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Kanook Tlingit NationMarch 2010
Gods Country
Some 100 million years ago (mya) volcanoes were forced up though the crust of
the Pacific Northwest, from northern Washington up through British Columbia, into
the Alaskan Panhandle and onto the southwestern part of the Yukon. These
mountains of life and destruction were the result of the Kula and the then Farallon
Plates, this land mass has become famous in being the largest granite outcropping
in North America, and is sometimes referred to as the Coast Plutonic Complex or
the Coast Mountains Batholith.
About 85 mya a huge rift developed near the center of the
oceanic Farallon Plate, this rifting event created the oceanic
Kula Plate there is no known event tied to this major event
causing a rupture of the Farallon Plate, where some scholars
believe there was some fundamental change in theconvection within the Earths mantle, while others believe
the huge Farallon Plate became mechanically unstable as it
continued to subduct beneath the Pacific Northwest.
The Kula Plate than became part of a triangle of plates, a
triple junction consisting of the now extinct Farallon Plate
and the Pacific Plate, whereas the Kula Plate was subducted
under the North American Plate at a fairly steep angle,
creating the a set of mountains that are primarily made of
thrusted sedimentary sheets with very little of a continental
uplift, the Canadian Rockies. The American Rockies contain
a significant amount of continental uplift, as a result of the
shallow subduction of the Farallon Plate. Around 55 mya
the Kula Plate took a turn moving more in a northerly
direction and riding on the Kula Plate was the Pacific Rim
Terrane consisting of volcanic and sedimentary rocks. It
was scraped off and plastered against the continental margin forming what is today
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Vancouver Island. By 40 mya the compression forces of the Kula Plate stopped, and
the Kula Plate was absorbed into the Pacific Plate.
Around 60 mya volcanism began to decline along the length of the arc during the
Albian1 and Aptian2 faunal stages of the Cretacious epoch as the rapid movement of
the Kula Plate became parallel with the Pacific Northwest, creating a transformer
fault plate boundary, similar to the Queen Charlotte Fault as this passive plate
came into being the Kula Plate began subducting under Alaska and the
southwestern edge of the Yukon during the early Eocene period (55.8 to 33.9 mya).
Now this area about 50 mya had some of the most dangerous and explosive
volcanoes in the land, whereas cataclysmic eruptions were the order of the day
such as the one that occurred without interupption in the Bennett Lake Volcanic
Complex, that at one time spewed forth some 203 cubic miles of glowing pyroclasitc
rock, and the subsequent evacuation of the underlying magma created a series of
calderas that covered and area some 12 miles by 19 miles across with calderas
ranging from 656 feet deep to 8,858 deep albeit the Kula Plate had shifted
direction its diving beneath Alaska and the Yukon, just moved all the action.
Needless to say the Bennett Lake Volanic Complex is now considered extinct, this
happening after the Kula Plate slowed its dive, around 40 mya, beneath the NorthAmerican Plate.
Since the activity in most of the Coast Range Arc deminished around 40-50 mya,
many volcanoes have went the way of the past due to erosion, leaving their granite
instrusions which were forme when the magma cooled at great depts beneath the
1http://en.wikipedia.org/wiki/Albian 2http://en.wikipedia.org/wiki/Aptian
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violent mountains of fire. Today, remenants of some of these magnificent
mountains of thunder and fire still exist in southwestern Yukon, including Montana
Mountain area located south of Carcross in the Yukon.
Mount Montana area taken from the Highway to Whitehorse, just north ofthe Carcross desert
Another extinct volcanic mountain is Mount Nansen, a deeply eroded LateCretaceous stratovolcano about 33 miles west of Carmacks a village with apopulation of 450 and 6 miles west of Victoria Mountain in the central Yukon. Thenthere is the Mount Skukum Volcanic Complex located 27 miles west of Carcross and20 miles northwest of Mount Porsild a complex that includes the Skukum Group allwith high concentrations of hard to retrieve gold.
Mount Skukum tailings impoundment from tailings damn, facing north
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The northernmost volanic center of the Skukum Group is the Sifton Range
Volcanic Complexand early Tertiary (66 to 1.8 mya) which is made up of 2,300 feet
of a shallow-dripping sequence riddled with middle lavas and pyrocastic deposits.
Many granite rocks of the Coast Range
Arc are visible in the North Cascades of
the Cascade Range, which is the
southernmost boundary of the Arc.
Locations here show the highly
deformed oceanic rocks and assorted
fragments from pre-existing island
arcs, most remnants of the anicent
Bridge River Ocean that existed
between North America and the a
giant chain of active volcanic islands
somewhere in the Pacific Ocean during
the Cretaceous epoch that rode on top
of a micro-plate called the Insular
Plate, somewhere around 130 mya.
The Insular Islands were surrounded by
two pre-historic oceans, the
Panthalassa3 Ocean and the Bridge
River Ocean to the east. Beginningaround 115 mya the islands collided with the North American continent, fusing into
the North American Plate therefore closing the Bridge River Ocean during the mid-
Cretaceous period.
