A record of Early Pleistocene glaciation on the Mount Edziza Plateau, northwestern British Columbia

1995 ◽  
Vol 32 (12) ◽  
pp. 2046-2056 ◽  
Author(s):  
I. S. Spooner ◽  
G. D. Osborn ◽  
R. W. Barendregt ◽  
E. Irving
Keyword(s):  
British Columbia ◽  
Lacustrine Sediments ◽  
Early Pleistocene ◽  
Volcanic Complex ◽  
Pleistocene Glaciation ◽  
Sedimentary Record ◽  
Basalt Flow ◽  
Glacial Ice ◽  
Normal Polarity

Mount Edziza is a Plio-Pleistocene volcanic complex that is located in the Stikine Terrane in northwestern British Columbia. A sequence of diamictites preserved between Ice Peak Formation basalts on the northwestern blank of Mount Edziza records an Early Pleistocene regional glaciation. The lowest Ice Peak Formation basalt flow (IP1; about 1 Ma) was probably extruded onto glacial ice because it is deformed and brecciated, it is pillowed at the base, it lies directly on hyaloclastite deposits, and there is a lack of fluvial and lacustrine sediments at the base. Fabric measurements from the underlying diamictites are consistent with lodgement processes and indicate northwest and southwest transport directions. These data, and an abundance of striated exotic cobbles, indicate that the sediment was deposited by Coast Mountain ice. Radiometric, paleomagnetic, and stratigraphic data all support the interpretation that diamictites at the section are the sedimentary record of an Early Pleistocene (about 1.1 Ma, isotope stage 32–34) regional glaciation(s). The normal paleomagnetic polarity of one of the Ice Peak Formation basalts (IP2) records extrusion during the Jaramillo normal polarity subchron (1.07–0.99 Ma) and further constrains the age of the underlying diamictites.

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.

A Middle pleistocene (isotope stage 10) glacial sequence in the Stikine River valley, British Columbia

1996 ◽  
Vol 33 (10) ◽  
pp. 1428-1438 ◽  
Author(s):  
Ian S. Spooner ◽  
Gerald D. Osborn ◽  
H. Barendregt ◽  
E. Irving
Keyword(s):  
British Columbia ◽  
Magnetic Polarity ◽  
River Valley ◽  
Middle Pleistocene ◽  
Glacial Period ◽  
Basalt Flow ◽  
Coast Mountains ◽  
Normal Polarity ◽  
Ice Retreat ◽  
Glacial Advance

In the Stikine River valley, northwestern British Columbia, glacial and nonglacial sediments are preserved beneath Middle Pleistocene basalt-flow remnants that originated from Mount Edziza. The magnetic polarity is consistently normal, indicating that the sediment and the basalts were probably deposited within the Bruhnes normal polarity chron (<780 ka). The sediments record a regional glacial advance. Initial ice advance in the Coast Mountains blocked the westward drainage of the Stikine River and formed an advance-phase glacial lake. Sediments deposited in this lake form a coarsening-upwards sequence; debris-flow diamicton units that originated from the valley sides are common. The lacustrine sequence culminates in a poorly sorted ice-marginal gravel deposited as ice encroached upon the study area. There is little record of ice retreat. The basalts are deposited on fluvial and (or) glaciofluvial gravels, indicating that postglacial reincision was taking place at the time of eruption. Hence, the sediments were deposited in the glacial period immediately prior to the emplacement of the basalt. Evidence is presented that indicates that glacial conditions occurred between 341 and 352 ka, which corresponds to pre-Illinoian isotope stage 10.

