QUATERNARY GEOWGY AND STRATLGRAPHY OF ïHE BEAVER MINES MAP ARE& SOUTHWEST ALBERTA
Philip J. Hoime Department of Earth Sciences
Graduate Program in GeoIogy
Submitted in partial fulfillment of the requirements for the degree of Master of Science
Faculty of Graduate Saidies The uni ver si^ of Western Ontario London, Ontario December, 1998
O Philip J. Holme 1998 National Libraiy Bibliothèque nationale ml ofcalada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 3sWeUigtari Street 395. rue Wellington OttawaON K1A ON4 Ottawa ON K1A canada Canada
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The author retains ownership of the L'auteur conserve la propiete du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni la thèse ni des extraits substantiels may be printed or otherwise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. ABSTRACT
Drift distribution, ice limits and Pleistocene stratigraphy were studied in the
Beaver Mines map area (82 G/8, 150 000). At its maximum, montme ice formed a
discontinuous sheet 320 - 350 m thick over most of the area. Two montane tills (Ml,
M2) occur at seven sections in the Cade valley and indicate that montane ice retreated
fiom a maximum (Ml) position beyond the mountain front to within the study area. This
was followed by a lesser readvance (M2), then ice retreaS stagnation, and the formation
of glacial lakes during deglaciation.
Coalescence of montane and continentai ice is indicated by the absence of
continental till (Cl) in most of Cade valley whose montane glacier presented a barrier to
continental ice. Absolute dating outside the snidy are& and lack of weathered horizons in this saidy, indicate that ail sediments investigated were fonned during the Late
Wiswnsinan Substage. ACKNOWLEDGEMENTS
While working on this thesis, 1have benefitted greatly fiom so many people in so many ways. 1would like to thank my supervisor Prof. Stephen R Hicock whose guidance, support and patience were essential to the completion of this work. Steve bought the beer more times than I could possibly count and was always available for consultation. 1am very grateful to the Geologicai Survey of Canada, and in particular,
Dr. Lionel E. Jackson Jr. who fully bded dlmy fieldwork and labwork. Lionel hired me on as a junior assistant in 1992, kept me on through the Eastern Cordillera NATMAP project and taught me how to map. Field summers with the NATMAP field crew, Lionel,
Liz Leboe, Kaz Shimamura and Ted Little were a blast. Kaz Shimamura worked his computer magic to produce my map and, with Liz Leboe, helped me out a lot with diagrams. T'ha& also to Stephen Mumu and Crystal Huscroft for their able and enthusiastic assistance in the field - thanks in particular to Crystai for being such a sport when the tmck went upside dom. Thank you to Bruce and Marianne Mowat for letting us stay on their ranch for two wondemil summers. Thank you also to the kind people of the Snake Trail who were so helpfil when 1rolled the tr~ckinto the ditch.
The time 1have spent here at Western is something 1will treasure. 1 couldn't possibly have made it through without the care and support of al1 my fnends and 1 can't imagine a better group of people. We celebrated the good times and the in between days too. With your help 1 was able to push through the lows (th& Rox). Finally, I would like to thank my family, who have given me endless support and encouragement throughout my Me. TABLE OF CONTENTS TKLEPAGE ...... i .. CERTIFICATE OF EXAMINATION ...... 11 ... ABSTRACT ...... 111 ACKNOWLEDGEMENTS ...... iv TABLE OF CONTENTS ...... v ... LIST OF FIGURES ...... viri LIST OF APPENDICES ...... x
CHAPTER 1 INTRODUCTION ...... 1 Regional Physiography ...... 3 BedrockGeology ...... 4 Non-local bedrock signifiernt to tü1 provenance ...... 6 Till Unit Desipatious ...... 6 Previous Work ...... 6 Quaternwy/Su$cial Geology ...... 6 Stuàïes of montane àri' ...... 8 Resentstudy area ...... 9
CHAPTER 2 METHODS ...... 10 Mapwork ...... 10 Field Mqping ...... 10 SectionWork ...... 12 Sampling ...... 12 CImt Fabric, Structurai Meclrsurements and Data Enw ...... 14
CHAPTER 3 DESCRIPTIONS AND OBSERVATIONS ...... 17 Drift / Geomorphology Distribution ...... 17 DriipDWbution ...... 17 Geomorpiology Disbibution ...... 18
section08 ...... 78 Se&n 09 ...... 78 Sectr'on 10 ...... 79 M~tninMiII (Seciion IO) Moraine ...... 80 Absulute Age of the Seîüments ...... 82 Secfion 11 ...... 84 Simple Data ...... 85 Taturd TernqDiagram ...... 85 Pebble&mpIes ...... 86 Interactions of Glaciers ...... 87
CHAPTER 5 GLACIAL HiSTORY. ABSOLUTE CHRONOLOGY AND REGIONAL CORRELATIONS ...... 89 Reconstruction of Glacial History ...... 89 MI Advance ...... 89 MlRetreat ...... 92 M2Amtume ...... 93 M2 Retteat and the Cl Mm*mum ...... 93 Degrafiotion ...... 95 Absolute Chronology ...... 97 Regional Corrdations of Drift ...... 100
6 CONCLUSIONS
WiFERENCES ...... 104 APPENDICES ...... 109 VITA ...... 123
vii
Section 11 .sedimentology and stratigraphy ...... 57 i . Photograph of Section 11; ii . Sheared and deformeci channel deposits .... 58 Orientational data fiom Section i 1 ...... 60 Orientational data from Section 11 ...... 61 Orientational data from Section 11 ...... 62 Temary diagrams of diamicton matrix grain-sire ...... 64 Temary diagrams of diamicton matrix grain-size control data ...... 65 Pebble lithology histograms ...... 68 Section correlations dong the Castle River and its tributaries ...... 73 Area of detailed glacial history reconstniction ...... 90 Onset of montane glaciation ...... 90 Maximum position of Ml montane advance and inferred ice flow ...... 91 Minimum position of montane ice during retreat fiom Ml maximum ...... 91 Readvance of montane ice to M2 maximum position ...... 94 Maximum continental advance (Cl) and still-stand 1 of montane ice ...... 94 Second still-stand of M.2 ice showing stranded. stagnating continental ice mass 96 Third still-stand of Castle Valley Glacier ...... 96 Glacial Lake Caldwell ...... 98 Glacial Lake Cardston ...... 98 LIST OF APPENDICES Appendix Page Appendix 1 : Pebble a-axis Fabric Data ...... 109 Appendix 2: Structurai and other orientational data ...... 112 Appendix 3 : Pebble lithology data ...... 113 Appendix 4: Grain-size analyses for diamicton matrices ...... 114 Appendix 5: Publications resulting fiom thesis work ...... 115 CHAP'IXR 1
INTRODUCTION
This thesis presents a reconstruction of Pleistocene glacial history for the 82 G18
(Beaver Mines) map area and a southem portion of the 82 Gl9 (Blairmore) map area in southwest Alberta (Figure l), based on surfi~cialgeology rnapping and stratigraphic investigations. Emphasis will be placed on the glacial history of the northeast corner of the study area. Geological mapping has contributed data on drift distribution, ice limitî and geomorphology while stratigraphic investigations of 11 CIE-bank exposures permitted interpretation and correlation of subsurface deposits. Mapping was conducted as a contribution to the surficial geology component of the Geological Survey of Canada's
Eastern Cordillera National Geoscience Mapping Program (NATMAP) Project which involved the rnapping of surficial and bedrock geology in twelve contiguous 150 000 scale mapsheets. The Beaver Mines sheet was mapped, and six exposures investigated, during the
1995 and 1996 field seasons. Five additional exposures were visited and described during the surnmers of 1997 and 1998. Mapping of the Blaimore rnapsheet was conducted by LE.
Jackson. Jr. and EX. Leboe.
The study of Pleistocene glaciation dong the eastern edge of the Canadian Cordillera contributes to the Iarger ongoing study of North American Quatemary glaciation. During the late Pleistocene almost ail of Canada was giaciated by either the continental Laurentide
Ice Sheet (LIS) originating fiom the Canadian Shield or the montane Cordilleran Ice Sheet
(CIS)formed by the coalescence of alpine and piedmont glaciers in mountainous regions of
British Columbia and Alberta. Only a very smali portion of Canada, dong the eastem Figure 1. Location of shidy area and Eastern Cordillera NATMAP Project Cordillera, was affecteci by both ice masses. The study area lies within this narrow Wnge of land and investigation of its deposits provides a special perspective on late Pleistocene gIaciation.
In this thesis, two tenns will be used in reference to the region included in the study. nie term rnap mea will be used in the context of suficial sediments mapped by the writer
and refers strictly to the Beaver Mines rnap area which encompasses approximately IO00
lan' of highly varied topography in the Rocky Mountain Front Ranges, Foothills and Interior
Plains immediately southwest of the town of Pincher Creek, Alberta. The term srudy mea
will be used in a stratigraphic context and will inciude both the rnap amand the southem fringe of the adjacent Blainnore mapsheet to the north where three stratigraphic exposures were described. The largest waterway is the Castle River which drains the Castle River valley (CRV)and its two main tributaries, the Westcastle and Carbondale river valleys.
Regionai Physiography
For the purpose of describing drift distribution (presented later in Chapter 3) the
Beaver Mines rnap area is subdivided into four distinct physiographic subregions: Rocky
Mountain Front Ranges, Mountain Front, Foothills and Cade River Lowland (Holme 1997;
Holme et al. 1998; see appendix 5). The Clark Range of the Rocky Mountain Front Ranges occupies the southem third of the rnap sheet and exhibits the highest relief with numerous peaks over 2438 m (8000 fi). The Mountain Front subregion consists of a gently sloping, low-lying region between the Clark Range and the Foothills to the northeast. The Foothills subregion is typified by a series of diswntinuous, sub-parallel hills trending northwest- southeast across the centre of the rnap reflecting the general strike of their sedirnentary beds . Elevations in this part of the Foothills rareIy exceed 1524 m (5000 fi) though some attain
1676 m (5500 ft). Another significant component of the Foothills subregion is the Blahnore
Range in the aorthwestem-most corner of the rnap area where elevations reach 1829 m (6000
ft). The northem edge and northeastern corner is dominated by the Cade River Lowland
and is typified by a broad, gently undulating to flat plain incised by numerous small streams.
Elevations in this subregion are the lowest in the map area, ranging hm1341 m (4400 fi)
to 1189 m (3900 ft).
Bedrock Geology (Figure 2)
The Lewis Thmt is the dominant structural feature in the rnap area and serves to
divide the region into two main structural subdivisions: Roclcy Mountain Front Ranges and the Foothills (Fermor and Price 1983). Heavily folded and faulted middle Proterozoic Belt-
Purcell Supergroup rocks of the Clark Range form a signifiicant component of the Lewis thmt sheet, a large allochthonous salient extending south fiom North Kootenay Pass into
Montana (Fennor and Price 1983). The Lewis thnist sheet has been dispiaced over 80 km to the northeast to overlie Mesozoic strata and its surface trace can be seen dong the mountain front where the underlying Mesozoic strata are exposed (Pnce 1962). Slope failures are ubiquitous in the Clark Range where erosion of outcropping Mesozoic rock bas undermined more resistant Proterozoic rock, resulting in catastrophic failures (Jackson
1995).
The larger subregion of the Foothills subdivision consists of late Cretaceous clastic strata which are extensively faulted by numerous southwestward dipping thnists (Price
1962). In contrast, tbnists in the Blairniore Range dip rnainly to the wat due to a re-entrant 1-1 1-1 Tertiary; dtiefly shale, siîtstone and Paieozoic; chiefly Iimestone, dolomite, sandsto ne sa nddone and shak m CRhceour; chiefly shak, piltslDne and Precarnbrfan; chiefîy igneous and metamorphic, sanâsto ne mfnorpadirnentarymcks
Figure 2. Bedmck geology of western Canada (after Klassen 1989). lying immediately south of the Blairmore Range (Femor and Price 1983).
Non-local bedrock signifiant to till provenance (Figure 2)
Clasts originating in the Keewatin region of the Canadian Shield, hereafter refend to as shieldcI&s&,are important to the determination of till provenance in southwest Alberta
No source exists in the Cordillera or Plains for schist, gneiss, rnigmatite, metaquartzite, or granitoid rocks with distinctive pink feldspar as are found in the Canadian Shield. Given that the source of these clasts is over 750 km to the northeast of the map ara, the only possible mechanism for their transportation into the area is by glacial ice emanating fiom the
Keewatin spreading centre.
Till Unit Designations
Till unit designations used in this study are based on ice provenance and, if necessary, stratigraphie position. The descriptor M is used for a till containing no shield clasts while
C is used for tili that does contain shield clasts. The numerical modifier following an M or
C indicates the relative position of the ti11, with 1 being stratigraphically Iower than 2. In the saidy area two montane advances are recognised: an earlier one (MI)and a later one (Mî); only one continental advance is identified and is Iabeled C 1.
Previous Work
Quatetn.y/surficial Geofogy
Initial investigations of Pleistocene stratigraphy in southem Alberta began in the late
1800's during general reconnaissancestudies of western Canadian geology. This ini tial work spurred numerous, more detailed shidies as workers attempted to decipher the PIeistocme activity of continental ice sheets (those originating in the Keewatin region of the Northwest
Temtories). Investigations of drift distribution, Quaternary stratigraphy and ice limits have produced two contradictory models of southem and central Alberta's Pleistocene glacial history. These two hypotheses are as follows:
1) Up to four continental glaciations are represented by saatigraphy dong the
Oldman, Belly and Waterton rivers, and ice limits and paleosols in the Foothills and
Rocky Mountains.
2) Continental drift was deposited during a single incursion of ice from the Keewatin
region during the late Wisconsinan.
For comprehensivesummaries of previous work conducted in the adjacentBlairmore,
Brocket and Pincher Creek map areas, and the Waterton, Caniston and Raley map areas the reader is referred to Leboe (1996), and Littie (1995), respectively.
Dawson and McComell (1895) conducted the first significant investigation of
Quaternary stratigraphy in southwat Alberta. From their study of sediments in cliff-bank exposures near Lethbridge, Alberta, they found two boulder clays bearing shield clasts, and separated by silt beds. This sequence of continental tills was underlain in the west by a montane boulder clay that graded eastward into a quartz-rich gravel. Al1 deposits were considered to be pre-Wisconsinan, with each boulder clay resulting from a different glaciation. This multiple-glaciation hypothesis has been modified and refned by subsequent studies (e.g. Alley 1973; Stalker 1977; Stalker and Harrison 1977; Jackson 1980; Jackson et al. 1989) based largely on the re-interpretation of stratigraphy exposeci in the Oldman river basin near Lethbridge. An altemate hypothesis was proposed by Horberg (1954) fiom 6is study of
subsurface stratigraphy along the Oldman, Belly and Waterton nvers. He concluded that al1
continental drift on the Intenor Plains was deposited by a fluctuating ice margin durhg a
single, late Wisconsinan glaciation. This hypothesis was corroborated by Wagner (1966) and
Bayrock (1969) and has since received renewed interest as ment detailed stratigraphic
studies in the Foothills and western Interior Plains (Little 1995; Jackson et al. 1996; Leboe
1W6), and applications of radiometnc and cosmogenic dating techniques in the Foothills and
central Alberta (Liveman et al. 1989; Young et al. 1994; Jackson et al. 1997) have lent
Mersupport. These latter studies, although not the first to apply absolute dating
techniques in the area, provide crucial data to the reconstruction of glacial history in both
stratigraphic and geographic contexts.
Studies of montane dnfl
With few exceptions, past studies of drift and subsurface smtigraphy have focused on the activity of continental ice sheets while little attention has been given to drift deposited by Cordilleran mountain glaciers. Investigations that included a significant montane component have been wnducted in Montana, southern Nb~aan4 to a limited extent, in the Main Ranges of the Roc& Mountains.
Dawson and Mccomeli (1895) identified montane quartnte grave1 at the base of
Pleistocene stratigraphic exposures along the Oldman River valley as "Saskatchewan gravels" and conelated them to a moatane boulder ciay farther west, tentatively assigning both to an Albertan (later Nebraskan) stage. Calhoun ( 1906) and Alden and Steb inger (19 13) rejected a glacial ongin for the graveis. Calhoun attributed them to pre-glacial fluvial activity during the Tertiary Penod and considered overlying montane drift to be of
Wisconsinan or Iowan (now an obsolete tem) age. Alden and Stebinger believed the gravels to be interglacial fluvial deposits reworked from pre-Wisconsinan drift and correlated overlying montane drift on the Plains to the Wisconsinan Stage. Alden and Stebinger Mer recognised that montane drift preserved on uplands (e.g. Cloudy Ridge and Mokowan Butte) was much more weathered than that preserved in river valleys on the Plains and therehe assigned it to a pre-Wisconsinan glaciation. Horberg (1 954), working in the Waterton Park area just north of the international border, recognised two ages of montane drift exposed in valleys: early Wisconsinan drift associated with moraines lying about 10 km from the mountain front, and late Wisconsinan drift associated with moraines lying within them. He used the texm Kennedy Drift to refer to pre-Wisconsinan drift preserved on Mokowan Butte.
Richmond (1960) correlated moraines and montane drift on the Plains to the Pinedale and Bull Lake glaciations of Wyoming.
Stalker (1963), in his description of southem Alberta's Quatemary smtigraphy, interpreted Mccomell's Saskatchewan gravels as pre-glacial (pre-Nebraskan). He regardeci the overlying montane till as having been deposited during the first inmionofglaciers, an4 therefore probab ly Nebras km:"If Nebras kan ice reached this region, as is probable, this till is Nebraskan in age." (Stalker 1963, p. 4).
Resent study area
The present study area was previousiy mapped at 1:250 000 scaie by Stalker(1962).
Stalker retumed in 1963, as part of his review of Quatemary stratigraphy in southwest
Alberta, to describe stratigraphy at sites dong the Cade River (Stalker 1963). He assigned till found there to pre-Wiscunsinan glaciations and concluded bat a continentai ice sh- did not reach southwestern Alberta during the Wisconsinan glaciation. The area was later mapped at 1:150 000 sale by Wagner (1966) for his PhD. fieldwork, during which he desaibed drift and geomorphology in numerous valleys throughout the study area. Wagner also describd stratigraphy at five exposures within the present shidy ma. He found no evidence to suggest that a non-glacial interval was represented anywhere in the saatigraphy O and therefore correIated al1 drift on the Plains to the late Wisconsinan.
In 1969, Stalker exarnhed stratigraphy at a site almg the Cade River (section 10 in this study) which led him to conclude that a buried montane terminal moraine dahg to between 6200-7200"C yrs B.P. was preserved there (Stalker 1969). This work was disputed by Wagner and Eschman (1970) who rejected both the presenceof the moraine and Staiker's proposed age for the drift (see Chapter 4). For clarity, the Methods chapter will be subdivided into three main components: mapwork, section work and sarnpling.
Mapwork
Field Mqphg
The s~cialgeology mapping component of the study consisted of preliminary airphoto interpretation, field sampling and description of sediments (ground-truthing), delimiting map-unit polygons on the airphotos and then tramferring them to the topographie mapsheet for digitising. Any nahtral or artificia! exposures of sediment were examineci and their stratigraphy descnbed.
Preliminary mapping was done using 1 : 60 000 scale airphotos to delimit surficial gedogy map units based on topography and geomorphology. Once the airphoto work was completed for an area, ground-tmthing was then conducted to achieve more detail and betîer resolution of the initial rnap unit boundaries. Regions where the surficial geology couid not be interpreted during preliminary airphoto work received special ernphasis during ground- truthing to ensure proper classification.
Ground-truthing was generally conducted in a systematic rnanner with road stops every 1-1.5 km to ensure optimal coverage throughout the map area. This regimen was easiest to follow in the northeastem quater of the map ana where roads are built on the township and range-grid system with rightsf-ways every square mile. Active secondary and grave1 roads on many right-of-ways in this area permitted description stops to be made at the desired grid points. In the rest of the rnap area passable roads are generally restncted to major river valleys or otherwise controlled by hopography with only deactivateci logging roads providing access to more remote regions. As a result, description stops are located sornewhat sporadically across the greater part of the map area
Most stops involved the use of a hand-held auger to retrieve the upper 1 m of sediment for description and sampling. This method proved practical except in excessively stony sediments where it was necessary to dig pis. Due to the corkscrewing action of the auger, extracteri sediments were highly disturbed and any stratification, lenses or subtle feahires were destroyed. However, characteristics such as sediment texture and degree of consolidation were not altered so these criteria were generally used to differentiatesediment units at many stops. Where a suspected till was encountered with the auger (suggested by the presence of an over-consolidated diamicton), a pit was dug to permit more detailed description and to retrieve undisairbed material for sampling. Sampling was mainly limiteci to suspected tills and commonly involved taking sarnples of diamicton matrix for textural and geochemical analyses, and a sample of 50 pebbles.
In total, over 300 stops were made throughout the map area with many located dong roadways in the northeastem third of the mapsheet. This emphasis was necessary to map drift distribution with sufficient detail to determine ice limits in this region of relatively wmplex stratipphy.
Transportation throughout the rnap area was achieved by 4x4 truck, mountain bike,
Quad-mer al1 terrain vehicle, helicopter and on foot. In general, access to the map area favoured the northeastem third where human habitation was more dense and topography more subdued. The 4x4 truck was the main mode of transportation while the other foms were used where necessary in the more remote or less accessible portions of the rnapsheet
htion Work
In total, eleven cliff-bank exposures were desded and sampled; eight were found within the rnap area and three were present dong the southem edge of the Blaimore sheet to the north (Figure 3). The eleven sections provide a representative cross-section of subsurface deposits dong the CRV and its tributaries whiie emphasising the northeastem corner of the map area where the stratigraphy is more cornplex- Sections selected for description and sampling exposed sediments which were seen to be in situ and not slumped
(or otherwise redeposited by gravity). This critenon is of paramount importance because stratigraphie relations are invalidated, and measurernents of clast fabrics and glaciotectonic deformation stnictures become meaningless, if the sediment bas undergone postdepositional resedimentation. Additional aitena were that the section provide a significant exposure of stratigraphy and be located in a region for which knowledge of the subsurface seatigraphy was of pwticular importance in determining regional glacial history.
Stratigraphy in the northeastem third of the map area was considered to be the moût usehl for determining glacial history. It was known that continental ice advanceci fiom the northeast and therefore evidence for any interaction between it and the montane ice sheet would likely be found here.
Sampling
Field sampling was conducted to &eve material for bulk texture, geochemical and Physiographic regions
.-. . . :.I Fmnt Ranges -. l -Mau* -_- pebble lithology analyses. Sampling was restncted to suspected tills. A buik diarnicton sample consisted of approximately 1 kg and was taken for the purpose of conducting grain- size anaiysis, Atterberg bits tests and heavy minera1 rnalysis. A geochemical sample consisted of approximately 300 g of diamicton with the larger clasts removed and was collected for Chittick analysis of carbonates (Dreimanis 1962). Metal-bladed tools were not used for the collection of geochemical samples to avoid contaminatingthe sample. A pebble sample consisted of 50 stones and was taken for the purpose of determinhg the lithology of the clasts and thus indicating ice provenance should the diamicton later be interpreted as till.
Texhiral and geochemical analyses for 1995-1997 samples were conducted by
Miriam Wygergangs at the GSCs Quaternary Services Laboratory while 1998 samples and pebble samples were analysed by the writer. The grain-size boundaries used for textural analyses were sand (2 - 0.063 mm), silt (0.063 - 0.002 mm) and clay (< 0.002 mm).
CIast Fabdc, Structurai Measurements and Data Entty
Three dimensional pebble a-axis fabrics were measured in selected diamictons at cliff-bank exposures. For each fabric the trend and plunge of pebble a-axes were recorded from about 50 cIasts with a:c ratios of no less than 3:2. Fabrics were measured in an area approximately 1 m20n the exposure face, generally fiom the same place on the exposure where sarnples were collected.
Where time permitteci, diamictons were carefùlly cleaned of sunace slump and examined for planar features and glacially modified clasts (i.e. those with surface striae and lee-ends). The orientations (strike I dip; or trend) of these various features were recorded.
