Creek Lake, British Columbia, Canada

2014 ◽  
Vol 27 (3) ◽  
pp. 233-256 ◽  
Author(s):  
Andrea C. Voit ◽  
Richard J. Hebda ◽  
Julien M.J. Racca ◽  
Reinhard Pienitz ◽  
Ian R. Walker ◽  
...  
Keyword(s):  
British Columbia ◽  
Open Water ◽  
Late Glacial ◽  
High Elevation ◽  
Low Light ◽  
Subalpine Fir ◽  
Engelmann Spruce ◽  
South Central ◽  
Inferred Ph

Diatom analyses of sediments from a high elevation lake situated in an Engelmann Spruce - Subalpine Fir (ESSF) forest of south-central British Columbia, Canada, reveal long-term climate and water chemistry change. During the transition from the late-glacial / Pleistocene to the xerothermic early Holocene, small, benthic Fragilaria diatoms species that grew under low light conditions in Sicamous Creek Lake gave way to planktonic Cyclotella species that require open-water conditions. Warm temperatures in the mesothermic Holocene are indicated by smaller Cyclotella species and large, benthic pennate diatoms. Diatom communities reflected Neoglacial cooling in the late Holocene, with abundant Nitzschia fonticola and Achnanthes minutissima. Small, benthic Fragilaria regained abundance, suggesting cooling and conditions similar to the late-glacial interval. Diatom community composition responded to the deposition of the Mt. Mazama and Mt. St. Helens tephras, though the Mazama eruption caused greater change in relative abundance of various taxa within the assemblage. Correspondence analysis shows distinct communities have occurred since the initiation of sedimentation, likely due to climate controlled landscape and vegetation changes; diatom-inferred pH values using various models and training sets show limited acidification change occurred through the lake’s history.

The Gang Ranch – Big Bar area, south-central British Columbia: stratigraphy, geochronology, and palynology of the Tertiary beds and their relationship to the Fraser Fault

1984 ◽  
Vol 21 (10) ◽  
pp. 1132-1144 ◽  
Author(s):  
W. H. Mathews ◽  
G. E. Rouse
Keyword(s):  
British Columbia ◽  
Middle Eocene ◽  
Lacustrine Sediments ◽  
Fraser River ◽  
Drainage Pattern ◽  
The West ◽  
West Side ◽  
South Central ◽  
Metavolcanic Rocks ◽  
Fault Trace

Tertiary rocks in the Gang Ranch – Big Bar area, south-central British Columbia, consist of (1) Early or Middle Eocene (50 Ma) lavas, breccias, and tuffs capped by a mappable unit of conglomerate and clays, totalling 1600 m in thickness; (2) Early Miocene basalt and obsidian, only locally present on high summits; (3) Mid-Miocene gravels and tuffs estimated to be up to 300 m thick; and (4) Pliocene "plateau basalts" up to 130 m thick, locally underlain by fluvial and lacustrine sediments. A rich, probably subtropical, palynoassemblage supports the correlation of the first unit with the Kamloops Group of south-central British Columbia, and the palynomorphs from unit (3) indicate equivalence with the Fraser Bend Formation of the Quesnel area.The northwest-trending Fraser Fault transects the area. Eocene and underlying mid-Cretaceous beds are confined to the west side of the fault; Triassic metasediments and metavolcanic rocks form the east wall. The west side of the fault has been structurally lowered by at least 1.6 km in Eocene and(?) later time. Some 70 km of dextral displacement since mid-Cretaceous time is suggested but is not unequivocally demanded. Major movement has occurred since and possibly during deposition of the Eocene beds. Pliocene beds overlying the fault and Mid-Miocene beds adjacent to the fault trace are apparently undisturbed.Pliocene drainage appears to have been northward. Slight northerly tilting has occurred since, but notwithstanding this the southward-flowing Fraser River has become established here. Glacial diversion of an earlier drainage pattern is suspected.

scholarly journals Conservation Evaluation of Lemmon's Holly Fern, Polystichum lemmonii, a Threatened Fern in Canada

