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.

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 Humpback Whale (Megaptera novaeangliae) observations in Laskeek Bay, western Hecate Strait, in spring and early summer, 1990–2018

2020 ◽  
Vol 133 (3) ◽  
pp. 263-269
Author(s):  
Anthony J. Gaston ◽  
Neil G. Pilgrim ◽  
Vivian Pattison
Keyword(s):  
British Columbia ◽  
Humpback Whale ◽  
Early Summer ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
The West ◽  
Peak Period ◽  
West Side

We describe observations of Humpback Whales (Megaptera novaeangliae) made along the west side of central Hecate Strait, British Columbia, during the spring and summer of 1990–2018. From none in March, the frequency of sightings increased from early April to a peak in May, then fell in June with few in July. The frequency of sightings during the peak period (1 May–20 June) increased over the course of the study at a mean rate of 6% a year, similar to increases recorded elsewhere in British Columbian waters. The frequency of sightings was highest in years when the Oceanic Niño Index for January–March was low and peaked earlier in years when the Oceanic Niño Index was high. Both of these relationships suggest a connection between Humpback Whale sightings in western Hecate Strait and the larger oceanographic context, with sightings more frequent in years of lower water temperatures.

scholarly journals Conservation Evaluation of the Small-flowered Tonella, Tonella tenella, in Canada

2006 ◽  
Vol 120 (2) ◽  
pp. 179
Author(s):  
George W. Douglas ◽  
Jenifer L. Penny
Keyword(s):  
British Columbia ◽  
Private Property ◽  
Columbia River ◽  
The West ◽  
Rock Outcrops ◽  
West Side ◽  
Central California ◽  
Gulf Islands ◽  
Talus Slopes ◽  
Conservation Evaluation

In Canada, the Small-flowered Tonella, Tonella tenella, is restricted to the west side of Saltspring Island in the Gulf Islands of southwestern British Columbia. This population represents the northern limits of the species which is disjunct from its main range in southern Washington (Columbia River gorge), through Oregon to central California. In British Columbia, Tonella tenella is associated with rock outcrops and dry, steep, sparsely forested talus slopes at elevations of 50 to 300 m. The population on Saltspring Island is on private property and not directly imperilled at this time. There is, however, a potential for housing development in the future on this waterfront site, thus the authors consider the species endangered.

RECORDS OF ADDITIONAL EUROPEAN SAWFLIES IN AMERICA AND DESCRIPTIONS OF NEW VARIETIES OF NORTH AMERICAN SPECIES

1932 ◽  
Vol 64 (11) ◽  
pp. 247-251 ◽  
Author(s):  
Herbert H. Ross
Keyword(s):  
British Columbia ◽  
North American ◽  
West Coast ◽  
River Valley ◽  
North American Species ◽  
Alnus Rubra ◽  
Fraser River ◽  
The West ◽  
New Varieties ◽  
The Common

This species has apparently been introduced in recent years and become established as a pest of the common native alder (Alnus rubra) on the west coast of Washington and British Columbia, particularly in the lower part of the Fraser River Valley. The earliest specimens I have at hand are a series of 15 females taken at White Rock, B. C., June 28, 1929, collected by Mr. G. Beall.

Petrology and geochemistry of the Kamloops Group volcanics, British Columbia

1981 ◽  
Vol 18 (9) ◽  
pp. 1478-1491 ◽  
Author(s):  
Thomas E. Ewing
Keyword(s):  
British Columbia ◽  
Fractional Crystallization ◽  
Middle Eocene ◽  
Volcanic Rocks ◽  
Primary Source ◽  
Low Pressure ◽  
Rock Types ◽  
South Central ◽  
High K ◽  
Petrology And Geochemistry

The Kamloops Group is an alkali-rich calc-alkaline volcanic suite of Early to Middle Eocene age, widespread in south-central British Columbia. Rock types in the suite range from high-K basalt through andesite to rhyolite. The suite is characterized by relatively high K2O, Sr, and Ba, but low Zr, Ti, and Ni concentrations, only moderate Ce enrichment, and little or no Fe enrichment. Initial ratios 87Sr/86Sr are about 0.7040 in the western half, and about 0.7060 in the eastern half of the study area. No difference in chemistry or mineralogy marks this sharp transition. Chemically similar suites include the Absaroka–Gallatin suite in Wyoming and the lower San Juan (Summer Coon) suite in Colorado. The content of K2O at 60% SiO2 increases regularly eastward across southern British Columbia. The chemical data support the subduction-related continental arc origin of the Kamloops Group volcanics.The volcanic rocks consist in the main of augite–pigeonite andesites ranging from 52 to 62% silica, with subordinate quantities of olivine–augite–pigeonite basalt and biotite rhyodacite and rhyolite. The andesites and basalts were derived by a combination of low-pressure fractional crystallization, higher pressure fractional crystallization, and variable parental magmas, whereas low-pressure fractional crystallization of plagioclase, biotite, and apatite from parental basalt and andesite produced the rhyolites. The parental magmas were basalts and basaltic andesites with high K, Sr, and Ba. The primary source of these magmas is inferred to have been an alkali-enriched hydrous peridotite with neither plagioclase nor garnet present in the residuum.

