mount mount extinct shield volcano oregon high near activity ceased years ago glaciers heavily eroded volcano structure creating slopes horn like peak like shape attracts lightning strikes creates unusual mineral prominent horn forms centerpiece mount wilderness reserve recreational activities skiing hiking produced near dates million years ago extends british_columbia california branch main range includes million years old member group extinct distinguished sharp peaks area surrounding volcano originally inhabited native americans later encountered polish settlers visitors early explorer area named volcano engineer later explorers discovered nearby crater lake volcano analyzed team survey sampled deposits history area originally inhabited native americans referred mountain polish explorer renamed volcano railroad engineer builder played major role construction california oregon railroad united_states geological survey team headed began studying mountains cascade range intended destinations included climbed sampled variant like hit lightning frequently rocks summit melted rare known variety mountain earned nickname lightning rod apart study rest area features heavily early 20th century exploration miners described called water seen deep blue lake published description written recalled expedition gold passed lake deep blue color native americans lived area grew new settlers area built protective sanctuary wagon road built connect building late hunters ventured lake explorers followed lake famous distinctive color crowds non native american stand shore crater lake sergeant climbed friend captain gave lake majesty tourism continued day designated lake surrounding area national park geography regional cascade range produced convergence active taken place approximately million years nearby features complexes old believe activity relatively intermittent producing volcanic time frequent years created complexes mount british_columbia north california complex remarkably different state state ranges large zones smaller features lava shields cascade divided large sectors called east local formed lies west lies eroded younger sharp peak prominent feature skyline visible oregon high range sections oregon younger million years include sisters broken remnants rock area ages comprise newer atop high major volcanic centers include mount hood sisters broken crater lake produced diverse including lava flows composition mount hood known produced series extinct oregon termed steep like highest feet include jack unlike mountains extinct years ago endured ice ages accounting distinct shapes geology deeply eroded glaciers summit crater upper mountain horn relatively old cascade volcano cone building stopped relatively early erosion caused ice ages remains visible material crater moved youngest lava feet active crater mountain past lava flows diverse thick feet thin foot stack like figures composed past flow deposits thick feet placement flows suggest generated emitted cone sides mountain bands clay formed iron rich making body volcano taken volcano contained material notable formations vicinity include little water flows surface excavated glaciers small streams formed composition volcanic cone sits atop prior shield volume cubic miles cone built common component shield oregon volcanic cone formed erupted lava glaciers cut deformed cone upper sector erosion opened interior observation cone lava flows flow deposits strata volcanic ash easily visible potassium dating deposits cone suggests years old eruption stopped years ago period activity short time cone came phases period lava flows built cone explosive took place final period material lava based origin erupted forming weak cone encircled long deposits glaciers present volcano conclusion beginning 20th century pleistocene glaciers largely eroded leading exposure contents small northern volcano extant extensive volcanic ash activity mount certainly masked contents substances form lightning rock volcano restricted pinnacle mountain found feet feet summit lightning strikes summit regularly creating patches brownish black olive black glass resemble paint range centimeters diameter long narrow lines centimeters long appearance varies patches rough flat inspection reveals glass layer materials exists ecology grove enormous exists near forest pine nearby features douglas rocky mountain deer black bears mountain lions live national forest forest rivers support populations trout lakes contain fish bass forest inhabited species american bald eagles canada warner enter boundaries lower slopes heavily forested low diversity plant species forest mountain fir grows feet near peak volcano pine recreation lies southern section mount wilderness national forests west wilderness borders square mile km2 area set aside congress wilderness forests offer activities related mountain hiking skiing wilderness covers acres volcano featuring lakes alpine parks contains miles accessible oregon highway trail selected oregon best skiing trails exist mountain black diamond rating follow trails wilderness bowl mountain
Mount Thielsen