Statisticd analysis and plotting of orientational data were done using StereoNet for Windows (1.41) developed and sold by Per Ivar Steinsund (Varden 94, N-9018 Tromsii,
Norway). Measurements were plotted on a lower hemisphere Schmidt equal-area stereonet projection (hereafier referred to as a stereonet)using the method ofWoodcock (1977). Two plots of each dataset were made: a scatter-plot of the points themselves, and a contour plot in which point density is represented using contours derived using a step-f'unction. Contours were plotted, at 40% resolution, as 1,2,3 etc. points per 100 1 n % of the projection area where n is the number of measurements. The modality of fabric distribution patterns was described using the approach of Hicock et al. (1996).
The orientation tensor method of Scheidegger (1965) was used to calculate eigenvalues for the fabnc data. This method is used to determine mean vecton of orientational data (VI, V, and V,) and the degree to which data cluster about these vectors
(S,, S, and Sa; (Woodcock 1977). In this scenario, VI is the vector of strongest mean orientation, V, is tue vector of weakest mean orientation and V, is perpendicular to both; SI is the strength of clustering about the VI eigenvector while S3and S2 eigenvalua indicate the clustering of points about the V, and V, eigenvecton respectively, so that S, + $ + S3 = 1
(Woodcock 1977). The applicability of these statistics to the interpretation of ice-flow direction and / or sediment genesis is limited by the modality of the fabric pattern. The V, eigenvector usually coincides with a fabric's main orientation mode only if the distribution of points is unimodal and will often lie between modes if the fabric shape is bimodal or multimodal (Woodcock 1977). The use of pebble fabrics for the interpretation of sediment genesis can be enhanced by the study of their modal distribution (e.g. Hicock et al. 1996).
It is appropriate at this point to define the term till as it will be used in this study.
The broad definition used will be that proposed by the INQUA Commission on genesis and lithology of Quatemary deposits, "Till is a sediment that has been transported and subsequently deposited by or from glacier ice, with little or no sorthg by water", (Dreimanis
1989; Menzies and Shilts 1996; Benn and Evans 1998). Usage of the tem lodgment tif2 will imply a "sedimentdeposited by plastering of glacial debris from a sliding glacier sole by pressure melting or other mechanical processes", preirnanis 1989, Benn and Evans
1998). The term &formation tiff will refer to a "rock or sediment that has ban disaggregated and completely or largely homogenised by shearing in a subglaciai defoming iayer" (Benn and Evans 1998, p. 390). CHAPTER3
DESCRIPTIONS AND OBSERVATIONS
Drift / Geomorphology Distribution
Drift cover throughout the Beaver Mines map area shows considerable variation
(Figure 4), but strong distribution patterns can be identified. For the purpose of describing drift and geomorphology distribution, sedimentological terms will be used that indicate genetic interpretation (e.g. till, esker) instead of purely descriptive terms (e-g. diarnicton, sinuous grave1 ridge). This is necessary for clarity and to properly convey the overall picture of surficial geology in the map area. Hence, this subsection is a description of the Beaver
Mines surficial geology rnap sheet (Figure 4).
Dr@ Distribution
In the Rocky Mountain Front Ranges till deposits are mainly limited to valley bottoms and occasional, thin veneers plastered onto valley sides, while higher elevations are dominated by bedrock outcrops. Highiy active mas-wasting processes have resulted in burial or reworking of drift throughout the region; well established alluvial plains in the
Westcastle, Cade and Mill valleys indicate signûicant erosion and reworking of drift in the very bottoms of those valleys.
The ubiquity of landslide activity in the Clark Range created difficulties for attempts to determine drift limits within mountain valleys. Suficiai sediments in the Pincher,
Drywood and South Drywood valleys were found to be completely colluviated. Mill valley is dominated by alluvial plain and landslide deposits with drift limited to a thin veneer dong the base of the vailey and thicker depsits in three cirques on the east fia& of Windsor
Ridge. A broad alluvial plain flanked by numerous fluvial tenaces occupies the base of the
Castle valley. Five significant landslide scars cover much of the west slope of Windsor
Ridge. The eastem slope of Lys Ridge, hmthe southem boundary of the rnap northward for 3.5 km, is covered with a thin veneer of drift. No stops were made dong this slope, and since colluvial cover was not evident, the presence of drift was assumed. The Westcastie vailey has extensive colluvial deposits dong its flanks with an apron of debris commonly extending downslope to the alluvial plain at the base. Bodies of drift are present in cirque floon and in the base of the vdley where colluvial material has not covered it Stops made in Middle Kootenay Pass revealed outwash gravel, indicating the former flow of meltwater through the pass at elevations over 1920 m (6300 fi).
At the mountain fiont and in the Focthills, till cover dominates with only the
Blairmore Range, and higher peaks in the central portion of the Foothills, showing significant exposures of bedrock. In general, till blankets many vaileys, lowlands and uplands in the Foothills, although large bodies of glaciofluvial outwash fi11 many large valleys. In the northeast corner of the rnap area, the Plains are blanketed by a uniform cover of gtaciolacustrine silt and clay beiow about 13 10 m (4300 feet). In most places these deposits form a flat or gently undulating plain that rnasks the underlying topography.
Continental till is present at higher elevations above the glacial lake limit and within the region ovemn by the LIS.
Geomorphology Distnmbution
The most significant glacial geomorphologic features in the Rocky Mountain Front Ranges are abundant cirques and arêtes. End moraines are present in some cirques while lateral moraines are preserved dong the flanks of some large vdleys. Small meltwater channels are present but rare. In the Mountain Front and Foothills regions large meltwater channels are present and small meltwater cha~e1sare common. Eskers occur in clustersjust south of the confluence of the Cade and Westcastle rivers, near the confluence of Lost
Creek and Carbondale River and at the mountain Front dong Mill Cr& A couple of small eskers are present in Beaver Mines Creek valley while crevasse fills and hummocky terrain occur at the mouth of the vailey just north of the 507 Secondary road. Underlying topography in the Plains region has been obscured by the cover of lacustrine deposits so no glacial geomorphologic features are exposed in this region.
Ice Limits
Introductory Retnarks
Three ice limits are present in the study area, those related to the Ml, M2 and Cl advances. The search for ice limits focussed on the Cade River Lowland and Foothills in the northeast quater of the map area because drift ftom both montane and continental ice sources occurs there.
Detemination of an M 1 or C 1 limit at a given site was done by hiking up a hiIl slope and looking for emtics of montane or Laurentide lithology, respectively. If either were found to be present on lower slopes, but absent on upper slopes, the elevation where they became absent is regarded as the upper iimit of ice influence. The correlation of elevation data from several foot traverses on different hiils permits a reasonabie estimate of ice limits.
Limits associated with the M2 advance were much more difficult to locate or estimate because no diagnostic aiteria could be found which would clearly distinguish them from M 1 limits. The past ocmence of M2 ice can be infemed where two montane tills are found in cliff-exposures (e.g. along the CRV), but a limit of the extenf of M2 ice could not be determined in this study.
A complication arising in an area that has experienced more than one glacial advance is the potential for reworking of drift by later advances. Erratics diagnostic of a particular ice source can be transporred by a second glacier to a much higher elevation than the glacier which had initidly emplaced them. In this study a remring pattern of the Ml lirnit occ~gat higher elevation than the Cl limic combined with the stratigraphie indications that the Ml advance preceded the Cl advance, helped to alleviate this problem.
Ice Li?nits
Ice limits associated with the Ml advance are preserved along valley wdls and mountain slopes in the Front Ranges and at the Mountain Front and along the flanks of some high Foothills northeast of the Front Ranges. Some lateral and end moraines are identifieci on the map (Figure 4) as beingM.2, but this interpretation is tentative. The presence of these features near the mountain front reveals that they were deposited by a small alpine glacier, not a large ice sheet. They must postdate the Ml advance because they would have been destroyed by its advance had they preceded it. Ice limits associated with the C 1 advance are preserved dong the northeastem slopes of hogback ridges in the Foothills.
The mapping of drift along the Roclq Mountain front and the associated search for ice limitc were mainly done using airphotos and making occasional spot checks. Numerous field stops were made along the mountain dope in the soudieastern quarter of the map where passable roads provided access to naturd gas extraction sites. The majority of these stops,
however, did not provide the opportunity to determine limits, but rather were used to
establish the presence or absence of drift at a given location because roads there parallel
slope contours rather than cross them. AIthough highly active mas-wasting processes dong
the mountain front made the estimate of a drift limit d.Ecult, an approximate range of 1494 -
1646 rn (4900 - 5400 feet) was detemined based largely on breaks in dope as seen on
airphotos. The highest elevation of drift was found on the north dope of Table Mountain
which is located in the middle of the map area.
Elevations of Luteral Moraines
At the mouths of some valleys, laterai moraines can be seen extending beyond the
momtain front. The highest elevations of these were recorded for correlation with other ice
limit data. In South Drywood valiey a moraine is preserved dong the east flank and reaches about 1676 m (5500 A) at the mountain front A lateral moraine on the west flank of
Gardiner Creek valley is preserved up to 1798 rn (5900 A) at its up-valley extent.
Stratigraphic Sections
Descriptions of cliff-bank exposures are summarised below as they occur dong the
Cade River and its tributaries from the mountain front to the Plains. Section diagrarns are accompanied by more detailed field notes in culumns to the right of each section. The term ped is purely descriptive and does not imply weathering or soi1 foxmation. A ped refen to a small (c 1cm) block of diamicton. Al1 section annotations are based on the legend given in figure 5. Plots of orientational data utilise symbols given in figure 6. LEGEND
SEDIMENT TBCWRES AND PROVENANCE: SEDIMENTARY FEATURES:
A) syndepositional loading or A) day or silty day slump stnidures
8) silt
C) sandy silt C) glaaogenic shearing -
E) pebble gravel 1) montane E) sîriated boulder pavement
2) rnixed continental and montane F) fluvial lag gravel
F) cobble gravel 1) montane
2) mixed continental H) ice-weâge psuedornorphs and mantane cryoturbation
G) diamicton 1) large plucked 1) mixed continental bedrodt blocks and montane J) paleosol, soif 2) montane
BEDD ING:
Gap in cdumn; no pattern
M) graded: nomaüreverse
CONTACTS: N) rippled
A) conforniable SAMPLE TYPES:
B) emsional A) pebble sample #X taken at this height C) grada tional 8) 3D pebble fabric #X taken at this height O) sheared C) diamidon sandlsilt/day texture El obscureci sample #X taken at this height Tx
Figure 5. Legend for section diagrams $ main eigenvector
single data point
= pole to plane f clast lee-ends striae on upper surfaces of stones
Figure 6. Legend for fabric diagrams (scatter plot and contoured as explained in texi). Sectiin O1 (Figure 7)
Section 01 is located about 3 km southwest of Beaver Mines Lake on Castle River where it emerges fiom the mountains. The exposure is 28.9 m hi& 60 rn wide and is incised into the lower dopa of the mountain hntjust north of Southfork Mountain.
The exposure comists of fve uni6 inciudhg a slump covered base (unit A). Unit B comprises dYee unsorted gravel beds interstratifieci with two stony silt and clay beds. The lowermost grave1 bed fines upward and is well-imbricated throughout, while the other two grave1 beds coarsen upward and display imbrication in their upper parts. The stony silt and clay layen are rhythmically bedded, with the lower possessing dropstones. Contacts between the silt and clay beds and the gravel beds are abrupt. Unit C, overl y ing the topmost gravel bed of unit B, is a moderately stony diarnicton with a highly consolidateci, pinkish sandy silt mairix. Three striae were measured on a large boulder (Figure 8). Ovedying this is unit D, a poorly to moderately sorted grave1 with horizontal stratification in the centre of the exposure and foreset beds at the upstream end. The topmost unit is E, thinly bedded sands displaying some sofi-sediment defornation.
Section 02 (Figure 9)
Section 02 is located about 1 km downstream €rom the confluence of the Cade and
Westcastle rivers on the outside of a sweeping bend in the (Castle) river. The exposure is
38 m high by about 200 m wide and is incised into an unduiating plair. east cf the river. The contact between bedrock and Quaternary sediments was exposed at an outcrop 50 m upstream f'rom the main description site where the cliff-bank section was 15 m high and slmp covered- SECTION 1 Coldfoot Section cnGia(~Minar):893a)5.~1
Figure 7. Section 01 - sedimentology and stratigraphy Section 1 striae N=3
Figure 8. Orientational data from Section I SECTlON 2 Castle Bridge Section 82(38(~~):~.5475300
...... 1 .+834 o...... 4::::::::::::::bjjiiJi;:::::::::::;::i..-.-...... -1 ...... t:::::::::::::: i::::::::::::::
Figure 9. Section 02 sedirnentology and stratigraphy Five sedirnentary units were identifed at section 02, including a slump-covered base
(unit A). The lower 10 m of unit B is stratifieci, foreset and extensively cross-bedded sand.
The sand is uniform, medium-grained and stoneless. In its upper part, the sand is interbedded with 10 cm thick, discontinuous, cementeci and uasorted gravel beds. Overlying this is about 10 m of unsorted gravel with discontinuous, well-sorted gravel lenses; it becornes interstratified with sand and gravel in the upper 3 m of the unit. The lower part of unit C consists of a consolidated, stony diamicton with a blocky ped structure and abrupt lower contact. A boulder concentration can be seen at the base of the unit with boulders up to 1.5 m in diameter. The upper part of the unit is a less consolidated diamicton with a weak ped structure. There is a gradational contact between the two diamictons about 1 rn thick and there are isolated sand lenses 24cm thick just above this contaa. Unit D is an imbricated, moderately sorted pebble and cobble grave1 interstratified with sand. Unit E is silt and fine sand.
Two pebble a-axis fabrics were measured in unit C (Figure 10): the lower fabnc
(fabric 01) was done 1.5 m above the unit's lower contact while the upper (fabric 02) was done about 3 m higher. Fabnc 01 is fairly weak (SI=û.5607S,=û. 103) with a spread bimodal distribution (secondary mode transverse to main mode) suggesting flow from the southwest
(V,=243°/260). A pole to a fiacture in the lower part of the unit does not appear to relate fabnc modes. Fabric 02 is considerably stronger than fabric 01 (S,=û.698, $=0.097) and possesses a spread unimodai distribution suggesting flow from the east (V,=û90°/170).
Seciion 03 (Figure 11)
Section 03 is located about 7.1 km south of the harnlet of Beaver Mines dong the 774 Section 2 fabric 1 C - lower N = 50
Section 2 -. unit C -
Figure 10. Orientational data frorn Section 2 SECTION 3 Gasline Section ôî Oa (WW): 699851.545473326
II- A4 / A j T2 PZ* / TI pi+ ?'.,'.* \\\yA Figure 11. Section 03 - sedirnentoiogy and stratigraphy Seconday road. The section ocnirs in a roadside ditch through which flood waters in 1995
surged to scour an exposure 550 m Long and up to 4 m in depth. For the length of the
exposure the road rises to the south at about 5O, but does not provide an ideal cross-section
through the stratigraphy because the sedimentary beds are also inclined at about the same
angie.
The exposure comprises two units overlying bedrock. Unit A directly overlies bedrock and in its lower part consists of highly consolidated and cuhesive diamicton with an abrupt upper contact. The upper part of unit A is a consolidated but non-cohesive, stony diamicton with a clayey silt matrix in which possible fiow features were seen. Unit B is poorly sorted, slightly imbricated gravel. A 3 rn by 6 m inset of silt and sand deformed with load features is present within unit B.
Two pebble a-axis fabrics were measured in unit A (Figure 12): one in the lowerpart
(fabric 03) and one in theupper (fabric 04). Fabric 03 is quite cornplex and weak (S1=0.441,
S3=û.241). Although a single distinct concentration can be seen in the contour p10~ numerous steeply plunging clusters occur in a multimodal distribution. The main eigenvector fails between clusten (V,=078*/05*). Fabric 04 is aiso multimodal and has similar eigenvalues (S,=û.495, S3=û.145), but lacks any panicular concentration of points.
Three striae on the top surfaces of Stones are parailel to a small west-southwest - east- northeast fabric mode.
Sedm 04 (Figure 13)
Section 04 is located dong the southern edge of the Blairmore (82 G/9)mapsheet in a deep gully cut by a tributary stream of the Castle River. The entire exposure, including Section 3 fabric 3 unit A - lower part N N = 30 N
I
Section 3 fabric 4 A- upper N = 30
Figure 12. Orientational data from Section 3 SECTION 4 Tapay Section 82 619 (Bbimiore): 698330.5487100
I Smg .t::::::::::::::...... -. - - 77"= zz~a=rs
Figure 13. Section 04 - sedimentology and stratigraphy bedroclq is 35 rn in height. The sediment exposure is about 15-20 m wide at the bedrock contact and narrows toward the top.
The section exposes Quaternary sediments down to a bedrock contact and consists of three units of which the topmost (unit C) is slump. The lower part of unit A is a diamicton with a compacted, but not indurated, silty sand matrix which displays no fissility. In the middle part of the unit, this changes abruptiy to a highly indurated, stony and fissile diamicton with a sandy silt matrix. In the upper part of unit A the sediment abruptly becomes a highly compacted and consolidated stony diamicton with a sandy silt matrix displaying pronounceci fissility. A sheared sand lem is present in this portion of the unit.
Overlying this is stony sand (unit B).
Three pebbie a-axis fabrics were measured at section 04 (Figures 14, 15): fabric 18 was measured in the lower pan of unit A, 1.7 m above the bedrock contact, fabric 19 was measured in the middle part of the unit and fabric 20 was measured in the upper part, 1.5 m above fabric 19. Fabric 18 is weak to moderate (S,=0.573, S34.153) with a spread bimodal distribution. The main eigenvector (V,=197"/20°) correlates fairly closely with a main cluster plunging to the south. Fabric 19, in the middle part of the unit, is very weak
(S,=0.464, S3=0.210) and multimodal. There is a mode in the east where the main eigenvector plots (V,=û93"/23").Fabnc 20 is stronger than fabnc 19 (S,=0.549, S*. 119), although still relatively weak. The fabnc is cornplex and multimodal with a very spread out concentration in the southeast (VI=12g0/26*).
Section OS (Figure 16)
Section 05 is located on the west side of the 507 Secondary road about 6 km norrh Section 4 fabric 18
Section 4 fabric 19 unit A
I
Figure 14. Orientational data from Section 4 Section 4 @bric 20 unit A - N=
Figure 15. Orientational data hmSection 4 SECTION 5 Washout Section 82GIII(~MimS):ms805.5488558
Figure 16. Section 05 - sedirnentology and stratigraphy of the hamlet of Beaver Mines and just south of the Castle River. The exposure occuned in the ditch alongside the road where 1995 flood waters scoured out detrital material to expose in situ deposits (the ditch is now covered in grass). The entire exposure was about 330 m long and up to 2.5 m deep. The deposits are horizontally bedded, while the road along the exposure rises at a 4' angle to the south, so miderable horizontal exposure was provided.
Section 05 consists of three stratigraphie units with bedrock exposed at the base of the exposure. Unit A overlies bedrock and is a very stony and indurated diamicton with a highly fissile dark silty sand ma&. Numerous gravel lenses are present which appear to follow a shear zone in the diamicton. Also present are a succession of joints which dip almost vertically. Overlying this is a complex sequence of interstratified gravel, sand, diamicton and clay beds (unit B). A single shield clast was found at the base of the unit.
Many beds are distorted and dropstones are present in silt and clay units. Overlying this unit is rhythmically interbedded silt and clay (unit C).
Section 06 (Figure 17)
Section 06 is located along the north bank of Screwdriver Creek about 3 km due north of the intersection of the 507 and 774 Secondary roads. The exposure is 23 rn high, including bedrock, and is about 10 m across at the bedrock contact.
Section 06 consists ofthree units and has bedrock exposed at the base. The lower part of unit A is a highly consolidateci and fissile diamicton. No structures or stratification are present except for occasional sand beds interlaminated with silt and clay . A cobble was seen lodged into the top of one sand bed, deforming the bed. The upper 50 cm of unit A is a slightly stony diamicton which is les cohesive near the top of the unit It is moderately SECTION 6 Screwdriver Creek Section 82 G18 (WMlrar):703810. S4ô549û
Figure 17. Section O6 - sedimentology and stratigraphy consolidated - less so than underlying diamicton. Bloch ofthe more consolidated diamicton are incorporateci within the overlying diamicton. Unit B consists of altemating beds of fine sand and silt with gradational contacts and occasional clasts present in the sand beds. In the lower part of the unit the sand beds are slightly more stony and some contacts are abrupt and appear erosional. In the middle of the unif some of the beds are replaced by clayey silt beds with clay laminae. Unit C is an indwated and moderately cohesive diamicton which becornes less cohesive upwards and has an abrupt and irregdar lower contact.
Two pebble a-axis fabrics were measured at section 06 (Figure 18): one (fabric 16) in unit 4 2.5 m hmthe base of the unit, and one (fabric 17) in unit C. Fabric 16 is relatively weak (S14.524,S34. 1 16) with a multimodal, almost girdled, distribution. The main eigenvector plunges to the West (V1=28O0/11°), but this does not coincide with a major concentration of points. Two striae are roughly parallel to a western concentration ofpoints.
Poles to two fractures in unit A do not appear to relate to fabnc concentrations. Fabnc 17 is stronger than fabric 16 although their eigenvalues are similar (Sl=û.S20,&=O. 163). The fabric is spread bimodal with an east-northeast - west-southwest trend, that is supported b y the main eigenvector (V,=073°/060). PoIes to two fractures are oriented dong the edges of a concentration of east - West points.
Section 07 (Figure 19)
Section 07 is located dong the southem edge of the Blairmore (82 G/9)mapsheet on the north bank of the Castle River about 1.5 km west of the 507 Secondaiy road. The exposure of Quatemary sediments is 30 m high and extends for over 200 m dong the river.
Section 07 consists of six units and has bedrock exposed at the base. Unit A is Section 6 fabric 16
Section 6 fabric 17 unit C N = 50
Figure 18. OrientationaI data from Section 6 SECTION 7 Reners Fams Sedeon a2 as (Bbhlomk 7a3370. -
Figure 19. Section 07 - sedimentology and stratigraphy consolidated diamicton with a silty sand matrk and abrupt upper contact. Unit B is weakly
stratifieci, inversely graded, pebble gravel; poorly sorted at the base, becoming moderately
sorted upwards. Unit C is consolidated diamicton. Unit D is rhythmically bedded fine sand
and silt. Unit E is unsorted gravel and unit F is unifom £he sand.
Two pebble a-axis fabrics were measwed at section 07 (Figure 20): one (fabric 14)
in unit 4 1 m fkom the base of the unit and one in unit C (fabnc 15) 60 cm fiom the base of the unit. Fabnc 14 is moderately strong (S1=û.667, S34.130) and spread unimodal. The
main eigenvector lies between two closely spaced main clusters (V,=266"/07").Fabric 15
is weaker than fabric 14 (S1=0.563, S3=0.20 1) and is spread bimodai with amain eigenvector plunging northwest (V,=3 MO/l0'). North - south onented striae are inconsistent with fabric modes.
Section 08 (Figure 2 1)
Section 08 is Iocated on Mill Creek about 4.5 km due west of the hamlet of Beaver
Mines and about 5.5 km south of the confluenceof Mill Creek and CadeRiver. The section is an exposure about 20 m high and 25 m wide on the north bank of the creek with bedrock exposed at the base (Figure 22).
