Stratified Water of a Glacial Lake in Northern Ellesmere

108 SHORT PAPERS AND NOTES jects are scheduled for a more distant Ust-Ilim area on the Angara, and the date,after strings of hydrostations Osinovsky area on the Yenesey. The have been completed along the middle Bratsk water-power station has already reaches of the Yenesey and on the gone into operation. It will reachits Angara. projected output of 4 million kw. within Thenatural resources of theenor- the next few years, and will generate mous tracts of land from Norilsk to the eventually 20,000 million kw.-hrs. of Angarahave not yet been surveyed electricity per year. An industrial cen- thoroughly, but in this region are 10- tre, withplants for the production of cated theTunguski and other coal aluminium,and various other power- fields, the largest in the U.S.S.R. Their consumingenterprises, is beingbuilt reservesexceed the coal resources of there.Preparations have been started the Kuznetsk coal deposits in West for the erection of the Ust-Ilim station, Siberiaand those of the Donets coal which will beeven largerthan the basin in theEuropean part of the Bratsk plant. The Bratsk timber com- U.S.S.R. However, this wealth will have bine will supply the project with build- to wait for exploitation, because Sibe- ing materials. There are rich forests on ria still has large quantities of cheaper the right bank of the Angara and be- coal in more accessible places. tween the Angara and the Podkamen- Rich deposits of iron ore have been nayaTunguska. Several large timber found in the lower reaches of the Nizh- combines are being established there nyaya Tunguska, but they will not be anda railway line will beextended tapped in theforeseeable future for the towards this area shortly. same reason. Before the more valuable Creation of the world’s largest centre and easily accessible forestsin the for the production of cheap electricity Angararegion and along the middle andthe building of an aggregate of reaches of the Yenesey have been open- power-consumingindustries inthe edup the commercial exploitation of Angara-Yenesey region will provide a timber to the north of the river Pod- springboard for further advance to the kamennayaTunguska would not ap- north. Widely used in the process will pear to be economically feasible. be thetimber resources and useful Thus, except for minor scattered cen- minerals of the vast area from the tres of industry,the establishment of Podkamennaya Tunguska to the lower which will be encouraged on the Ku- reaches of the Yenesey. reika and Nizhnyaya Tunguska rivers Since the natural resources of North forthe mining of graphiteand other Siberia are not yet fully known, it is valuable minerals, industrialdevelop- not possible to predict the future de- ment will be limited to the areabetween velopment of these landsin greater the Angara andthe Podkamennaya detail. However, theground is being Tunguska, 1,500 to 2,000 km. (1,000 to broken in the Ob and Yenesey basins 1,250 mi.) from Norilsk and Igarka. for large-scale industrialconstruction Water-power stations, as well as and the building of an extensive trans- thermal stations, which will burn coal portation system, which will get under minedby the open cast method, are way within the next decade or so. being built in theAngara-Yenesey area. SAMUILV. SLAVIN Theamount of electric power, the (Translation kindly provided by cheapest in theU.S.S.R., to be generated The Novosti Press Agency (APN) ) here, will equalin time the present total power output in the Soviet Union. The Irkutsk, Bratsk, and Krasnoyarsk hydro-power plants are to be the first STRATIFIED WATER OF A in this construction effort. Three of the GLACIAL LAKE IN NORTHERN industrial centres, whichwill be created ELLESMERE ISLAND onthis basis, belong to thenorthern AntoinetteBay constitutes the cen- zone. They include the Bratsk area, the tral arm of Greely Fiord and extends SHORT PAPERS AND NOTES 109 40 km. east-northeastwardfrom its the glacier is bounded by an ice-cored junction with Tanquary Fiord in about moraine, indicating recent recession of 80'50'N. 79"W. A large tidewater gla- up to about 100 m.On its western or cier, flowing northwestwardfrom the fiord sidethe glacier calves from an Mer de Glace Agassiz to the southeast, active ice cliff, which appears to be in has blocked off the head of the bay (or, part floating and in part grounded be- more properly, fiord) and separates it low sea-level. The glacier hasbeen from the long narrow lake that is the damming the lake at least since 1883, natural extension of the fiord tothe when J. B. Lockwood of theLady east (Fig. 1). Franklin Bay Expedition (under A. W. Photo: It.C.A.7~.,JllZ? 