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.

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.

Lithostratigraphy and paleomagnetism of pre-Fraser glacial deposits in south-central British Columbia

1999 ◽  
Vol 36 (8) ◽  
pp. 1357-1370 ◽  
Author(s):  
Olav B Lian ◽  
R W Barendregt ◽  
R J Enkin
Keyword(s):  
British Columbia ◽  
Early Pleistocene ◽  
Fluvial Sediments ◽  
Optical Dating ◽  
Late Pliocene ◽  
South Central ◽  
Last Glaciation ◽  
Matuyama Chron ◽  
Sedimentary Succession ◽  
Cordilleran Ice Sheet

Lithostratigraphic records spanning considerable parts of the Pleistocene were studied at three sites in south-central British Columbia. A sedimentary succession near Pavilion includes three distinctly different till units. While the surface till can be associated with the last glaciation (the Fraser Glaciation δ18O stage 2), the ages of the two older till units are presently unknown. However, optical dating of outwash silt resting on the oldest till indicates that this outwash unit and all the overlying units are younger than ~160 ka. In Big Bar Creek valley, about 50 km north of Pavilion, an aggradational sequence of indurated glaciofluvial sand, gravel, and till is exposed. A silt unit and a sand lens within an overlying till bed near the top of the section have reversed magnetization, indicating deposition prior to 780 ka, probably during the Matuyama chron. The Big Bar Creek sequence also includes glacio(?)fluvial sediments near the base that are normally magnetized, suggesting that they were deposited, at the latest, during the Jaramillo subchron (~1.0 Ma), but probably during the Gauss chron, before 2.6 Ma. Reversely magnetized glacio(?)fluvial gravel and sand also occur along Jesmond Road between the Marble Range and Edge Hills. These units give support for the development of at least one Cordilleran ice sheet in the Early Pleistocene or Late Pliocene.

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.

Reconsidering the Cause of Cultural Collapse in the Lillooet Area of British Columbia, Canada: A Geoarchaeological Perspective

2001 ◽  
Vol 66 (4) ◽  
pp. 692-703 ◽  
Author(s):  
Ian Kuijt
Keyword(s):  
British Columbia ◽  
Volcanic Eruptions ◽  
Archaeological Sites ◽  
Fraser River ◽  
Settlement Systems ◽  
South Central ◽  
High Magnitude ◽  
Landslide Event ◽  
Cultural Responses ◽  
Fraser Valley

The potential interconnections between human settlement systems, subsistence practices, and rapid, high-magnitude transformation of the physical landscape (e.g., earthquakes, volcanic eruptions, and landslides) is an important issue of discussion in archaeology. This paper critically examines the argument that prehistoric abandonment of Classic Lillooet pithouse villages of south-central British Columbia, Canada, at approximately 1200-1000 B.P., was linked to one or more catastrophic landslides at Texas Creek that blocked the Fraser River, destroyed salmon resources, and caused the abandonment of this area. Examination of the location and depositional condition of several excavated archaeological sites within the Fraser Valley, as well as reflection on the expected environmental and cultural responses to a catastrophic landslide, challenge previous interpretations of the existence, location, and magnitude of such a landslide event, and indicate that archaeologists need to reconsider deterministic environmental explanations for the abandonment of pithouse villages in the interior of British Columbia.

Neogene Chilcotin basalts in south-central British Columbia: geology, ages, and geomorphic history

1989 ◽  
Vol 26 (5) ◽  
pp. 969-982 ◽  
Author(s):  
W. H. Mathews
Keyword(s):  
British Columbia ◽  
Early Miocene ◽  
Early Pleistocene ◽  
Small Scale ◽  
Original Form ◽  
Coast Mountains ◽  
Base Level ◽  
South Central ◽  
Columbia River Basalt ◽  
Land Surfaces

An extensive but generally thin mantle of basalt flows, the Chilcotin Group, covers much of the Interior Plateau of south-central British Columbia. It provides material for dating and for reconstructing the original form of the paleosurface on which it was deposited. K–Ar whole-rock dates demonstrate that several ages of basalt are represented, from Early Miocene (or even Late Oligocene?) to Early Pleistocene, with particularly abundant eruptions about 14–16, 9–6, and 1–3 Ma ago.Basalts of Middle Miocene and later ages, if not the Early Miocene relics as well, clearly rest on land surfaces of low local relief. In places the low-relief surfaces had been incised to depths of 100–200 m and the valleys backfilled with mid-or late Cenozoic sediments prior to burial by the basalts. The low-relief surfaces throughout the area are believed to have been developed close to a common base level, and regional differences in their present elevation are thus largely a product of post-basalt deformation. This is recorded by Miocene or later uplift of the southern Coast Mountains and gentle flexing in parts of the Interior Plateau.Major stream incision to depths of up to 1000 m following uplift provides a convenient, but not infallible, means of distinguishing Chilcotin basalts from mid-Pleistocene and younger "valley basalts."The Chilcotin Group is, for the most part, a small-scale counterpart of the roughly contemporaneous Columbia River basalt group of Washington and Oregon.

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.

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