Section 08 consists of three units with bedrock exposed at the base. Unit A is unsorted cobble and boulder gravel overlain by unsorted pebble gravel. Interposeci between the base of unit A and the bedrock is a layer of calcrete about 5 cm thick. Unit B is consolidated and cohesive diamicton which is quite fissile, has a strung ped structure and a gradational lower contact. The upper hdf of unit C is consolidated diamicton with a strong ped structure. There is a boulder concentration in the upper part of this subunit. Sand unit A N=29
Section 7 fabric A5 unit C N =3O
Figure 20. Orientational data from Section 7 SECTION 8 Wedgie Section et GR3 (B.sva Uiisr):701830. Mt620
Figure 21. Sedion 08 - sedirnentology and stratigraphy Figure 22. Photograph of section 08 showing typical unsorted grave1 at base of Pleistocene stratigraphy. Dashed line indicates bedrock contact whiie dotted line indicates contact between unsorted grave1 and overlying consolidated diamicton. Photo is looking just west of north. stringen occur just above the contact with the lower half of the unit and appear to be sheared
up hmit. The lower half of unit C consists of consolidated diamicton similar to that in the
upper part of the unit which is interbedded with worted pebble gravel. Pockets of the
consolidated diamicton are also present in the gravel beds. Toward the base of the unit the
beds of diamicton and gravel becorne more mixed.
Two pebble a-axis fabrics were measured at section 08 (Figure 23): one (fabnc 21)
in unit B, 50 cm above the base of the unit and one (fabric 22) in unit C, 2.7 m fiom the base
of the unit Fabric 21 is weak (S1=0.480, S34.167) with avery spread bimodal distribution.
A pole to a fracture is consistent with a northwest - southeast fabric mode. There is a main
cluster plunging to the northeast with which the main eigenvector (V1=0200/080)does not
coincide. Fabric 22 is similar to fabric 21 (S,=0.485, S,=û. 199), but is multirnodal with
distinct clusters of points. Poles to two fractures are consistent with a minor north-south
fabric mode.
Section 09 (Figure 24)
Section 09 is located on the CadeRiver, about 2 km upstream of its confluence with
Mill Creek, at a sharp bend in the river where it begins to flow north. The exposure
comprises 16 m of Quatemary sediments overlying 17 m of steeply dipping bedrock-
Section 09 consists of four units, including 2 m of slump (unit A) at the base of the exposure. From 2 m to 10.5 m is very consolidated diamicton (unit B) with a cohesive silty loam matrix which exhibits a smng ped stnicaire. Fissility is praent, but the fissility planes strike parallel to the slope and could be due to dope movement and winter frost action. From 7.9 to 9.0 m, sand beds inter-lens with the diamicton and fmm 9.0 - 9.9 rn there unit B N = 50
Section 8 fabric 22 unit C N =50
Figure 23. Orientational data from Section 8 SECTION 9 McRae Section rncia(~Idliar~fQ19aO.s4a4410
Figure 24. Section 09 - sedimentology and stratigraphy are many laminated, slightly cross-bedded sand beds with oxidized smd stringers extending
upward nom them. The lower part of unit C is consolidateci and stony diamicton with a
cohesive sandy silt matrix and strong ped structure. A block of vertically dipping, dirty,
unsorted gravel with beds 15 - 45 cm thick is present between 10.5 to 12.5 m. Below 12.2
m there is a vertically dipping sand bed 10 cm thick lying between the vertical gravel -
diamicton contact. At 12.9 m there is an abrupt change and the diamicton becornes very
stony and slightly less cohesive. Pockets of diamicton from the lower part of unit C are
incorporated in the more stony diamicton and sand stringers are present within 20 cm of the
contact. Overlying unit C is sand and silt with a clay bed near the base of the unit.
Two pebble a-axis fabrics were measured (Figure 25): one (fabnc 10) in the upper
part of unit B, and one (fabric 11) in unit C. Fabric 10 is moderately strong (S1=0.6 15,
S3=û.085)with aspread bimodai distribution. PoIes to five fractures are generally consistent
with the minor fabric mode, north-northeast - south-southwest. The main eigenvector
(V,=276O/O 1') plots within the main cluster suggesting an east - West trend. Fabnc 11 is weaker than fabric 10 (S1=0.503, S3=û.118) and its pattern is multimodal. The main eigenvector (V1=35 1 O/OgO) falls between clusters.
Section IO (Fipure 26)
Section 10 is located on the south bank of Castle River about 2.5 km northeast of the intersection of the 504 and 775 Secondary roads (Figure 27). This site is the same as
Mountain Mill Bluffwhich was fmt descnbed by Stalker (1 969). Staiker discovered a single till (his unit B; unit C in this study) at the base of the section. For his description and discussion see Stalker (1969). Section 9 fabric 10 unit B N = 50
Section 9 fabric 11 unit C N =50
Figure 25. Orientational data from Section 9 SECTlON 10 Mountain Mill Secüon aZ Gia (WU):711880. -10
sridonror#rnrimnoroaon -mm mis-
2490 * la) B.P. (GX - #n) -Quimrl
Radiocarbon data. and descriptions above the low two unitS. mm (Stalker 1969)
bmmrymalumn U\+ar#-nd anmdycaaolgM Uilrborndwdhronw rJt Navyqi*lir- AhPsiaMaigporad 0.I conintibcltSWnnch5m0n0bomtarrjO an. !amrlho)bgarinœdystniCd
Figure 26. Section 10 - sedimentolog y and stratigraphy Figure 27. Phot0 of sedion 10 exposure. Note: the location of Salker's (1969) 'moraine" is obscured by colluvial material at the base of the Sedon. As part of this saidy, the site was visited in 1995 following a 100-year flood event to see ifany more stratigraphy had been exposed. The base of the section was found to be scoured free of slump by flood-waters exposing stratigraphythat was unavailable to Stalker.
The fies h exposure revealed an over-consolidatecf diamicton which was overlain by unsorted sand and gravel. The site was revisited in 1996 to measure till fabrics and to sample both
Stalker's till and the over-consolidateci diarnicton at the base of the exposure (unit A).
The lower diamicton (unit A) is unstratified and very stony, although not clast supported; clast content is approximately 25%. The matrix is extremely consolidated and indurated sandy silt The diamicton grades upward into overlying sand and gravel over about
50 cm. The base of the exposed diamicton is at river level and no bedrock is exposed at the site.
Separating the lower diarnicton and Stalker's till is unit B, an extremely consolidated and well-sorted sand and gmvel which grades upward into an unsorted, bouldery gravel with a rnatrix of coarse sana granules and pebbles. The unit's upper contact is obscured by slump. About 50 m upstrearn a second description was done.
At this second description site, slump obscures the lower 3.2 m of the exposure.
Well-sorted and niable medium sand inter-lensed with gravel are present up to 5.4 m above river level. At 5.4 m the contact between Stalker's till and the underlying gravel is exposed.
Although the contact is generally abrupt, diamicton dykes and large blocks and wedges of plucked sand and gravel are present Winthe diamicton. A wedge of diamicton 40 cm long is present just below the contact.
Two pebble a-mis fabrics were measured at section 10 (Figure 28): one (fabric 12) in unit 4 1.5 m from the base of the unit and one (fabnc 13) in unit C. Fabnc 12 is unit A N = 50
Section 10 fabric 13 unit C N = 50
Figure 28. Orientational data from Section 1O relatively weak (S1=0.553, &=û. 122) with a girdle-Iike patteni. The main eigenvector plots
near the main cluster of values (v1=284"/13"). Fabric 13 is moderately strong (S1=0.705,
S,=û.070) and has a spread bimodal distribution with a minor transverse mode. The main
eigenvector (v,=257°/020) coincides with the main cluster in the West and supports a strong
east - west trend.
Section II (Figure 29)
Section 11 is located on the east bank of the Cade River in the southeast corner of
the Blairmore (82 GI9) mapsheet about 5.5 km West of the tom of Pincher Creek. The
exposure consists of 23 m of Quatemq sediments overlying 19 rn of exposed bedrock and
is about 150 m across (Figure 30 i). Given the size of the exposure, two descriptions were
made, one at the north (downstrearn) end of the section and one at the south end. The
thickness of Quatemary deposits is much greater in the northem haif of the exposure, but
required significant trenching to ciear extensive slurnp cover. Although sediment cover is
thinner at the south end of the section, the exposure is mostly vertical so in situ sediments
are easily accessible. The description presented here is a composite of the two descriptions
done at section 11: unit thicknesses are an average of thicknesses at the two sites.
Section 1 1 consists of six units with bedrock exposed at the base. Unit A is unsorted, consolidated grave1 with a strong ped structure. Unit B is highly consolidated, stony diamicton with a strong ped structure and abrupt upper contact. Nurnerous fractures are present throughout the unit and chaotic sand pockets and stringen occur in the lower two thirds. Unit C is a chaotic mix of sand beds and diamicton pockets. Beds are strungly cross- bedded, faulted and folded. At the south end of the section the unit changes facies to a fissile SECTION 11 Hunting EagIe Section 82 G@ (ülwmom): 713100.5487250
Figure 29. Section 11 - sedimentology and stratigraphy Figure 30i. Photogra~hof section 11. A. A' comprise downstrearn desaiption site and B is upstreamdescription site. Note dumping of siit and clay deposits overlying downstream site. Photo k looking southeast.
Figure 30ii. Sheared and defomied chaine! deposits lying between two consolidated rnontane diamidons, Dotted Gne indicates a folded sand bed. diamicton overlain by sand with lenses of open-work grave1 which is in tum overlain by a
very stony diamicton (Figure 30 ii). Unit D is a consolidateci, fissile diamicton with a strong
ped structure and gradational upper contact. Sand stringers are present, especially near the
base of the unit. Unit E is highiy fissile and sheared silt overlying sheared diamicton. The
silt is stoneless at the nortbern end of the section and becomes stony near its base at the
southern end. Unit F is consolidated, sandy silt diamicton which is highly fkactured and has
a strong ped structure. Shield clasts are present in this unit.
Five pebble a-axis fabn~~were rneasured at section 11 (Figures 3 1,32,33): three
(fabncs 05,06,07)in unit B, one (fabric 08) in unit D and one (fabric 09) in unit F. Of
the three fabncs measured in unit B, two (fabncs 05,07) were done at the downstream
description site while the third (fabric 06) was measured at the upstream site. Fabric 05 is quite weak (Sl=û.445,$=O. 170) with a spread bimodai to multimodal distribution. The main eigenvalue (V,=3O1°/000) does not reflect a significant trend in the data. A pole to a fracture does not appear to relate to the fabnc. Fabric 06 is cunsiderably stronger than fabnc 05 (S1=0.654,Sp0.148) and has a spread bimodai distribution with a minor transverse mode. The main eigenvector (V,=28 1°/OSO)suppom a west-northwest - east- southeast trend. Poles to four fractures appear to be unrelated to the fabric. Fabnc 07 is multimodal and is not significantly stmnger (S,=0.504,S,=O. 156) than fabric 05. The main eigenvector (V,=306°/190)suggests a northwest - southeast trend. Stone surface striae are variable, but are mainly oriented north-northwest - south-southeast, roughly parallei to the main fabric mode. Two main groups of leeends coincide with distinct east
- West and north - south fabnc modes. Poles to two hctures do not appear to relate to the fabric. Fahic 08 is relatively weak (S,=û.59 1, S3=0.175) with a spread bimodal Section If fabric 5
Figure 31. Orientational data fmm Section 11 Section 11 hbric 7 unit B - N =
O -
Section 11 fabric 8 unit D N=50
Figure 32. Orientational data from Section 11 Section il fabric 9 unit F N = 50
Figure 33. OrientationaI data from Section 11 distribution. There is a main cluster in the west which corresponds fairly closely with the
main eigenvector (Vr28g0/ 19'). Stone striae are variable, but are generally oriented
east-west parallel to the main fabric mode. Two clast lee-ends, and poles to three
fractures, do not appear to relate to fabric modes. Fabric 09 is relatively weak (S,=0.5 16,
S34.124) with a spread bimodal distribution. The main eigenvector (V,=20S0/16O) lies
between point clusters. Poles to hcnires are generally oriented consistently with the
main fabric mode, whereas striae on one Stone, and three lee-ends, are oriented transverse
to the main mode.
Sample Data
Texturd Ternaty Diagrams
Bulk diamicton samples were analyseci for textuni1 composition based on weight percent of sand, silt and clay and the results were plotted on standard temary diagrams
(Figures 34,35). Control values for the upper and lower diamictons were taken from the upper and lower units, respectively, at sections 06,07, 10 and 11 where the two diamictons are clearly separated by sorted sediments at these sites. The upper and lower montane consolidated diamictons represented by these data will be referred to as Upper and Lower (the first letter will be capitaliseci) to indicate that they are the specific sources for the control data, and therefore the control units. Data values for the other sections are categorised by section and identified by unit.
Control data for Upper and Lower diamictons plot on a ternary diagram as two overlapping fields (Figure 34). Upper diamictons are slightiy clayier than Lower diamictons, but this dEerence is very slight and it is not possible to differentiate between sand sand
1 LEGEND 1 A Open symbol indicates uppe1 Field of mntrol data diamicton for upper diamicton A Filled symbol indicates lower diamicton Field of contra1 data lor lower diarnicton + Sections possessing one ' diarnicton 1
Figure 34. Ternary diagrams of diamicton matrix grain-site for, a) control units, Upper vs. Lower and, b) non-control uniCs plotted by section sand
O clay
LEGEND
A Section O6 A Upper diamicton Section 07 A Lower diarnicton D Section 10 * continental diamicton + Section 11
Figure 35. Ternary diagram of diarnicton mat& grain-size control data by section - Upper Vs. Lower. the two units based on ma& grain-size alone. If nonantrol data for upper and lower diamictons tiom al1 sections possessing two over-consolidated diamictons are examineci relative to each other, a general pattern can be seen (Figure 35). At three sections (07,08 and IO), the upper diamicton is finer than the Iower while at two sections (06 and 09),the reverse is me. At three sections possessing a single over-consolidated section where the diamicton was sampled more than once (sections 02,03 and 04), the upper part of the diamicton was found to be finer than the lower part in figure 34. The relative difFerences between upper and lower parts of a single diamicton were fond to be as sigmficant as those between upper and lower diamictous at other sections.
Pebble Lithologies
Pebble samples were sorted and counted according to lithology and classified into one of seven categories:
1) Rocky Mountain and Foothills: limestone, dolostone, calcareous shale,
coquinoidal limestone
2) Rocky Mountain and Foothills: grey and white orthoquartzite, lithic
sandstone, micaceous sandstone, conglomerate, chert, silîstone
3) Oldman River headwaters : Crowsnest Volcanics Trachyte, p honolitic
tuff and Waceous sandstone
4) Gog Group, Main Ranges and Purcell Supergroup, Lewis and Clarke
Ranges: purple and maroon quartzite
5) Purcell Supergroup, Lewis and Clark Range: red and green argillite,
gabbro, metagabbro, basalt and andesite 6) Canadian Shield: granite with pink feldspar, schist, gneiss, migmatite
and metaquartnte
7) ûther: vein quartz, mal, unidentifiable, etc.
Data for each site were plotted by category in histograms for cornparison with other sites and to see if any trends could be detected. (Figure 3 6). Figure 36. Pebble lithology histograms
50 i
Category I Category 2 [7 Category 3 Category 4
Category 5 Category 6 1Category 7 Pleistocene Ice Distribution
The reconstniction of past ice distribution is based on drift (specifically, till) and erratic distribution and so is restncted by theu preservation. Potential for drift preservation is greatest in areas where mas-wasting activity and erosion are minimal (generally low relief areas), and poorest in areas where mass-wasting and erosion are high (generally high relief regions). Drift preservation in the Front Ranges, and parts of the Mountain Front and
Foothills, was found to be poor while the Foothills' lowlands and the Plains provided good preservation except in Stream valleys which are commonly filled with outwash and pst glacial alluvial deposits.
Given the Iow preservation potential for till in the Front Ranges and the Mountain
Front, it is assurned that the uppermost lirnits of till most accurately reflect the limit of glacial ice. Occasional distinct, linear breaks in dope were noted dong the flanks of some mountain valleys and were initially thought to be aimlines or, possibly, lateral moraines.
Further investigation and ground-truthing, however, revealed that they are bedrock controlled and parallel the local strike of bedrock Ice limits in the FwthilIs reveal that a discontinuous sheet fonned there which filled al1 valleys and was pierced by only the highest peaks. Ice thickness in mountain valleys likely varïed among the valleys because they have different ice-sheds. Estimates in the Castle valley suggest that minimum ice thickness was approximately 400 m, while lateral moraines in Gardiner and South Drywwd creek vaileys suggest minimum ice thicknesses there of 2 10 m and 1O7 m respectively. The low estimate in South Drywwd Creek valley suggests that the morainal feature may be associated to the
M2 advance.
Large bodies of outwash preserved in major vaileys and lowlands of the Foothiils
show the meltwater drainage pattern which developed during deglaciation. The pattern
shows that significant amounts of meltwater flowed through recently deglaciated valleys,
either reworking or burying till. The height of terraces above modem Stream charnels
indicates the original thickness of outwash before erosion by modem fluvial activity.
The western limit of the LIS, within the map area, was determined by the distribution
of continental tiil and glacially deposited shield erratics. The distribution of continental till
shows that the LIS advanced to the hogback ridges in the northeast corner and invaded small
valleys dong the eastem edge of the map area. An isolated body of continental till was
mapped a few kilometres northeast of the mouth of Beaver Mines Creek valley. It is likely that C 1 till is found throughout the northeast corner, within the maximum limit, but has been covered by glaciolacustrine deposits. It should be noted that shield clasts found beyond the mapped limit ofthe LIS are associated wiîh glaciolacustrine deposits and are regarded as ice rafted debris; these shield clasts were not deposited by the LIS, and so do not represent its limit.
The glaciolacustrine deposits in the northeast corner of the study area likely represent the Glacial Lake Caldwell (13 10 m) and Glacial Lake Cardston (1 2 13 m) stands. Deposits associated with these lake stands were found by Leboe (1996) in map areas adjacent to
Beaver Mines.
A number of linear erosional features were noted which provide direct evidence of glacial flow direction. Four Iinear fea~iresat the Mountain Front between Mi11 and Pincher valleys show that ice flowed southeast dong the mountain front. Lineations on the lowland
just north of Syncline Mountain, between the Carbondale and Castle rivers, show that ice
flowed east fiom cirques in Gardiner Creek valley and possibly fiom the Carbondale River
valley itself.
Evidence of Neoglacial activity was found in some srnail, high cirques where end
moraines were presewed.
Stratigraphie Sections
The following interpretationsof sedimentary units are based mainly onthe sediments'
texhiral characteristics, stratigraphie associations and pebble a-axis fabrics. Detailed
interpretation of till genesis would require additional data gathered from glaciotectonic
defonnation structures, clast lee-end orientatiolis and clast striae. Given the scope of this
project it was not logistically possible, nor was it a goal, to conduct a detailed study of
glacial geology at each site, but rather to combine studies of drift distribution,
geomorphology and glacial sedimentology to produce a reconstruction of glacial history within the study area. The main goal of these interpretations is not to determine till genesis
in detail but to clearly establish a deposit as subglacial till for the purpose of conelating it wîth other till units to build a pichire of local Pleistocene stratigraphy.
In general, defonnation was found to play a signifiant role in the deposition of subglacial till in the region. Many tills in this study are classified as defonned lodgement till based on pebble a-mis fabric pattern showing values spread around distinct main and transverse modes with several steeply plunging clasts (Dreimanis 1989; Hiaock et ai. 1996;
Menzies and Shilts 1996; Benn and Evans 1998). Occasiondly, highly deformed till with lodgement characteristics superimposed by ovemding ice was interpreted where the distinct
main fabnc mode cuincided with striae and lee ends which would have rotateci ifdeformation
followed lodgement. Application ofthe latter interpretation, however, was limited to those
sites where dam on striae and lee-ends were recorded,
Sections described in Chapter 3 are correlated as depicted in Figure 37. These
correlations are elaborated systematically in the text that follows.
Section 01 (Figure 7)
Unit B was deposited in a proglacial environment by meltwater fiom the advancing
Castle Valley Glacier (CVG).The unit consists oftwo distinct, interbedded facies: locally
stratified, unsorted outwash gravel and stratified stony clay and silt glaciolacustrine deposits.
Reverse grading exhibited by the upper two gravel beds suggests an approaching glacial
margin. The lowemost gravel bed is also thought to be glaciofluvial due to its highly
unsorted nature and the angularity of the clasts, however, the bed may be fluvial, with the
lower portion being a bouldery lag deposit nie clay and silt beds were probably deposited
into proglacial lakes dammed by landslide events hmthe vailey side. The beds' stoniness
is more likely due to the ongoing release of material hmthe adjacent unstable rock-face
than meltout of debris-laden icebergs because the fine grain size is more consistent with a
distal, rather than proximal, proglacial lake. The highly cowolidated nature and stratigraphie
relations of unit C lead to its interpretation as till associated with the Ml advance (Figure
37). No pebble fabric was measured at this exposure, but three striae, oriented between 2 10 -
213*,suggest ice flow from the south-southwest. Unit D is likely outwash gravel deposited during glacial retreat. Foreset bedding at the upstream extent of the exposure are possibly
large sdebedfoms seen in profile. Sofi-sediment deformation features in the stratified sand of unit E suggests that the material was deposited rapidly, perhaps as overbank sediments. Unit E is not likely a Pleistocene deposit.
Seeion 02 (Figure 9)
nie lower 10 m ofunit B, with its extensive cross- and foreset bedding, is most likely deltaic, while the coaner, unsorted and horizontally bedded upper portion of the unit is deposited in the main channel of the outflow Stream. Reworking of landslide deposits by rneltwater may be the reason for the unit's considerable thickness.
The blocky ped structure and oonsolidated nature ofthe lower part of unit C suggest that it is a subglacial till. The relatively weak pebble fabric (fabric 0 1) suggests that significant defornation of the sediment occurred; with the strong concentration of values in the southwest and distinct transverse mode, it appears that deformation was superimposed on lodgement. A pole to a fiacture in the lower part of the unit does not appear to relate to fabnc modes and is probably non-glacial in ongin (eg. slump fiacture, frost featt.ue, dessication crack, or other non-glacial tectonic feature). The fiable diamicton in the upper part of the unit is interpreted as a slightly deformeci subglacial meltout till based on its low consolidation and relatively strong fabric (fabric 02). The fabric pattern (Figure 10) infers ice flow from the est, but montane Stone provenance and local topogniphy suggest othenvise. A more plausible scenario is for englacial clasts to have been plunging down-ice locally while the CVG ice flowed eastward into Beaver Mines Creek valley through a low pass about 4 km northeast of section 02. This eastward flow was enhanceci by ice flowing east from Mount McCar&hyand the Carbondale River valley to join the CVG near section 02. The unit is associated with the Ml advance in figure 37.
Seclion 03 Figure 11)
The lower 1.4 m of unit A is deformed lodgement till; the material's cohesion and high consolidation indicate a subglacial environment while the fabric (fabric 03) suggests defornation of a lodgement till. The material's consolidation and the concentration of clast orientations (in the east of the fabric plot) suggest that till lodgement was followed by deformation which caused Stones to rotate, thereby altenng and weakening the fabric. The upper 1.4 m of the unit is thought to be the upper dilatant horizon (e.g. the A horizon of
Boulton 1996) of the underlying deformed lodgement till based on its more friable nature and weaker fabnc (fabric 04; Figure 12). Although the fabric has a higher S, value, it is weaker than the lower fabric because it is more spread out. Striae consistent with a srnall fabric mode may reflect the latest ice movement at the site dusing unit A deposition associated with the Ml advance.
Section 04 (Figure 13)
Although unit A was initially described during fieldwork as three separate units, with a fabric done in each, these were later recognised as a singie depositional unit. The unit is interpreted as deformed lodgement till grading up into deformation till. This interpretation is based on the unit's high degree of coosolidation and the decrease in strength of the upper two fabrics relative to the lowat one. The spread bimodd pattern of the lowest fabnc (fabric
18) suggests till lodgement followed by deformation, whiie the multimodal patterns of the two upper fabrics (19, 20) show only defonnation (Figures 14, 15). Flow direction, as interpreted hmfabric 18, is hmthe southwest. There is no sedimentoIogica1 or structural evidence to indicate that more than a single glacial advance occurred at the site, therefore, the unit is associated with the Ml advance.