27, rcjgg. Fig. 1. Western end of glacial lake (right) at the head of Antoinette Bay (left). We visited AntoinetteBay and the Greely) discovered it1, and in all prob- lake on June 2 and 3, 1963 during the ability for a very much longer period. course of an oceanographic traverse Thelake is 20 km.long andin its over the sea-ice from the field station westerntwo-thirds averages 3 km. in of the Defence Research Board at the width, it narrows to about 1 km. in the head of Tanquary Fiord. Antoinette eastern one-third. An active glacier at Bay isa typical steep-sided fiord; a the eastern end calves occasional small single sounding, taken 10 km. from its icebergs intothe lake. Readingsfrom mouth, showed no bottomat 240 m. The apocket aneroid indicated thatthe lake, which is unnamed, was visited on level of the water in the lake was 10 the chance of finding interesting struc- to 12 m. above sea-level. This altitude tural and temperature conditions in the precludes any possible connection with lake water. An easy passage was found fiord waterunder the glacier atthe along the northern margin of the gla- present time; indeed theglacier (except cier by following the frozen and snow- nearthe seaward edge)shows every drifted bed of the river that drains the appearance of beinggrounded below lake. On its northern and eastern sides sea-level. The level of the lake is not 110 NOTES AND PAPERS SHORT an indication of land uplift, for it is Unfortunately, reversing thermometers strictly controlled by the glacier dam, were not carried to the lake and no ab- which permits only a limited drainage solute check on the bathythermograph down the marginal river.At the eastern record is available, butthe tempera- end of the lake ice-rafted boulders and tures are probably accurate to +O.l"C. alow wave-cut silt bank indicate a Watersamples were collected in a seasonal rise in lake level of about 1m., "Knudsen" bottle at depths of 3, 45.5, caused by summer run-off. There are 53, and 57 m. The salinities at these also signs of a former level 20 to 25 m. depths, fromanalyses at the Bedford higherthan the present. Thesnow Institute of Oceanographyunder the cover during our visit consisted of hard supervision of Dr. A. E. Collin, were re- drifts from25 to 75 cm. deep, with wide spectively 0.46, 0.46, 5.75, and 25.594 %o areas of glare ice, particularly near the (thelast the mean of foursamples), western end where there was only 50 Fig. 2. The sharp rise insalinity appears per cent snow cover. to correspond to the sharp rise in temperature near the bottom. TEMPERATURE ("C.) It seems probable that the saline wa- ternear the bottom of thelake was originally sea-water trapped by the advance of the glacier across the fiord, but considerations of density and temperature relationships indicate thatquite complex processesmay have deter- mined thesubsequent history of the waters of the lake. The upper isothermal layer of 27 m. strongly suggests an overturning of the water, probably in the summer of 1962, which was unusu- ally warm.Because this layer had a temperature of only 0.8"C., therecan only be limited surfaceheating after the ice cover melts, for, if there were substantial heating, a temperature of near 4°C. couldbe expected inthis layer of virtuallyfresh water. It is possible thatthe lowerisothermal Fig. 2. Temperature and salinity layer,from 44 to 50 m., representsa of the glacial lake. remnant of an overturn in a previous summer.These deductions are neces- sarily speculative, but they point to the About 3 km. from the western end of need for detailed investigations of tem- thelake an 8-inch (20-cm.) diameter perature, salinity, and also oxygen hole was drilled through 2.7 m. of ice content of the water. Carbon-14 dating and a sounding gave adepth of 60 m. A of the bicarbonate in the highly saline 78-m. bathythermographwas lowered bottomwater might provide informa- to a depth of 59 m. and recorded a tem- tion on the dateof advance of the glacier perature-depth curve shown in Fig. 2, across the fiord. It is notable that this with depths given below the ice sur- highlysaline layer lies about 45m. face. Below a depth of 6 m. the water below sea-level, for which there is no was isothermal at approximately 0.8"C. ready explanation. down to 33 m. At 44 m. the temperature We are most indebted to Dr. W. L. had risen to approximately 1.4"C. and Ford of the DefenceResearch Board remained steady to a depth of 50 m. be- for advice on the interpretation of the low which point there was a steep rise temperature andsalinity profiles. We in temperatureto 2.5"C. at 56 m. also acknowledge with thanks the as- SHORT PAPERS AND NOTES 111 sistance inthe field of Mr.

Load more