The Bridge River4 in the British
Columbia about 100 miles north of
Vancouver is a namesake of this
ancient ocean. At this collision
massive amounts of molten granite
were injected over this period,
burning the old oceanic sediments
into a glittering medium grade
metamorphic rock called schist.
The older intrusions of the Coast Range Arc were then deformed under the heat
and pressure of the later instrusions, converting them into a layered metamorphic
3http://en.wikipedia.org/wiki/Panthalassa 4http://en.wikipedia.org/wiki/Bridge_River
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rock known as gneiss, as in some places the mixture of the older intrusive rocks and
the origial oceanic rocks were distorted and warped under the intense heat,
creating unusual swirled patterns known as migmatite. Visible evidence of this
process can be found in Skagit and Chelan regions in Washington State. During this
process about 70 to 57 mya, the northern motion of the Kula Plate was between 5.5
to 4.3 inches per year, whereas some geological studies reveal that the plate couldhave moved over 7.9 inches per year.
In addition there were other widespread volcanic belts, such as the Anahim
Volcanic Beltthat lies in the middle of the Coast Range Arc, albeit the volcanics are
not directly related to the Coast Range Arc subduction, but have formed as a result
of the North American Plate sliding over the Anahim hotspot, which during its
formation lie beneath the granitic intrusions of the Coast Range Arc.
Note the significant basaltic dikes, such as the ones located in Gale Passage (4-
mile dike swarm) and around 12 mile long dike swarm at Bella Bella, whereas these
dikes are widespread through out the Coast Range Arc system demonstrating themassive force behind the collision of the plates. Dating these dike swams were
used to calculate the age of the hotspot putting its creation around 13 to 12 mya.
As the Kula Plate died, volcanic activity along the Coast Range Arc remained
active, albeit in later years as the continental drifting continued one of the largest
and most active regions was the Level Mountian Range that began forming around
14.9 mya in Northwestern British Columbia. Where the North American Plate is
being stretched even today at around 1 inch per year as this happens the
continental crust of the North American
Plate slides north along the Queen
Charlotte Plate on its way to the Aleutian
Trench, the rifting opens the mantle
beneath.
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As the continental crust stretches the near-surface rocks fracture along steeply
dipping cracks parallel to the rift, we call them faults whereas hot basalitc
magma rises along these fracture to create passive lava eruptions, the Level
Mountain Range is a product of this action. It is located in Cassiar Country,
northeast of Callison Ranch, southwest of Dease Lake and about 31 miles north of
Mount Edziza and is made up of a very large shield volcano on the Nahlin Plateaucomprising of a series of buttes and ridges, it is a lightly glaciated range, compared
to the Coast Mountains just to the west, and has only one named mountain within
its boundaries, Meszah Peak on the north side of the range at an elevation of
7,185 feet which makes it the highest point
in the Level Mountain Range. Located to the
west, is another related volcanic range just
east of Sheslay River at the edge of the
Nahlin Plateau that has on other set of named
mountains called the Heart Peaks.
The rift zone, that created the Level
Mountain Range has existed for at least 20
million years, and overall has created a line of
volcanoes called the Northern Cordilleran
Volcanic Provice, (Stikine Volcanic Belt) a line that stretches from the Alaska-Yukon
border to near Prince Rupert, British Columbia. Today, it contains serveral presently
dormant volcanoes that have the potential for future eruptions, having erupted
during the past few hundred years. One especially the Tseax Cone located at the
southern end of the Stikine Volcanic Belt in the Nass River area, whereas lava
flowed copiously once, 625 years ago and again 220 years ago some 6.9 miles from
the Nass River to the Tseax River damming and forming Lava Lake, the area today
is the Nisgas Memorial Lava Beds Provincial Park. Prindle Volcano5 in east-centralAlaska is generally considered the northernmost volcano in the Stikine Volcanic
Belt.
The Level Mountain Range rises above adjacent forested lowlands andundulating alpine areas surround the steeper central peaks.
5 Prindle Volcano, named for Louis by another geologist, is one of the loneliest volcanoes inAlaska. While most of Alaska's volcanoes make up the curve of the Aleutian Islands, withbunches of others on the Alaska Peninsula, in Cook Inlet and in the Wrangell Mountains,Prindle stands alone in the Fortymile River country close to the Canada border, about 50miles northeast of Tok.
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The Level Mountain Range is the most voluminous and most persistent volcanic
region of the Northern Cordilleran Volcanic Province (NCVP) with an area of 695
square miles and it has been determined that it is the earliest in the NCVP, it has
more than 20 volcanic vents dating from 66 mya to 12,000 years ago, albeit activity
from 10,000 years ago to today is uncertain. On either side of the range are twofaults, the King Salmon Fault and the Nahlin Fault, which experienced extreme
activity during the Mesozoic (180 to 251 mya) and the Cenozoic (65.5 mya to
present). Its glaciation history extends back to the Pilocene (5.322 mya to 1.806
mya), proven by numerous examples of volcanic and glacial evidence. Albeit is
adjacent to the Tuya Volcanic Field6 it is not part of the same volcanic formation,
simply because the Level Mountain Range is a long-lived volcano, whereas the Tuya
Volcanic Fieldconsists of small volcanoes noted for only having one short eruptive
event.