Sixtion OS (Figure 16)
Unit A is interpreted as lodgement till associated with the Ml advance. No pebble fabrics were measured at the site, but several steeply-dipping planar features were noted, some of which were filled with grave1 and are probably glaciotectonic. Unit B is interpreted as an ice-marginal deposit consisting of till, glaciolaaisaine and glaciofluvial deposits. A shield cIast was found at the base of the unit,
Section 06 (Figure 17)
Unit A is subglacial till which experienced lodgement and deformation, and possibly flow, during Ml deposition. Fissility and a high degree of consolidation are suggestive of lodgement while the weak, girdle-like fabric (fabnc 16) indicates that other processes were involved (Figure 18). The girdIe-like pattern of the fabric may be a remnant of the matenai's original deposition as a gravity-flow tiil at the advancing ice margin, but more data are needed to confirm this. Two striae split two parts of a spread out fabric mode and poles to two fractures appear to bear no relation to the fabric or striae, suggesting Stone rotation during deformation. The more fiable upper 50 cm of the unit is thought to be Boulton's
(1996) deformation till A horizon because of its fiable nature and stratigraphie association to the lower part of the unit. Unit B is glaciofluviai outwash in its lower pmion and giaciolanistrine in its upper. These facies are believed to have been deposited at the ice marsin, initiaily on a sandur and later in small lakes. Unit C is interpreted as defonned lodgement till based on the fabric pattern (fabric 17) and degree of consolidation. Poles to two hctwes are oriented between fabnc modes, suggestingthat they are not glaciotectonic.
The portions of the unit fiom 10.9 - 11-4 m and 12.1 - 12.9 m aremore fiable and may have experienced more deformation than more consolidatai parts of the unit. This unit is associated with the M2 advance.
The location of section 06 dom-vdley fiom an exposure where two tills are present
(section 07 - gresented below) establishes that M 1ice retreated upstmm of section 06 before readvancing. This scenario removes the necessity of proving that two glacial advances occurred over the area based solely on stratigraphie interpretation of the sediments at section
06.
Seah07 (Figure 19)
Unit A is interpreted as Ml defonned lodgement till although aiteration from true lodgement is not great. The fabric (fabric 14) is moderately strong, showing a distinct east -
West trend and indicating flow corn the West, with no detectable transverse mode and only a few steeply plunging clasts to suggest deformation (Figure 20). Unit B is outwash gravel.
Unit C is M2 deformation till or highly defoxmeci lodgement till with a weak fab& (fabnc
15). Several stnae are oriented between fabric modes and May suggest a late shift in ice flow north-northwest - south-southeast. Unit D is a thick glaciolacustrine deposit with altemating beds of fuie sand and silt; bed thichess decreases with height suggating decreased sediment input, possibly due to a retreating ice front. Seeiion (Figure 21)
Unit A is proglacial outwash deposited during the fmt glacial advance. Unit B is subglacial ti1I which experienced deformation and some lodgement during the Ml advance.
Consolidation and fissility suggest subglacial deposition while the very spread bimodal fabnc (21) shows that while till lodging occurred, deformation dominated. The fabric's girdle-like plot suggests that the materid may initially have bendeposited as a gravity-flow till (Figure 23). However, since over-consolidation of the sediment would most likely occur in thesubglacial environment, it was likely ovemby the glacier and inherited its subglacid characteristics then. A single pole to a fr C consists of interbedded till and outwash, but it is unknown whether the outwash was deposited subglacially or subaerially. The sediment likely represents either the fluctuation of an ice margin at the site or rapidly changing subglacial hydrologic conditions. Section 09 (Figure 24) Unit B shows considerable variation in response to highly changeable bed conditions during the Ml advance. The fissility, strong ped stmcture, generally high degree of consolidation and spread bimodai fabric (fabric 10)suggest that lodgement was the dominant depositionai mode (Figure 25). Numerous sand stringers sheared up from sand beds are evidence of defonnation. Although the fabric is moderately strong, the pattern has quite spread out modes which is suggestive of deforrnation. Poles to three fractures are aligneci between fabric modes and are subparallel to the faceof the exposure; two are consistent with a minor south-southwest - north-northeast mode. The lower 2.4 m of unit C has a girdle-like fabric (fabric 11; Figure 25) which suggests that the sediment was deposited initially as a gravity-flow till and was then ovemin and deformed during the Mî advance. The upper part of unit C may be either subglacial meltout till or Boulton's (1996) dilatant upper A horizon of a deformation till. This speculation is based on the horizon's relatively poor consolidation and stratigraphicposition overlying asubglacid till, but cannot be determineci without fabric, structural, striae and Iee-end data. Section 09 is interpreted as possessing two tills, with the upper (M2) directly overlying the lower (Ml). There is no direct evidence that the till units were deposited by different advances of montane ice. However, the section also lies downstream of section 07 and thus it is known that the stratigraphy cm represent two tills. Section IOFigure 26) Unit A (the lower consolidateci Ml diamicton) is interpreted as subglaciai till which experienced both lodgement and deformation based on its extreme consolidation and weak multimodal fabric (fabric 12; Figure 28). In the fabric plot, a main concentration of pebble a axes in the West suggests flow from that direction, while significant deformation is hinted at by the spreadsut nature of the plot in general. The grave1 units lying between unit A till and Stalker's till (his unit B; my unit C) are interpreted as outwash deposited subaerially. Stalker's description (Stalker 1969, p. 2 119) of the upper till suggests a montane origin while the plot of fabric measurements (fabric 13; Figure 28) from this study suggests a subglacial till which underwent lodgement and deformation during M2 deposition. The fabric pattern shows a strong east - West main mode with a distinct transverse mode and several steeply plunging clasts. The pattern suggests ice flow hmthe west. Stalker (1969) interpreted the section 10 exposure (his Mountain Mill Bluff) as consisting of a single till obscured at its base by slump and overlain by thick outwash, fluvial and aeolian deposits (see Figure 26). Stalker drew two main conclusions fiom his study of the section 10 site: 1) the morphology of the till unit indicates the presence of a terminal moraine 2) the advance associated with the moraine occurred between 6200-7200 l4Cyr B.P. These conclusions were disputed by Wagner and Eschman (1970), who rejected both the presence of a terminal moraine at the site and the proposed age of the deposit. Mountain Mill (Section IO) Moraine In the praent study, the morphology of the upper till was not examined, so no new data can be presented and the writer's opinions are based on re-interpretation of Staiker's descriptions. Stalker inferreci the presence of a moraine at the site fiom his observations that his unit B (upper) till thickens near the east end of the -sure before pinching out farther east (Stalker 1969, his Figure 3). Just east of this unit's termination, his unit C grave1 occurs lower in the exposure, at the same elevation above river level as his unit B till did before pinching out. He describes the base of unit C as being obscureci by slump so this writer questions whether the till tdydoes pinch out or if the overlying outwash has simply scoured out a portion of the underlying till. In addition, Staiker's Figure 3 suggests that slump could be obscurhg an equally thick, horizontaily continuous extent of unit B till in the western end of the section. Wagner and Eschman (1 970) rejected Staiker's interpretation and regarded the "morainal" feature as just a local thickening of the till sheet. Staiker's Merassertion, that the moraine is a terminal moraine, is based on the following points: i) absence of other end moraines fanher down-valley ii) areai distriiution of Laurentide till: no shield clasts were present on the surface within the valley West of section 10, but were present to the north, south and east of it niis was interpreted as suggesting that a Holocene advance of montane ice destroyed or removed shield Stones which had previously occurred west of the moraine. iii) irnprobability of the glacier advancing farther dom-vailey than it did. (Stalker 1969) In (iii), Staiker reçognisa the unlikelihnod of the glacier advancing as far as it did and asserts the increasing improbability of it having advanced any farther. The discovery, during this study, of recently exposed gravel underlying Suer's unit B till, and a second tiil underlying the gravel, give cause for a re-evaluation of StalkeZs interpretations. Through correlation with stratigraphy at other sediment exposures the lower till at section 10 is correlated to the Ml advance and the upper till, as described by Stalker, is cmelated to the M2 advance. The presence of a moraine at section 10 is neither supported nor rejected by this study since the morphology of the upper till was not investigated. However, the evidence presented by Stalker (1969), especially his Figure 3, suggest that the apparent thickening of unit B till could be due to slump cover and glaciofluvial erosion. His assertion that the feature is specificdly a teminal moraine is rejected here because the upper till is correlated to the M2 advance. This study has shown M2 till to be found at section 11, down-ice hmsection 10 so an end moraine at section 10 would most tikely be recessional. Absdute Age of the Seciments Stalker obtained three 'Cages from two bones and one tooth found about 6 rn hm the base of his unit C: 6150 * 140 yr B-P.; 6100 * 180 yr B.P.; 6340 * 140 yr B.P.. The samples were obtained from material lying in coane sand beds interstratified with thin grave1 beds, "They [the bones] were not wîdciy dispeaed and mauy were still in articulate position ...leg and foot bones in contact and in proper sequence... The bones were littie waterwom. .." (Stalker 1969, p. 2 120). Stalker took this to mean that cornplete carcasses had been deposited in a single event and had not been transported far. Given that the dated matenal lies in sediment apparentiy conformably overlying till, Stalker interpreted the dates to be a close approximation of the moraine's (minimum) age. Wagner and Eschman (1970) regarded section 10 as being badly slurnped (a stance disputed by Stalker (1970)) and considered the bones to be not in situ within the outwash sequence. They emphasised the unlikelihood of a significant Holocene advance of the CVG and proposed that the bones had been deposited by fluvial activity about 6200 14C yr. B.P. and then covered by slump matenal to give the appearance of being in sequence with the Pleistocene sediments. Since Stalker's work was published, detailed studies conducted in the Canadian and American Cordillera (e.g. Osbom and Luckman 1988, and references therein) have produced no evidence to corroborate a Holocene event of suficient magnitude to support ice advance in the CRV to over 30 km from the rnountain front. Thus Staikefs suggested age of the moraine as being between 6200-7200 14C yr B.P. is rejected. Ifthe till and "moraine" are of Pleistocene age, the significance of the 14C dates must be established. Wagner and Eschman's proposal that slumpinghad resulted in the sequenceavailable to Stalker (1969) during his investigation mut account for the articulation of the bones as observed by Stalker. Either the slumping did not disturb the bones, or slumping occwed shortiy after deposition, while ligaments and tendons still held the bones together. The miter proposes three more possible scenarios: 1) the dates are wrong and the host sediment is of Pleistocene age 2) the host sdiment is of Holocene age and lies unconfomably on Pleistocene age gravel 3) the dated material and host gravel are a Holocene age pocket "nested" within Pleistocene gravel. In this last scenario the Castie River could have cut into the cl8 face and deposited an isolated pocket of younger gravel along with animal carcasses. Some subsequent dumping may have aided the rapid burial of theHoIocene material. One possible way to determine the relative age of the sediment at section 10 would be to detennine if shield clasts are found lower in the stratigraphy than the bones. If the source of shield clasts was a stagnant mass of Laurentide ice that was trapped on the West side of a ndge following the C 1 maximum, it would suggest that the material containing shield clasts is Pleistocene in age. Ifthe clasts were deposited in the Holocene, they would be present in gravel deposits farther upstream, but they are not This suggests that they were deposited during the Pleistocene while the CVG ocaipied the CRV with its snout at section 10 and the meltwater cqingthe shield clasts flowed along the top of the CVG or along its side. Section II (Figure 29) Unit B is classined as a highiy deformed lodgement till associated with the Ml advance. Fabnc 05 at the downstream description site is very weak and it is dmcult to determine main versus transverse modes (Figure 3 1). The two main clusten plunge to the south and west while a third, weaker cluster plunges to the east. A pole to a fracture lies between fabric modes and is probably non-glaciotectonic. Fabric 06 at the upstrearn description site foms a moderately strong plot (Figure 3 1) with the main cluster plunging to the west, suggesting ice flow fiom the west. Some steeply plunging points suggest defornation of the sediment, but to a much lesser degree than at the downstream end of the exposure. Poles to four fractures are not oriented with any fabric modes and may not be glaciotectonic. Fabnc 07 at the downstream end contains several distinct clusters of points, but the two main clusters are adjacent to each other and plunge to the northwest and west, respectively (F$gu.re 32). Other orientational data were also collecteci at this site. Orientations of striae on clam are highly varied, but a crude northwest - southeast trend can be seen. The orientations of lee-ends of stones cluster with west - east and south modes. Poles to two fractures are oriented between fabric modes and may not be glaciotectonic. The inconsistency between the fabric mode in the northwest and the west-east lee-end data may reflect a change in local ice 80w. It is possible that ice emerging fiom the Crowsnest valley (to the north of the study ara) rnay have locally influenced the flow of the CVG. These data (fabrics 05,06,07, and their additional orientational data), fiom within the same unit and less than 150 m apart, reveal local variability of hydrological conditions at the glacier sole. Unit D is interpreted as highly deformed M2 lodgement till. The main cluster of fabnc points plunges to the west (fabric O$), but the remainderform discrete, random clusters (Figure 32). One clast lee-end coincides with some striae, but striae, lee-ends and poles to fractures do not cuincide with the fabric data. This suggeçts stone rotation during deformation. Unit F is classified as a subglacial till which has undergone both lodgement and deformation during the C 1 (continental) advance. Although fabnc 09, measured in thk unit, is weak and very spread out, a main mode plunging to the south-southeast and a transverse mode can be clearly identifid (Figure 33). Numerous measurements of planar features within the unit coincide with the main fabric mode while striae and Iee-ends coincide with the transverse mode, suggesting stone rotation during till deposition. Sample data T4XtUtd Ternary Diagrams The distribution ofcontrol values formatnx gain-size does not reveal any significant trends to aid in differentiating between Ml and M2 tills (Figure 34). Comparing the Upper and Lower values at a given section to see their relative differences also fails to clearly reveal trends; the Upper till is finer at sections 07 and 10, and coarser at section 06 (Figure 35). Examination of non-control values From sections possessing two tills yields similar results, with the upper till being finer than the lower at section 08 and coarser at section 09. At sections 02,03 and 04, where a single till was sampled in its upper and lower parts, the upper part of the unit was found to be fher than the lower part (Figure 35). The magnitudes of these differences are comparable to, or paterthan, those between upper and lower tills at the other sections. It therefore appears that intra-till texnird variability is as high as inter-till texhiral variability. Most grain-size differences probably result from glaciai-ovemdmg of local substrate and reflect its characteristics. The poor correlation of rnatrix grain-ste data between different arposures of a given till unit (as presented in Chapter 3) can be ateibuted to local bedrock geology . Bedrock in the Rocky Mountain Foothills of the Beaver Mines map area consists of steeply dipping sedimentary beds striking northwest / southeast, perpendicular to local ice rnovement. This results in a highly erodible substrate with great variability over short distances producing sipifkant lateral changes in till mat* composition and reducing the likelihood of textural correlation between stratigraphie uni6 over a kilometre-scaie area- The variability of matrix grain-size within a single till rnay be partly amibuted to the decreasing influence of the local substrate in the upper part of the till column, but the trend of the upper part beingfiner cannot be explained, unless ice overrode locally ponded proglacial and / or subglacial sediments. Pebble SampIes (Figure 36) An analysis of pebble Iithology distribution in tills sampled in the study area yielded only one detectable trend. A decrease in the percentage of carbonate lithologies was noted in tills in the south relative to those in the northeast, This reflects the dilution of carbonate lithologies in the Front Ranges by clastic sedimentary rocks of the Foothills during subglacial erosion and entrainment. The presence of a small amount of rock fiom the Crowsnest Formation in Crowsnest Pass was noted in a till sampled in the Blairmore Range between Hastings Ridge and Maverick Hill. This shows that ice fiom the Crowsnest Pass advanced southward here and breached a low pass to flow farther south towards the CRV. Interactions of Glaciers The presence of tilis conelated to the MI and M2 advances at a givm stratigraphie exposure requires that Ml ice retreated to a point up-ice of the exposure before advancing to the M2 maximum. Given the significance of this interpretation to the reconstruction of glacial history, correct identification of the stratigraphy is critical. In the stratigraphy component of this study two scenarios were encountered in which both Ml and M2tills were identified at agiven exposure: 1) two tills separated by outwash or glaciolac~fstrinedeposits, and 2) two tills separated by a unit of interstratifi~edtill and outwash. The most reliable scenario is that in which two till unit. are separated by outwash or glaciolacustrinedeposits. The recurrence of this sequence at different sites strongly suggests that subaerial conditions existed in the interim between deposition of the two tills, the result of glacial retreat upstream of the exposures befcre readvance. A related, but more difficult scenario to interpret is when ice marginal deposits lie between two tills. The complexity of sediments deposited in the ice marginal environment increases the dificulsr of their interpretation. This sequence indicates the retreat of ice to the location of the exposure before readvance, thereby establishing the deposition of two tills by two separate glacial advances. The inter-till deposits in this scenario are correlated with the overlying M2 advance because their deposition ocnirred after the Ml advance. The presence of Ml and M.tills at sections 07,lO and 11 is recognised based on the presence of an intertill outwash unit, while at section 06 an intervening glaciolaaistrine deposit separates the two. Sections 05 and 08 are interpreted as havingtwo tilis based on the presence of intervening ice marginal deposits. niese deposits indicate the retreat of montane ice hmthe Ml maximum to these sections before readvancing to the M.2 maximm. Section 09 is also interpreted as possessing two tills, but the interpretation is relatively difficult because no deposits separate the two inferreci tills. Fortunately section 09 lies down-valley fiom both sections 06 and 07 where the stratigraphy clearly shows the presence of MI and M2 tills. From this it can be inferrd that Ml ice retreated upstream of section 09 and, although not suppomng the speafiic stratigraphie interpretation offered here, establishes that tills hmthe two advances may be preserved at section 09. In the next chapter, results from the study area are examined in a regionai context. CHAPTER 5 GLACIAL HISTORY, ABSOLUTE CHRONOLOGY AND REGIONAL CORRELATIONS Reconstruction of Glacial History The following reconstruction of Pleistocene glacial history will focus mainly on the Castle, Beaver Mines and Mill Creek valleys - the region delimited in Chapter 1 (Figure 3; Figure 38). Ml Advance With the omet of glaciation (Figure 39), montane glaciers emerged fkom alpine valleys of the Clark Range and flowed northeast through preglacial river valleys in the Foothills. As individual valley glacien increased in ice volume, they spilied over bordering uplands and coalaced. Eventually an ice sheet formed across the map area (Figure 40) reaching elevations of 1661 - 1722 m (5450 - 5650 ft) near the mountah hnt, descending in elevation northeastward to 1527 m (50 10 A) in hogback hills along the western edge of the Interior Plains. Ice thickness varied among the mountain valleys because of their local topography and the difference in sue of their ice-sheds, but an average thiclmess of 400 m or more was common. Ice thickness in the Foothills was generally greater than 300 m, based on the elevations of erratics mapped there. The montane ice sheet in general was almost continuous, with only mountain peaks and the highest Foothills protniding through as nunataks. At the M 1 maximum position, the montane ice sheet extended approximately 100 km fiom the mountain front, reaching almost to Lethbridge (Stalker 1963). Figure 38. Area of defailed glacial history reconstruction. Contour inteml 122 m (400 ft). Figure 39. Onset of montane glaciation. Figure 40. Maximum position of Ml montane advance and infened ice fiow (indicated by armws). Figure 41. Minimum position of montane ice duhg retreat from Ml mmSmum The dominant sources of glacial ice in the Beaver Mines map area were the Westcasde and Castle deyswhose glaciers coalesced to form the CVG, the largest vailey glacier in the study area. Cirques at the mountain hnt, at Mount McCarthy, Syncline Mountain and in Gardiner Creek valley produced ice which evenhially coalesced with the CVG to the east flowed into the Carbondale valley to the West. The Beaver Mines Creek valley does not extend into the Front Ranges and it possesses no cirques; therefore, it cannot produce its own ice. Al1 ice flowing through the valley had its source either in the CRV to the West (cf. Wagner 1966) or Mill Creek valley to the east. Ice emerging hmBeaver Mines Creek valley cualesced with the CVG as did the Mill Valley glacier to the east. Ice from Pincher Creek valley likely joined the CVG farther dom-vdley while glaciers fiom Drywwd and South Drywood valleys flowed east onto the Plains. MI R&eat (Figure 41) mer reaching its maximum position in the vicinity ofLethbridge (Stalker 1963). M 1 montane ice retreated to within the Beaver Mines map area. Within the CRV,ice retreated to a point up-valley of section 07 and dom-valley of section 04 at approxirnately 1220 m elevation. This is based on the presence of two tills, correlated to the MI and M.advances, that sandwich outwash at section 07, and a single till at section 04. In Mill Creek vdley to the southeast, retreat of ice to a pointjust upstrearn of section 08 (approx. 