MUFONET-BBS NETWORK - MUTUAL UFO NETWORK SCIENCE NEWS -

MUFONET-BBS NETWORK - MUTUAL UFO NETWORK ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SCIENCE NEWS - WIRE ~~~~~~~~~~~~~~~~~~~~~ ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄż ł=START= XMT: 18:13 Thu Aug 08 EXP: 18:00 Fri Aug 09 ł ł ł łGEOLOGISTS DEBATE VOLCANIC HISTORY OF NEVADA NUCLEAR WASTE ł łDUMP SITE ł ł ł łWASHINGTON (AUG. 8) UPI - Geologists disputed estimates ł łThursday that the last volcanic activity at a proposed ł łnuclear waste dump in Nevada occurred 20,000 years ago, ł łsaying they think it dates back some 140,000 years. ł ł ł łResearchers from the U.S. Geological Survey in Menlo Park, ł łCalif., said their analysis of magnetic fields and the decaył łof radioactive elements indicate two closely timed volcanic ł łeruptions occurred near the Yucca Mountain, Nevada, site ł łabout 140,000 years ago. ł ł ł łThat scenario contrasts sharply with work by Steve Wells of ł łthe University of California-Riverside, whose research basedł łon the structure and spacing of soil and rocks found ł łevidence of five distinct volcanic eruptions running from ł łabout 100,000 years ago to about 20,000 years ago. ł ł ł łThe Energy Department chose Yucca Mountain as a potential ł łrepository for high-level radioactive waste like fuel rods ł łfrom nuclear power plants because it was thought to be a ł łgeologically stable area where buried waste could remain ł łundisturbed for centuries. ł ł ł łUnder federal mandate, such radioactive wastes must be ł łisolated for 10,000 years. The Nuclear Regulatory Commissionł łwould have the final say on whether it is safe to use Yucca ł łMountain as a dump site. ł ł ł łIn their study published in the journal Science, Brent ł łTurrin and his colleagues from the geological survey said ł łthey think Wells's age estimate of volcanic activity is ł ł''miscalibrated.'' ł ł ł łHowever, Wells countered that there are ''inherent ł łproblems'' in Turrin's dating approach and he sees nothing ł łin the latest study to make him change his mind about his ł łoriginal estimate. ł ł ł łBruce Crowe, the Los Alamos National Laboratory scientist inł łcharge of volcanism studies for the Yucca Mountain site, ł łsaid he is ''trying to stay open minded and look at all ł łpossible alternatives'' for the volcanic history of the ł łsite. ł ł ł łIn any case, the age of the latest volcanic eruption may ł łmean little when it comes to the safety of the site for ł łdisposing of high-level nuclear wastes. ł ł ł łSome models suggest the younger the volcanic activity is, ł łthe greater the risk of an eruption damaging the site, whileł łother models suggest more recent eruptions may point to a ł łlonger resting spell before volcanic activity starts up ł łagain. ł ł ł łIn planning for a dump site, Crowe said he would prefer to ł łerr on the side of caution. ''The error we don't want to ł łmake is assume that it's volcanic activity is old when it's ł łreally young. There's nothing wrong with assuming it's youngł łwhen it's really old,'' he said. ł ł ł łCrowe added that the potassium-argon radioactive dating ł łmethod used by Turrin's team has limitations and the margin ł łof error is not well known for the age of rocks they are ł łdating. ł ł ł ł=END= ł