The Level Mountain Range experienced three distinct phases of volcanic activity
evidences points to a hotspot located in the region and a leaky continental drift
volcanism.
The 1st phase of its creation looks back some 14.9 mya with the creation of a
massive oval-shaped shield volcano, forming a broad cliff-bounded lava plateau 43
miles long and 28 miles wide with an average thickness of 2,461 feet and an
elevation of 4,593 feet on the eroded Nahlin Plateau marking an extensive Neogene
(23,03 to 2.588 mya) regional uplift. The shield consists of 4 distinctive layers,
dominated by 3.28 foot to 26.25 foot thick basaltic lava flows separated by thin
layers of fluvial sediments and glacial sediment.
Before the shield volcano was finished around 7.1 mya another eruptive period
occurred forming a massive stratovolcano, this 206 cubic mile stratovolcano acts as
a volcanic plug centrally located atop the shield made up of several volcanic vents,some of which used to be 9,202 feet in elevation albeit the layers of the
stratovolcano are complex due to the influence of adjacent vents and to the
tremendous variation in the erupted magmas five bimodal packages of lava flows
and ejecta comprise the stratovolcano.
The deeply dissected stratovolcano of the Level Mountain RangeThe shield-forming phase ended some 6.9 mya, whereas the stratovolcano-
forming phase ended some 5.3 mya- evidence shows that at one time there was an
eruption through an ice age field, this demonstrate by the number of tuyas
present, whereas a tuya is a type of distinctive, flat-topped, steep-sided volcano
6
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formed when lava erupts through a thick glacier or ice sheet. They are somewhat
rare worldwide, being confined to regions which were formerly covered by
continental ice sheets and also had active volcanism during the same time period.
The tuyas within Level Mountain Range formed when magma intruded into and
melted a vertical pipe in the overlying continental ice sheets, and cooled as a large
block, with gravity flattening its upper surface. The shield margins have beensculpted by continental ice, and its uppermost member includes volcano-glacial
faces.
The final phase of activity constructed a series of lava domes some 4.5 mya, these
post-date the alpine valley system and cut the glacially eroded core of the
stratovolcano evidence of continued regional uplift with canyon development is
found on all the adjacent major river systems, including the Stikine River with its
prominent section of Tertiary basaltsabout 2.5 mya the dome-forming eruptions
ceased.
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The Mount Edziza Volcanic Complex is another large
and potentially active north-south trending volcano complex
in the Stikine Country, located about 24-miles from the small
community of Telegraph Creek on the Stikine River. It sits
within the Tahltan Highland7, and upland area of plateaus
and lower mountain ranges, lying east of the Boundary
Ranges and south of the Inklin River, which is the east fork of
the Taku River. Within the complex are many types of
volcanoes, shield volcanoes, calderas, lava domes,
stratovolcanes and cinder cones.
Most of the complex is within the large provincial park of
Mount Edziza Provincial Park, this 1,027.4 square mile park
was established in 1972 it is a remote complex whereas
there are no roads, with access only along wild trails, with its
easiest access from Highway 37 (Stewart-Cassiar Highway)
and a spur road from Dease Lake to Telegraph Creek. And
from Kinaskan Lake on Highway 37, a poorly maintained trailthat extends west for 19-miles into the heart of the complex,
and from Telegraph Creek another trail goes east for 16-
miles to the northern slope of Mount Edziza.
The Mount Edziza Volcanic Complex began forming
around 7.5 mya and has grown steadily since then, it is like
7http://en.wikipedia.org/wiki/Tahltan_Highland
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the other volcanoes in northwestern British Columbia being born due to continental
rifting it to is along a divergent plate boundary.
The Mount Edziza complex is Canadas 2nd largest volcano of young volcanic
activity, with its 390 square miles only exceeded by the Level Mountain Range north
of Edziza with its square miles at 690.
There are four central volcanoeswithin the complex, one is Armadillo
Peak8, Spectrum Range9, Ice Peak10,
and Mount Edziza they all lay along
the northerly trending axis of an oval
shaped composite shield volcano.
Whereas the composite shield volcano
is made up of overlapping shields, two
of which are noticeable on maps. This
composite shield volcano forms a
broad lava plateau some 40 miles long
and 12 miles wide, primarily made of
basaltic lava flows, it is clustered with
cinder cones and surround by steep
ridges, which expose layers of black
columns of basaltic lava flows with distal rock fragments and pyroclastic deposits.
