Minimum age of deglaciation of upper Elk Valley, British Columbia

1981 ◽  
Vol 18 (10) ◽  
pp. 1635-1636 ◽  
Author(s):  
Angus Ferguson ◽  
Gerald Osborn
Keyword(s):  
British Columbia ◽  
Minimum Age

Bog sediments at an elevation of 1582 m in the upper Elk Valley of British Columbia were dated at three horizons. The lowermost of these, radiocarbon dated at 13 430 ± 450 years BP, provides a minimum age for deglaciation of Elk Valley. This date is probably also a minimum for the Canmore advance in the Bow Valley, Alberta, and suggests that the Canmore was not related to deposition of the Bighill Creek Formation at Cochrane. Pollen samples from the bog indicate a shrub–herb pioneer assemblage following deglaciation of that portion of the valley.

Devonian Plutonism in South-Central British Columbia

1975 ◽  
Vol 12 (10) ◽  
pp. 1760-1769 ◽  
Author(s):  
Andrew V. Okulitch ◽  
R. K. Wanless ◽  
W. D. Loveridge
Keyword(s):  
British Columbia ◽  
Middle Devonian ◽  
Metamorphic Complex ◽  
Western Margin ◽  
South Central ◽  
Minimum Age ◽  
History Of ◽  
Shuswap Metamorphic Complex

An apparently tabular body of granitoid gneiss, 3 to 5 km wide and more than 70 km long, that lies along the western margin of the Shuswap Metamorphic Complex between Shuswap and Admas Lakes, shows intrusive relationships with Palaeozoic and older rocks and has yielded zircons whose minimum age is 372 Ma. This intrusion, together with other granitoid plutons in the area that appear to be related to it, provide evidence of widespread plutonism during Middle Devonian time near the western edge of the Paleozoic Cordillera geosyncline and necessitate significant revisions in the interpretation of the crustal history of this region.

Geology and Geochronology of the Hellroaring Creek Stock, British Columbia

1971 ◽  
Vol 8 (1) ◽  
pp. 85-95 ◽  
Author(s):  
B. D. Ryan ◽  
J. Blenkinsop
Keyword(s):  
British Columbia ◽  
Contact Aureole ◽  
Sr Isotope ◽  
Minimum Age ◽  
Structural Event ◽  
Isotope Measurements

Hellroaring Creek Stock intrudes rocks of the Precambrian Purcell Supergroup which crop out in southeastern British Columbia. Previous K–Ar measurements (Lowdon 1961) indicated a minimum age of 700 m.y. for this stock. Present Rb–Sr isotope measurements indicate an approximate age of 1260 m.y. Cleavage in the contact aureole of the stock indicates a structural event prior to intrusion.

Quadra Sand and its relation to the late Wisconsin glaciation of southwest British Columbia

1976 ◽  
Vol 13 (6) ◽  
pp. 803-815 ◽  
Author(s):  
J. J. Clague
Keyword(s):  
British Columbia ◽  
Climatic Change ◽  
Late Pleistocene ◽  
Marine Sediments ◽  
Strait Of Georgia ◽  
Coast Mountains ◽  
Widespread Distribution ◽  
Source Areas ◽  
The North ◽  
Minimum Age

Quadra Sand is a late Pleistocene lithostratigraphic unit with widespread distribution in the Georgia Depression, British Columbia and Puget Lowland, Washington. The unit consists mainly of horizontally and cross-stratified, well sorted sand. It is overlain by till deposited during the Fraser Glaciation and is underlain by fluvial and marine sediments deposited during the preceding nonglacial interval.Quadra Sand was deposited progressively down the axis of the Georgia–Puget Lowland from source areas in the Coast Mountains to the north and northeast. The unit is markedly diachronous; it is older than 29 000 radiocarbon years at the north end of the Strait of Georgia, but is younger than 15 000 years at the south end of Puget Sound.Aggradation of the unit occurred during the climatic deterioration at the beginning of the Fraser Glaciation. Thick, well sorted sand was deposited in part as distal outwash aprons at successive positions in front of, and perhaps along the margins of, glaciers advancing from the Coast Mountains into the Georgia–Puget Lowland during late Wisconsin time.The sand thus provides a minimum age for the initial climatic change accompanying the Fraser Glaciation. This change apparently occurred before 28 800 y BP, substantially earlier than glacial occupation of the southern Interior Plateau of British Columbia. Thus, several thousand years may have intervened between the alpine and ice-sheet phases of the Fraser Glaciation.

