CJ AREA MAPPED IN 1978 FOR QUATERNARY GEOLOGY ~ AREA MAPPED IN FOR QUATERNARY GEOLOGY. I I I j I I I -44-

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1 -44- ~. ~/ <i ' 56', j 55'/ km Mi CJ AREA MAPPED N 1978 FOR QUATERNARY GEOLOGY ~ AREA MAPPED N FOR QUATERNARY GEOLOGY Fig. 1 - Location of Quaternary Geology Reconnaissance Mapping, Saskatchewan Precambrian Shield

2 -45- Reconnaissance Quaternary Geology, Northwestern Part of the Shield * by B. T. Schreiner Quaterna~y deposits were mapped at reconnaissance scale for the areas designated in the NTS 1:250,000 map series as Livingston Lake (74J), William River (74K), Tazin Lake (74N), and Fond du Lac (740), and the western half of Pasfield Lake (74) and the southwestern corner of Stoney Rapids (74P) south of the Fond du Lac River and Black Lake. More detailed investigations were carried out along the roads surrounding Uranium City, Stoney Rapids and Black Lake. Cluff Lake as well as Key Lake to nearly 195,000 km 2 (Fig. 1). Work was also done at This mapping brings the total area mapped since? Approximately one site per 100 km- was investigated. This was supplemented by more detailed work in areas of prime interest to a total of 587 sites. Wherever possible, samples of all quaternary units including lake sediments were taken and each site was photographed and documented on computer-coded field cards. Samples are being analyzed at the Saskatchewan Research Council to determine their sorting, carbonate content, clay mineralogy, and geochemistry. A portable seismic unit was used to study drift thickness mainly along the road from Stoney Rapids to Black Lake, and profiles were taken across a valley, an esker and a drumlin. A truck mounted auger was used to bore holes along the winter road to Cluff Lake in February of 1978 to provide drift thickness, stratigraphic information and also material for radio carbon dating and geochemical analyses. A preliminary map at a scale of 1:250,000 similar to the Quaternary Geology map of the Lac La Ronge area (73P) is being prepared for each NTS area. A summary of the information obtained from all the field seasons has been completed at a scale of l:lm in the map accompanying this report. Winter Drilling 1978 A truck-mounted power auger was used to bore a total length of 215 min holes along the road to Cluff Lake from Tumor Lake south of Latitude 58. exposures in shallow borrow pits along the road were examined. reached was nearly 37 metres in sand. Additionally, The ma~imum depth However, in coarse till with large boulders the normal was about 15 metres. n most holes bedrock was Saskatchewan Research Council

Shield is substantially gr eater than in the east. Multiple till sections wer e r evealed i n several of the holes. n some cases t ills were separated by a sand unit.

3 -46- not reached. The aver age 20 metres penetrated, when compared with the average of about 8 metr es to bedrock along the road to Wollaston Lake indicates t hat t he drift thickness on the western side of t he Shield is substantially gr eater than in the east. Multiple till sections wer e r evealed i n several of the holes. n some cases t ills were separated by a sand unit. Two peat samples were obtained from the base of bogs for age determination by Cl4 analysis. n all, 114 samples were coll ected from the drift. These samples a r e being analyzed to determine their sorti ng, carbonat e content, clay mineralogy and heavy mineral assemblage. Reconnaissance Mapping - 74N, 740, 74P, 74, 74J, 74K Areas Tazin Lake (74N). North of Lake Athabasca where crystalline basement r ocks are exposed the drift is t ypically thin and discontinuous. Till predominates, sand and gravel occur sporadically as f luvial sediments, followed by few deposits of l acustr i ne silt and sand. The geomorphology i s dominated by a bedr ock r eli ef only slightly moderated by the thin drift. A few eskers and drumlins occur especiall y in the nor thwest along with several groups of parallel linear features t r ansverse to them. The ice d'irection according to these drumlins is f r om the northeast. Outwash sands form flat pl a ins along some of the major r ivers. Along the north s hore of Lake Athabasca evidence for a glaci a l l ake stage is present. These include surficial s ands north of Maurice Bay and a l ong Collin River, beaches west of Spring Bay, ot hers along the northwest shor e, at Charlot Peninsul a, Fish Hook Bay, and on the i slands south of the Cr ackingst one Peninsula. Ar ound Uranium City s uch sands may be deltai c. These apparently pass down-slope i nto s i l t deposits overl ying till. South of Lake Athabasca wher e sandst one is the underlying rock the dr ift is much thicker and sand i s the dominant surficial deposit, The sand occurs i n eskers, outwash plains and other fluvial deposits pitted with kettles, and most str ikingly in dunes which range f r om barchans to large pat ch~s of shifting sand. Fond du Lac (740). Cryst alline basement rocks a r e exposed nor th of Lake Athabasca and the Fond du Lac River. The drift i s thin and discontinuous and composed primarily of till. Sand and gr avel occur sporadical ly usually as fluvial deposit s. A few discontinuous eskers whi ch gr ade t o outwash sands, are found particularly a l ong the Tazin River and on the northwest shor e of Fontaine Lake. The area south of the lake and river is underlain by sandstone. The drift i s