Mount Edziza, one of the main volcanoes of the Mount Edziza volcaniccomplex
The lava plateau is flanked by the Klastine River (which joins the Stikine) to the
north, Mess Creek and the large Stikine River to the west and the Iskut River to the
8http://en.wikipedia.org/wiki/Armadillo_Peak9http://en.wikipedia.org/wiki/Spectrum_Range 10http://en.wikipedia.org/wiki/Ice_Peak
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east. The elevation of the Lava Plateau range from 4,900 to 5,900 feet with the
volcanic mountains up to 8,500 feet, there has been three sections of the Lava
Plateau given official names, the Arctic Lake, Big Raven and the Kitsu. Historically
the Mount Edziza Volcanic Complex has had at least two period of regional
glaciation, where deep ice sheets covered the land, and several lesser advances of
mountain glaciers.The Mount Edziza region is rich in obsidian which is produced by the rapid
cooling of molten lava or some liquid fraction of molten lava most is above the
5,900 feet to 6,200 foot altitudes and is noted in history as being an important
source for the 1st Nations People. Two columnar basalt formations are found in
the area, one the Tahltan Eagle at the confluence of the Tahltan and Stikine
Rivers and Pipe Organ Mountain within the Mt Edziza zone. Both display radiating
columns of basalt. The Tahltan Eagle is of cultural significance to the Tahltan 1st
Nations, the other if there is any significance is unknown.
Four hot-springs have been identified in the Mt Edziza region, one at Elwyn Creek,
the 2nd at Taweh Creek a 3rd one at Mess Lake and the 4th at Mess Creek, three of
them the Elwyn, Taweh and Mess Lake are the only hot springs known in Canada
that appear to be related to recent volcanic activity. The three are found close to
recent eruptive centers and may be a result of discharge from shallow hydrothermal
systems driven by residual magmatic material, Mess Creek Hotsprings lie on a
major fault bounding the west side of Mess Creek Valley and is believed to be part
of a deep circulating hydraulic system. The springs range in temperature from 77F
to 113F and are diluted with varying amounts of cooler water from creeks and
ground runoff. The Elwyn Creek springs consist of six springs (two warm, and four
cold) forming three large pools at the head of the creek with tufa11 formations in
mounds and terraced benches along the creek valley. Taweh Creek has extensive
tufa formations along a 2,100 foot cliff of the creek, whereas Mess Creek has twoprincipal vents at the base of a 66 foot cliff that form a pool approximately 2,152
square feet to 3.3 feet deep. The Mess Lake hotsprings have produced tufa
deposits that cascade down gentle hill-slopes and through lowlands covering about
297 acres. Deposits around recent vents indicate that discharge likely took place as
a geyser. One of the fossil vents stands 33 feet high.
During the last Ice Age (in the Pleistocene) the Cordilleran Ice Sheet reached
depths of 8,200 feet in some parts of British Columbia, on the east side of Mount
Edziza the ice moved in a southward direction, whereas many of todays lakes are
oriented in the direction of the ice movement, especially found in the areas where
the glaciers gouged on the valleys the retreating ice also deposited of copiousamounts of sediments. And drainage and erosion of the years have filled in a great
deal of the gouged out valley with sands and gravel. Albeit the Pleistocene Ice Age
ended about 10,000 years ago, remnant alpine glaciers have shaped the mountain
peaks, cirques and ridges typical of mountains in the region. About 450 years ago
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during the little ice age, glaciers once again advanced to their maximum limits
since the Pleistocene Ice Age, and about 200 years ago they began their retreat.
The Mount Edziza region has experienced the most recent volcanic activity with its
last eruptions occurring during the last 2000 years.
The Lava Fork Volcano or The Volcano is the name of a cinder cone in
northwestern British Columbia located immediately north of the British Columbia-Alaska border near Behm Canal just northeast of Ketchikan. It is believed it is the
youngest volcano in Canada, whereas in recent history its lava flows traveled south
3.1 miles crossed the border into Alaska and dammed the Blue River, a very short
tributary of the Unuk River which has its headwaters on Mount Lewis Cass
(Boundary Peak 47). The lava flows were approximately 13.5 miles long and still
show the original features and pits formed when the overlying lava collapsed into
the tubes and tree molds. It is estimated that the youngest of the flows is around
150-years old, with the oldest eruption at around 350-years old. It is the
southernmost of ten volcanoes in the Iskut volcanic field, which include the
volcanoes at Hoodoo Mountain and the Iskut-Unuk River Cones.
Some 57 miles directly south of this location is the New Eddystone Rock in the
middle of Behm Canal, which is said to be part of a volcanic vent that had spread
massive amounts of lava over a large area, similar to pancake batter on a griddle.
After the basalt flows covered the floor of Behm Canal, subsequent glacier advances
and retreats scoured away much of the deposits leaving behind the New Eddystone
Rock and some of its neighboring islands to the northeast.
New Edddystone Rock
About 46 miles northwest of Wrangell, Alaska on the north side of the lower Iskut
River and about 19 miles east of its junction with the majestic Stikine River sits
Hoodoo Mountain, a potentially active flat-topped stratovolcano, it is smack dab
within the Boundary Ranges and has been around for 130,000 years.
