Cooks paddler Ella Nicholas misses semis at World Champs

first_imgThe 24 year old was 51st in the K1 first round with a time of 115.25 seconds.She improved to 23rd in the repecharge race with a time of 101.77 seconds but only the top ten progressed to the next round.Nicholas will have another chance to qualify directly for the Rio Olympics at next year’s Oceania Championships but is already assured a spot in Brazil as the sole Cook Islands female paddler.Her brother Bryden Nicholas and Fiji’s Daniel Tuiraviravi will contest the men’s K1 heats on Friday.last_img read more

The Grand Canyon as Frankenstein

first_imgIt’s a debate that has vexed scientists for decades: Is the Grand Canyon young or old, geologically speaking? Both, a new study declares. A group of scientists reports that the famed formation is a hybrid of five different gorges of various ages that the Colorado River only tied into a single continuous canyon and deepened since 5 million or 6 million years ago.The debate over the age of the Grand Canyon has been so drawn out largely because nature leaves so few clues as to the shape of the land tens of millions of years ago. Water must flow downhill to create canyons, but which way was down ages ago? Over the past 100 million years—since before the death of the dinosaurs—the incessant jostling of plate tectonics has repeatedly reshaped the landscape of the U.S. Southwest. The Rocky Mountains and the Colorado Plateau rose to the east of the present-day canyon, the Sierra Nevada grew to the west, the Basin and Range of Nevada and Utah stretched the crust to the north, and the Gulf of California split the crust to the south.So, to figure out which way the land was sloping at a given time, geologist Karl Karlstrom of the University of New Mexico, Albuquerque, and 10 colleagues pulled together the relevant published data and added some of their own. Geologists have long recorded where sand, gravel, and cobbles have ended up as a sign of how, when, and where running water had been cutting into the rock. More recently, geochemists have been gauging when river erosion removed most of the crust overlying a particular rock now exposed at the surface. That is possible because the deeper a bit of rock is in the crust, the hotter it is. So as a river removes overlying rock to form a canyon, that once-deep bit of rock cools as it slowly nears the surface. Geochemists can now date when a rock cooled to a certain temperature—and therefore when the overlying rock was removed and a canyon formed—using three semi-independent techniques, each involving the decay of a different element.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)As they report today in Nature Geoscience, Karlstrom and colleagues conclude that two of the present Grand Canyon’s five segments formed early on and two are relatively young. They found that two of the three middle segments formed long ago—between 70 million and 50 million years ago and between 25 million and 15 million years ago. (The third middle segment lacked sufficient data.) But the two end segments were carved in the past 5 million to 6 million years, since the Colorado River first began flowing down the length of the present canyon and into the Gulf of California. “There will be battles yet,” Karlstrom says, but “I think this really is the solution to the 140-year debate.”The paper is getting a warm if not quite as categorical reception. “It doesn’t try to say the entire Grand Canyon is all very old or all very young, which is probably more realistic,” says geochemist Peter Reiners of the University of Arizona in Tucson. “Most in the geological community will consider this to be the more plausible scenario. The reception will be very positive.”But battles there will be. They would be shorter and more productive, Reiners says, if the geochemical methods for determining the timing of ancient erosion and canyon formation were improved. Karlstrom would settle for researchers’ applying all three of the current methods to the same rocks so that interpretations would be more likely to converge. That will likely take more collegiality than seen to date.last_img read more