1208 m elevation) is suggested by sedimentology and an inference of local ice volume. Two till units at section 08 sandwich a unit of interbedded till and unsorted gravel, and Mill Creek valley has a much smaller ice-s hed than the CRV, so ice retreat should have been more significant there. The activity of glaciers in the other valleys within the study area is not known, but it is assumed that ice retreated in those vaileys also, based on the same reasoning of their lesser ice-sheds as for Mill Creek valley. M2 Advame (Figure 42) A subsequent minor advance of montane ice again reached beyond the limits of the study ara (the Ad2 maximum position), based on the occurrence of M2 till at dl sections downvalley of section 07. M2 Retreat and the CI Maw*mrcm Retreat from the h42 maximum was cornplex, with at lestthree still-stands occurring in the CRV,and rnarked by coalescence with continental ice as the Laurentide Ice Sheet advanced to its maximum (C 1) position. Once the M2 maximum position was reached, montane ice receded to the west as the LIS advanced into the area from the east and northeast. The reWating CVG experienced a still-stand at about 1060 m, between sections 10 and 1I, as continental ice ovem and coalesced with it (Figure 43), depositing continental till at section 11. Continentai ice was prevented from entering the CRV upstream of section 11 by the CVG, but was unimpeded to the north and south. Immediately north of the CRV the LIS overtopped a northwest - southeast trending ridge and reached 13 10 m (4300 feet) (Jackson and Leboe 1998). South of the CRV,the LIS pushed south-westward into the Foothills between Mill and Pincher vdleys where it reached 1356 m (4450 feet) on hogback ndges and 13 10 - 1341 m (4300 - 4400 feet) at its limit dong the Foothills just northeast of Beauvais Lake. From the presence Figure 42 Readvance of montane ice to M2 maximum poslion. Figure 43. Maximum continental advance (Cl; darker blue - deplion of unit F at section 11) and stilbstand (1) of montane ice during retreat from M2 mm.mum readvanœ position. of a small patch of continental till at 1280 rn (4200 feet) elevation, about 2km northeast of the mouth of Beaver Mines Creek valley, it is infend that a srnall tongue of continental ice flowed dong the southem edge of the CVG and intnided west of Mill Creek valley. The absence of continental till on srnall hills immediately east of its occurrence near Beaver Mines lllnits the path of the ice to that described above. Deglaciation Mer reaching the Cl maximum position, the LIS retreated eastward beyond the study area. Its retreat was punctuated by pauses or still-stands which resulted in numerous glacial lake stands (Leboe 1996) including the two noted. Laurentide ice that overran the northwest - southeast trending ridge north of the CRV Iikely became trapped on the lee of the ridge as the LIS retreated. This trapped ice melted as a stagnant mass and its meltwater probably flowed alongside the north flank of the CVG and mixed with montane outwash at its snout in the vicinity of section 10 (Figure 44). The thickness of the outwash unit which contains shield clasts at section 10 suggests that the CVG experienced a (second) still-stand there while ou~hfmm glaciers of two provenances was deposited. During Laurentide retreat hmthe C 1 advance, the CVG receded up the CRV until it reached the location of section 05 at an elevation of approximately 1257 m (4125 ft) where it expenenced a third still-stand based on the presence of a cornplex suite of ice-contact sediments (Figure 45). As the CVG retreated, ice volume in the CRV decreased until ice was unable to spi11 across into Beaver Mines Creek valley. The presence of eskers, crevasse-fills and kettled topography near the mouth of Beaver Mines valley indicates that while other valley glaciers retreated from the mountain Front, ice in the Beaver Mines valley became Figure 44. Second still-stand of M2 ice showing stranded, stagnating continental iœ mas (darker Mue). Meltwater from continental ice (bold amw) is contributing shield lithologies to outwash deposits at section 10. Figure 45. Third still-stand of Castle ihlley Glacier showing input of shield material @old arrow) to sedion 05 Frorn final remnant of continental [ce. stagnant and downwasted. A series of glacial lakes formed as retreating continental ice experienced several minor readvances (Leboe 1996). Two lake stands, Glacial Lake Caldwell (13 10 m) and Glacial Lake Cardston (12 19 m); Geboe 1996), flooded most of the northeastern corner of the map area while stagnant ice lay within, and immediately north of, Beaver Mines Creek valley (Figures 46,47). This presence of ice in Beaver Mines Creek valley during the hi& lake stand is indicated by ice stagnation topography at the mouth of the valley at an elevation below that of smunding glaciolacustrine sediments. Stagnation of montane ice likely occurred around the confluence of the Castle and Westcastle rivers where eskers are numerous. The presence of eskers at the rnountain front near Mill Creek valley suggests that ice stagnation also occurred in this region. As deglaciation progressed, vast amounts of meltwater coursed through valleys and lowlands that had been recently vacated by glaciers. Absolute Chronology Debate over Pleistocene glacial history of central and southem Alberta has been fuelled by poor dating control of glacial deposits. However, ment applications of absolute dating techniques have helped to cl&& the region's Pleistocene glacial chronology. The age of the montane drift in the region can then hopefully be determined by conelating it to continental drift. Paleomagnetic sampling of Quatemary sediments was conducted by Leboe (1996) at a stratigraphie exposure (her Castle River section) located 3.5 km north of section 11 on the adjacent Blairmore sheet. Al1 59 sa~iples,sampled throughout the stratigraphy showed normal polarity, indicating that al1 Quatemary deposition there occurred after the Matuyarna Figure 46. Glaaal Lake Caldwell (131 0 m) formed by the damming of meltwater by retmating continental ice, Note stagnating montane ice mass at mouth of Beaver Mines Valley. Figure 47. Glacial Lake Cardston (1 21 3 m) fbrmed by the damming of meltwater by retreating continental iœ. - Bninhes boundary (780 ka); corroborating Wagner (1966) and reftting Staiker (1963). Furthermore, detailed studies of fossil material from basal montane gravel in central Alberta by Liverman et al. (1989) and Young et al. (1994) have produced evidence that restricts the most extensive advance of continental ice in Alberta to the late Wisconsin, Finite radiocarbon ages obtained fiom wood and bone material by these workers in fossiliferous quartzite gravel underlying a single continental till in the Edmonton region, and farther west, have established a middle Wiscunsinan age for the gravel and, therefore, a late Wisconsinan age for overlying continental till. The absence of pre-late Wisconsinan continental till near Edmonton was cited as evidence that continental ice did not reach the region and therefore could not have reached regions south of, or elevations higher than, the Edmonton area prior to the late Wisconsin (Liverman et al. 1989; Young et ai. 1994). These conclusions are supported by recent dating of the Foothills erratics train by Jackson et al. (1997) and the incorporation of this data into a stratigraphie reconstruction of glacial history by Leboe (1996). The Foothills erratics train is a narrow band of pebbly quartnte erratics extending almost 600 km south from its source in the Gog Group near Jasper, Alberta, through the Foothills and south into Montana (S talker 1956; Jackson 1993 ; Jackson et al. 1997). The erratics were transported by montane glaciers emanating from the Athabasca valley and flowing south dong the western edge of the LIS (Jackson et ai. 1997) and were deposited as the ice retreated. This advance must have been the most extensive because a subsequent, more extensive advance would have reworked and destroyed the erratics train (Stalker 1956). Leboe (1 996) found boulden of the erratics train to overlie continental till dong the eastern edge of the Brocket map area, to the northeast of the present study area. The age of emplacement of the dcstrain was recently established through the use of cosmogenic =CI exposure dating b y Jackson et al. (1 997). Their analysis of eight samples collected hmseven different erratics over a 180 km stretch of the erratics train produced seven results which show the age of the Foothills erratics train to be late Wisconsinan (approx. 14-1 7 ka). Stalker (1956), stated that the Foothills erratics train marks the western limit ofthe most recent advance of continental ice into southwestern Alberta, and that any continental till found West of this limit must antedate the erratics train. Leboe (1996)'s reconstruction of glacial history modifies this interpretation by showing that the Foothills erratics train was deposited by continental ice during retreat from its maximum, and therefore, does not mark the limit of the most recent advance, but rather a recessional stand. Continental till lying west of the erratics train antedates emplacement of the erratics train, but, as shown by Leboe (1996), was deposited during the maximum position of the same ice sheet and therefore is of late Wisconshan age. From these studies, it is recognised that continental drift found in the Beaver Mines area cannot be older than late Wiswnsinan. It is Merrecognised that montane drift is also of late Wisconsinan age based on the absence of paleosols, weathering profiles, buried organics etc. that would indicate a significant hiatus in drift deposition. Regionai Cordations of Drift Montane clrifi in the study area is correlateci to Unit 2 of Leboe (1996) and the M2 advance of Wagner (1966). Littie (1995) identifiai montane and continental till in the Waterton Lakes and Cardston map areas to the southwest of the study am, but correlation with the montane tills is dificuit because they occur in different valleys far removed fiam this shidy area. Local climatic responses, glacial dynamics and chronolog-wuld be quite different fkom the Beaver Mines area. A single continental till found at section 11 is correlated to Leboe's (1996) subunit 4a and with Liale's (1995) single continental till. CHAPTER 6 CONCLUSIONS Drift distriiution of the Beaver Mines rnap area, as detennined hm150 000 scale mapping, reveals that the area was covered by a discontinuous ice sheet during the last glaciation and that during deglaciation, ice retreated up some valleys while stagnating in small patches in others. Two montane tills at seven exposures in Castle River valley represent separate advances (Ml and M2) while a single continental till present at one exposure represents a single continental advance (Cl). Pleistocene stratigraphy of the study area represents glacial sediments that were ail deposited during the Late Wisconsinan Substage. No evidence of an extended period of weathenng (e-g. a paiaeosol) was found anywhere in the stratigraphy to suggest a significant hiatus in glacial sedimentation. This is supported by recent radiocarbon and cosmogenic dating of Late Wisconsinan drift outside the study mea. A reconstruction of glacial history for the Beaver Mines rnap area has been presented in which an initial advance (Ml) of montane glacial ice extended beyond the limits of the study area and was followed by retreat to within the map area, upstream of section 07. Subsequently, a less extensive readvance (MZ) occmed, again reaching beyond the study area. A single advance of continental ice (C 1) reached the study area and, at its maximum position, coalesced with retreating montane ice as it was excludeci From the Castle River deyupstream of section 11. The presence of Canadian Shield clasts in montane grave1 at section 10, and at the base of an ice-contact suite at section 05, is attributed to meltwater emanating fmm a detached stagnant block of the Laurentide Ice Sheet that was trapped by a ridge following retreat kmthe continental maximum position. Deglaciation of the area was characterised by retreat and stagnation of montane ice near valley mouths while retreating continental ice dammed meltwater to form glacial lakes. Montane drift in the study area is correlateci to Unit 2 of Leboe (1996) and the M2 advance of Wagner (1 966) while a single continental till found at section 11 is correlated to Leboe's (1996) subunit 4a and Little's (1995) single conMemal till. Recognition that montane drift encountered in this study is of Iate Wisconsinan age enables to writer to assign it to the Pinedale Stage of glaciation recognised farther south in Montana by Richmond (1960). Aiden, W.C.,and Stebinger, E., 1913, Pre-Wisconsin glacial drift in the region of Glacier National Park, Montana: Geological Society of America Bulletin, v. 24, p. 529- 572. Ailey, N.F., 1973, Glacial stratigraphy and the limits of the Rocky Mountain and Laurentide Ice Sheets in southwestem Alberta, Canada: Canadian Petroleum Geology Bulletin, v. 2 1, p. 153-177. 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Dreimanis, A, 1989, Tills: their genetic terminology and classification, in Goldthwait, RP., and Matsch, CL.,eds., Genetic Classification of Glacigenic Deposits: Rotterdam, A.A. Bakema, p. 17-83. Fermor, PR, and Price, RA., 1983, Stratigraphy of the lower part of the Belt-Purcell Supergroup (middle Roterozoic) in the Lewis thnist sheet of southem Alberta and British Columbia: Canadian Petroleum Geology Bulletin, v. 3 1, p. 169-194- Hicock, S.R, Goff, JR, Lian, OB., and Little, E.C., 1996, On the interpretation of subglacial till fabric: Journal of Sedimentary Research, v. 66, p. 928-934. Holme, P.J., 1997, Quaternary geology and terrain inventory, Eastern Cordillera NATMAP Project. Report 4: investigation of conthenal and montane advances in the Beaver Mines rnap area, southwestem Alberta, in Current Research 1997- A: Geological Swey of Canada, p. 177- 182. Holme, P.J., Hicock, SR, and Jackson, LE., Jr., 1998, Quatemary geology and terrain inventory, Eastern Cordillera NATMAP Project. 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Stalker, AM., 1963, Quatemary stratigraphy in southem Alberta: Geological Survey of Canada Paper, v. 62, no. 34.52 p. Stalker, AM, 1969, A probable Late Pinedaie terminal moraine in Castle River Valley, Alberta: Geological Society of America Bulletin, v. 80, p. 21 15-2122. Stalker, AM., 1970, A probable Late Pinedale terminal moraine in Castle River Valley, Alberta: Reply: Geological Society of Amerka Bulletin, v. 81, p. 3775-3778. Staker, AM, 1977, The probable extent of classical Wisconsin ice in southem and centrai Alberta: Canadian Journal of Earth Sciences, v. 14, p. 2614-2619. Stalker, A.M., and Harrison, J.E.,1977, Quaternary glaciation of the Waterton - Castle River region of Alberta: Canadian Petroleum Geology Bulletin, v. 25, p. 882-906. Wagner, WP., 1966, Correlation of Rocky Mountain and Laurentide glacial chronologies in southwestern Alberta, Canada PhD. thesis]: AM Arbor, University of Michigan, Department of Geology, 141 p. Wagner, WP., and Eschman, DE., A probable Late Pinedale teminal moraine in Castle River valley, Alberta: Discussion: Geological Society of Amenca Bulletin, v. 8 1, p. 3773 -3 774. Woodcoclc, Na., 1977, Specification of fabric shape using an eigenvalue method: Geological Society of America Bulletin, v. 88, p. 123 1- 1236. Young, RR, Burns, J.A., Smith, D.G.,Arnold, LD., and Rains, RB., 1994, A single, late Wisconsin, Laurentide glaciation, Edmonton area and southwestern Alberta: Geology, V. 22, p. 683-686. Appendix 1: Pebble a-axis Fabric Data Fabric 16 Section 9 Section 1O Section 7 Section 6 Mplwige qunge -piungs wpiunga 336 108 274 127 182 126 043106 332 1 15 182102 133 116 303112 218 104 2001 15 008 161 3451 15 160107 244 1 15 308143 223109 318 104 O71 107 195104 6591m 289 1 23 255 1û2 295 134 223 1 12 238 1 03 096 1 12 Q29 144 302138 220 1 O0 095110 298 1 12 284 127 337 126 197 128 314 Il8 141 1 17, 330129 195 1 09 321 137 086105 232 1 07 078 1 11 327 1 14 026 143 005102 252 1 08 201 136 127 134 239 1 13 177126 346 1 25 136 1 18 283 Il3 O75 106 290 142 273 1 38 O18 Il6 058 1 15 138 114 136 120 287 137 O511 12 226 1 15 224 123 231 119 231 118 348 103 104108 282 1 00 on106 334 1 a3 13/09 277 1 O2 242 1 22 006145 152 1 10 201 121 295 1 M 088 Il4 240 145 278 1 10 0021 10 338 Ill 265 1û2 031 1 16 265 101 084 118 234 1 15 322 1 52 151 157 272 1 54 155 IO3 322 1 16 075 120 277 1 31 272 i 05 135102 0881 17 139 126 347 104 069102 281 126 108120 319 114 053 104 083105 115 118 126 1 13 160 / 05 043 1 10 137 1 18 274 136 260105 105109 112123 178 105 102109 114143 264 1 23 044118 302104 261 110 283 111 337 1 32 087102 172121 154 154 093 1 03 280 1 17 0201 10 270 1 32 204 133 O10 145 265 1 12 242 135 147 107 222132 329 104 203 132 120 1 19 262 143 008117 148 134 220 1 15 134 120 093 1 17 005108 021 115 084104 236106 1451 15 039 1 02 O73 107 319 134 068108 035116 167100 2581 13 103102 224 1 71 260 126 326 1 14 021 133 2501 13 2951 11 027 103 280 1 16 306144 274 153 284 102 237 1 12 173 1 26 092104 279 1 30 323 127 249 110 311 142 204106 la6130 Appendix 1: Pebble a-axis Fabric Data Fabric 22 Section 4 Section 8 Section 8 -piunge -prunge tr'nd~oiwige 125 1 75 239 106 321 131 300 107 033 138 126150 015 1il7 205 142 241 136 048 127 186 146 089 142 181 104 335 100 061118 175 121 059130 020 1 14 225 123 315150 250 124 0341 10 278 126 262 158 1% 125 320 103 029114 307 127 OB81 10 118120 193 1 55 120 121 217 120 107 126 007100 038 148 O1 O 1 16 064124 222 / 46 070 1 23 310160 134104 122 1 16 288 115 306106 186104 213 1Oô 020 120 1291 11 022100 118123 2991 15 034102 270 1O2 070 152 315 123 142 124 241 172 208105 348 120 0861 10 035148 080106 084107 220 1 12 059 126 127 129 CW 138 059118 107 1 17 056140 004 1 O1 091 Il4 038130 271 105 0021 10 068 135 027 145 053105 345 1 10 345 139 083113 107 110 118132 101 103 084122 2.24 105 090174 060100 333 126 029106 030 120 184105 066102 128 103 J50121 160 IO5 215 146 070 148 120 120 210 140 257 1 19 078 138 170 1 12 174 1 08 080100 117127 066104 105 137 2001 14 246 1 14 108 156 oSora8 236 103 102 110 164 1 O7 221 148 185 152 3071 11 222 133 207 1 15 344 125 155 142 172 108 125105 101 118 085 120 298 135 342 122 295 155 027 123 306151 330 145 1551 16 035111 ml21 170100 028 107 097111 2% 150 254 1 30 016 178 025 1 12 224 1 O2 015 156 003 102 033148 273177 031 Il6 Appendbc 2: Structural and other orientational data Stnictural Data Striae on stone surfaces f Clast lee-end orientations I I Saccion ) mit sirikeldip 1 unit bidiredionai Section 1 unit hz-end 2 i c 219156 1 sbiae 1 I mmuth 1 6 C 1194113 3 A 1075-255 ' 11 :~upper/270-00. 6 C [ 201 125 3 A / 080 -260 11 B upper f 240-00 8 B 217111 3 A 081 -261 11 l~upper(082-00 8 C 263118 6 A 245 -065 11 / B upper 1 035 - 00 8 C 110104 17 C 355 - 175 1 11 j 0 upper / 278 - 00 1 9 1 6 3181211 7 C 1034-214' 11 ~upperi162-001 9 1 6 300 170 / 7 C 171 - 351 1 11 B upper 270 -00 1 9 B 108112 1 7 C 170-350 1 11 i~upper 250-00 9 , B 075111/ 11 Bupper 170-350 1 11 IBupper 165-00 9 B 1080111 1 11 Bupper 160-340) 11 j~u~peri192-00 9 B 087111 11 Bupper 191-011 1 11 Buppert270-00 9 c 031177 11 Bupper 160-340 11 B upper 077 -00 1 11 /8lower 153180 11 Bupper 146-326 180-001 / , 11 , 0 11 ] F 240183 11 B upper 306 - 126 1 i I 11 F 360112 11 D 280-100 j 11 F 035 190 11 1 D 204-024 1 11 F 0651 87 11 1 D 264-084 1 t 11 F 231188 11 1 D 250-070- 1l t Appendix 3: Pebble lithology data Sample Sample # Category 1 Category 2 Category 3 Category 4 Category 5 Category 6 Category 7 JJP95008 1 143 28 2 O 6 O O JJP95027 2 12 23 3 i 11 O O JJP95030 3 16 24 1 2 6 O 1 JJP95033 4 15 11 1 6 16 O O JJP95036 5 15 33 2 O O O O JJP95039 6 20 27 1 O 2 O O JJP96021 7 7 39 1 O 3 O O JJP96028 8 11 22 O i 14 O O JJP97002 9 19 28 O O 1 O 2 JJP97005 10 11 26 4 1 8 O O JJP97002 11 19 28 O O 1 O 2 JJP97005 12 11 26 4 1 8 O O JJP97008 13 10 29 2 1 8 O O JJP97012 14 9 30 2 O 8 O 1 JJP97015 15 4 42 O O 3 O 1 JJP97018 16 6 33 4 2 5 O O JJP97022 17 5 39 O O 6 O O 3JP97025 18 11 32 O O 6 O 1 JJP97028 19 16 31 3 O O O O JJP97031 20 8 36 O O 5 O 1 P98002 21 10 27 O 2 10 O 1 P98004 22 7 39 1 1 2 O O P98006 23 3 37 1 2 7 O O Appendbc 4: Grain-size analyses for diamicton matrices Sample # Field % Sand % Silt % Clay Total Label Sample # jjp950007 17.350 100.000 05-A jjp950026 32.535 100*000 O3 -A jjp950029 8.338 100.000 03-A' jjp950032 8.561 100.001 01 -C jp950035 13.700 100*000 O7 -A jjp950038 l9.SOO 100.000 O7 - C jjp96020 19.780 100.000 10-C jjp96027 8-440 100.000 10-A jjp96034 6.970 100.000 02-C jjp96037 12.030 100.000 02-C jp97001 5.70 1 99.992 11 -F jjp97004 1.731 lOO.OO7 11 -0 jjp97007 3.186 99.993 11 -B jjp97011 3.256 100,000 11 -B' Jp97014 4.509 lOO.014 08 - C jjp97017 2.697 99.995 08 - 8 jjp97021 2.759 100.000 09-C jjp97024 3.078 lOO.OO7 09 - B jjp97027 2.903 100.01 3 06-C jjp97030 3.509 100.000 06-A P98001 10 1O0 04-A P98003 6 100 04 - A' P98005 8 1O0 04-A" Appendix 5: Publications resulting from thesis work Quaternary geology and terrain inventory, Eastern Cordillera NATMAP Project. Report 4: investigation of continental and rnontane advances in the Beaver Mines map area, southwestern Alberta1 Philip J. ~olme' GSC Pacific Holme. P J.. 1997: Qrtaternary geology and terrain inventory. Eastern Cordillera NATMAP Project. Report CC: investigarion of continental and monfaneadvances in the Beaver Mines map area. sourhwesrern Alberta; in Currenr Research 19974; Geological Srirvey of Canada. p. 177-152. A bstract: The al1 time limitr of montme and continental glacial ice wen determined from field mapping and stntigraphic investigations of Beaver Mines map ma(82G/8). Preiiminary interpretauon of Quaternary sediments in six major cliff-bmk exposures suggests evidence for a retreat of montane ice following the climax of the late Wisconsinan Glaciation in Rocky Mountains and a subsequent smaller readvance. A single clast from the Canadian Shield was found within a till at one exposure. Preliminary glacial histories compatibIe with the stntigraphy are: an initiai pnmary rnontme advance followed by retreat and a smaller readvance prior to a continental advance into the map area or 3 continental advmce in the interim between the primq and secondary montme advances- Résumé : Les limites maximales d'avancée du glacier alpin et du glacier continental ont été déterminées A partir d'études cano-mphiques et stnti-mphiques effectuées sur le temin dms la région cartographique de Beaver Mines (82 GB). L'interprétation provisoire des sédiments quaternaires exposés dans six falaises indiquent un retrait du glacier alpin après le pléniglaciaire du Wisconsinien supérieur dans les Rocheuses et une réavancée subséquente moins importante. On n'a trouvé qu'un seul claste provenant du Bouclier canadien dans un till exposi. L'histoire provisoire des avancées qui est compatible avec la stratigraphie comporte une première avancée du glacier alpin suivie par un retrait et par une réavancée moins importante avant une avancée du glaciercontinental dans Ia région canogmphique ou une avancée du glacier continental entre l'avancée et la réavancée du glacier atpin. - -- ' Contribution to the Eastern CordiIlen NATMAP Project Depmment of Emh Sciences. University of Western Ontario. London. Ontario N6A 587 Rocky ~MountainFront (Fig. 2). Erratics of Canadian Shield provenance were found up to 1340 m on a low hiil in the northerist corner of the map This subregion refers to the mountain front of the Clarke area (UTM N5183200. E712630) and up to 133 m on the Range east of the Castle River. Extensive deposits of colluviaI northeast slope of a hi11 6 km to the southwest (UTM material. some of it colluviated till. were found on the upper NS4798ûû. E707370). Scattered lacustrine or glaciolacus- slopes of the mountain front. whereas the Iower slopes were trine deposits were found in the small vaileys between the dominated by till. either as a veneer or a blanket. The lower- Fwthill ridges, most slopes and the lowimd between the mountain front and the southwesternmost foothills were blruiketed by extensive gfaciofluvial deposits. CastIe River Lowland The Castle Rivervalley in the northeast corner of the map area is largely incised into an extensive lowland underlain by thick gIaciolacustrine sediments. The approximate upper limit of The Foothills occur as roughly pmilel rows of discomected these slacial lake sediments is 13 10 m. although it is lower in sandstone ridges trending northwest/southerist which reflect some areas. These lake sediments generilly overlie Lauren- the general strike of their bedding. Montane provenance till tide till where exposures occur along their mugins. was found to blanket most slopes of the southwestern-most FoothilIs up to an elevation of about 1615 m. whereas the remainder of slopes are covered in coIluvium. Above 16 15 m. montane erntics are the only evidence of pst glacial ice cover. Close to the mountain front, montane erratics occur on The subsurface Quaternary stntigraphy of the study mais Foothills ridges as high as 1735 m. but are scarce above about based upon the study of six extensive cIiff-bank exposures 1675 m. (Fig. 2. 