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Southern flank of Hoodoo Mountain
Studies have shown that the Hoodoo Mountain has gone through consistently
three different cycles every 24,000 years, whereas its activity shifts from a sub-
glacial to post-glacial and then back to sub-glacial, a unique sequence found among
the Northern Cordilleran volcanoes. The records demonstrate that from 85,000 to
80,000 years ago the mountain was more active than today, more than 90% of
Hoodoo Mountain formed during its early eruptive phase, at least 100,000 years ago
and over the years has added material to its present size today.Regional ice thickness during the sub-glacial period is estimated to have been
more than 1.25 miles. While the main volcanic debris is phonolite12 and comedic13
trachyte14 lava and hyaloclastites15, there are found some pyroclastic rocks the
trachyte and comendic magmas that erupted from the mountain and other Northern
Cordilleran volcanoes are believed to be a result of the fracturing of alkali basaltic
magma in crustal reservoirs. The estimated volume of erupted material from
Hoodoo is 4 cubic miles, and at least six phases or eruptive activity have been
identified with the mountain. Some 85,000 years ago erupting through glaciers
over 328 feet thick is generally believed to be the 1st phase of activity, this
produced lava flows, lava domes and breccias16 deposits.
Then 2nd eruptive phase some 80,000 years ago albeit
not from beneath a glacier the mountain was
surrounded by ice at 2,625 feet thick, whereas the lava
flows melted some of the thick glacier ice and
developed ponds around it perimeter, that quickly
solidified to form barriers upon which more lave stacked
up. These ice-marginal lava flows were thick and are
normally bounded by steep cliffs with fine-scale cooling
joints and contained copious amounts of volcanic glass.
It is this type of activity that formed the massive lava
cliffs near the base of Hoodoo Mountain, and are amongHoodoos most prominent features.
12http://en.wikipedia.org/wiki/Phonolite 13http://en.wikipedia.org/wiki/Comendite 14http://en.wikipedia.org/wiki/Trachyte 15http://en.wikipedia.org/wiki/Hyaloclastite 16http://en.wikipedia.org/wiki/Breccia
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The 3rd eruptive phase between 80,000 and 54,000 years ago was when an
explosive event occurred that produced the pyroclastic flows down the northern and
western flanks of the mountain, creating welded and un-welded ignimbrite17
deposits up to 328 feet thick. This explosion is one of the few explosive eruptions
throughout the mountains history, and is believed to have been caused by magma
breaching thin ice.The 4th eruptive phase again found no eruptions through ice, whereas lava flowed
over the previous pyroclastic deposits from the 3rd period and over the ice-dammed
lavas from the 2nd phase.
The 5th phase, between 54,000 and 30,000 years ago occurred from beneath
another glacier and produced two distinctive types of lava-breccia, the 1st sub-
glacial eruption between 54 and 40 thousand years ago produced lava domes and
monomict breccias, while the sub-glacier eruption took place 40k to 30k years ago
under much thinner ice.
The final phase of eruptive activity was effusive in nature, that produced lava
flows with well-preserved lava channels on the northwest and southwest flanks of
the mountain some 12,000 years ago and in large ice-free environment the lava
flows originated from the mountains flat-topped summit and from various volcanic
vents of its flanks. There is a scientific debate on the exact dates of this period,
whereas some say nine-thousand years ago and other say 7,000 years ago.
Albeit Hoodoo Mountain shows only one massive explosive event in the history
that modern man has been able to determine, it is still considered to be one of the
eleven seismically active Canadian volcanoes that are very capable of explosive
eruptions, whereas massive magma chambers have been detected beneath the
mountain.
17http://en.wikipedia.org/wiki/Ignimbrite
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Hoodoo Mountain, as seen looking to the northwest across the Iskut River
Another potentially active volcano is Mount Garibaldi or as the 1 st Nations people
the Squamish call it Nchkay (Dirty Place or Grimy One). It is located 50 miles
north of Vancouver within the southernmost Coastal Mountains, and needless to say
is one of the most recognized peaks in the South Coast region, and is British
Columbias best known volcano.
Mount Garibaldi as seen from Squamish
The eroded dome complex occupies the southwest corner of Garibaldi Provincial
Park overlooking the town of Squamish, and is known to be the only Pleistocene age
(2.588 million to 12 000 years ago) volcano in North America to have formed upon a
glacierit is not considered part of the Cascade Volcanic Arc.
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Mount Garibaldi is one of the few Cascade volcanoes that is made exclusively ofdacite18, its unique asymmetrical shape is attributed to its main core being
constructed on top of the Cordilleran Ice Sheet, and unlike other Cascade volcanoes
to the south it does not dominate the landscape, therefore many residents of
Vancouver are not aware that there is a volcano closer to their city than the one
they observed over the International Border they share with Washington State,
Mount Baker.