Evidence for an Early Pleistocene glaciation in the Okanagan Valley, southern British Columbia

2014 ◽  
Vol 51 (2) ◽  
pp. 125-141 ◽  
Author(s):  
Murray A. Roed ◽  
René W. Barendregt ◽  
Jeff A. Benowitz ◽  
C.A.S. Smith ◽  
P.T. Sanborn ◽  
...  
Keyword(s):  
British Columbia ◽  
First Nation ◽  
Early Pleistocene ◽  
Pleistocene Glaciation ◽  
Pleistocene Glaciations ◽  
The West ◽  
Glacial Sediments ◽  
Fabric Analysis ◽  
Minimum Age ◽  
Okanagan Valley

Depositional evidence of Early Pleistocene glaciations in British Columbia are documented at only a few sites. Near Kelowna, in southern British Columbia, a construction project exposed glacial sediments beneath Lambly Creek Basalt, providing a minimum age for this glaciation. The basalt is composed of a number of flows yielding ages that range from 0.76 ± 0.11 to 1.5 ± 0.1 Ma. The sediments consist of a diamicton, interpreted to be till, up to 3 m thick mantled by a weakly developed paleosol. The diamicton is underlain by fluvial sands up to 5 m thick, in places revealing injection features, and minor faulting. A unit of stratified gravel underlain by grey clay is inferred to underlie the exposed sediments, based on nearby outcrops and excavations. Sediments and overlying basalts are normally magnetized and are assigned to the Jaramillo normal subchron (1.069–0.987 Ma). The till is here referred to as the Westbank First Nation Till. It is Early Pleistocene in age and represents the earliest evidence of glaciation in the Okanagan Valley. Stone fabric analysis and clast lithologies suggest that ice movement was from northwest to southeast, and is here referred to as the West Kelowna Advance; we infer that this advance was part of a larger regional glaciation. Other Early Pleistocene glaciations in the Cordillera are briefly reviewed.

Minimum age of deglaciation of upper Elk Valley, British Columbia: Reply

1982 ◽  
Vol 19 (5) ◽  
pp. 1100-1100 ◽  
Author(s):  
Angus Ferguson ◽  
Gerald Osborn
Keyword(s):  
British Columbia ◽  
Minimum Age

Deformation of the western margin of the Omineca Belt near Crooked Lake, east-central British Columbia

1990 ◽  
Vol 27 (3) ◽  
pp. 414-425
Author(s):  
Jeffrey A. Fillipone ◽  
John V. Ross
Keyword(s):  
British Columbia ◽  
North America ◽  
Middle Jurassic ◽  
Phase 1 ◽  
Late Devonian ◽  
East Central ◽  
Western Margin ◽  
Metasedimentary Rocks ◽  
Narrow Zone ◽  
Minimum Age

The western margin of the Omineca Belt near Crooked Lake, British Columbia, consists of metasedimentary rocks (Snowshoe Group) and orthogneisses of the Barkerville terrane, structurally overlain by a mafic volcanic – sedimentary package of rocks belonging to the allochthonous Slide Mountain (Crooked Amphibolite) and Quesnel terranes (Triassic phyllite and Nicola Group). At least two episodes of regional deformational (phases 2 and 3) affected this composite package. Deformation and metamorphism (phase 1) in the Snowshow Group predate the formation of this package and are nowhere evident within the allochthonous terranes.Middle Jurassic metamorphism ranging from chlorite zone through sillimanite zone affected all units. Isograds are folded, together with the junction between the terranes, indicating that the metamorphic assemblages developed prior to folding of this boundary. Granitic orthogneiss (Boss Mountain, Quesnel Lake, and Perseus gneisses), having a minimum age of Late Devonian to Early Pennsylvanian, was intruded into and deformed with the Snowshoe Group during the earliest recognizable phase of deformation in the Barkerville terrane (phase 1). Slide Mountain terrane rocks occupy a narrow zone where large eastward displacement occurred during overthrusting of the Intermontane superterrane upon the western margin of North America in Middle Jurassic time.

Age and origin of advanced argillic alteration zones and related exotic limonite deposits in the Limonite Creek area, central British Columbia

2000 ◽  
Vol 37 (8) ◽  
pp. 1093-1107 ◽  
Author(s):  
C L Deyell ◽  
J FH Thompson ◽  
R M Friedman ◽  
L A Groat
Keyword(s):  
British Columbia ◽  
Low Ph ◽  
Late Triassic ◽  
Alteration Zones ◽  
Argillic Alteration ◽  
Subsequent Conversion ◽  
Minimum Age ◽  
Propylitic Alteration ◽  
Host Rocks ◽  
Age Constraints