3). These give a representation of the stntignphy from the Rocky Mountains northeastwiud into the Cade The Foothills ridges in the northezist quimer of the map River Lowland (Fig. 2). They are summarized in chat order. area rue lower than those closer to the mountains. The dl-cime Sections are described from the base of the exposure upward. Laurentide maximum limit in this mawas deterrnined based Al1 tiils described are montane in origin. Units designated in on the locations of Lriurentide erntics found whilç mripping Unit 1 is interpreted as a lodgement till maidy due to its Unit 1: Bedrock high degree of consolidation. The preliminary interpretation Unit 3: indurated diamicton of unit 2 is a flow tiIi due to the presence of fiow features. Bedrock exposed nearby, but was not exposed at the base of Unit 3: Glaciofluvial pvel. the described exposure. Unit 4: Indunted diamicton Unit 5: Glaciolacusmne clayey silt. Underlies the glacio- Mountain Mill section lacustrine plain of Castle River Lowland. This section is Iocated on the Castie River dong the north Unit 6: Poorly soned pvel. edge of the map sheet about 8 km due West of Pincher Creek It was described first by Stdker (1969) and his descriptions Unit 7: Eolian sand. are incorponted in Figure 3 (units 3-9). The June 1995 flood The diamictons (units 1 and 4) and intervening pvel washed away much of the slurnp material at the base of the (unit 3) lack any clasts from the Canadian Shield. The diamic- cIiff reveding stntigraphy unavailable to Staiker. The newly tons were interpreted to be basal till based on fabric data. clast exposed sediments consisted of a diamicton (unit 1) overlain lithologies, and correlation with till units at other exposures. by two glaciofluvial grave1 layers (unit 2), ail underlying the A fabric determined in the lower diarnicton indicated flow Iowest diamicton (unit 3) described by Stalker. Fabrics were from the West (S 1 Eigen value = 0.67, S3 value = 0.13). A rneasured on units I and 3. Unit 3 has a strong fabric retlecting fabric determined in the upper diarnicton indicated ice flow ice-flow from the west-south (principal S 1 Eigen value = from the northwest (S 1 = 0.56, S3 = 0.20). 0.7 1. S3 value = 0.07). The fabric from unit 1 indicates ice-flow from the southwest (S 1 value = 0.56, S3 = 0.12). Both diamictons are interpreted to be basal tills due to their induration. montane clast Iitholo_eiesand fabrics. The 34 m of PRELIMINARY JNTERPRETATIONS glaciofluvial gnvel (unit 4) overlying the upper diamicton (Stalker. 1969) contains clasts from the Canadian Shield. The following preliminary findings have been reached based There are no Shield clasts found in units 1-3. upon surficial geology mapping and stratigraphic interpretations. Washout section Montane glacial advances This exposure is Iocated at the northern edge of the map area on the West side of Highway 507 North immediately south of Montane tiIl correlated to the late Wisconsinan "Maximum the bridge over Castle River. The exposure was created by Glaciation" (infornial term) of Jackson et d. (1996) was flood water scouring out a gulfeydong the roadside in June found at ail six stratigraphic exposures (Fig. 3). Two montane 1995. The exposure was up to 3 m in depth. but has since been tills. separated by fluvial sediments, are present at only two back-filled completely by highways crews. The exposure of the exposures: Mountain Mill and Rener's Fanns sections. descended through the Quaternary fiIl in this areaof the Castle Of the other four major exposures, only one (the Washout River valley over a distance of about 330 rn from north to Section) has the Quaternary valley fil1 exposed to bedrock. south and thus gave ri good horizontal ris well as vertical The succession of two montane tills sepmted by glacioflu- cross-section. vial deposits at Mountain Mill and Rener's Fmsections is interpreted as documenting reueat of ice to near the Rocky Unit 1: Striated bedrock. Mountain front afterthe major rnontane glaciai advance of the Unit 2: Indunted. fissile diamicton. Maximum Glaciation followed by ri subsequent smaller rad- vance. Since the Coldfoot, Gasline, or Castle Bridge sections Unit 3: Diamicton. Contains at least one clast of grrinodiode are not exposed to bedrock ruid intertill outwash is lacking at from the Canadian Shield which was noted at the contact with Washout section, it is not possible to determine the extent of the underiying unit. ice retreat upstream from the Mountain Mill and Rener's Unit 4: A complex assemblage of interstntified sand. silt, Fmsections. The single or brisal tills exposed at these three clay, diamicton. and gravel. upsmam sections have ken prelirninarily comlated with the upper till at Washout section (Fig. 2). Unit 5: Glaciolacustrine sand. silt. and clay. This unit under- lies the gIaciolacustrine plain of the Castle River Lowland. Laurentide Ice Sheet advance Unit 7 was interpreted to be a lodgement till due to its high degree of fissility and induration. Unit 3 is interpreted as a Although till from the al1 rime (late Wisconsinm) advmce of distinct tilI due to the presence of ri Shield clast. the Laurentide Ice Sheet (Jackson et ai.. 1996) was mapped dong the edge of the glriciolacustrine lake plain in the north- east corner of the map maand shield erntics are found ris Rener's Farm section high as 1340 m. a single Cmadian Shield Stone was found in This 30 m cliff-bank exposure is located just north of the only one till unit rit one of the six exposures (Washout section) nonhern boundary of the map on the Blairmore map sheet described above. However. clasts from the Canadian Shield (82 G/9). were found in abundance in the thick glaciofiuvid deposits Quatemary geology and terrain inventory, Eastern Cordillera NATMAP Project. Report 5 : stratigraphic correlations of glacial deposits in the B eaver Mines map area, southwestern Alberta1 Philip J. ~olme~,Stephen R. ~icock~,and Lionel E. Jackson, Jr. Terrain Sciences Division, Vancouver Holme, P.J., Hicock, S.R., and Jackson, LE., Jr., 1998: Quatemary geology and terrain inventory, Eastern Cordaïlera NATMAP Project. Report 5: stratigraphic correlations of glacial deposits in the Beaver Mines map area, southwestern Alberta; in Current Research 1998-E; Geological Survey of Canada p, 11-1 7. Abstract: A stmigmphic mss-section of glacial deposïts was consûucted hmthe investigation of sedimcnts in 10 ciiff-bankexposures dong the Cade River vatley and its tributaries in southwest Alberta The presence of two montane tiUs at seven sections is suggested as evidence for retreat of montane ice hm the maximum of the late Wisconsinan glaciation and a subsequent minor readvance. Continental till is not found in the Castie River vdey upstrearn of Hunting EagIc section, although it occurs at higher elevarions immediately adjacent to the valley. A single clast of Canadian Shield lithology was found in montane tiii at one exposure, Washout section. A reconstruction of g1acia.I history compatible with these fuidings excludes continental ice hmthe Castle River valley by dl-stands of montane ice retreating hmreadvance psitions. Résumé : Une coupe stratigraphiquede dépôts glaciaires a été constituée à partir d'une étude effectuée sur des sédiments prélevis dans dix affleurements de berge et de falaise le long de la vallée de la rivière - Castle et de ses affluents dans le sud-ouest de l'Alberta La présence de deux tills subalpins dans sept coupes témoignerait du retrait des glaces subalpines du pléniglaciaire du Wisconsinien supérieur et d'une réavancée mineure subséquente, Le till continental est absent dans la vallée de la rivière Cade en amont de la coupe de Hunting Eagle, même si on en a observé dans des terrains plus élevés jouxtant la vdlée. Un seul claste de la lithologie du Bouclier canadien aété repéré dans un till subalpin, soit dans lacoupe de Washout Selon une reconstitution de l'histoire glaciaire qui tient compte de ces observations, l'arrêt des glaces subalpines en retrait par rapport aux positions de réavanc& aurait ernpikhé les glaces continentales en progression d'envahir la vallée de la rivière Cade. Contribution to Eastern Corciillem NATMAP Roject * Department of Earth Sciences, University of Western Ontario. London, Ontario N6A 5B7 120 P.J. Hdrne et ai. Unit 3 is a stony, slightly consolidated diamicton becom- Quaternary cover in the cliff section thins rapidy upstream hg more consolidated and indurateci with depth. Its maak and disapptars about 200 m hm the described section. becornes lcss sandy with depth except near the base where Slumping obscures the sediment-bedrock contact. sand content inncases. Clam range hmgranuIes to 20 cm Unit 1 is a consolidated, cohesive diamicton with a sandy cobbles. The lower contact is abrupt and irreguiar. silt loam ma!rix, A large block of vertically dipping, unsorted The lower diarnicton (unit 1) is interpftted as a deformed cobble gravel, present in the upper 2 m. was klyincorpo- lodgernent till (Fig. 3). Lodgement is suggested by the high rated into the unit as a frozen block and then rotateci The dia- degree of consolidation and the presence of clearly lodged micton becornes highly consolidated and less stony in the clasts. The tiii fabric plot is biiodal with Skû.524 and lower 8 m of the unit. At this depth the matrix is a mottied and S3lS 1 =0.221, suggesting deformation. The lower haif of the banded sirty loam. Numerous sand pockets with sand dg- upper diamicton (unit 3) is interpreted as a deformation till. ers sheand out of them are present hughout rncst of unit. This is suggested by the bimodal to muttirnodal fabric plot Occasional sand Ienses are present within the diamicton, with S 14,520 and S3/S 1=0.3 13. The upper haif of the unit is Unit 2 is a very stony diamicton with clam ranging hm thought to be a meltout o11 due to its laser consolidation, but grandes to cobbles. fts sandy mamix is cohesive and quite no fabric data was gathered to support this interpretation. consolidated- It has an abrupt and hguiar upper contact. Its Iower contact is irregular and inchdes incorporated bIocks of the underlying unit. This section is located at the downsmend of a 350 rn long Unit 3 is a cohesive fine sand and silt (upper half), A bedrock ciiff dong the south bank of Castle River about coarse-grained sand lens is present in the upper 12 cm of the 1.5 km upstream hmthe river's confluence with Mill Creek. unit. The lower half of unit consists of chaotically interbed- ded silt and strongly crossbedded medium sand. SECTIONS 1996 CF Coldfoot CB Castle Bridge GL Gasline WA Washout RF Rener's Farms MM Mountain Mill 1997 SD Screwdriver Creek MC McRae WD Wedgie HE Hunting Eagle 8 Limit of shield Figure 2. Locations of described sections and local western Canadian Shield erraticsfound on the surface. PJ. Holme et al. The diamicton comprising the lowermost unit in the sec- Unit 2 is a highly mnsolidated, stony diarnicton. It has an tion (unit 1) is interpreted as a basal dl. Two fabrics were abrupt and irre&Ü upper contact and then are numemus measured within the unit, both in the upper third. The lower frachires throughout it Shearing is cvidem in the lower two- fabric was quite strong with S1=0.615 and S3/Sl=0.138 thirds of the unit where numerous sand stringers are sheared while the upper was considerably weaker with S 1=0503 and up hmchaotically bedded sand pockets, S3/S1=0.235. The Iowa fabric is bimodal and suggests Unit 3 is a chaotic mix of coarse-grained sand beds with deformed lodgement whereas the upper fabric is multimodal, diamicton pockets. Sand beds are strongly crossbedded, indicarhg a deformation W. faulted, and folded, Facies chge across the section to exrremely stony diamicton overlying medium sand with grave1 Ienses which in tum overlies fissile diamicton. The upper contact of the unit at the northern end of th exposure is This section is located on the north bank of Miiî Creek about transitional over 25 cm whereas it is abrupt and irregular at 5 km above the creek's confluence with Castle River. The southem end of the exposures. section is 20 m high by about 20 m across witb bedrock exposed at the base. Unit 4 is diamicton with silty sand matrix, It is consoli- dated and fissile and siightiy cohesive. Its upper contact is Unit 1 is unsorted cobble and bodder gravel. Clasts are gradational over IO cm. It is moderately stony with clam subangular to rounded and the matrix coarsens downward hmgrandes to 10 cm cobbles. Sand stringers are present, hmgranules to pebbles. A few lenses of granules and peb- especiaiiy near base. bles arc present in the Iower two-thirds of the unit A layer of cairnte 15 cm thick is present at the bedrock contact Unit 5 is highly sheared silt overlying highly sheared dia- micton. Its upper contact is irregular. It becornes more Unit 2 is a fissile, consolidated and cohesive diamicton diamicton-rich with depth. with a greyish-dark brown sand and silt rnaaix. Clam range hmgranules to 60 cm boulders. Sand and gravel content Unit 6 is extrtrnely fissile sil~It is stoneless at northem increases toward the base. The upper contact is abrupt and end of section but it becornes moderately stony at the south- undulating, em end of the section in lower part of unit. Unit 3 (lower half) is diamicton interbeddcd with ma&- Unit 7 is consolidated, moderately stony diamicton. It has rich, unsorted, pebble gravel. Grave1 units are rnoderately a medium brown clayey silt matrix with orange motties. It is consoiidated and contain pockets of the diamicton. Diamic- highly fracnueci; many fiactlires are filleci with gypsum crys- ton and gravel beds becornt more mixed at depth resulting in tais. Clasts hmgranules to cobbles. Four clam hmthe a sandier, les stony rnatrix. The upper half of unit 3 is con- Canadian Shitld were found within this unit soridated diamicton with an isolated boulder concentration in The Iowermost diamicton (unit 2) is interpreted as a the upper third of this interval. In the lower haif of this inter- localiy defoxmed lodgernent tiii. Three till fabrics were meas- val, it contains sand which was incorporated through sheuing ured in unit 2, two at section A and a third at section B, The of the uppermost gravel bed in lower haif of unit 3, upper fabric at section A is muIhmodaI (S1=0.504 and The lower diamicton (unit 2) is interpreted as a strongly S3lS 1=O.3 10) whereas the Iowa fabnc is bimodal (S 1=0.445 deformed lodgement till based on its birnodal fabric and S3/S 1=û.382). Despite the low eigenvaiues of the lower (S 1=0.480 and S3lS 14.348). The lower half of unit 3 (con- fabric, it is stronger than the upper fabric as is evident from its sisting of interbedded diarnicton and gravel) is interpreted as bimodality. Both fabrics suggest a deformation till. The fab- an ice-marginal deposi~The upper haif of unit 3 (consisting ric done in the upper part of unit 2 at section B is a unimodal of the consoiidated diamicton) is interpreted as a deformation plot with S 1=O,6S4 and S3lS ld.226 suggesting a lodgement till based on its rnultimodd fabric with SI=0.480 and till. S3IS1=0.410. The unit of heaviiy sheared silt and diamicton (unit 5) which overlies unit 4 is interpxeted as adeformation till based Hunting Eagle secfion on the degree of shearing evident within the sediment The uppermost till (unit 7) is interpreted a a deformation tilI The section is located on the east bank of the Casde River based on the mdtimodal nature of its fabric (S ld.5 16 and immediately northeast of the map area in NTS 82 GI~,about S3lS 1=O-240). 6 km west of the tom of Pincher Creek. The section is exposed in a large slurnp scar approximately 35 m hi& by 150 m long with bedrock exposed at the base. The surnmary PROPOSED INTERPRETATXONS presented here is a composite of two separate exposures (sec- OF GLACIAL HlSTORY tions A and 8)at the section. Section A was about 26 m in height, focated at the downstream end of the exposure whereas section B was about 20 m high and located at the Montane ice advances upstream end of the exposure. Wolme (1997) established a minimum extent for the remat of Unit 1 is a consolidated, unsorted gravel containing clasts montane ice hmthe Maximum Glaciation (informai term of hmgranules to boulders. Jackson et al. (1 996) and here referred to as the M 1 advance) as lying upstream hmRener's Farms section in the Castle PJ. Hdme et ai. LJL JG Rettcr, N*Wv OL.nd Qngac, JJ* 1969: Incamplete continentai glacial mord of Aibcrta UQuamn- 1989: GIaciated fnoge; in Chaptcr 1 of Quaremary Geology of Canada ary Gcology and Climatt, Pubtidon 1701. National Acadtmy of aud Gracnland (ai)RI. Fuiton; Geological Survey of Cida, Sucnçts. Washington, D.C. p. 99- 103. Gtology of Canada. 110.1 (doGcoiogical Society of Atnaica, T& B-b DL Gcoiogy of NdMca. v. K- 1). 1994: Fabric sitape and the intaprriation of stdimntary fahic dara; Lcboe,= Journal of Sedimcntary Rtstarch, v. A64 No- 4. Oaober. 1995: Quamary gtology and tmain invcntory, Eastern Cordillera p. 9 10-9t 5. NATMAP hjaRepon 2: surficiai gtology and Quatanary ma- HieSR., Gd*J& LIPn, o.B., mdLiüit, EC ugraphy, Pinchtr Crieck and Brocka map Albata; in Cumt 19%: On the interprctation of subglaciai ti11 fabric; Journal of Rtstarch 1995-A; GeoIogical Survey of Canada. p. 167-175, Sedimntary Researcb, v. 66, no. 5, Scpremkr, p. 928-934. we,EC. Hotmt, PJ, 1995: Quarcrnary gcotogy and terrain inventory, Eastern CordiUera 1997: Quatcrnary gtology and -n inventory, Easum Cordillera NAWRojecL Rcport 3: two conthenta1 gkid advance in NATMAP Rojca Repart 4: investigationsof continental aad mon- Wamton and Cardston map arcas, Aikrra; ut Cumnt Research tarie advances in tbc Beava Mimap arca. southwtstan AIbew; 19954; Geological Sunny of Chada. p. 177-182 in Currcnt barch 1997-A; Gcologicai Survey of Cana& Liverman, D.C& Catto, NA., and Ratter*NM. p. 177-182 1989: Laurenude giaaation in wcst-centrd Albertz a single (Latc Horbug, L. Wikconsùlan) evcnt; ranaAian Jodof EaTLh Sciences. v. 26. 1954: Rocky Mauntain and continental PIeistoccne deposiu in the p. 266-274. Watutou rtgion. Alkna. Canada; Bulletin of the GcoIogical ,May, RW, Dnimrais, A, ruid SrnnLo- W. Society of Amnca. v. 66, p. 1093- 1150. 1980: Quantitative cvaluation of clast fabricj within fk Cadish Crrelt JPciuon, LS. Jr. Tï1, BradorilIc Oatario; Canadian Journal of Eanh Sciences. v. 17, 1980: Glaciai saarigmphy and bryof the Albcrta pomon of the p. 1064-1074. Kammkh idus map arca; Canadian Journai of Eartb Saenas, Sucer* A *Md* v- 17. p. 45Wî7. 1969: A pbable iatc Piritdale tumiad moraine in Cade River Vailey, 1994: Quatanary geology and tciain invcntory, Foothih and adjacent Aiberta; Geologicai Society of America, Bulletin. v. 80. plains, soulbwtstan Alberta: somt new insighrs into the kttwo p. 21 15-2122 glaciations; in Currtnt Resuuch 1994-A; Gcological Survcy of Stakrr, A &fa&. and anmMn, JL Chda, p- 237-242 19ïï: Quatentary glaQation of Watmon-Cade Rivaregion; Bulletin of Jackson, L-E, Jr., Little, EC ER, and Holmt, P.J. Canadian bkumGcology, v. 25. p. 882-906. 1996: A re-cvduation of the paleoglaaology of tbe maximum contineatal Wagner, WS. and montanc advances. southwesfcm Alberta; in CwntRrjearrh 1966: Corniafion of RoEky Mountain and Laurrntide glacial chronolo- 1996-A; Geologicai Swcy of Canada. p. 165475. gies in southwescan AIbena. Canada; PhD- thesis. Departmcnt of Gcology. Univmity of Michigan. Am Arbor. Michigan, 141 p. Young, RR, Burns, JA., Smith, DG, Arnold, L, and Rniiu, RB. 1994: A single late Wiscousia, Laurrntidc glaciation. Edmonton ami and souihwestcm Alberta: Gcology. v. 22. p. 683-686. Geoiogicd Swey of Canada Rojcct 9MW3 VITA Philip J. Holme Year of Birtb : Post-secondary University of Westem Ontario Education and London, Ontario, Canada Degr ees : 1996-1 998 M. Sc. Geology Vancouver, British Columbia, Canada 1988-1993 Associate of Arts Human Geography University of British Columbia Capilano College Vancouver, British Columbia, Canada 1993-1996 B.Sc. Physical Geography Professional Geological Association of Canada Associations : Related work Teaching Assistant Experience : University of Western Ontario 1996- 1997, 1997- 1998 Senior Geological Assistant Geological Survey of Canada summers 1995, 1996, 1997 Junior Geological Assistant Geological Survey of Canada surnmers 1992, 1993, 1994 Publications : Holme, P.J., Hicock, S.R. and Jackson, LE, Jr., 1998, Quatemary geology and terrain inventory, Eastern Cordillera NATMAP Proj ect. Report 5 : stratigraphic correlations of glacial deposits in the Beaver Mines map are%southwestem Alberta, in Current Research 1998-E: Geological Suntey of Canada, p. 11-1 7. Holme, P.J., 1998, Surficial Geology, Beaver Mines, Alberta. Geological Survey of Canada map 1932A (1 50 000). Holme, P.J.,Jackson, L.E., Jr., and Hicock, S.R., 1998, Glacial history of the Beaver Mines (826/8) map area, southwest Alberta, in Geological Association of Canada / Mineralogical Association of Canada 1998, Programs and Abstracts of the Annual Meeting: Quebec City, v. 23, p. A-80. Holme, P.J., 1997, Quatemary Geology and terrain inventory, Eastern Cordillera NAWProject. Report 4: investigation of continental and montane advances in the Beaver Mines rnap area, southwestern Alberta, in Current Research 1997- A: Geological Survey of Canada, p. 177- 182. Jackson, L.E. Jr., Little, E.C., Leboe, E.R. and Holme, P.J., 1996, A re-evaluation of the paleoglaciology of the maximum continental and montane advances, southwestern Alberta, in Current Research 1996-A: Geological Survey of Canada Paper 1996- IA, p. 165-173. Jackson, L.E. Jr., Little, E.C., Leboe. E.R. and Holme, P.J., 1996, A re-evaluation of the palaeoglaciology and chronology of the maximum continental and montane advances sothwestem Alberta. Abstracts, Geological Society of Amenca Cordilleran Section annual meeting, Portland, Oregon. ~ NOTE TO USERS Oversize maps and charts are microfilmed in sections in the following manner: LEFT TO RIGHT, TOP TO BOTTOM, WlTH SMALL OVERLAPS The following map or chart has been microfilmed in its entirety at the end of this manuscript (not available on microfiche). A xerographic reproduction has been provided for paper copies and is inserted into the inside of the back cover. Black and white photographic prints (17"x 23") are available for an additional charge. Natural Resources Ressources naturelles IblCanada Canada STRATIG RAPHIC SECTl 3 Poorly sorted slightly imbricated pebble and cobb lens of sand fining upward Io stratifiedsilt and sar Stony glacial diamicton (till). Brown matrix is weal with possible flow features. Matrix is consolidated 4.3 m of thinly bedded Sand with some soft sediment deformation structures to subrounded. < 1 cm to 1 m in size. Many clasts overlying 2.2 rn of poorty to moderately sorted pebble and cobble gravel containing scattered boulders throughout. Gravel beds range from foreset-bedded at Diarnicton (till). Matrix is a highly consolidated an( upstrearn end of the exposure to horizontally strattfied downstream are predominanily pebbles. Monled grey and brov Upper contact is abrupt - - . LE-. Rhythmically interbedded silt ana clay Slightly to moderately stony, unsoned and highly consolidated diamicton (till). Matrix is brownish pink sandy silt. Clasts are subangular to rounded and range $ from granules Io boulders. Striations on a 50 cm-long boulder indicate ice flow Stony diamicton with clay matrix interstratified witt from the southwest Sandy silt contains deformation structures. Diami and clastic dikes occur along the contact with the I Medium and fine sand with dropstones interstratifi 50 cm thick. Sand lenses are deformed where ovd Z Alternating diamicton and gravel beds. Contacts il Rhythmically bedded sand and dayey silt with dro Massive gravel. Clasts range from granules to boulders. Clasts coarsen upward Io lens is present. The top 60 cm of this unit is a shed a boulder gravel. Clasts are imbricated near the top. but not at the base of the unit slickensided throughout 1 lnterbeddedstony diamicton and stratified slightl distorted and some dip steeply. Lower 80 cm of t less stony diamrcton. A single Canadian Shield p diamicton although the diamicton was clearly de Reddish stony clay. Clasts range from < 1 cm to 3C cm and those > 2 cm appear imbricated. Contains 3 cm-thick interbeds of tan cotoured silt. Abrupt lower contact 4 Diamicton (till). Very stony and indurated. Matrix i! Massive to crudely stratified gravel. Clasts coarsen upward from 5 cm to 10 cm Lithologies indude Purcell Volcanics. Crowsnest 7 and are imbricated near top. Contains pebbly sand lenses near the base and green quamite. Poarly sorted gravel lenses i zone in the diamicton. The diarnicton is cut by a s Rhythmically bedded red clay and brown silt with dropstones and scattered Sand beds. Bed thickness 0.6-3 cm (clays) and 0.4-4 cm for silts. Upper and lower contacts of unit are abrupt. Thin (< 4 cm) sand tnterbeds are present lmbricated angular boulder gravel.Clasts range up to 30 cm. Clasts fine upward to pebble gravel with occasional cobbles. Matrix is silty and almost cohesive Covered by slumped sediments j E / ciimop dune. Siit and fine sand 1 Pebble and cobble gravel. lmbricated and moderately swted. Clasts are rounded / A ! to subangular. Stratified sand and pebbly sand units are interbedded with pebble 1 / and cobble grave1 units. Lower contact is abrupt. regular. and even STRATlGRAPHlC SECTIONS 3 5* Poorly soRed slightly imbricated pebble and cobble gravel. Contains a 3 m by 6 m I lens of sand fining upward to stratified silt and sand disturbed by loading ~ Stony glacial diamicton (till). Brown matrix is weakly stratified silty fine sand with possible flow features. Matrix is consolidated but friable. Clasts subangular , to subrounded. < 1 cm to 1 m in size. Many clasts are s:riated 1 ; E , Eolian (?) sand. Overgrown with vegetation Diamicton (till). Matrix is a highly consolidated and ,hesive silty fine sand. Clasts are predominantly pebbles. Mottled grey and brown (du- to oxidation) 1 Upper contact is abrupt I Alluvial (and eolian?). Sand with scattered stones. Partly contains one or more buried soils and scattered terrestri! A Radiocarbon age of shelfs 1790 I140 BP (GSC 898). 