Conodont biostratigraphy of the Lower to Middle Devonian Deserters Formation (new), Road River Group, northeastern British Columbia

2003 ◽  
Vol 40 (1) ◽  
pp. 99-113 ◽  
Author(s):  
Leanne J Pyle ◽  
Michael J Orchard ◽  
Christopher R Barnes ◽  
Michelle L Landry
Keyword(s):  
British Columbia ◽  
Black Shale ◽  
Middle Devonian ◽  
Grizzly Bear ◽  
Temporal Constraints ◽  
Conodont Biostratigraphy ◽  
The Road ◽  
The North

A new Lower to Middle Devonian basinal unit of the Road River Group, herein formally named the Deserters Formation, contains argillaceous, crinoidal limestone and black shale deposited in a linear sub-basin of the Ospika Embayment, southern Kechika Trough. The abrupt lateral facies changes in the region, facies thickness, and occurrence of volcanics indicate a period of extensional tectonism. A total of 53 (4–5 kg each) samples from the Deserters Formation yielded 7766 conodont elements assigned to 14 genera representing 33 species. The formation ranges from the Lochkovian (eleanorae Zone, or lower part of the delta Zone of the Cordilleran Region) to Eifelian (australis Zone). The temporal constraints established by conodont biostratigraphy allow correlation to the Grizzly Bear Formation, a regionally restricted Lower to Middle Devonian unit in the Selwyn Basin to the north.

The record of jökulhlaups from Summit Lake, northwestern British Columbia

1993 ◽  
Vol 30 (3) ◽  
pp. 499-508 ◽  
Author(s):  
William H. Mathews ◽  
John J. Clague
Keyword(s):  
British Columbia ◽  
Water Level ◽  
River Valley ◽  
Water Level Fluctuations ◽  
Salmon River ◽  
The Road ◽  
The North ◽  
Large Numbers ◽  
Dammed Lake ◽  
Effective Seal

Summit Lake, which is impounded by Salmon Glacier, is the largest self-draining, ice-dammed lake in Canada. Until 1961, it contained few icebergs and was stable, overflowing to the north into me Bowser River valley. The first jökulhlaup occurred in December 1961, after a lengthy period of thinning and retreat of Salmon Glacier, when a subglacial runnel developed in the weakened ice dam, allowing the lake to drain suddenly. This flood and two others in 1965 and 1967 caused major damage to the road system in the Salmon River valley south of the lake. Since 1965, with three exceptions, Summit Lake has drained annually; minor floods along Salmon River in 1966, 1969, and 1973 may record partial drainings of the lake, although other explanations are possible. Jökulhlaups in recent years have been smaller and have occurred earlier in the year than most of the early floods. Rapid water-level fluctuations associated with the annual emptying and refilling of Summit Lake have generated large numbers of icebergs, derived from the Salmon Glacier dam; these icebergs presently choke the surface of the lake. The present jökulhlaup cycle is likely to continue either until the glacier readvances or until it retreats to the point that it no longer forms an effective seal.

Stable isotope record of the Eifelian–Givetian boundary Kačák–otomari Event (Middle Devonian) from Hungry Hollow, Ontario, Canada

2008 ◽  
Vol 45 (3) ◽  
pp. 353-366 ◽  
Author(s):  
Peter J. van Hengstum ◽  
Darren R. Gröcke
Keyword(s):  
High Resolution ◽  
Middle Devonian ◽  
Isotopic Analysis ◽  
Conodont Biostratigraphy ◽  
Faunal Change ◽  
The North ◽  
Anoxic Events ◽  
Isotope Record ◽  
Sedimentary Carbonate ◽  
Otomari Event

