Late Wisconsinan glacial history in the Bonaparte Lake map area, south-central British Columbia: implications for glacial transport and mineral exploration1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.2Earth Sciences Sector Contribution Number: 20100093.

2011 ◽  
Vol 48 (6) ◽  
pp. 1091-1111 ◽  
Author(s):  
A. Plouffe ◽  
J.M. Bednarski ◽  
C.A. Huscroft ◽  
R.G. Anderson ◽  
S.J. McCuaig
Keyword(s):  
British Columbia ◽  
Mountain Pine Beetle ◽  
Mineral Exploration ◽  
Source Region ◽  
Mineralogical Composition ◽  
Glacial History ◽  
Ice Flow ◽  
Glacial Sediments ◽  
South Central ◽  
Late Wisconsinan

This study is centred on the Bonaparte Lake map area located in the southern Interior Plateau of south-central British Columbia. The reconstruction of the Late Wisconsinan glacial history of this part of the southern sector of the Cordilleran Ice Sheet incorporates (i) the analysis and interpretation of landforms of various scales, (ii) the sedimentology and stratigraphy of glacial sediments, and (iii) the geochemical and mineralogical composition of till and analysis of regional glacial dispersal of these components. The onset of the last glacial event was initiated by ice advancing westerly and southwesterly into the study area from an alpine source region located in the Cariboo Mountains. As glaciation intensified, ice from the Coast Mountains coalesced with the Cariboo Mountain ice over the Interior Plateau and developed into an ice divide around 52° north latitude, which resulted in ice flow to be diverted to a southerly direction over the study area. The two dominant ice-flow directions produced palimpsest dispersal that was measured by three tracers in till including thorianite grains and terbium concentrations in the heavy mineral fraction, and granitoid pebble percentage. The two main phases of ice flow identified within our study area have significant implications for mineral exploration that uses mineral tracing in glacial sediments, especially in the area underlain by the highly prospective Quesnel Terrane.

Integrating ice-flow history, geochronology, geology, and geophysics to trace mineralized glacial erratics to their bedrock source: An example from south-central British Columbia1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.2Earth Sciences Sector Contribution Number: 20100079.

2011 ◽  
Vol 48 (6) ◽  
pp. 1113-1129 ◽  
Author(s):  
A. Plouffe ◽  
R.G. Anderson ◽  
W. Gruenwald ◽  
W.J. Davis ◽  
J.M. Bednarski ◽  
...  
Keyword(s):  
British Columbia ◽  
Mountain Pine Beetle ◽  
Bulk Material ◽  
Magnetic Data ◽  
Ice Flow ◽  
South Central ◽  
Bedrock Geology ◽  
Zircon Crystallization ◽  
Pine Beetle ◽  
Exploration Risk

This study demonstrates how ice-flow history, geochronology, geology, and geophysics may be integrated to enhance the effectiveness of boulder tracing in glaciated regions affected by multiple ice-flow events. Mineralized felsic granitoid boulders (erratics) were discovered 18 years ago on a claim block located 10 km northwest of Little Fort, in the Bonaparte Lake map area (NTS 092P), in south-central British Columbia. Although the boulders have yielded significant gold concentrations (up to 4.15 g/t), their bedrock source is not known. The till near the boulders contains up to 1382 gold grains per 15 kg of bulk material with 75% of the grains having pristine morphology, suggesting a short distance of glacial transport. A U–Pb zircon crystallization age of 198.1 ± 0.5 Ma on one mineralized boulder indicates derivation from an Early Jurassic intrusion. Using a vector addition model based on regional ice-flow patterns, the most recent and detailed bedrock geology map, and recently acquired airborne radiometrics and magnetic data, the northeast sector of the Thuya Batholith (195–205 Ma) is interpreted as the most likely bedrock source of the mineralized boulders.

scholarly journals Glacial Stratigraphy of the Bulkley River Region: A Depositional Framework for the Late Pleistocene in Central British Columbia*