3 underlying unit 1 Stony diamicton with clay matrix interstratifiedwith sanc and stony sandy silt. Sandy silt contains deformation structures. Diamicton ienses, slump structures. and clastic dikes occur along the contact with the overlying unit i Mostly eolian. Stoneless sand and silt. Generally massiy firebands with pieces of charcoal. scattered terrestrial si Medium and fine sand with dropstones interstratifiedwilh diamicton lenses up to Sharp contact with underlying unit. Radiocarbon ages 33 50 cm thick. Sand lenses are deformed where overlain by the diamicton lenses 2680 t 140 BP (GSC 743); and 2490 ? 180 BP (GSC 9C on this unit Alternating diamicton and gravel beds. Contacts are predominantly gradational Rhythrnically bedded sand and clayey silt with dropstones. A 1 rn thick diamicton lens is present. The top 60 cm of this unit is a sheared siltlclay lens which is slickensided throughout 1 lnterbedded stony diamicton and stratified slightly silty pebbly sand. Beds are Mostly alluvial. Sand and silt with scatîered stones up td distorted and some dip steeply. Lower 80 cm of this unit is interlensing stony and massive. but contains reddish. disconttnuous firebands ( less stony diamicton. A single Canadian Shield pebble was found within the A Rare scattered terrestrial snail shells and pieces of bon diamicton although the diamicton was clearly deposited by montane glacial ice up to 60 cm thick on top. Sharp contact with underlying it Diamicton (till). Very stony and indurated. Matrix is htghly fissile, dark sandy silt. Lithologies include Purcell Volcanics, Srowsnest Voicanics, argillite, and red, white and green quartzite. Poorly sorted gravel lenses approximately follow a shear zone in the diamicton. The diamicton is cut by a succession of nearly vertical joints I Alluvial. Medium to coarse sand. Stoneless. Strongly i A bedded. Deposited hom southwest. Unit has a sharp Io Eolian (?) sand. Overgrown with vegetation Alluvial (and eolian?). Sand with scattered stones. Partly overgrown and contains one or more buried soils and scattered terrestrial snail shells and bones. Radiocarbon age of shells 1790 r 140 B? (GSC 898). Sharp contact wtth underlying unit Mostly eolian. Stoneless sand and silt. Generally massive. but contains reddish firebands with pieces of charcoal. scattered terrestrial snail shells and bones. Sharp contact with underlying unit. Radiocarbon ages 3380 r 170 OP (GSC741), 2680 t 140 BP (GSC 743): and 2490 I180 BP (GSC 901 ) determined on this unit Mostly alluvial. Sand and silt with scattered stones up !O 10 cm long. Generally massive, but contains reddish. discontinuous firebands with pieces of charcoal. Rare scattered terrestrial mail shells and pieces of bone present. Dark brown soi1 up to 60 cm thick on top. Sharp contact with underlying unit Alluvial. Medium Io coarse sand. Strineless. Strongly crossbedded and ripple bedded. Deposited frorn southwest. Unit has a sharp lower contact QUATERNARY HOLOCENE - Post Erratics Train Glaciation MADE LAND: Amficial frll and mine waste EXlSTING GLACIERS. /CE: Flowing or stagnant glacral icq contains or is covered by variable amounts of rock debrrs rd from Clay ro boulders: thickness of ice 20 - JO m ORGANIC SEDIMENTS: Water-saturated Sphagnum srlt formed predominantly by the accumulation of vegetal m. in bogs. fens. and swamps, organrc depasits are usually uni lacustrine srlt and clay: thickness up to 5 m EOLIAN SEDIMENTS: Sand and srlt transpmed by wind 3 * Eb Eolian blanket: Sand. well sorted. massive, forms gently ui / plains rnarked by qrescent-shaped dunes. ihickness up to ? -r COLLUVIAL SEDIMENTS: Stony dramicton resulting from fi varying amounts of broken bedrock. sorl. and glacial sedrrnc4 nonfluvral gravitahonal processes such as creep. solrfluctrci~ debris flow. snow avalanchmg. and rockfall Reworked gla- in colluvium occur withrn the limrts of past glaciations 2 Colluvial blanket sediments: Dramrcton, stony. massrve. i 1 ro 2 m thrck % Colluvial veneer sediments: Dramrcton. stony. massive. 4 thick or parchy: ovsrlies bedrock Colluvial apron sediments: Bouldery diamicton andpoorri stratified Sand and gravel: sediments forrn a wedge-shapec complex of small steep debris flow and avalanche-domina1 solifluction deposits derrved from bedrock or glacial debris thrckness ranges from <1 rn at the up slope lirnit to up to 1 C , in the thickest part of the apron in;] 1 Rockfall sediments: Boulc'ery rockfall deposrts: forms cok landforms at the angle of repose below steep bedrock thickness ranges from < 1 rn at the margin to 1O m near the midpoint of :9e cone Landslide sediments: Diamicton formed of broken rock. sd glacial deposits: forms a hummocky or rrdged topography M ridges transverse to direction of movement; thickness varia,, may range up to 10 m (direction of movement indicated by I symbol) . . Undivided colluvial sediments: Hummocky apron terrain to mounta~nousupldnds. possibly of mass wasting origin ALLUVIAL SEDIMENTS: Grave1 to silt size sediments dep streams either within channels or as overbank deposits. De, are commonly stratified and moderately to well sorted, with exception of some alluvial tan deposits . i L I LEGEND Not al1 coloured unrts and symbols in legend necessarily appear on this map Thrs legend 1s common to rnaps 7 925A to 1936A MORAINAL SEDIMENTS (fil/): Diamicton (pebble to boulder size clasts t Erratics Train Glaciation suspended in a poorly sorted clay to sand size matrix) deposited directjy &y glacial ice; redeposition. where it has occurred. has been by sediment gravity flow andlor ductile deformation. Tills of two : LAND: Amficral fil1 and rnrne waste provenances were deposited during the Erratics Tra~nGlaciation: T' contains clasts of Rocky Front and Main ranges Precambrian and Paleozoic limestone. dolostone, and quamite: Foothills and lnterior Plains Mesoroic and lower Tertiary sandstone. mudstone. and coal; as well as 'ING GLACIERS. /CE:Flowing or stagnant glacral ice, Canadian Shield provenance granitic and metamorphic rocks. confains '1 ns or is covered by variable amounts of rock debris ranging Rocky Mountain Precambnan and Paleozoic limestone. dolostone. lay to boulders: thickness of /ce 20 - 40 m argillite. and quamite (may inclu~ePrecambrian igneous rocks south of Crowsnest River); and Foothills Mesozoic and lower Tertiary sandstone. shale. and coal (includes lower Cretaceous volcanics in the Crowsnest Pass area). Trace amounts of Canadian Shieldprovenance clasts r LNlC SEDlMENTS: Water-saturated Sphagnum peat and organrc medpredomlnantly by the accumulation of vegetal material are present only wbere rnontane ice overran pre-existing drift containing ~s,fens, and swamps: organic deposits are usually underlarn oy Canadian Shield provenance clasts 'rine silt and clay: thickness up to 5 m Till veneer: <1 m thick or discontinuous diamrcton wittr parches of TV Q exposed bedrock or colluviurn. rvvgegera/ly contains more and coarser j pebble and larger clasts than does TV' and both may contain extensive AN SEDIMENTS: Sand and sdt transported by wind areas of thrn (< 7 rn) and patchy colluv~um;overlies bedrock 1: Sand. well sorted. massive; forms gently undulafrng by crescent-shaped dunes; rhrckness up to 5 rn Hummocky moraine: Diamicton and interstratified g/ac~ofluvial gravel and sand, massive to thick bedded; bedding slumped. faulted. and folded by syndepositional ice meltout; ma y contain*variable amounts of ice-walled lake fine sand and silt: forms hummocky. kame and kenle topography: local relief up to 30 m; thickness rnay be tens of metres Rolling till plain: More than 5 rn of diamicton: surface al veneer sediments: Diamrcron. stony. massive, < 1 m morphology undulates with 1-2 rn local relief; totally or patchy; overlies bedrock largely obscure surface morphology of underlyrng bedrock via1 apron sediments: Bouldery diamrcton and poorly sorted 3nd ed Sand and gravel: sediments form a wedge-shaped slope-ioe ex of small steep debrrs flow and avalanche-dominated fans and Till? blanket: Stony diamicton cemented to a calcrete; contains ction deposits derived from bedrock or glacial debris up sloce strrated clasts; thickness 2 to 3 rn; rests on a successron of ess ranges from c 1 m at the up slope limit to up to 1 O rn srmdar sedirnents of glacial or nonglacial origin thickest part of the apron PALEOZOlC TO EARLY TERTIARY ROCK ockfall deposits: forms cone-shaped Sandstone. sikstone, shale. mudstone. conglomerate. coal. and mmor below steep bedrock slopes; volcanic rocks of earfy Terliary and Mesozoic age and Iimesrone. dolostone. e margin to 10 m near the and quamite of Paleozoic ana Precambrian age (includes areas of thin colluvial cover. blockfields. sort~dStone plygons in alpine areas) dslide sediments: Diamicton formed of broken rock. soil. and 1 deposits; forms a hummocky or ridged topography wrth Areas of iock as above subiect to rapid mass wasting processes (rockfall transverse to direction of movement: thickness variable. and snow avalanches) ge up to 10 m (direction of movement rndicated by . ded colluvial sediments: Hurnmocky apron terrain aulacent ntainous uplands. possibly of mass ~aai,.~qgorigrn lnterbedded stony diamicton and stratified di distorted and some dip steeply. Lower 80 cm less stony diamicton. A single Canadian Shiel diamicton although the diamicton was clearly Reddish stony clay. Clasts range from < 1 cm to 30 cm and those > 2 cm appear imbricated. Contains 3 cm-thick interbeds of tan coloured silt. Abrupt lower contact Diamicton (till). Very stony and indurated. Massive to crudely stratified gravel. Clasts coarsen upward from 5 cm to 10 cm Lithologies include Purcell Volcanics, Cro and are imbricated near top. Contains pebbly sand lenses near the base and green quartzite. Poorly sorted gravel zone in the diarnicton. The diamicton is c Rhythmically bedded red clay and brown silt with dropstones and scattered sand beds. Bed thrckness 0.6-3 cm (clays) and 0.4-4 cm for silts. Upper and lower contacts of unit are abrupt. Thin (< 4 cm)sand interbeds are present lmbricated angular boulder gravel. Clasts range up to 30 cm. Clasts fine upward to - pebble gravel with occasional cobbles. Matrtx is silty and almost cohesive Bedrock Covered by slumped sediments E Cliffiop dune. Silt and fine sand Pebble and cobble gravel. Imbricated and moderately sorted. Clasts are rounded A to subangular. Stratified sand and pebbly sand units are interbedded with pebbie and cobble gravel units. Lower contact is abrupt. regular. and even -* - .*'- . O...& .y- .- 3- ' .. . .--+\;<> Diarnicton (till) Silty sand matrix Breaks easily rnto weak. angular peds. L i ( Moderately consolidated Clasts range from granules to small angular to .: {~.:subrounded boulders lsolated lenses (2-4 cm thick) of silt and sand are present ', ." ;;., ;;., in the lower part of the unrt. Gradational with underlying unit over about a 1 m Stony diamicton (till). More consolidated than overlying unit. Blocky ped structure. Possible boulder pavement at base of unit with boulders 0.4-1.5 m long. Sand pocket at base of unit with fault planes oriented with strike = 219" and dip = 56" Muddy gravel. Upper 2.1 m is unsorted. pebble and cobble gravel. Clasts are rounded to subangular with no imbrication seen. Upper contact is gradational with the overlying unit lnterbedded sand and pebble gravel. Sand is medium to coarse. The lower most sand bed is continuous. but succeeding uni!s are lentrcular. Beds and lenses are forested. Gravel units are weakly imbricated [ ..' :q , Consolidated. moderately sorted. pebble and cobble gravel Unsorted angular gravel Contains 2-4 cm-thick lenses of imbricated. open work pebble gravel and a consolidated Sand pocket 1 rn in diameter % Unsorted muddy cobble and boulder gravel. Matrix is friable sand and granules. Upper contact is abrupt Stratified. crossbedded well sorted. medium grained stoneless sand. Thickness varies across exposure. Upper contact is undulatory. rregular, and sharp. Foreset beds dip ta the south. The lower part of the unit coarsens upward at upstream end of this 50 rn long exposure. The lowermost 4 m is sand and pebble gravel succeeded by pebbie gravel overlain by pebble and cobble gravel slickensided throughout lnterbedded stony diamicton and stratified slightly silty pebbly sand. Beds are Mostly alluvial. Sand and silt with scanered Stones up distorted and some dip steepiy. Lower 80 cm of this unit is interlensing stony and massive. but contains reddish, discontinuaus fireband less stony diamicton. A single Canadian Shield pebble was found within the Rare scattered terrestrial snail shells and pieces of b diamicton although the diamicton was clearly deposited by rnontane glacial ice up to 60 cm thick on top. Sharp contact with underlyin Diamicton (till). Very stony and indurated. Matrix is highly fissile. dark sandy silt. Lithologies include Purcell Volcanics. Crowsnest Volcanics, argillite. and red. white and green quartzite. Poorly sorted gravel lenses approximately follow a shear zone in the diamicton. The diamicton is cut by a succession of nearly vertical joints I l A Alluvial. Medium to coarse sand. Stoneless. Strongly i R Bedrock bedded. Deposited from southwest. Unit has a sharp Glaciofluvial. Alternating beds of sand and gravel ou till-like with silt and sand rnatrix and with boulders to upwards sequence. A few Canadian Shield clasts fo 6.1 m from base of unit. Material deposited from the underlying unit. Radiocarbon ages determined on bi Note (P.J.H.) Radiocarbon ages are totally inco glaciofluvial unit. Bones were likely inset by sedi formation or associated slumping (see Wagner, probable late Pinedale terminal moraine in Castl Geological Society of America Bulletin, v. 81. p. A.M. Stalker (p. 3775-37773 ' Mostly alluvial. Sand and silt with scattered Stones un to 10 cm long. Generally massive, but contains reddish. discontinuous firebands with pieces of charcoal. : A Rare scattered terrestrial mail shells and pieces of bone present. Dark brown soi1 up to 60 cm thick on top. Sharp contact with underlying unit Alluvial. Medium to coarse sand. Stoneless. Strangly crossbedded and ripple A bedded. Deposited from southwest. Unit has a sharp lower contact Glaciofluvial. Alternating beds of sand and grave1 outwash. The basal bedç are till-like with silt and sand matrix and with boulders to 1 rn diameter. Generai lining upwards sequence. A few Canadian Shield dasts found. Bison bones found about 6.1 m from base of unit. Material deposited from the West. Gradational contact with underlying unit. Radiocarbon ages determined on bison bones: 6150 i 140 BP (GSC 447), $1 00 t 180 BP, and 6340 I140 BP (GSC 705) Note (P.J.H.) Radiocarbon ages are totally incompatible with an obviously glaciofluvial unit. Bones were likely inset by sedimentation during Holocene tenace . formation or associated slumping (see Wagner. W.P. and Eschman. D.F.. 1970. A probable late Pinedale terminal moraine in Castle River valley, Alberta: discussion). Geological Society of America Bulletin, v. 81, p. 3773-3775 and reply by A.M. Stalker (p. 3775-3777) . Colluvial apron sediments: Bouldery diarn~ctonan1 stratrfied sand and gravel: sediments form a wedge-! cornplex ot small steep debns flow and avalanche-dc solilluction deposrts denved from bedrock or glacial c thrckness ranges frorn < 1 rn al the up slope lirnit to ul in the thrckest part of the apron Rockfall sediments: Boulde~jrockfall deposits; forr; landforms at the angle of repose below steep bedroc thickness ranges from < 7 m at the rnargin to 7 0 m ne rnrdpornt 01 the cone Landslide sedimenfs: Dramrcton formed of broken r glacral deposits: forms a hurnmocky or ridged topogr{ ndges transverse to directron of movernent: thicknes: may range up to 10 m (directron of movement indicatr symbol) Undivided colluvial sediments: Hummocky apron II to mountarnous uplands. possibly of mass wasttng ori ALLUVIAL SEDIMENTS: Gravel ro silt slze sedrmenl strearns efther withn channels or as overbank demsi are commonly stratrfred and moderately to well smed exception of some alluvra/ fan deposrrs Alluvial plain sediments: Grave1 and sand. massrve ro well soned: locally overlarn by or includes lacustrint mrnor peat and organrc stlt depos~fedrn abandoned cl floodplarn margrns. forms plarns withrn about 7 rn of pi whrch are sublect to inundatron durrng floods: thrckned Alluvial terrace sedirnents: Gravel and sand. massa rnoderately tb iveIl soned; sedimenls are of floodnlain -T - - !solated from iloodrng by Stream rncisron. thrckness r -- drscontrnuous covenng on bedrock to several metresy are cut into glac~ofluvialplarns. total rhrcknesses ot gril may be 5 m or more ; Alluvial fan sediments: Gravel and gravelly dtarnrcra A f poorly to rnoderateiy soned: forms fan-shaped Iandfd ' strearns enter larger valleyr: rn mountarnous ferrarn. al rnay be sublecr to mundatron of debris flows thrckneq Alluvial complex sediments: Floodplams. fans. an , cannot be subdivrded at the scale of mapprng WISCONSINAN - Erratics Train Glaciation Sediments deposited during advances and retreats of frorn Rocky Mountains and continental interior GLACIOLACUSTRINE OEPOSITS: Well stratfie deposited m lakes dammed by glacral rce. Where [rom /ce margrns. glacrolacustrrne sedrrrents under rollrng terrarn. Where deposrtron was near !ce. they ridged. hummocky. or piîted terrarn caused b y subs May include some portglacral lacustr~nesedrments Glaciolacustrine veneer sediments: Srlt, clay. an stratrfled. thrnly bedded to lamrnated or drscont~nuou Glaciolacustrine blanket sediments: SrIr. clay. and .-, morphology conforms !O underlying topography . - Glaciolacustrine plain sediments, local relief <1 and fine sand. thrnly bedded to lamrnated: surface 1s a plarn and qnderlyinc~topography 1s generally obs sedrments; thrckness 1 to 20 m underly~ngtopography 1s gener . Rolling till plain: More than 5 m of diamicton: surface Colluvial veneer sediments: Diamicron. stony. massive. < 1 rn morphology undulates with :-2 rn local relief; totally or rhick or patchy; overlies bedrock largely obscure surface morphology of underlying bedrock EARLY PLEISTOCENE OR PLIOCENE GLACIAL Colluvial apron sediments: Bouldery diamicton and poorly sorted 3nd OR NONGLACIAL SEDIMENTS stratified sand and gravel: sedrments form a wedge-shaped slope-tce complex of small steep debns flow and avalanche-domrnated fans and Till? blanket: Stony diamrcton cemented to a calcrete: contarns solifluction deposits derwed from bedrock or glacial debrrs up slope; strrated clasts: thickness 2 !O 3 m: rests on a succession of thickness ranges frmc 1 m al the up dope !imrf to up to 1 O m srmilar sediments of glaclal or nonglacial ongrn in the thickest part of the apron PALEOZOIC TO EARLY TERTIARY ROCK Rockfall sediments: Bouldery rockfall deposrts: forrns cone-shaped landforms at the angle of repose below sfeep bedrock slopes: 1 Sandstone. siltsrone. shale. rnudstone. conglomerate. coal. and mrnor volcanic rocks of early Terfjary and Mesozorc age and limestone. dolosti thickness ranges from < 1 rn at the margrn to IO rn near the R ] i and quartz~teof Paleozoic and Precambr~anage (includes areas of thin midpoint of the cone colluvfal cover. bl~ckfield~.sorfed Stone polygons rn alpine areas) Landslide sediments: Diamrcton forrned of broken rock. soi/, and glacial depasits; forms a hummocky or rrdged topography with ! Areas of rock as above sublect to rapd mas wasting processes (rockfa ridges transverse to direction ûf movsment: Ibickness variable, R-A and snow avalanches) may range up to 1 O m (direction of movement indicated by 1 symbol) Upper Mesozorc and Eariy Ternary rock eroded rnto badland topograph~ Undivided colluvia1 sediments: Hurnrnocky apron terrain adjacent R-G to mountalnous uplands. possibly of mass wastrng orrgin ALLUVIAL SEDIMENTS: Gravel to srlt sue sediments deposte" iy strearns either wrthin channels or as overbank deposrls. Deposrts are commonly siratified and rnoderafely to well soned. wrth the exception of some alluvlal fan depsits Alluvial plain sediments: Gravel and sand. massrve to srratifred. rnoderately to well saRed: locally overlain by or includes lacwrrne srlt and clav and minor peat and organic si0 deoosited in abandoned channels and dong VENEER floodplarn marg~ns;forms plarns withtn about 1 m of present sveam !evel whlch are sublect to ~nundatronû'unng floods: thlckness 7 ro 5 rn Glacroiacustr~ne Alluvial terrace sediments: Gravel and sand. massrve to sfratihed. --v moderately to well softed; sedimenrs are O/ floodplain ongin now isolared frorn flooding by sfream incrsron: thickness ranges from a - - discur~ilnuouscovering on bedrock to several metres: where alluv!al !erraces -- are cut into glaciofluvral plarns. total rhrcknesses of grave! and sanc Eoiian imay be 5 m or more . orly to rnoderately sorfed: forrns fan-shaped iandforms where ' Organic lluvial complex sediments: Floodplains. fans. and ferraces tha: be subdivided at the scale of mapplng AN - Erratics Train Glaciation deposited during advances and retreats of glaciers Mountains and continental interior % LACIOLACUSTRINE DEPOSITS: Well stratified sand, sdt. and cBy eposited in lakes dammed by glacial ice. Where deposition was di;ranl rom ice margins. glaciolacustrine sedimenis underlie plains or gtx'y Geological boundary (defined. assumed, inferred) ...... ----,.. olling terrain. Where deposition was near ice, they may underlie idged, humrnocky. or piffed terrain caused by subsequent ;ce me~tout. Neoglacial lateral or end moraine ...... - ay include some pastglacial lacustrrne sediments laciolacostrine veneer sediments: Silt. clay. and fine sand, ir/e : ~r6te...... /- tratjfied. thinly bedded to laminated or discontinuous: thkkness 1 m thick to discontinuous Cirque ...... n Meltwater channei: . ' Y !laciolacustrine blanket sediments: Silt. clay. and fine sand: suriace large ..... v orphology conforms Io underlying topography - small (How direction known. unknown) ...... L' 2 a edge of ice-walled charnel...... --- ' laciolacustrine plain sediments. local relief nd fine smd, thinly bedded to laminated; surface rnorphology Esker (flow direction defined. undefined) ...... "" "" O ' " " a plain and underlying topography is generally obscured by these 7 /' lhickness 1 to 20 m Landform streamlined by glacial ;ce (direction of ftow known. unknown) .....:. olling glaciolacustrine plain sediments, local relief 1-2 m: Fine Ice limit (defined, assumed, tnferred); ...... ,and, silt. and clay. fhinly to rnassively bedded; surface morphology Unsoned muddy cobble and boulder gravel. Matrix is friable Sand and granules. Upper contact is abrupt Stratrfied, crossbedded well sorted. medium grained stoneless sand. Thickness varies across exposure. Upper contact 1s undulatory, irregular. and sharp. Foreset beds dip to the south. The lower part of the unit coarsens upward at upstream end of this 50 rn long exposure. The lowermost 4 m is sand arid pebble grave1 succeeded by pebble gravel overlain by pebble and cobble gravel Covered by colluvium SUBSURFACE UNlTS * Postglacial -Wisconsinan - Erratics Train Glaciation Pre-Wisconsinan t Lamrnated and thrniy bedded glaaolacustrrne Sand. silt. end clay Ounc-ash gravel and sand c~~-~arningclasts Preglacial , lrom Canadian Shield - i R Sanbstone and4 1 Eolran /;ne rand and srlr Oupash gravel and sand (Rocky Mountains - E and Foolhrlis provenance) -- A Alluvral sand and gravel Tl11 and relared glacrogenic drarn~ctodscontainmg ! TC I cssts rransmn~/rom the canacran S~I~IU Lacurane rand, silr and clay Trll and relared glacrogenic drarnrctons of Rocky Mountarns and Foorhills provenance 8 upwards sequence. A few Canadian Shield clasts found. Bison bo 6.1 rn from base of unit. Material deposited from the West. Gradati~ underlying unit. Radiocarbon ages determined on bison bones: 6150 * 140 BP (GSC 447). 