The Kačák Event in the Middle Devonian (Eifelian–Givetian (E–G) boundary) is a period of apparent global anoxia coincident with widespread deposition of black shale in hemipelagic, pelagic, and some neritic facies. Conodont biostratigraphy in the North American Appalachian Basin has proven to be problematic in precisely demarcating the E–G boundary. In this study, we show that the E–G boundary may be defined more accurately through isotope stratigraphy (δ13C) in conjunction with a conodont faunal change across this boundary, identified as the Kačák– otomari Event. The Canadian Hamilton Group outcropping in Hungry Hollow, Ontario, is a 22 m sedimentary succession spanning the Middle Devonian. Conodont biostratigraphy for this section makes it difficult to define the E–G boundary, but the otomari Event can be detected. High-resolution isotopic analysis of bulk sedimentary carbonate and organic matter for this succession records a significant negative δ13C excursion (δ13Ccarb = up to 2‰; δ13Corg = ∼3.0‰) that is synchronous with total organic carbon (TOC) values up to 12.5%. We identify this negative δ13C excursion as a result of marine anoxia associated with the Kačák–otomari Event and suggest that the excursion is a global event driven by a source of isotopically light carbon, followed by a productivity event, similar to Mesozoic oceanic anoxic events. Such similarities between Devonian and Mesozoic oceanic anoxic events may become more evident with increased high-resolution isotopic and geochemical investigations of Devonian successions.

scholarly journals A Middle Devonian basin-scale precious metal enrichment event across northern Yukon (Canada)

Geology ◽  
2020 ◽  
Vol 48 (3) ◽  
pp. 242-246 ◽  
Author(s):  
M.G. Gadd ◽  
J.M. Peter ◽  
D. Hnatyshin ◽  
R. Creaser ◽  
S. Gouwy ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Black Shale ◽  
Middle Devonian ◽  
Global Scale ◽  
The Road ◽  
Basin Scale ◽  
Biotic Events ◽  
Host Rocks ◽  
Age Constraints

Abstract Hyper-enriched black shale (HEBS) Ni-Mo-Zn-Pt-Pd-Au-Re mineralization is geographically widespread across the Richardson trough in northern Yukon (Canada), where it discontinuously outcrops at the regional contact between the Road River Group and overlying Canol Formation. Stratigraphic relationships indicate that the contact is Middle Devonian, but there are no precise age constraints for the HEBS. We apply Re-Os geochronology to HEBS mineralization from two localities that are 130 km apart, the Nick prospect and the Peel River showing, to date directly the age of sulfide mineralization. The Nick prospect yields an isochron age of 390.7 ± 5.1 (2σ) Ma, whereas the Peel River showing yields an isochron age of 387.5 ± 4.4 (2σ) Ma. Within error, these ages are identical and overlap with the biostratigraphically constrained age of the sedimentary host rocks, indicating that mineralization and sedimentation were coeval. Significantly, the ages of the HEBS overlap those of Middle Devonian Kačák, pumilio, and Taghanic global-scale biotic events which are characterized by eustatic sea-level rise and black shale deposition. Linkage of the Yukon HEBS to one (or more) of these bio-events indicates that sea-level rise may have been requisite to formation of basin-scale HEBS mineralization in northwestern Canada during latest Eifelian and Givetian time.

scholarly journals Grizzly bear toe amputation due to seasonal overlap with furbearer trapping in southeast British Columbia

2021 ◽  
Author(s):  
Clayton Lamb ◽  
Laura Smit ◽  
Luke Vander Vennen ◽  
Garth Mowat ◽  
Michael Proctor ◽  
...  
Keyword(s):  
British Columbia ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Active Season ◽  
The North ◽  
New Information ◽  
American Model ◽  
Innovative Solutions ◽  
Wildlife Populations ◽  
Management Approaches