It is believed it began its life some 250,000 years ago a product of the Cascadia
subduction zone, a long-convergent tectonic plate boundary that stretches from
mid-Vancouver Island to Northern California whereas the subduction zone
separates the Juan de Fuca, Explorer, Gorda and North American plates. Here the
oceanic crust of the Pacific Ocean dives beneath the North American plate at a rate
of over 1.6 inches per year. And the hot magma upwelling above the descending
oceanic plate creates volcanoes up and down the west coast of North America.
With sporadic eruptions happening every few million years at each volcano, this
subduction zone is estimated to have existed for 37 million years and has created
the Cascade Volcanic Arc.
18http://en.wikipedia.org/wiki/Dacite
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The mountain grew in three phases, the 1st being the creation of a broad
composite cone made of dacite and breccias, which has been potassium-argon
dated giving up the 250,000 year date. Part of this proto-Garibaldi or ancestral
volcano are exposed on Garibaldis lower northern and eastern flanks and on the
upper 787 feet of Brohm Ridge. And within the vicinity of Columnar Peak and
many Glacier Peaks a series of coalescing dacite lava domes were constructed, butduring a long period of dormancy, the Cheekye River eventually cut a deep valley
into the cores western flank that was later filled with a glacier.
The 2nd event happened when the Cheekye Glacier
had reached its maximum and along with a part of the
regions ice sheet an eruption of the Atwell Peakplug
dome from a ridge surrounded by the several
thousand foot ice sheet. As the plug dome rose,
massive sheets of broken lava crumbled as broken
rock fragments down its sides. Accompanying this
action were numerous pyroclastic flows made up
super-heater mix of gas, ash, and pumice forming a
fragmental core 1.5 cubic miles in volume and an
overall slope of 12 to 15, erosion has since steeped
this slope also during the time the ice melted forming a small lake against the
Brohm Ridges southern arm, the volcanic sandstones seen today on top of Brohm
Ridge were created by ash settling in the lake.
Between the 2nd and the 3rd eruptions, melting glacier ice initiated a series of
avalanches and mudflows on Garibaldis western flank that removed nearly 50% of
the original cones volume pushing it into the Squamish Valley whereas .6 cubic
miles of the mountain flowed and covered 10 square miles of the valley with some
300 feet of debris.Soon before or after the buried ice had melted away, dacite lava quietly erupted
from Opal Cone southeast of Atwell Peak plug dome between 10,799 to 9,300 years
ago and flowed some 12 miles down Ring Creek on Garibaldis southern and
southwestern flanks, both flows did not encounter any residual glacial ice it is
calculate that about 0.15 cubic miles of dacite erupted in the 3rd period.
Red outline indicates the ancestral Garibaldi volcano
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Mount Cayleyis another potentially active stratovolcano located in the Squamish-
Lillooet Regional District in southwestern British Columbia, about 28 miles north of
Squamish and 15 miles west of Whistler in the Coastal Mountains, it is 7,428 feet
above the Squamish River to the west and 6,052 feet above the Cheakamus River
to the east.Mount Cayley is made up of ridges, rounded
lava domes and sharp eroded rocky pinnacles;
with the highest reaching 7,799 feet in elevation
it lies at the southern end of a glacier field of ice
called the Power Mountain Icefield.
To the Squamish the mountain is called,
t'ak'takmu'yin tl'a in7in'a'xe7en or Landing
Place of the Thunderbird, a legendary creature in
many indigenous people of North America,
whereas local legend says the rocks were burnt
black by the Thunderbirds lighting, and is a sacred mountain to the local 1st Nations
people.
Mount Cayley began erupting some 4-million-years-ago and is the largest and
oldest volcanic complex of the Garibaldi Volcanic Belt, with explosive eruptions
ejecting viscous magma, glowing avalanches of hot volcanic ash and huge
pyroclastic events its magma is high in silica, such as rhyolite, dacite or andesite,
making it very acidic in nature.
The 1st phase erupted spewing forth lava and ash, including plagioclase19-
hypersthene20-hornblende21-phyric dacite flows, and pyroclastic breccias, and
concluded with the formation of a central lava dome, which eventually developed
the summit spires on Mount Cayley.The 2nd phase vented breccias,
enormous lava, and welded breccias with
plagioclase-hypersthene-hornblende-
biotite-phyric dactite, forming the largest
number of small pinnacles extending from
the jagged summit ridge of Pyroclastic
Peak called the Vulcans Thumb on the
southwestern flank of the mountain, all
this around 600,000 years ago
After a lengthy period with anextended erosion cycle removing almost
all of the original cone of pyroclastic
material, the satellitic vents went into action. This 3rd and final phase began about
300,000 years ago with the eruption of a dacite lava flow into the valley of
19http://en.wikipedia.org/wiki/Plagioclase 20http://en.wikipedia.org/wiki/Hypersthene 21http://en.wikipedia.org/wiki/Hornblende
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Shovelnose Creek and concluded with the construction of two small satellitic
plagioclase-hypersthene-biotite-phyric dacite lave domes about 200,000 years ago.
