Examine individual changes

'{{Infobox lake | lake_name = Clearwater Lakes<br>''Lac à l'Eau Claire'' | image_lake = STS61A Clearwater Lakes.jpg | caption_lake = Clearwater Lakes as seen from a [[Space Shuttle]] (North is top right) | image_bathymetry = | caption_bathymetry = | location = [[Baie-d'Hudson, Quebec|Baie-d'Hudson]], [[Kativik, Quebec|Kativik]], [[Quebec]] | coords = {{coord|56|08|N|74|18|W|type:waterbody_region:CA-QC_scale:400000|display=inline,title}} | type = [[impact crater]] lake | inflow = | outflow = [[Clearwater River (Quebec)|Clearwater River]] | catchment = | basin_countries = Canada | length = | width = | area = {{convert|1383|km2|sqmi|abbr=on}} <ref name=SClakes>Statistics Canada > summary tables > [http://www40.statcan.gc.ca/l01/cst01/phys05-eng.htm Principal lakes, elevation and area, by provinces and territories]</ref> | depth = 8 inches | max-depth = {{convert|178|m|ft|abbr=on}} <ref name="pmp"/> | volume = 0 | residence_time = FOREVER!!!!!!!! | shore = | elevation = {{convert|241|m|ft|abbr=on}} <ref name=SClakes/> | islands = | cities = Where I met your Mother. }} [[File:Clearwater Lakes 2013180 labels.jpg|thumb|400px|Clearwater Lakes, 2013 image by NASA Earth Observatory]] The '''Lac à l'Eau Claire''' (the official name, in [[French language|French]]), also called the '''Clearwater Lakes''' in English, is a calque of '''Wiyâšâkamî''' in Northern East [[Cree]] (changed form of ''wâšâkamî'' or ''wâšekamî'' in more southerly Cree dialects) and '''Allait Qasigialingat''' by the [[Inuit]],<ref name="CTQ">{{cite web |url=http://www.toponymie.gouv.qc.ca/ct/topos/carto.asp?Speci=20177&Latitude=56,16666&Longitude=-74,41666&Zoom=1700 |title=Lac à l'Eau Claire |accessdate=2009-01-30 |publisher=Commission de Toponymie Québec |language=French}}</ref> are a pair of annular lakes on the [[Canadian Shield]] in [[Quebec]], Canada, near [[Hudson Bay]]. The lakes are actually a single body of water with a sprinkling of islands forming a "dotted line" between the eastern and western parts. The name is due to the clear water it holds. There are actually 25 lakes with that name in the province (26 if the ''Petit lac à l'Eau Claire'' — the Small Clearwater Lake — is included). These are the largest and northernmost, and the second largest natural lake in Quebec after [[Lake Mistassini]].<ref name="pmp"/> <!--- {{coor dms|56|10|00|N|74|25|00|W|}} {{coor dms|51|39|00|N|71|40|00|W|}} Eau Claire, Petit lac à l' * {{coor dms|50|38|37|N|62|36|59|W|}} {{coor dms|50|10|00|N|75|10|00|W|}} {{coor dms|51|37|00|N|71|40|00|W|}} {{coor dms|49|19|00|N|73|19|00|W|}} {{coor dms|49|11|00|N|72|17|00|W|}} {{coor dms|48|54|00|N|70|00|00|W|}} {{coor dms|48|52|35|N|68|59|56|W|}} {{coor dms|48|03|00|N|74|58|00|W|}} {{coor dms|48|02|00|N|76|18|00|W|}} {{coor dms|47|56|40|N|78|38|30|W|}} {{coor dms|47|36|16|N|73|52|12|W|}} {{coor dms|47|20|00|N|72|16|00|W|}} {{coor dms|47|19|55|N|75|21|37|W|}} {{coor dms|47|16|00|N|72|20|00|W|}} {{coor dms|47|16|00|N|72|20|00|W|}} {{coor dms|47|15|00|N|72|07|00|W|}} {{coor dms|47|11|00|N|79|15|00|W|}} {{coor dms|47|04|00|N|78|35|00|W|}} {{coor dms|46|40|28|N|79|03|12|W|}} {{coor dms|46|32|37|N|73|03|35|W|}} {{coor dms|46|31|00|N|74|08|55|W|}} {{coor dms|46|25|17|N|73|17|57|W|}} {{coor dms|46|25|17|N|73|17|57|W|}} {{coor dms|45|39|59|N|75|37|11|W|}} ---> In 1896, the explorer and geologist [[Albert Peter Low]], a member of the Geological Survey of Canada, provided a probable explanation for the lakes' descriptive Cree name by highlighting the extraordinary clarity and depth of their icy waters.<ref name="CTQ"/> ==Impact craters== The Clearwater Lakes occupy the near-circular depressions of two eroded [[impact crater]]s ([[astrobleme]]s).<ref name="R&G1975">Robertson, P.B. & Grieve, R.A.F. 1975 Impact structures in Canada: Their recognition and characteristics. Journal of the Royal Astronomical Society of Canada, v. 69, pp. 1-21.</ref> The eastern and western craters are {{convert|26|km|mi|abbr=on}} and {{convert|36|km|mi|abbr=on}} in diameter, respectively.<ref>{{Cite Earth Impact DB| name = Clearwater West | linkname = clearwaterw | accessdate = 2008-12-30 }}</ref><ref>{{Cite Earth Impact DB| name = Clearwater East | linkname = clearwatere | accessdate = 2008-12-30 }}</ref> Both craters were previously believed to have the same age, 290 ± 20 million years,<ref>Reimold, W.U., Grieve, R.A.F. and Palme, H. 1981. Rb-Sr dating of the impact melt from East Clearwater, Quebec. Contrib. Mineral. Petrol. 