2006 ◽  
Vol 58 (2-3) ◽  
pp. 217-228 ◽  
Author(s):  
Andrew J. Stumpf ◽  
Bruce E. Broster ◽  
Victor M. Levson
Keyword(s):  
British Columbia ◽  
Late Pleistocene ◽  
Late Glacial ◽  
Ice Flow ◽  
Glacial Sediments ◽  
Fine Grained ◽  
Local Erosion ◽  
River Region ◽  
Flow Directions ◽  
Late Wisconsinan

Abstract A depositional framework for late Pleistocene sediments in central British Columbia was developed from the composite stratigraphy of glacial sediments found in the Bulkley River region. Nonglacial deposits correlated to the Olympia Nonglacial Interval, are overlain in succession by sub-till, ice-advance sediments, Late Wisconsinan (Fraser Glaciation) till, and late-glacial sediments. Due to local erosion and depositional variability, some of the units are not continuous throughout the region and differ locally in their thickness and complexity. At the onset of the Fraser Glaciation, ice advance was marked by rising base levels in rivers, lake ponding, and ice marginal subaqueous deposition. Physiography and glacier dynamics influenced the position of drainage outlets, direction of water flow, and ponding. The region was completely ice covered during this glaciation and ice-flow directions were variable, being dominantly influenced by the migrating position of ice divides. Deglaciation was marked by the widespread deposition of fine-grained sediments in proglacial lakes and glaciofluvial sands and gravels at locations with unrestricted drainage.

Lithostratigraphic and tectonic framework of Jurassic and Cretaceous Intermontane sedimentary basins of south-central British Columbia1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia.

2011 ◽  
Vol 48 (6) ◽  
pp. 870-896 ◽  
Author(s):  
Janet Riddell
Keyword(s):  
British Columbia ◽  
Mountain Pine Beetle ◽  
Sedimentary Basins ◽  
Hydrocarbon Exploration ◽  
South Central ◽  
Technological Advances ◽  
Exploration Risk ◽  
History Of ◽  
Geophysical Imaging ◽  
Glacial Cover

The south-central Intermontane belt of British Columbia has a complex architecture comprising late Paleozoic to Mesozoic volcanic and plutonic arc magmatic suites, marine and nonmarine clastic basins, high-grade metamorphic complexes, and accretionary rocks. Jurassic and Cretaceous clastic basins within this framework contain stratigraphy with hydrocarbon potential. The geology is complicated by Cretaceous to Eocene deformation, dismemberment, and dislocation. The Eocene to Neogene history of the southern Intermontane belt is dominated by non-arc volcanism, followed by Pleistocene to Recent glaciation. The volcanic and glacial cover makes this a difficult region to explore for resources. Much recent work has involved re-evaluating the challenges that the overlying volcanic cover has historically presented to geophysical imaging of the sedimentary rocks in this region in light of technological advances in geophysical data collection and analysis. This paper summarizes the lithological and stratigraphic framework of the region, with emphasis on description of the sedimentary units that have been the targets of hydrocarbon exploration.

Coalescence of late Wisconsinan Cordilleran and Laurentide ice sheets east of the Rocky Mountain Foothills in the Dawson Creek region, northeast British Columbia, Canada

2016 ◽  
Vol 85 (3) ◽  
pp. 409-429 ◽  
Author(s):  
Adrian Scott Hickin ◽  
Olav B. Lian ◽  
Victor M. Levson
Keyword(s):  
British Columbia ◽  
Flow Direction ◽  
Ice Sheet ◽  
Rocky Mountain ◽  
Ice Flow ◽  
Oxygen Isotope Stage ◽  
Digital Elevation ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet ◽  
River Valleys

Geomorphic, stratigraphic and geochronological evidence from northeast British Columbia (Canada) indicates that, during the late Wisconsinan (approximately equivalent to marine oxygen isotope stage [MIS] 2), a major lobe of western-sourced ice coalesced with the northeastern-sourced Laurentide Ice Sheet (LIS). High-resolution digital elevation models reveal a continuous 75 km-long field of streamlined landforms that indicate the ice flow direction of a major northeast-flowing lobe of the Cordilleran Ice Sheet (CIS) or a montane glacier (>200 km wide) was deflected to a north-northwest trajectory as it coalesced with the retreating LIS. The streamlined landforms are composed of till containing clasts of eastern provenance that imply that the LIS reached its maximum extent before the western-sourced ice flow crossed the area. Since the LIS only reached this region in the late Wisconsinan, the CIS/montane ice responsible for the streamlined landforms must have occupied the area after the LIS withdrew. Stratigraphy from the Murray and Pine river valleys supports a late Wisconsinan age for the surface landforms and records two glacial events separated by a non-glacial interval that was dated to be of middle Wisconsinan (MIS 3) age.