2004 ◽  
Vol 118 (2) ◽  
pp. 164
Author(s):  
George W. Douglas
Keyword(s):  
British Columbia ◽  
Road Construction ◽  
Montane Forest ◽  
Mountain Area ◽  
Forest Road ◽  
South Central ◽  
Northern Idaho ◽  
Mining Exploration ◽  
Conservation Evaluation ◽  
Forest Road Construction

In Canada, Lemmon's Holly Fern, Polystichum lemmonii, is restricted to the Baldy Mountain area on the eastern side of the Okanagan River valley in south-central British Columbia. This population represents the northern limits of the species which ranges south through northern Idaho, Washington and Oregon to northern California. In British Columbia, P. lemmonii is associated with ultramafic rocky ridges within a montane forest at an elevation of 1900 m. The population in the Baldy Mountain area is relatively small, unprotected and potentially imperilled by mining exploration, forest road construction or wildfires.

scholarly journals Conservation Evaluation of the Pacific Population of Dwarf Woollyheads, Psilocarphus brevissimus var. brevissimus, in Canada

2006 ◽  
Vol 120 (2) ◽  
pp. 163
Author(s):  
George W. Douglas ◽  
Jenifer L. Penny ◽  
Ksenia Barton
Keyword(s):  
British Columbia ◽  
Coalbed Methane ◽  
Groundwater Levels ◽  
Gas Drilling ◽  
Pacific Population ◽  
South Central ◽  
The Pacific ◽  
Recreational Vehicles ◽  
Forest Openings ◽  
Conservation Evaluation

In Canada, Dwarf Woolly-heads, Psilocarphus brevissimus var. brevissimus, is restricted to the Similkameen River valley, south of Princeton in southwestern British Columbia and the extreme southeast and southwest corners of Alberta and Saskatchewan, respectively. This paper deals with the three British Columbia populations which represent the northwestern limit of the species which ranges from south-central British Columbia, southward in the western United States to Montana, Idaho, Washington, Oregon, Nevada, Utah, Wyoming, California and Baja California, Mexico. In British Columbia, P. brevissimus is associated with calcareous vernal pools and ephemeral pond edges in large forest openings. This habitat is rare in the area the few existing populations could easily be extirpated or degraded through slight changes in groundwater levels, coalbed methane gas drilling, housing development or recreational vehicles.

Trap response of cutworm moths (Abagrotis orbis) to a sex-attractant lure in grape vineyards

2010 ◽  
Vol 142 (2) ◽  
pp. 135-142 ◽  
Author(s):  
Peter J. Landolt ◽  
D. Thomas Lowery ◽  
Lawrence C. Wright ◽  
Constance Smithhisler ◽  
Christelle Gúedot ◽  
...  
Keyword(s):  
British Columbia ◽  
Vitis Vinifera ◽  
Field Experiments ◽  
Sex Attractant ◽  
Early Spring ◽  
South Central ◽  
Tetradecenyl Acetate ◽  
Feltia Jaculifera ◽  
Multiple Field ◽  
Lepidoptera Noctuidae

AbstractLarvae of Abagrotis orbis (Grote) (Lepidoptera: Noctuidae) are climbing cutworms and can damage grapevines, Vitis vinifera L. (Vitaceae), in early spring by consuming expanding buds. A sex attractant would be useful for monitoring this insect in commercial vineyards. (Z)-7-Tetradecenyl acetate and (Z)-11-hexadecenyl acetate were found in extracts of female abdominal tips. In multiple field experiments, male A. orbis were captured in traps baited with a combination of these two chemicals but not in traps baited with either chemical alone. Males were trapped from mid-September to early October in south-central Washington and south-central British Columbia. Other noctuid moths (Mamestra configurata Walker, Xestia c-nigrum (L.), and Feltia jaculifera (Guenée)) were also captured in traps baited with the A. orbis pheromone and may complicate the use of this lure to monitor A. orbis. Abagrotis discoidalis (Grote) was captured in traps baited with (Z)-7-tetradecenyl acetate but not in traps baited with the two chemicals together.

scholarly journals Identifying and Characterizing Important Trembling Aspen Competitors with Juvenile Lodgepole Pine in Three South-Central British Columbia Ecosystems