Sedimentary environments and postglacial history of the Fraser Delta and lower Fraser Valley, British Columbia

1983 ◽  
Vol 20 (8) ◽  
pp. 1314-1326 ◽  
Author(s):  
John J. Clague ◽  
John L. Luternauer ◽  
Richard J. Hebda
Keyword(s):  
British Columbia ◽  
Lacustrine Sediments ◽  
Fraser River ◽  
Large Area ◽  
Borehole Data ◽  
Strait Of Georgia ◽  
Sea Levels ◽  
The Holocene ◽  
Sedimentary Environments ◽  
Channel Deposits

The Fraser River delta, which is about 1000 km2 in area above low tide level, has been built into the Strait of Georgia in southwestern British Columbia during the Holocene. Present-day sedimentary environments, including foreslope, tidal flat, river channel, floodplain, and bog, also existed earlier during the delta's development. Borehole data reveal a succession of sedimentary environments related to Holocene progradation of the delta south and west of New Westminster. At each site, marine basin and distal foreslope sediments are overlain by proximal foreslope materials, which in turn are overlain by coarser intertidal platform and channel deposits capped by floodplain and bog sediments.Initial growth of the Fraser Delta was preceded both by deglaciation of the region and by the rapid westward extension of the Fraser River floodplain down a partially submerged, glacially scoured trough east of New Westminster. Irregularities on the trough floor were covered by fluvial, deltaic, marine, and lacustrine sediments as the floodplain extended westward. About 10 000 years ago, the Fraser River began to empty directly into the Strait of Georgia through a gap in the Pleistocene uplands at New Westminster. A delta was constructed south and west from this site as the sea dropped below its present level relative to the land. Deltaic progradation continued after sea level stabilized at about −12 m elevation after 8000 years BP. A marine transgression between 7000–7500 and 5000–5500 years ago inundated parts of the Fraser proto-delta and temporarily inhibited its seaward advance. This transgression ended with the sea perhaps 1 or 2 m below its present position, whereupon a large area of the delta became emergent and large bogs began to form. During the remainder of the Holocene, the Fraser Delta grew westward, but apparently not southward, under a regime of relatively stable sea levels.

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.

Eocene Ginkgo leaf fossils from the Pacific Northwest

2002 ◽  
Vol 80 (10) ◽  
pp. 1078-1087 ◽  
Author(s):  
George E Mustoe
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Ginkgo Biloba ◽  
Middle Eocene ◽  
Washington State ◽  
North Central ◽  
Lacustrine Deposits ◽  
South Central ◽  
The Pacific ◽  
Ginkgo Leaf

Middle Eocene lacustrine deposits in south-central British Columbia and north-central Washington state preserve two types of Ginkgo leaves. A morphotype characterized by deeply divided multiple lobes is herein described as Ginkgo dissecta sp.nov. Leaves that are either undivided or shallowly divided into bilobate symmetry are indistinguishable from foliage of extant Ginkgo biloba Linnaeus. These fossils contradict the widely held belief that only a single Ginkgo species, Ginkgo adiantoides (Unger) Heer, inhabited Cenozoic forests.Key words: British Columbia, Eocene, fossil, Ginkgo adiantoides, Ginkgo biloba, Ginkgo dissecta, McAbee, Republic, Tertiary, Washington.

Geology of the Chatham Sound region, southeast Alaska and coastal British Columbia

2001 ◽  
Vol 38 (11) ◽  
pp. 1579-1599 ◽  
Author(s):  
George E Gehrels
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Upper Jurassic ◽  
The West ◽  
Southeast Alaska ◽  
Coast Mountains ◽  
Early Tertiary ◽  
Metavolcanic Rocks ◽  
Upper Paleozoic ◽  
Coastal British Columbia

The Coast Mountains orogen is thought to have formed as a result of accretion of the Alexander and Wrangellia terranes against the western margin of the Stikine and Yukon–Tanana terranes, but the nature and age of accretion remain controversial. The Chatham Sound area, which is located along the west flank of the Coast Mountains near the Alaska – British Columbia border, displays a wide variety of relations that bear on the nature and age of the boundary between inboard and outboard terranes. Geologic and U–Pb geochronologic studies in this area reveal a coherent but deformed and metamorphosed sequence of rocks belonging to the Yukon–Tanana terrane, including pre-mid-Paleozoic marble, schist, and quartzite, mid-Paleozoic orthogneiss and metavolcanic rocks, and upper Paleozoic metaconglomerate and metavolcanic rocks. These rocks are overlain by Middle Jurassic volcanic rocks (Moffat volcanics) and Upper Jurassic – Lower Cretaceous strata of the Gravina basin, both of which also overlie Triassic and older rocks of the Alexander terrane. This overlap relationship demonstrates that the Alexander and Wrangellia terranes were initially accreted to the margin of inboard terranes during or prior to mid-Jurassic time. Accretion was apparently followed by Late Jurassic – Early Cretaceous extension–transtension to form the Gravina basin, left-slip along the inboard margin of Alexander–Wrangellia, mid-Cretaceous collapse of the Gravina basin and final structural accretion of the outboard terranes, and early Tertiary dip-slip motion on the Coast shear zone.

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