The thickness of Neogene and Quaternary cover across the central Interior Plateau, British Columbia: analysis of water-well drill records and implications for mineral exploration potential1This article is one of a series of papers published in this Special Issue on the theme of New insights in Cordilleran Intermontane geoscience: reducing exploration risk in the mountain pine beetle-affected area, British Columbia. 2Geological Survey of Canada (GSC) Contribution 20100036; Mineral Deposit Research Unit (MDRU, Department of Earh and Ocean Sciences, The University of British Columbia) Contribution p-261.

2011 ◽  
Vol 48 (6) ◽  
pp. 973-986 ◽  
Author(s):  
Graham D.M. Andrews ◽  
Alain Plouffe ◽  
Travis Ferbey ◽  
James K. Russell ◽  
Sarah R. Brown ◽  
...  
Keyword(s):  
British Columbia ◽  
Mountain Pine Beetle ◽  
Mineral Exploration ◽  
Three Dimensional ◽  
Research Unit ◽  
Mineral Deposit ◽  
Basic Knowledge ◽  
Data Sets ◽  
University Of British Columbia ◽  
Water Well

Analysis of over 10 000 water-well records has been used to produce new depth-to-bedrock maps for areas around five cities on the central Interior Plateau of central British Columbia: 100 Mile House, Prince George, Quesnel, Vanderhoof, and Williams Lake. Hitherto, exploration for mineral and hydrocarbon resources has been hampered by a lack of basic knowledge of the thickness of Neogene and Quaternary lithologies. Interpretation of these new maps provides first-order constraints on the localization of thick drift in pre-Late Wisconsinan bedrock paleovalleys, some of which are now buried. Basalt lavas of the Chilcotin Group are restricted to erosional remnants of previously extensive sheets emplaced onto an older peneplain. Our results confirm that the Neogene and Quaternary cover is primarily controlled by paleotopography and is generally thin and patchy across much of the region. Increased understanding of the three-dimensional distribution of cover produces a corresponding increase in the utility of geological, geochemical, and geophysical exploration techniques, and a reduction in the risk for future mineral exploration activities, especially when combined with more sophisticated data sets.

Quaternary stratigraphy of the Prophet River, northeastern British ColumbiaThis article is one of a selection of papers published in this Special Issue on the theme Geology of northeastern British Columbia and northwestern Alberta: diamonds, shallow gas, gravel, and glaciers.

2008 ◽  
Vol 45 (5) ◽  
pp. 565-575 ◽  
Author(s):  
Michelle Trommelen ◽  
Vic Levson
Keyword(s):  
British Columbia ◽  
Oxbow Lake ◽  
Laurentide Ice Sheet ◽  
Glacial Sediments ◽  
Boreal Plains ◽  
Fluvial Terraces ◽  
Quaternary Stratigraphy ◽  
History Of ◽  
Late Wisconsinan ◽  
Floodplain Sediments

Exposures in the Prophet River valley in northeast British Columbia provide a unique glimpse into the Quaternary history of the northwest Canadian Boreal Plains. The region shows evidence of Late Wisconsinan Laurentide glaciation in the form of widespread till, containing abundant erratic clasts derived from the Canadian Shield. Vertical sections along the Prophet River expose non-glacial and advance glacial sediments below this till. Pre-Late Wisconsinan non-glacial or interglacial floodplain sediments are interbedded with fluvial gravels at many sites. Macrofossils within horizontally laminated organic-rich black clay and silt indicate deposition on the floodplain of the paleo-Prophet River within an oxbow lake. The climate during deposition is interpreted to be similar to present, supporting a dominantly spruce forest. Wood obtained from eight sites provided non-finite radiocarbon ages, and one sample provided an age of 49 300 ± 2000 BP, which is also considered non-finite. Glaciolacustrine clays and silts, deposited during impoundment of eastward-flowing drainage by the advance of the Laurentide Ice Sheet (LIS) in the Late Wisconsinan, overlie the non-glacial sediments throughout the valley. A blanket of clast-poor, clay-rich till up to 20 m thick, and deposited by the LIS, drapes the glaciolacustrine sediments. Since deglaciation, the Prophet River has incised the valley and formed fluvial terraces at different levels above the modern river.