The Limonite Creek property in north-central British Columbia contains several zones of silicic and acid-sulphate alteration. These zones grade through advanced argillic and aluminous mineral assemblages to sericitic and regional propylitic alteration. Alteration assemblages are characteristic of high-sulphidation systems, although the abundance of pyrophyllite and andalusite suggests formation at depths below typical epithermal environments. Alteration occurred between 212 and 52 Ma as determined from field relations and U-Pb dating of intrusions. The deformed nature of the alteration assemblages and a minimum age of alunite (144 ± 8 Ma) suggest formation in latest Triassic to Middle Jurassic time. Based on these age constraints, alteration zones at Limonite Creek are significantly older than the Eocene Equity Silver deposit (ca. 60 Ma), despite the latter's proximity and similar styles of alteration. Based on the new dates, host rocks at Limonite Creek are Late Triassic or older, and hence regional stratigraphy needs reassessment. Extensive exotic limonite deposits occur around the alteration zones and at lower elevations to the south. Radiocarbon dating indicates that the deposits have been accumulating for at least 8000 years. Iron released during weathering was transported in low-pH waters and precipitated initially as ferrihydrite, with subsequent conversion to goethite. Water chemistry confirms that the process is still active. In addition to iron, the limonite contains minor copper and zinc. The formation of low-pH waters and the transport of iron resulted from weathering of pyrite-rich alteration assemblages with negligible buffering capacity.

New U–Pb age constraints on latest Cretaceous magmatism and associated mineralization in the Fawnie Range, Nechako Plateau, central British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 619-637 ◽  
Author(s):  
R M Friedman ◽  
L J Diakow ◽  
R A Lane ◽  
J K Mortensen
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Western Margin ◽  
Fine Grained ◽  
The North ◽  
Continental Arc ◽  
Igneous Activity ◽  
Minimum Age ◽  
Plateau Central ◽  
Cretaceous Magmatism

New U–Pb ages and K–Ar dates, primarily for rocks proximal to mineral occurrences in the Fawnie Range of central British Columbia, document latest Cretaceous (ca. 74–66 Ma) continental-arc igneous activity and date associated base and precious metal mineralization. U–Pb ages of ca. 73–69 Ma for the Capoose pluton and hypabyssal to extrusive garnet rhyolites at the Capoose prospect demonstrate a latest Cretaceous age for mineralization and a likely plutonic source for mineralizing fluids. A U–Pb age of ca. 67 Ma for a late mineralized felsic dyke and two K–Ar dates (ca. 70 and 68 Ma) for hornfelsed Jurassic volcanic rocks at the Blackwater–Davidson prospect constrain a latest Cretaceous age for mineralization. A U–Pb age of ca. 74 Ma for a fine grained diorite sill that cuts a significant epithermal gold vein at the Tsacha prospect places a minimum age on mineralization at this probable Jura-Cretaceous deposit and documents latest Cretaceous magmatism. Latest Cretaceous K–Ar dates are reported for an andesite flow adjacent to the Eocene Holy Cross deposit (ca. 66 Ma), about 35 km north of the Fawnie Range, and a Kasalka Group rhyolite (ca. 68 Ma) exposed near the western margin of the Nechako Plateau. Latest Cretaceous magmatism and mineralization in the Fawnie Range represent the waning stages of Bulkley suite magmatism and porphyry-style mineralization, which was concentrated along the western margin of the Nechako Plateau at circa 88–70 Ma. The distribution of latest Cretaceous arc igneous rocks along the North American Cordilleran is reviewed and tectonic implications discussed.

U–Pb and K–Ar dates related to the timing of magmatism and deformation in the Cache Creek terrane and Quesnellia, southern British Columbia

1990 ◽  
Vol 27 (1) ◽  
pp. 117-123 ◽  
Author(s):  
N. Mortimer ◽  
P. van der Heyden ◽  
R. L. Armstrong ◽  
J. Harakal
Keyword(s):  
British Columbia ◽  
Early Cretaceous ◽  
North American ◽  
Late Jurassic ◽  
Early Jurassic ◽  
Early Permian ◽  
Magmatic Arc ◽  
Plutonic Complex ◽  
Minimum Age ◽  
Coast Plutonic Complex

U–Pb dating of zircon from the Guichon Creek batholith indicates an emplacement age of 210 ± 3 Ma. Comparison with previously published K–Ar (211–188 Ma) and Rb–Sr (205 and 196 Ma) dates reveals that intrusion, mineralization, cooling, and uplift of the batholith took some 20 Ma, spanning the Triassic–Jurassic boundary on the Decade of North American Geology (DNAG) time scale.The Mount Martley pluton and Tiffin Creek stock yield Late Jurassic dates of 155 ± 2 Ma (U–Pb, zircon) and 152 ± 5 Ma (K–Ar, hornblende), respectively, and provide a reliable minimum age (Kimmeridgian) for penetrative deformation in the Cache Creek terrane. K–Ar whole-rock dates from Cache Creek terrane and Ashcroft Formation argillites range from Early Permian (266 ± 8 Ma) and Early Jurassic (194 ± 6 Ma) to Late Jurassic, Kimmeridgian (154 ± 5 Ma). We interpret the younger dates as recording Middle–Late Jurassic tectonism and the older ones as possible relics from earlier deformation episodes.An Early Cretaceous K–Ar date (129 ± 5 Ma) for a lamprophyre dike that cuts the Nicola Group suggests that the Early Cretaceous magmatic arc of the Coast Plutonic Complex had an eastern alkalic fringe in the Intermontane Belt.

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