 It is also the most unstable volcanic massif in Canada, which has dumped clay and rock several meters deep into the Pemberton Valley at least three times during the past 7,300 years.Hot springs near the Mount Cayley and Mount Meager massifs suggest that magmatic heat is still present.The long history of volcanism in the region, coupled with continued subduction off the coast, suggests that volcanism has not yet ended in the Garibaldi Volcanic Belt.