Bridge River tephra: revised distribution and significance for detecting old carbon errors in radiocarbon dates of limnic sediments in southern British Columbia

1980 ◽  
Vol 17 (11) ◽  
pp. 1454-1461 ◽  
Author(s):  
Rolf W. Mathewes ◽  
John A. Westgate
Keyword(s):  
British Columbia ◽  
Sedimentary Rocks ◽  
Lacustrine Sediments ◽  
Igneous Rocks ◽  
The South ◽  
Radiocarbon Dates ◽  
Carbon Contamination ◽  
Horseshoe Lake ◽  
Tephra Beds

Ash-grade Bridge River tephra, identified as such on the basis of shard habit, modal mineralogy, and composition of ilmenite, occurs in sedimentary cores from three lakes located to the south of the previously documented plume and necessitates a significant enlargement of the fallout area of that tephra in southwestern British Columbia.These new, more southerly occurrences are probably equivalent to the ~2350 year old Bridge River tephra, although it can be argued from the evidence at hand that the 14C dates and biotite-rich nature support relationship to a slightly earlier Bridge River event.Large differences exist in the 14C age of sediments immediately adjacent to the Bridge River tephra at these three lake sites; maximum ages of 3950 ± 170 years BP (GX-5549) and 3750 ± 210 years BP (I-10041) were obtained at Phair and Fishblue lakes, respectively, whereas the corresponding age at Horseshoe Lake is only 2685 ± 180 years BP (GX-5757). The two older dates are considered to be significantly affected by old carbon contamination for the bedrock locally consists of calcareous sedimentary rocks and the lacustrine sediments are very calcareous. The 14C date from Horseshoe Lake, which occurs in an area of igneous rocks, appears to be only slightly too old relative to the ~2350 year old Bridge River tephra.Well-dated tephra beds, therefore, can be very useful in assessing the magnitude of old carbon errors associated with radiocarbon dates based on limnic sediments. Calcareous gyttja deposits beneath Bridge River tephra within the study area exhibit old carbon errors of the order of 1350–1550 years.

A sedimentary record from the Makarov Basin, Arctic Ocean, reveals changing middle to Late Pleistocene glaciation patterns

2021 ◽  
Vol 270 ◽  
pp. 107176
Author(s):  
Wenshen Xiao ◽  
Leonid Polyak ◽  
Rujian Wang ◽  
Christelle Not ◽  
Linsen Dong ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Late Pleistocene ◽  
Pleistocene Glaciation ◽  
Sedimentary Record ◽  
Makarov Basin

Combining Distributed Acoustic Sensing and Beamforming in a Volcanic Environment on Mount Meager, British Columbia.

2021 ◽  
Author(s):  
Sara Klaasen ◽  
Patrick Paitz ◽  
Jan Dettmer ◽  
Andreas Fichtner
Keyword(s):  
British Columbia ◽  
Power Distribution ◽  
High Frequency ◽  
Low Frequency ◽  
Volcanic Tremor ◽  
Extreme Environment ◽  
Volcanic Complex ◽  
Acoustic Sensing ◽  
Distributed Acoustic Sensing ◽  
Volcanic Environment

&lt;p&gt;We present one of the first applications of Distributed Acoustic Sensing (DAS) in a volcanic environment. The goals are twofold: First, we want to examine the feasibility of DAS in such a remote and extreme environment, and second, we search for active volcanic signals of Mount Meager in British Columbia (Canada).&amp;#160;&lt;/p&gt;&lt;p&gt;The Mount Meager massif is an active volcanic complex that is estimated to have the largest geothermal potential in Canada and caused its largest recorded landslide in 2010. We installed a 3-km long fibre-optic cable at 2000 m elevation that crosses the ridge of Mount Meager and traverses the uppermost part of a glacier, yielding continuous measurements from 19 September to 17 October 2019.&lt;/p&gt;&lt;p&gt;We identify ~30 low-frequency (0.01-1 Hz) and 3000 high-frequency (5-45 Hz) events. The low-frequency events are not correlated with microseismic ocean or atmospheric noise sources and volcanic tremor remains a plausible origin. The frequency-power distribution of the high-frequency events indicates a natural origin, and beamforming on these events reveals distinct event clusters, predominantly in the direction of the main peaks of the volcanic complex. Numerical examples show that we can apply conventional beamforming to the data, and that the results are improved by taking the signal-to-noise ratio of individual channels into account.&lt;/p&gt;&lt;p&gt;The increased data quantity of DAS can outweigh the limitations due to the lower quality of individual channels in these hazardous and remote environments. We conclude that DAS is a promising tool in this setting that warrants further development.&lt;/p&gt;

scholarly journals Pliocene and Early Pleistocene glaciation and landscape evolution on the Patagonian Steppe, Santa Cruz province, Argentina