The late Quaternary stratigraphic record northwest of Montréal: regional ice-sheet dynamics, ice-stream activity, and early deglacial events

2006 ◽  
Vol 43 (4) ◽  
pp. 461-485 ◽  
Author(s):  
Martin Ross ◽  
Michel Parent ◽  
Beatriz Benjumea ◽  
James Hunter
Keyword(s):  
Late Quaternary ◽  
Late Glacial ◽  
Ice Flow ◽  
Glacial Sediments ◽  
Ice Stream ◽  
Digital Elevation ◽  
Flow Features ◽  
Ice Sheet Dynamics ◽  
Late Wisconsinan ◽  
Elevation Model

The Quaternary sediments of previously unstudied buried valleys and sections near Montréal are analyzed and other sites are revisited to further develop the stratigraphic framework of the St. Lawrence Lowland and to establish regional glacial and deglacial models. The southwest-trending buried valleys were investigated by stratigraphic drilling and high-resolution seismic profiling. The Quaternary succession consists, from base to top, of proximal glaciolacustrine sediments, two superposed till sheets (Argenteuil and Oka tills) of inferred Late Wisconsinan age, and Champlain Sea sediments. The glacial sediments of this sequence record an ice advance toward south (Argenteuil Till) followed by an abrupt ice-flow shift toward the southwest (Oka Till). Compositional and geomorphic data indicate that Oka Till is ubiquitous and is associated with a regional set of glacial landforms. The analysis of a regional digital elevation model in combination with published ice-flow indicators shows convergent flow patterns from the Ottawa–Montréal–Adirondack regions toward the Lake Ontario basin. Landforms produced by the inferred ice stream are locally crosscut by southward-trending ice-flow features. Hence southward flow in the upper St. Lawrence Valley seemingly took place in two distinct contexts: (1) during full glacial conditions, as ice margins stood at or near the late glacial maximum limits, and (2) during late deglaciation, as a post-ice stream reequilibration mechanism. Early deglacial events in the study area were also characterized by subglacial meltwater channelling and erosion along the valleys, subaquatic outwash deposition in glacial Lake Candona, and rapid infill of the valleys during the early stages of the ensuing Champlain Sea.

Density and distribution of advance regeneration in mountain pine beetle killed lodgepole pine stands of the Montane Spruce zone of southern British Columbia

2008 ◽  
Vol 38 (11) ◽  
pp. 2826-2836 ◽  
Author(s):  
Gordon D. Nigh ◽  
Joseph A. Antos ◽  
Roberta Parish
Keyword(s):  
British Columbia ◽  
Spatial Distribution ◽  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Spatial Scales ◽  
South Central ◽  
Advance Regeneration ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Pine Stands

Insect outbreaks, such as the current mountain pine beetle ( Dendroctonus ponderosae Hopkins) outbreak in lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) forests in British Columbia, are major disturbances in many forests. After an insect outbreak, the advance regeneration typically forms a new canopy, which may be adequate for timber objectives in some stands. Our purpose was to quantify and then model the abundance and spatial distribution of advance regeneration (trees <10.0 m tall). We sampled understory and overstory trees in 28 lodgepole pine stands in south-central British Columbia at two spatial scales: 0.1 ha plots and 25 m2 subplots. We developed models predicting advance regeneration abundance and spatial distribution. Density of advance regeneration averaged 2689 trees/ha (range 120 to 23 000 trees/ha), most of which were <1 m tall. Although advance regeneration was clumped, 75% of the subplots contained at least one individual. Models indicated negative relationships of advance regeneration abundance to overstory basal area and density. Over half the stands had enough advance regeneration to form new stands of adequate density, indicating that use of advance regeneration is a viable option in this mountain pine beetle outbreak and probably other insect disturbances.

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