4 -47- thicker but bedrock is exposed between the drumlins in many localities. Sand and gravel occur primarily on low-lying surfaces whereas till is found particularly in the drumlin fields. These drumlins are the most prominent land-forms and their long axes indicate an east-west ice direction. This direction is similar to that of striations on the northern shore of Lake Athabasca. The few eskers present trend east to southeast. Sand dunes in the extreme east are an extension of those in areas to the west. Raised beaches at Deadcree Point, Armstrong Point and the south shore of Riou Lake as well as beaches south of Lake indicate former high lake levels. Stoney Rapids (74P). Sandstone is the bedrock type for this area. Drift varies from thick in the drumlins to thin between drumlins or outside the drumlin field. Till is common at higher elevations but at lower elevations sand is the most common surficial sediment. Lesser amounts of silt are found especially along the Fond du Lac River. Seismic profiles along the road reveal a relatively thin drift cover and across a valley show an infilling of stratified sands and silts to a depth of 10 metres. Preliminary results of profiles done on an esker that extends from the road to Fir sland reveal a basal flat-lying bedrock under a layer of drift. Drumlins south of the Fond du Lac River and west of Black Lake are oriented nearly east-west, but more east-southeasterly south of Black Lake. Sand dunes are found on the south shore of Black Lake near the mouth of the Fond du Lac River. The surficial geology is typical of that on the Athabasca Formation sandstone. Drift is thick and dominated by fluvial gravel However, some sand and also silt occur as lacustrine over much of the area. Till is found especially within drumlin fields which are distributed like patches over the entire region. The drumlin axes vary from east-northeasterly in the north to more northerly in the south. On a regional scale this range of bearings reflects the variable directions of glacial ice movement. Eskers are conunon and well developed. Sand dunes are scattered throughout the area and are most commonly barchans. Two large spillways are present northwest and southwest of Pasfield Lake respectively. Livingstone Lake (74J). The Athabasca Formation underlies the drift which is thick and dominated by till. Sand and sometimes gravel occur as fluvial deposits such as eskers which interrupt the otherwise continuous till blanket. Drumlins cover nearly the entire area and are oriented nearly east-west in the north changing gradually to northeast-southwest in the south. Along southeastern and eastern margins of the area drumlins are less numerous and along a line southwest from Thompson Lake are wave cut and terraced.

5 -48- Sand dunes occur in patches and are usually barchans. A well-developed spillway transverse to ice direction is found northeast of Dautremont Lake. William River (74K). Sandstone is the dominant rock type; however a large circular mass of basement rocks occurs in the western half of the area. Sand and gravel are the predominant drift type occurring mostly as outwash deposits and eskers. Till is found in scattered localities, The high proportion of sand and gravel may be due to the fact that this area lies near the Cree Lake moraine. Minor moraines found in the northwestern part of the area also suggest nearness to glacial front. Sands lying at lower elevations may be associated with glacial predecessor of Lake Athabasca. Barchans are scattered throughout the area. Drumlins are not common except in the east central part where they are aligned northeasterly. Acknowledgments Thanks are extended to Amok Limited and Uranez Exploration and Mining Limited for permission to work on their respective properties and for their hospitality.

The Geology of Sebago Lake State Park

The Geology of Sebago Lake State Park Maine Geologic Facts and Localities September, 2002 43 55 17.46 N, 70 34 13.07 W Text by Robert Johnston, Department of Agriculture, Conservation & Forestry 1 Map by Robert Johnston Introduction Sebago