2020 ◽  
Vol 227 ◽  
pp. 105992 ◽  
Author(s):  
John J. Clague ◽  
Rene W. Barendregt ◽  
Brian Menounos ◽  
Nicholas J. Roberts ◽  
Jorge Rabassa ◽  
...  
Keyword(s):  
Landscape Evolution ◽  
Early Pleistocene ◽  
Pleistocene Glaciation ◽  
Santa Cruz ◽  
Patagonian Steppe

New paleomagnetic data from the hominin bearing Dmanisi paleo-anthropologic site (southern Georgia, Caucasus)

2008 ◽  
Vol 69 (1) ◽  
pp. 91-96 ◽  
Author(s):  
M. Calvo-Rathert ◽  
A. Goguitchaichvili ◽  
D. Sologashvili ◽  
J.J. Villalaín ◽  
M.F. Bógalo ◽  
...  
Keyword(s):  
Human Remains ◽  
Lava Flows ◽  
Early Pleistocene ◽  
Clear Correlation ◽  
Basaltic Lava ◽  
Basalt Flow ◽  
Lithic Industry ◽  
Reversed Polarity ◽  
Depositional Units ◽  
Southern Georgia

The Dmanisi site has yielded human remains and lithic industry associated with Late Pliocene–early Pleistocene fauna. The site is composed of volcanogenic sediments overlying basaltic lava flows. The lithostratigraphic sequence comprises two basic depositional units: Unit A, overlying the basalt flows, and Unit B on top. A paleomagnetic and rock-magnetic study has been carried out on 106 specimens from Units A and B and the uppermost basalt flow. The lava and Unit A provide normal polarities, while reversed polarities and anomalous directions are observed in Unit B, the latter probably due to overlapping of a secondary and a primary reversed polarity component. The lower part of the section shows a clear correlation with the Olduvai subchron, and the upper levels could be as young as 1.07 Ma. As human remains were found both in units with normal and reversed polarity, different non-contemporaneous human occupations might have been possible.

Evidence for catastrophic volcanic debris flows in Pemberton Valley, British Columbia

2006 ◽  
Vol 43 (6) ◽  
pp. 679-689 ◽  
Author(s):  
K A Simpson ◽  
M Stasiuk ◽  
K Shimamura ◽  
J J Clague ◽  
P Friele
Keyword(s):  
British Columbia ◽  
Debris Flow ◽  
Debris Flows ◽  
Clay Content ◽  
Volcanic Complex ◽  
Large Magnitude ◽  
Volcanic Material ◽  
Inundation Maps ◽  
The Matrix ◽  
Volcanic Debris

The Mount Meager volcanic complex in southern British Columbia is snow and ice covered and has steep glaciated and unstable slopes of hydrothermally altered volcanic deposits. Three large-volume (>108 m3) volcanic debris flow deposits derived from the Mount Meager volcanic complex have been identified. The volcanic debris flows travelled at least 30 km downstream from the volcanic complex and inundated now populated areas of Pemberton Valley. Clay content and mineralogy of the deposits indicate that the volcanic debris flows were clay-rich (5%–7% clay in the matrix) and derived from hydrothermally altered volcanic material. The youngest volcanic debris flow deposit is interpreted to be associated with the last known volcanic eruption, ~2360 calendar (cal) years BP. The other two debris flows may not have been directly associated with eruptions. Volcanic debris flow hazard inundation maps have been produced using the Geographic Information System (GIS)-based modelling program, LAHARZ. The maps provide estimates of the areas that would be inundated by future moderate to large-magnitude events. Given the available data, the probability of a volcanic debris flow reaching populated areas in Pemberton Valley is ~1 in 2400 years. Additional mapping in the source regions is necessary to determine if sufficient material remains on the volcanic edifice to generate future large-magnitude, clay-rich volcanic debris flows.

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