6100 2 180 BP. and 6340 r 140 BP (G Note (P.J.H.) Radiocarbon ages are totally incompatible with an O glaciofluvial unit. Bones were likely inset by sedimentation during I formation or associated slumping (see Wagner. W.P. and Eschma probable late Pinedale terminal moraine in Castle River valley. Alb Geological Society of Arnerica Bulletin. v. 81, p. 3773-3775 and re A.M.Stalker (p. 3775-3777) Pinkish buff to grey diamicton (till). Upper part includes sand and g Partly cemented by lime. Pebble and coarser clasts are mostly an5 many are strongly striated. No Canadian Shteld lithologies present * Very poorly sorted bouldery gravel: matrix is coarse sand. granules supporting cobbles and boulders up to 40 cm in size. clasts are ma Lower contact is gradational. No lithologies frorn the Canadian Shit lnterlensing and intergrading sand and gravel. Sand is medium-gra well sorted stony, and extremely consolidated. Gravel clasts are su subarigular andiange from pebbles to cobbles. Sand unit contai gravel beds (about 4 cm thick). No lithologies from the Canadian Bouldery diamicton (iill). Unstratified and highly consolidated. Mat with some silt. Very stony: clast content 2S0,0.Clasts range from 1 Carbonate clasts are highly striated. Contact with overlying unit is undulate over about 50 cm vertically. No lithologies frorn the Canaa are present Description of section above the lowest two units from Stalker. A. MacS. 1969, Pinedale moraine terminal moraine in Castla River valley. Alberta. Geological ! Bulletin. v. 80. p.2115-2122 S laciation Pre-Wisconsinan crolacusrr?ne Rocky Mounrarns provenance ?lacial sedrrnenfs and ~ntersrratifiedpaleosols Vertical scale (metres) ning clasrs Preglaciat 1 ctons conralnrng dian Shreld ctons of Rocky nce 6.1 m from base of unit. Material deposited from the West. Gradational contact with underlying unit. Radiocarbon ages deterrnined on bison bones: 6150 I140 BP (GSC 447), 61 00 f 180 BP. and 6340 r 140 BP (GSC 705) Note (P.J.H.) Radiocarbon ages are totally incompatible with an obviously glaciofluvial unit. Bones were Iikely inset by sedimentation during Holocene terrace formation or associated slumping (see Wagner. W.P. and Eschrnan. D.F..1970. A probable late Pinedale terminal moraine in Castle River valley, Alberta: discussion). Geological Society of America Bulletin. v. 81, p. 3773-3775 and reply by A.M. Stalker (p.3775-3777) Pinkish buff to grey diamicton (tilt). Upper part includes Sand and grave1 beds. Partly cemented by lime. Pebble and coarser clasts are mostly angular and rnany are strongly striated. No Canadian Shield lithologies present undulate over about soirriverticafly. No lithologies from the Canadian '~hield are present ription of section above the lowest two units from Stalker. A. MacS. 1969. A probable late lale moraine terminal moraine in Castle River valley. Alberta. Geological Society of America 1in, v. 80, p.21 15-2122 Vertical scale (rnetres) - 5 Copes of iha map may be Wned hmthe Gea(ogicltl Suwey of Canada 601 Booth Street. ûrtawa. Ontano K1A OEB 3303-33rd Sbwl, N.W .Calgary. Aibecta T2L 2A7 101 -605 Robson Street Vancouver. 6.C V6B 5J3 MAP 1932A SURFICIAL GEOLOGY I Dig~falbase map hmdata corn moâified by the Digital base map from data comp~edby Geomatics Canada. modified by the Geoscience Informabon Division npiied by Geomatks Canada. ,ce Information Division ridged. humrnocky. or pined terrain caused by subsequent ice meltout. May include sorne postglacial lacustrine sediments Glaciolacustrine veneer sediments: Silt. clay. and fine sand. well stratified. thinly bedded to laminated or aiscontinuous: thickness < 1 m thick to discontinuous Glaciolacustrine blanket sediments: Silt, clay. and fine sand: surface rnorphology conforms to underlyrng topography Glaciolacustrine plain sediments. local relief cl m: SrIt. clay. and fine sand. thinly bedded to laminated: suriace morphology 1s a plain and underlyrng topography 1s generally obscured by these sedirnents; fhickness 1 to 20 m Rolling glaciolacustrine plain sediments. local relief 1-2 m: Fine sand. silt. and clay. thrnly to massively bedded: surface morphology undulating; underlyrng topography 1s generally obscured by these sediments: thickness 1 to 20 m Ice-contact glaciolacustrine complex sediments: Predominantb/ silt and sand: gravel. diamlcton lenses and dropstones may comprise up to 1 OL'o or more of thrs unit: bedding thrn to massive; bedding IS commonly deformed due ro syndepositional slumping and ;ce mexout; surface morphology IS hummocky. prtred. and ridged with relief up to 10 m: comrnonly underlain by hummocky moraine sediments: thickness Sto 1Om GLAClOFLUVlAL SEDIMENTS: Sand. gravel. and mi,-or srlt and d.amicton deposited Sy streams !/owing away from. or rn contact with glacial ice Sonmg ranges from good ro poor and stratrfication from thinly bedded ro massrve Sediments may display evidence of syndeposrtional corlapse due to meltout of buned or supportmg rce In areas formerly covered by glacrers from the Rocky Mountarns ooly. lrthologies include Precambrian and Paleozorc hmesrone. dolostone. argillite. and quamite. and mai rnclude mafic and feisrc volcanic rocks ln the Oldman River basin In areas covered by montane glaciers and glacier rce from the contirlental rnterior. addihonal lrthologres include sandstone mudsrone. conglomerate and Canadran Shreld provenance granitrc and metamorphic 11tholog:es Glaciofluvial plain and fan sediments: Gravel and sand; massive !O thickly bedded: former ourwash plains and fans: thickness 1 to 1 O rv Terraced glaciofluvial sediments: Gravel and smd: masswe to thck bedded; former outwash plains and fans rncised in!o a succession O: terraces; lhickness 1 to 10 m Glaciofluvial delta sediments: Sand. gravel. and rnrnor silt and cl;. thinly bedded to massive. flat surfaced. delta-form rn plan view: deposited as a delta along the wargin of a for.ner glacral lahe. thrckness from 5 [O 7 0 rn Glaciofluvial ice stagnation complex sediments: Sand. gravel. diamicton. and minor silt and clay. thinly bedded to massive; bedding is comrnonly contorîed and folded due to syndeposrtional rce meltout: stirface rnorpbology includes hummocks. kenle. esker and crevasse-fiIl rrdges 2 to 10 m in relief with minor e!ements of unit Gp and Gt' (hickness 5 to 110 m Undivided glaciofluvial and gruund moraine sediments: A patct;s.ork of glaciofluvial sedimenrs and grounu moraine (till) too vanable to reso at the scale of mapprng Glaciofluvial veneer sediments: Gravel and sand. massive to thickly bedded; thrckness < 1 m or patchy: ouerhes bedrock ERRATUM: The dashcd ice-l corner of the map wpresen ice meltout. Neoglacial lateral or end moraine ...... Silt. clay. and fine sand. weil discontinuous: thickness Melhvater channel. laciolacustrine blanket sedimentsr SJt. clay. and fine sand: suriace large ...... m orpholog;/ conforms to underlying topography small (flow direction known. unknown) ...... - edge of ce-walled channel...... ' relief <1 m: Silt. clay. surface morphology Esker (How direcaon defined, undefined) ...... <<<.<<.O< ,.. r< a plain and underlying topography 1s generally obscured by rhese T rd dimenrs; thickness 1 to 20 rn Landform streamlined by glacral rce (direction of flow knovm unknown) ...... glaciolacustrine plain sediments. local relief 1-2 m: Fine Ice limit (defined. assumed. mferred); ...... nd. silt. and clay. thrnly to massrvely bedded: surface morphokg) dulatrng: underlying ropagraphy is generally obscured by these Ml Maximum ice timit of Lare Wrsconsinan montane dimenls: thickness 1 to 20 rn glacial ice M2 Ice hm~tof first malor readvance of Lare Wisconsinan montane glacral ice C 1 Maximum rce Iimrt of Late Wisconsinan contmental glacial ice 10% or more of this unit. beddrng thin to massrve; bedding C2 Readvance posibon of Lare Wisconsinan commonly deformed due to syndeposrtional slumping and ice rnel!out: continental glacral ice 10 m; commonly underlain by hummocky moraine sedimenrs. thickness M2. W. C Lateral and end morarne lassociated with advance M1 . or *',-> Q retreat of continental ;ce sheet from limit C2) ...... -,' Former rce contact face in stratrfied drift ...... posrted by streams flowing away from. or in contact with glacial ce Stratigraphie sectron ...... - ...... 3+ <. <. massrve Sedirnents may disolay evidence of syndepositional coilapse Vertebraie iossr~loca~iry ...... Ej e to meltout of buried or supportmg (ce In areas formerly covered glaciers /rom the Rocky Mountains onlv. Iithologies include Precarnbrian Radiocarbon age (years before present) ...... d Paleozoic limestone. dolostone. argrllite. and quartzire. and may 8 One or more Foothills Erratrcs Train Erratic > 1 m ln length ...... A areas covered by montane glaciers and glacrer rce from the confmental Cosmogenrc '"1 exposure age on Foo;hills erratrc ' SWOrJOQ d Canad~anShreld provenance granitrc and metamorphic btho/og:es (years before present) ...... v laciofluvial plain and fan sediments: Gravel and sand: massive to Montane erratic close :O or a t the al1 rime upper Iimrt ickly bedded: former ounvash plains and fans: th~ckness7 ro !O 7, ot montane glacrarron ...... Canadian Shield emtic at or near the al1 rime upper limit of contrnenfal glaciation ...... Terraced glaciofluvial sedimen ts: Gravel and sand: massive ro ihick Sedded; former outwash plains and fans incised into a succession or -. Cosmogenic "'CI exposure age of Canadian Shieid erratic ferraces; thickness 1 io 70 m al or near the ail bme upper limit of continental ~~~CIG:IZCOY gkicration (years before present) ' ...... - Glaciofluvial delta sediments: Sand. gravel. and mrnor silt and clzy: Arrows indrcahng direction of landslide movement 2 Ihinly bedded to massive; flat surfaced. della-form in plan vrew: (assocrated with the unit Ch) - deposited as a delta dong the margin of a former glacial lake; [hickness from 5 to 10 m ' Assumes a zero erosion rate and no cosmic ray blockage by snow cover laciofluvial ice stagnation complex sedimentsr Sand. gravei. iamicton. and mrnor silt and clay. thinly bedded to massive: edding 1s commonly contorted and folded due to syndepositronal ice1 meltout; surface morphology ~ncludeshummocks. kenle. esker and crevasse-fiIl ridges 2 to 10 m in relref wrth mrnor elements of unit Gp and Gt- thickness 5 to 10 m Undivided glaciofluvial and ground moraine sediments: A parchrvork of glaciofluvial sediments and ground moraine (hl!) too variable ro resolve al the scale of mapping Glaciofluvial veneer sediments: Gravel and sand. massive :c thickly bedded: thrckness < 1 rn or patchy; overlies bedrock ERRATUM: The dashcd ice-lirnit line crossing the northeast corner of the map represents the approm'rnate extent of continental ice influena?duting its late Wisconsinan maximum extent It includes a proposeci zone of malesence with montane SUBSURFACE UNlTS -Wisconsinan - Erratics Train Glaciation Pre-Wisconsinan Laminated and thinly bedded gbcrolacusrrine Rocky Mountains sand. silt. and cla y and merstrat~fied, Preglacial 1 GC ! Ourwash grave/ and sand conraning chsts 1 1 !rom Canadian Shreid E 1 Eolran trne Sand and sr& Ourwash grave/ and sand (Rock./ Mountains - and Foothrlls provenance) A Alluv~alsand and grave1 Till and relaled glaciogenrc diamicfons conrainrng 1 clasts transported from rhe Canadian Shreld Tt11 and relaled g!ac~ogenrcdramictons ot Rocky Mountains and Foothrlis provenance Pinkish buff to grey diamicton (till). Upper part inchdes sand Partly cemented by lime. Pebble and coarser clasts are most many are strongly striated. No Canadian Shield lithologies pr Very poorly sorted bouldery gravel: matrix is coarse sand, gr supporting cobbles and boulders up to 40 cm in size. clasts I Lower contact is gradational. No lithologies from the Canadi Interlensing and intergradmg sand and gravel. Sand is medi well sorted stony, and extremely consolidated. Grave1 clasts subangular and range from pebbles to cobbles. Sand unit CO gravel beds (about 4 cm thtck). No lithologies from the Cana are present Bouldery diamicton (till). Unstratified and highly consolidated with some silt. Very stony: clast content 25O.o. Clasts range fr Carbonate clasts are highly striated. Contact with overlying undulate over about 50 cm vertically. No lithologies from the fl are present Description of section above the lowest two units from Stalker. A. MacS Pinedale moraine terminal moraine in Castle River valley. Alberta. Geol Bulletin. v. 80. p.2115-2122 E UNITS irain Glaciation Pre-Wisconsinan dded glaciolacustrrne Fiocky Mounrarns provenanct. glacial sedrrnents and inlerslrai.. .?d paieosols Vertical scale (metres) Preglacial rd contatntng clasts I td (Rocky Mountains 8) nit diarnicions containing 'he Canadian Shreld nie diamictons of Rocky provenance Pinkish buff to grey diamicton (till). Upper part includes sand and gravel beds. Partly cemented by lime. Pebble and coarser clasts are mostly angular and many are strongly striated. No Canadian Shield lithologies present Very poorly sorted bouldery gravel: matrix is coarse sand, granules. and pebbles supporting cobbles and boulders up to 40 cm in size. clasts are mainly subrounded. , Lower contact is gradational. No lithologies from the Canadian Shield are present ,lnterlensing and intergrading sand and gravel. Sand is medium-grained. well soned stony, and extremely consolidated. Grave1 clasts are subrounded to subangular and range from pebbles to cobbles. Sand unit contain discontinuous gravel beds (about 4 cm thick). No lithologies from the Canadian Shieid are present \ Bouldery diamicton (till). Unstratified and highly consolidated. Matrix is sand with with some silt. Very stony: clast content 25O'o. CIasts range from 1 cm - 30 cm. Carbonate clasts are highly striated. Contact with overlying unit is abrupt and undulate over about 50 cm vertically. No lithalogies from the Canadian Shield are present tion of section above the lowest two units from Stalker. A. MacS. 1969. A probabie late 2 moraine terminal moraine ln Castle River valley. Alberta. Geological Society of America , V. 80, p.2115-2122 Vertical scale (metres) Capes of this map may be oblained hom ihe Geoiogicai Survy of Canada Ml1 Booth Street. Onawa. Ontano KlA OEE 3303-33d Street. N.W.. Cm.Abria T2L 2A7 toi-605 Robson Sbeet. Vancouver. B.C. V6B 533 LOCATION MAP :opes of this map may be oùtained rim the Geai+ Suwey of Canada 01 Booth Street. OMwa. Ontario Kt A OEB 303-3rdStreet. N.W.,Caigary. Alberfa T2L 2A7 01-605 Robson Sneet. Vancower. B.C. V6B 553 Geology by P.J. Holme. 1995. 1996. 199 Co-ordinatedby D. Lebel through the auspices Southeastern Cordillera NA TMAP Project Digital cartography by K. Shirnamura, Terraln Sciences M. Hudon. Geoscience Information Divisio Any re t rsions or additional geological informa wo~ldbe welcomed by the Geological S LOCATION MAP Geology by P.J. Holme, 1995, 1996. 1997 Co-ordinatedby D. Lebel through the auspices of the Southeastern Cordillera NA TMAP Project Digital carîography by K. Shimamura. Terrain Sciences Division and M. Hudon, Geoscience Information Division Any revisions or additional geological information known to the user would he welcomed by the Geological Survey of Cenada 20' 15' -- - ______- -_-- _ _ --_ - - -*- - - h MAP 1932A SURFICIAL GEOLOGY BEAVER MINES 9 ALBERTA Scale 1:50 000 - Échelle 1/50 000 3 J sion and Kilometres 1--- O 1 2 Univecsal Transverse Mercator Projection Projection transverse universelle de Mercator Crown copyrights rese~ed Droits de la Couronne reserves the user ida 1 i MAP 1932A SURFICIAL GEOLOGY BEAVER MINES ALBERTA Scale 1 50 000 - Échelle 1/50 000 51.. 0 ! ? 3 4 - - .-. Univerial Transverse Mercator Prqection Proleclion transverse universelle de Mercator Crown copyrighis teserved Droits de la Couronne reserves Digital base map from data compiled by Geornatics Canada. modified by the Geoscience Informar!on Division Copies of the topographie map for this area may be obtained from the Canada Map Office, Natural Resources Canada. Onawa. Ontario, K1A OE9 Some geographical names subiect !O revision Magnetic declination 1998. 1 7"301E,decreamg 6.2' annually Elevation~infeet above mean sea Ievel to'l00h or more of this unit: bedding thin to massive; bedding is commonly deformed due to syndepositional slumping and ;ce meitout; 2 surface rn~~~holo~~is hummocky. pilted. and ridged wÏth relief up to 1 O rn; comrnonly underlain by hummocky moraine sediments; thickness GLACIOFLUVIAL SEDIMENTS: Sand. gravel. and minor srlt and danicton deposrted by streams flowrng away frorn. or rn contact wrth glaual (ce. Sortmg ranges from good to poor and stratrfication from fhinly bedded to massive Sediments rnay display evrdence of syndepositional collapse due to meltcut ot buried or supportmg /ce. In areas formerly covered by glacrers from the Rc&-y Mountarns only. l~thologresinclude Precarnbrran and Paleozoic I~mesronc.dolostone. argillite. and quamrte, and may include rnafic and felsrc volcan~crocks in the Oldman Rrver basrn In areas covered by montane glacrers and glacier rce from the contrqentai interror. additional Irthoiogres include sandstone. mudstone. conglomerate and Canadran Shreld provenance granrtrc and metamorphic I~tholog!es Glaciofluvial plain and fan sediments: Gravel and sand: massrve ro thickly bedded: former oufwash plarns and Tans; thickness 1 to 1 O nt Terraced glaciolluvial sediments: Gravel and sand: massve to thrck bedded: former oufwash plarns and fans rncrsed into a succession O: terraces: thrckness 1 to 10 m Glaciofluvial delta sediments: Sand. gravel. and minor silt and cl;:. fhinly bedded to masslve: flar surfaced. delta-form in plan view: deposrted as a delta along the margin of a former glacial lake: thickness from 5 ro 1 O m Glaciofluvial ice stagnation complex sedirnents: Sana grzvel. diamrcton. and minor srlt and clay. thrnly bedded to mass~ve. bedding 1s commonly contoned and lolded due to syndepositional rce meltout; surface morphoiogy includes hummocks. kertle. esker and crevasse-fiIl ndges 2 fo 1 O rn in relief wrth minor elemenls of unrt Gp and Gt: thickness 5 10 IO m $ Undivided glaciofluvial and ground moraine sediments: A patcn~vorkof glacrofluvial sediments and ground morarne (till) roo varrable fo resoive at the scale of mapping Glaciofluvial veneer sediments: Gravel and sand. massrve to thickly bcdeed: thickness 11m or pafchy. overlies bedrock ERRATUM: The da~hcdice-limit line i corner of the map rcpresents the q continental ice influeno: during its late V exteni. It indudes a proposed zone of CO$ vailey glaciers. 1 continental ice W.C Lateral and end moraine (associated with advance M 1. M2, or *'-4'.C2 retreat of continental ice sheet from limit C2) ...... 'e' Former ice contact face in stratrfied drrh IClOFLUVlAL SEDIMENTS: Sand. gravel. and minor silt and djamrcton ~sitedby streams flowing away from. or in contact with glacial /ce. hgranges from good to poor and stratrfication from thinly bedded iassive. Sediments may display evidence of syndeposirional coilapse Verlebrate fossil localiîy ...... to meltout of buried or supponing /ce. In areas formerly covered laciers from the Rocky Mountains only. lithologres include Precambnan Radiocarbon age (years before present) . Paleozoic limestone. dolostone. argillite. and quartzde. and may rde mafic and felsic volcanic rocks in the Oldman Rrver basrn. One or more Foothills Erratics Train Erratic > 1 m in length ...... A .cas covered by montane glaciers and glacier ice from the contiqental 36 ior. additional lithologies include sandstone. mudstone. conglomerate Cosmogenic Cl exposure age on Foothills erratic Canadian Shield provenance granitic and metamorphrc I~tholog!es fyears before present)' .... :iofluvial plain and fan sediments: Gravel and sand; massive ro Montane erratic close to or at the al1 rime upper lrrnit cly bedded: former oulwash plarns and fans: thickness 1 to 1 O !ri of montane glaciatron ...... Canadian Shield erratrc at or near the al1 rime upper limrt of continental glaciaaon ...... a aced glaciofluvial sediments: Gravel and sand: massive to :hick Yed: former ourwash plains and fans incised rnto a succession of 36 Cosmogenic CI exposure age of Canadian Shield erraric ices; thickness 1 ro IO m a t or near the al1 trme upper limit 01 continental glaciation (years before present)' ...... :iofluvial delta sediments: Sand. gravel. and mrnor siit and ciay: Arrows indicating direction of landslide movement y bedded to massive; flat surfaced. delta-form ln plan view; lassociated with the unit Ch)...... xited as a delta along the margin ol a former glacial lake; mess from 5 to 1 O m Assumes a zero erosron rare and no cosmrc ray blockage by snow cover :iofluvial ice stagnation complex sedirnents: Sand. gravel. Iicton. and mrnor silt and clay. thrnly Sedded to massive: jing is commonly contoned and folded due to syndepositional neltout: surface morphology rncludes hummocks. kettle. esker crevasse-fil1 ridges 2 to 10 m in relief wrth minor elemenrs of Gp and Gt. thickness 5 to 10 m 'ivided glacioffuvial and ground moraine sediments: A patcnwork of iofluvial sediments and ground morarne (trll) tao variable to resolve a? ;cale ot mapping :iof/uvial veneer sediments: Gravel and sand. massive to :/y bedded: thickness < 7 m or patchy: overlies bedrock ERRATUM: The dashod ice-limit line croçsing the northeast corner of the map rcpresents the approximate extent of continental ice influeno?during its late Wis~onsinanmaximum extent. It includes a proposed zone of coalesence with montane valley glaciers. FiJ.4 Recommended citation: Holme. P.J. 1998: Suficial geology. Beaver Mines. Alberta: Geological Survey of Canada. Map l932A. scale 1:50 000