Science and adaptive management form crucial components of the North American model of wildlife management. Under this model, wildlife managers are encouraged to update management approaches when new information arises whose implementation could improve the stewardship and viability of wildlife populations and the welfare of animals. Here we detail a troubling observation of multiple grizzly bear toe amputations in southeast British Columbia and assemble evidence to inform immediate action to remedy the issue. During the capture of 59 grizzly bears in southeast British Columbia, we noticed that four individuals (~7%) were missing some or all their toes on one of their front feet. The wounds were all well healed and linear in nature. Further opportunistic record collection revealed that this pattern of missing toes occurred beyond our study area, and that furbearer traps were responsible for toe loss. We documented a problematic seasonal overlap between the active season for grizzly bears and the fall trapping seasons for small furbearers with body grip traps and for wolves with leghold traps. Instead of opening these trapping seasons on or prior to November 1, when more than 50% of bears are still active, we recommend delaying the start of these seasons until December 1, when most bears have denned. Innovative solutions, such as narrowing trap entrances to exclude bear feet while still allowing entrance of target furbearers, have the potential to minimize accidental capture of bears but the effectiveness of these approaches is unknown. Solutions that do not involve season changes will require monitoring of efficacy and compliance to ensure success.

THE BLACK SHALE RECORD OF THE ORDOVICIAN RADIATION: NEW INSIGHTS INTO REDOX CHANGE FROM THE ROAD RIVER GROUP OF YUKON, CANADA

2018 ◽  
Author(s):  
Beatrice M. Rodewald ◽  
◽  
Jacqueline Vogel ◽  
Richard G. Stockey ◽  
Tiffani Fraser ◽  
...  
Keyword(s):  
Black Shale ◽  
The Road ◽  
Redox Change

scholarly journals Physiological resilience of pink salmon to naturally occurring ocean acidification

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Andrea Y Frommel ◽  
Justin Carless ◽  
Brian P V Hunt ◽  
Colin J Brauner
Keyword(s):  
British Columbia ◽  
Elevated Co2 ◽  
Condition Factor ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Hypoxia Tolerance ◽  
High Co2 ◽  
The North ◽  
Naturally Occurring ◽  
Co2 Levels

Abstract Pacific salmon stocks are in decline with climate change named as a contributing factor. The North Pacific coast of British Columbia is characterized by strong temporal and spatial heterogeneity in ocean conditions with upwelling events elevating CO2 levels up to 10-fold those of pre-industrial global averages. Early life stages of pink salmon have been shown to be affected by these CO2 levels, and juveniles naturally migrate through regions of high CO2 during the energetically costly phase of smoltification. To investigate the physiological response of out-migrating wild juvenile pink salmon to these naturally occurring elevated CO2 levels, we captured fish in Georgia Strait, British Columbia and transported them to a marine lab (Hakai Institute, Quadra Island) where fish were exposed to one of three CO2 levels (850, 1500 and 2000 μatm CO2) for 2 weeks. At ½, 1 and 2 weeks of exposure, we measured their weight and length to calculate condition factor (Fulton’s K), as well as haematocrit and plasma [Cl−]. At each of these times, two additional stressors were imposed (hypoxia and temperature) to provide further insight into their physiological condition. Juvenile pink salmon were largely robust to elevated CO2 concentrations up to 2000 μatm CO2, with no mortality or change in condition factor over the 2-week exposure duration. After 1 week of exposure, temperature and hypoxia tolerance were significantly reduced in high CO2, an effect that did not persist to 2 weeks of exposure. Haematocrit was increased by 20% after 2 weeks in the CO2 treatments relative to the initial measurements, while plasma [Cl−] was not significantly different. Taken together, these data indicate that juvenile pink salmon are quite resilient to naturally occurring high CO2 levels during their ocean outmigration.

scholarly journals I.—On a New Cephalaspis Discovered in America, etc.

1870 ◽  
Vol 7 (75) ◽  
pp. 397-399
Author(s):  
E. Ray Lankester
Keyword(s):  
Middle Devonian ◽  
Lower Devonian ◽  
The North ◽  
North Side

Principal Dawson, of Montreal,. Canada, has placed in my hands for description a remarkably interesting specimen, indicating a species of the genus Cephalaspis in transatlantic Silurio-Devonian beds. He writes, “The specimen was found by one of my assistants, Mr. G. F. Kennedy, B.A., when collecting with me, in a bed charged with remains of Psilophyton, on the north side of Gaspé Bay. The geological horizon is below the middle of the Gaspé Sandstones, but several hundreds of feet above their actual base, so that the specimen may be regarded as either Lower Devonian or Lower Middle Devonian.

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