Several hot-springs on Cayleys southwestern flank indicate that magmatic heat is
still present, convincing the scholars and scientists that the mountain is far from
dormant, and in addition bore holes have been drilled in hope of establishing a
geothermal facility whereas high temperatures have been found at fairly shallowlevels in steps from 112F to 212F.
There is another potentially active volcano within the Garibaldi Complex, the
Silverthrone Caldera, classified as the largest of the calderas in Western Canada,
its size being over 18.6 miles long (north-south) and 12.4 miles wide (east-west).
Mount Silverthrone an eroded lava dome on the calderas northern flank is 10,368
feet high and may be the highest volcano in Canada.
East face of Mount Silverthrone
Most of the caldera lies within the Ha-Iltzuk Icefield, which is the largest icefield in
the southern-half of the Coast Mountains, there is also five primary glaciers within
the Silverthrone region. The Silverthrone region is located 220 miles northwest ofVancouver and about 31 miles west ofMount Waddington, which is the highest peak
(13,186 feet) that lies entirely within British Columbia.
It eruptive history is a mystery, however as at other calderas, it is suggested that
the eruptions at Silverthrone are and have been explosive in nature, with the ejecta
be acidic, having high to intermediate levels of silica, as in rhyolite, dacite and
andesitic. Andesitic and rhyolitic magma are commonly associated with the two
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forms of explosive eruptions called Plinian and Pelean eruptions. Dating of the
rhyolitic lava domes at 750,000 to 400,000 years ago makes Silverthrone much
younger that its nearest prominent neighbor to the east-southeast the Franklin
Glacier Volcano at 6 to 8 mya.
Albeit the Volcanic Explosivity Index (VEI 0-8) is not known for the Silverthrone
Caldera, its chemical makeup and the structure of the volcano compares it to othercalderas that have a history or producing some of the worlds most violent
eruptions, such as the Crater Lake Caldera (Oregon) which is 6 miles long and 5
miles wide, whereas it ejected some 12 cubic miles of material forming its caldera
which is 3 times shorter in length and approximately 2.5 times less in width than
the Silverthrone caldera. Crater Lake caldera VEI is estimated at 7.
Seismic readings obtained at Silverthrone indicate a magma chamber beneath the
volcano, albeit the data fails to reveal a concrete conclusion it is still considered a
future hazard albeit remoteness reduces its possibilities of the loss of human life.
But another VEI of 7 or more would cause considerable excitement along the
coastal range, and affect the landscape far into the future.
Northeast face of Mount Silverthrone
Mount Meager (Mount Meager Volcanic Complex) is the most unstable volcanic
massif22 in Canada, constantly sloughing clay and rock into the Meager Creek and
22http://en.wikipedia.org/wiki/Massif
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Devastation Creek valleys. The complex is located some 93 miles north of
Vancouver and 40 miles northwest of Pemberton.
The volcano lies above the west flank of the Lillooet River and just south of the
Lillooet Icecap, and has at least eight vents, and is considered the northernmost
major volcanic center of the Cascade Volcanic Arc and the Garibaldi Volcanic Belt,albeit Mount Silverthrone is a strong contender for this distinction.
The land beneath Mount Meager is hot, whereas the surface water seeps under
the volcano and returns to the surface along fractures in the Meager and Pebble
Creek areas as Hot Springs, springs that were originally used and revered by the 1st
Nations people, and are named Teiq in the language of the Lillooet people, and
further up the river is where the spirit-being/wizards known as the Transformers
reached in their journey to Lillooet Country. During this time the springs were a
training place for the young 1st Nations men looking to acquire their power and
knowledge. It was in this area that was found, a Blackstone Chiefs head pipe
that is a infamous amongst the Lillooet artifacts, it was found buried in volcanic ash
from around the 2350 year-ago eruption of Mount Meager.
The Bridge River Ash is considered to be from the
eruption of Mount Meager 2350 years ago, an
eruption what was similar to the 1980 eruption of
Mount St Helens, whereas the eruption came from a
vent on the north-east side of Plinth Peak. An,
eruption that produced a diverse sequence of
volcanic deposits that are well exposed in the bluffs
along the Lillooet River, which are defined as the
Pebble Creek Foundation. This eruption was of such magnitude that thin, very fine
grained, distal deposits of tephras have been identified in Alberta some 329 miles tothe east, and it is believe it ejected an ash column at least 12 miles high.
The eruption also blocked the Lillooet River, creating a 62 mile long lake that was
at least 164 deep, whereas the lake backed up to an elevation of 2,657 feet
eventually eroding it let loose a massive flow of water sending house-sized boulders
down the valley for several miles, which created Keyhole Falls and then continued
their path of destruction further on down the valley. In its final stages the eruption
ejected a 1.24 mile long porphyritic dacite lava flow that varies from 49 feet to 66
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feet thick, all this happening in very recent geological terms, therefore suggesting
very strongly that the volcano is not quite done spewing it contents once again
across the landscape.