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
Teresa A. Newsome ◽  
Jean L. Heineman ◽  
Amanda F. Linnell Nemec
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Geographic Range ◽  
Regression Analyses ◽  
Relative Height ◽  
Trembling Aspen ◽  
Ecosystem Productivity ◽  
Height Ratio ◽  
Critical Height ◽  
South Central

Critical height ratios for predicting competition between trembling aspen and lodgepole pine were identified in six juvenile stands in three south-central British Columbia ecosystems. We used a series of regression analyses predicting pine stem diameter from the density of neighbouring aspen in successively shorter relative height classes to identify the aspen-pine height ratio that maximizedR2. Critical height ratios varied widely among sites when stands were 8–12 years old but, by age 14–19, had converged at 1.25–1.5. MaximumR2values at age 14–19 ranged from 13.4% to 69.8%, demonstrating that the importance of aspen competition varied widely across a relatively small geographic range. Logistic regression also indicated that the risk of poor pine vigour in the presence of aspen varied between sites. Generally, the degree of competition, risk to pine vigour, and size of individual aspen contributing to the models declined along a gradient of decreasing ecosystem productivity.

Shackanite and related analcite-bearing lavas in British Columbia

1978 ◽  
Vol 15 (10) ◽  
pp. 1669-1672 ◽  
Author(s):  
B.N. Church
Keyword(s):  
British Columbia ◽  
Great Depth ◽  
Bulk Rock ◽  
Rock Composition ◽  
Bulk Rock Composition ◽  
South Central ◽  
Early Tertiary ◽  
Broad Field ◽  
New Localities

New localities of shackanite and related analcite-bearing lavas have been discovered in a broad field of early Tertiary phonolite and mafic phonolite in south-central British Columbia. The development of primary and secondary analcite in these rocks is probably the result of cooling lava during and shortly after extrusion.The possibility of leucite to analcite transformation in Daly's shackanite is unlikely because of lack of petrographic evidence and a preponderance of Na2O over K2O in bulk rock composition. It is also unlikely that analcite, and particularly groundmass analcite, crystallized at great depth and was transported to surface during eruption.

Paleomagnetism of the Triassic Nikolai Greenstone, McCarthy Quadrangle, Alaska

1977 ◽  
Vol 14 (11) ◽  
pp. 2578-2592 ◽  
Author(s):  
J. W. Hillhouse
Keyword(s):  
British Columbia ◽  
High Temperature ◽  
North America ◽  
Vertical Axis ◽  
Upper Triassic ◽  
Present Position ◽  
Stable Component ◽  
South Central ◽  
Early Mesozoic ◽  
Lamellar Texture

Paleomagnetic evidence indicates that the extensive early Mesozoic basalt field near McCarthy, south-central Alaska, originated far south of its present position relative to North America. Results obtained from the Middle and (or) Upper Triassic Nikolai Greenstone suggest that those basalts originated within 15° of the paleoequator. This position is at least 27° (3000 km) south of the Upper Triassic latitude predicted for McCarthy on the basis of paleomagnetic data from continental North America. The Nikolai pole, as determined from 50 flows sampled at 5 sites, is at 2.2° N, 146.1° E (α95 = 4.8°). The polarity of the pole is ambiguous, because the corresponding magnetic direction has a low inclination and a westerly declination. Therefore, the Nikolai may have originated near 15° N latitude or, alternatively, as far south as 15° S latitude. In addition to being displaced northward, the Nikolai block has been rotated roughly 90° about the vertical axis. A measure of the reliability of this pole is provided by favorable results from the following tests: (1) Within one stratigraphic section, normal and reversed directions from consecutive flows are antipolar. (2) Consistent directions were obtained from sites 30 km apart. (3) Application of the fold test indicated the magnetization was acquired before the rocks were folded. (4) The magnetizations of several pilot specimens are thermally stable up to 550 °C. The stable component is probably carried by magnetite with lamellar texture, a primary feature commonly acquired by a basalt at high temperature during initial cooling of the magma. Geologic and paleomagnetic evidence indicates that the Nikolai is allochthonous to Alaska and that, together with associated formations in southern Alaska and British Columbia, it is part of a now disrupted equatorial terrane.

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