The giant annular lake Manicouagan in Quebec is the combined result of one of the largest identified asteroid or comet impacts on Earth, the recent ice ages, and one of the largest retention dams on Earth. The near-circular central island and the annular reservoir together appear on photographs from space as the beautiful "Eye of Quebec", the most striking and beautiful impact structure on Earth.
Rietje and I kayaked the full circuit during three weeks in August 2006, a splendid wilderness expedition.
Manicouagan Reservoir kayak expedition picture
Manicouagan Reservoir kayak expedition report
Reisverslag Manicouagan Reservoir per kano
"Per kano een meteoorinslag rond" (PeddelPraat nr. 207, november 2006)
"Als ramptoerist de mooiste inslag rond" (Zenit mei 2007)
The bolide impact was 214 (+/-2) million years ago, during the Mesozoical Triassic, a warm era in which therapsids including pre-mammals throve, halfway the previous and present cold episodes. It caused a fireball as far as present-day New York, a melting pot mixing the Panagaean target area containing billion-year Grenville precambrian rock over 50 km extent and 9 km depth, a crater wall of 100 km diameter. Ejecta have been found as far as Britain and Japan. Surprisingly, the massive species extinction at the Triassic-Jurassic transition, starting the age of the dinosaurs and as bad as the K-T extinction (Chicxulub impact) ending it, is dated 13 My after the impact (the even worse Permian-Triassic "great dying" transition was 37 My before it). Why no mass extinctions from the Manicouagan impact? I speculate that the hard Triassic rock and harder underlying Grenville gabbro absorbed the shock as waves without pulverizing and liftoff, while the soft sulphur-rich Yucatan limestone went up into the atmosphere causing global acid rain, re-entry firestorms and winter.
During the last million years the glaciations of the present cold episode removed a kilometer of Triassic rock down to the precambrian Canadian shield, including the outer crater wall. The melt was harder and survived, at 1 km thickness, as a lonesome 2000 square km Triassic hump, the largest impactite mountain on Earth. Its nearly 1000 m high non-brecchiated peaks (Mont de Babel, Maskelynite Peak) represent terrestrial examples of planetary impact uplifts. The bedrock beyond the melt was shattered in the impact; the fragments were scooped up by the ice leaving a deep annular moat around the uplifted melt.
The dam ("Manic-5" or "Daniel-Johnson") is located about 60 km south of the excavated annulus, rising 214 meter atop a canyon of the former Manicouagan river along the (only) road to Labrador. During the 1960s this was the largest construction site in North America, taking 13000 workers and 2.2 million cubic meter of concrete to inundate an area of 2000 square km including the excavated impact annulus. The central molten impactite mountain emerged as "Isle René Levasseur" to become the second-largest lake island and the largest man-made island on Earth. The annular reservoir symbolizes that the Earth's water may have come from comets, replenishing outgassed hydrogen from the Big Bang.
Levasseur island was covered by pristine mature boreal forest but the Southern part has been devastated by the infamous Kruger company, scandalously permitted to convert much of the forest into toilet paper. Kruger probably also caused the immense 2005 forest burns seen on the ISS images below and with Google-Earth/maps satellite view.
Weblinks concerning Manicouagan topography, geology, hydrology:
Manicouagan impact bibliography Concise summary Manicouagan impact cartoons Wikipedia: Manicouagan Reservoir Earth impact database Charles O'Dale crater pages mass extinctions Trias Jura extinctions Triassic Europe Manicouagan faulting Manicouagan ejecta discovery Manicouagan ejecta proof Manicouagan extinction? crackpot interpretation Wikipedia: Isle René Levasseur Google Maps clicker 1950s map 1962 map impact melt map stereo & anaglyph radar images cloudless reservoir fogged reservoir clouds nearby winter overview with StLawrence reservoir plus aurora reservoir plus aurora reservoir fact sheet Doc Searls 2009 photos from plane reservoir level graph reservoir level rise?
Weblinks concerning the devastation of Isle René Levasseur by the
Reserve Louis Babel SOS Levasseur video Kruger logging map Kruger guilty of death at landing Kruger Levasseur devastation from the air Kruger Levasseur devastation from ISS-14 Kruger Levasseur devastation from ISS-15 Kruger Levasseur devastation from ISS-17 Kruger Levasseur landings from ISS-18 winter view ISS-30 winter view ISS-34
Weblinks concerning kayaking/canoeing/sailing the Manicouagan reservoir:
Manicouagan kayak information Manicouagan canoe information driving there where camp on impactite Pourvoirie Boreal 51 Station Uapishka splendid April Fools hoax 1895 Mouchalagane exploration Andrew Nuquist 1994 and 1998 paddle trips sail trips 2000 and 2005 Charles O'Dale aerial and 2004 paddle investigations smooth 2006 sailing 2006 canoe crossing our 2006 circuit report our 2006 circuit album fast 2007 kayak circuit 2007 Levasseur interior canoe expedition, 2009 manic paddlers circuit album 2010 solo circuit report, album 2011 Mouchalagane canoe expedition 2011 second thoughts 2011 mokai circuit 2012 kayak circuit 2012 sail circuit 2013 Mouchalagane canoe expedition 2013 Chad's return, album 2013 kayak crossing 2018 solo circuit per inflatable 2019 two kayak circuit 2019 four kayak circuit