76, 73–76.</ref> promoting the long held idea that they formed simultaneously. According to this doublet impact crater theory initially proposed by [[Michael R. Dence]] and colleagues in 1965,<ref>Dence, M. R., Innes, M. J. S. and Beals, C. S., 1965. On the probable meteorite origin of the Clearwater Lakes, Quebec. Royal Astronom. Soc. Canada J. 59, 13–22.</ref> the impactors may have been gravitationally bound as a [[binary asteroid]], a suggestion also made by [[Thomas Wm. Hamilton]] in a 1978 letter to [[Sky & Telescope]] magazine in support of the then-controversial theory that asteroids may possess moons (such as, for example, asteroid [[243 Ida]] with its satellite Dactyl<ref>Chapman, C.R., Veverka, J., Thomas, P.C., Klaasen, K., Belton, M.J.S., Harch, A., McEwen, A., Johnson, T.V., Helfenstein, P., Davies, M.E., Merline, W.J., Denk, T., 1995. Discovery and physical properties of Dactyl, a satellite of asteroid 243 Ida. Nature, 374, 783–784.</ref>). However, repeated [[Argon–argon dating|⁴⁰Ar/³⁹Ar dating]] of [[impactite|impact melt rocks]] from both impact craters suggests that Clearwater East has an age of approximately 460–470 million years, corresponding to the [[Ordovician]] time period, whereas Clearwater West was formed 286.2 ± 2.6 million years ago, in the early [[Permian]].<ref>Bottomley, R.J., York, D., and Grieve, R.A.F. 1990. ⁴⁰Argon-³⁹Argon dating of impact craters. Proc. 20th Lunar Planet. Sci. Conf., LPI, Houston, pp. 421–431.</ref><ref>Schmieder, M., Schwarz, W. H., Trieloff, M., Tohver, E., Buchner, E., Hopp, J. & Osinski, G. R. 2014. New ⁴⁰Ar/³⁹Ar dating of the Clearwater Lake impact structures (Québec, Canada) – Not the binary asteroid impact it seems? Geochim. Cosmochim. Acta (in press).</ref> Both Clearwater impact structures also carry different geophysical ([[natural remanent magnetization]]) signatures<ref>Scott, R. G., Pilkington, M. and Tanczyk, E. I. 1997. Magnetic investigations of the West Hawk, Deep Bay, and Clearwater impact structures, Canada. Meteoritics Planet. Sci. 32, 293–308.</ref> and different geochemical fingerprints of the impacting [[meteorite]] in the [[impactite|impact melt]] of each crater.<ref>Palme, H., Janssens, M.-J., Takahashi, H., Anders, E. and Hertogen, J. 1978. Meteoritic material at five large impact craters. Geochim. Cosmochim. Acta 42, 313–323.</ref> Clearwater East and Clearwater West are both [[complex crater]]s with distinct central peaks. These peaks are caused by the gravitational collapse of crater walls and subsequent rebound of the compressed crater floor. Lake water and sediments cover the central peak of Clearwater East, but bathymetric surveys of the lake floor and core drilling confirm the presence of a peak in its center.<ref>[http://earthobservatory.nasa.gov/IOTD/view.php?id=82433 A One-Two Punch] by NASA Earth Observatory</ref> ==Micro climate== Because of its size, Lac à l'Eau Claire can affect the [[micro climate|local climate]], as attested to by the distribution of plant species. Although the lake's shorelines are populated mainly by [[Boreal ecosystem|boreal]] species, the flora of the central islands in the western basin of the lake is characteristically [[arctic]], making the islands an arctic enclave.<ref name="pmp"/> ==National park== A vast area surrounding the lakes, [[Richmond Gulf]] (''Lac Guillaume-Delisle''), and Iberville Lake (''Lac D'Iberville'') are part of the {{convert|15549|km2|sqmi|abbr=on|precision=0}} [[Tursujuq National Park]], Quebec's largest national park, opened in 2012.<ref name="pmp">Ministère du Développement durable, de l'Environnement et des Parcs, ''Provisional Master Plan Parc national des Lacs-Guillaume-Delisle-et-à-l'Eau-Claire'', Quebec, 2008, ISBN 978-2-550-52710-7 ([http://www.mddep.gouv.qc.ca/parcs/projets/Guil-Delisle-Eauclaire/pdp_en.pdf Online version])</ref> ==References== {{Reflist}} ==External links== {{Commons|Clearwater Lakes}} *[http://ottawa-rasc.ca/wiki/index.php?title=Odale-Articles-ClearwaterWest Aerial Exploration of the Clearwater West Structure] *[http://ottawa-rasc.ca/wiki/index.php?title=Odale-Articles-ClearwaterEast Aerial Exploration of the Clearwater East Structure] {{Impact cratering on Earth}} [[Category:Impact craters of Quebec]] [[Category:Lakes of Nord-du-Québec]] [[Category:Permian impact craters]] [[Category:Annular lakes]]'