At least three-times during the past 7,300 years Meager has deposited clay and
rock several meters deep in the Pemberton Valley, two earlier debris flows around
4,450 and 7,300 years ago, pyroclastic rock traveled 20 miles into Meager Creek and recently the volcano has created every ten-years or so smaller landslides,
believed to have been caused by the volcanoes geomorphic activity, or an upwelling
of magma to shallow depths and movement caused by earth tremors with a result
of the weakening or deterioration of the volcanic rocks on the surface.
On the southwest side of the complex is Devastator Peak, a massive leaning tower
of rock which actually partially overlies the ice of Devastator Glacier and as the
glacier retreats, the rock is becoming unsupported and parts of it have collapsed.
Massive rock avalanches happen, which land on the glacier and due to its friction,
melt the glaciers surface during the collapse during the past the resultant
landslide blocked Meager Creek at its confluence with Devastator forming a
temporary lake when the lake grows to a large size it runs over the top of the
temporary landfill dam and creates a huge wave which roars own Meager Creek and
the Lillooet River for 12 miles or more before spreading out into a huge flood
scientist believe a wave large enough to reach Pemberton would be created by such
a landslide, an event such as this happened in 1930, and on July 22 nd, 1975 when a
flood buried and killed a party of 4 BC Hydro geologists exploring the region for
geothermal sites.
Another potentially active volcanic region is the Wells Gray-Clearwater Volcanic
Field (Clearwater Cone Group) classified as a Monogentic Volcanic Field (field of
small, scattered volcanic vents) in east-central British Columbia about 62 miles
north of Kamloops, and over time it has created numerous basaltic volcanoes andextensive lava flows.
A view from Green Mountain with Pyramid Mountain in the distance
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Most of the field is within a large wilderness park, Wells Gray Provincial Park, a
2,100 square mile park that was established in 1939, simply because of the fields
extreme beauty there is one single road that enters the park, which from it a
number of the parks natural wonders can be viewed, after some short hikesbut
most areas are accessible only by aircraft.
Scientist speculate that the field began forming some 3.5 mya, but they are notsure of the causes of the volcanism, albeit is 160 miles inland from the north-south
trending Garibaldi Volcanic Belt and is along-strike from the Nootka Fault on the
Coast, which as weve learned has been sub-ducting under the North American
Plate, they are still not certain of its origins and continue to research its actual
source. The region is believed to have formed by crustal thinning and the existence
of crustal penetrating structures which in theory tells us little.
Based on modern dating methods, it is estimated that the volcanic activity in the
field increased some 2.5 million years ago creating a valley-filling and plateau-
capped lava flows that had a volume of approximately 6 cubic miles. This action
occurred over at least three periods of glaciation, evidence of this is preserved in
the form of tuyas23, ice-pond valley deposits and sub-glacial mounds. The four
tuyas in the region, Gage Hill, Hyalo Ridge, McLeod Hill and Mosquito Mound having
been formed when magma erupted through a vertical pipe in the overlaying glacial
ice, and cooled as a large block, with gravity flattening its upper surface and over
the following years glacial erosion creating it eventual shape, this activity suggests
they erupted during the early Pleistocene period (2.5 mya).
It is believed that at least one explosive underwater volcano formed during the
Pleistocene, the White Horse Bluff, which is thought to have formed in three phases.
The 1st was involved with water, in that it might have been dammed by glacial ice
which filled the Clearwater River valley.
23http://en.wikipedia.org/wiki/Tuya
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Clearwater Valley
The water from the dammed lake was heated by the volcano then it flooded down
the vent creating violent steam explosions and broken lave fragments whereasonce the steam explosions had subsided, the broken lava fragments settled back
into the glacial water, thereby creating the un-volcano like form of White Horse Bluff
which is mostly made of fragmented volcanic glass called hyaloclastite. The volcano
stopped erupting soon after the
breech of the surface of the
glacial lake.
Clearwater Lake
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Volcanic events elsewhere, during the Pleistocene interacted with groundwater
and magma creating numerous pit volcanoes pit crates that have been filled with
water creating several crater lakes unfortunately glacial fill has left a thick blanket
of till over nearly all of the volcanic deposits and in doing so only an outcrop may be
found is some cliff-forming exposures in several valleys.
At the end of the last ice age, approximately 10,000 years
ago, the massive floods from the melting glacial icecarved deep canyons into the underlying plateau-capping
lava flows evidence of this can be found in the rivers and
waterfalls such as the ones at Murtle River, Canim Falls,
Spahats Falls and the 466 foot Helmcken Falls. More
recently the southern end of the volcanic field has
experienced continuous activity since the end of the last
ice age, in mainly three areas, Spanish Creek, Ray Lake
and Kostal Lake, where were followed by lave fountains
eruptions creating cinder cones and lava flows. Two
cinder cones were created in the Spanish Creek area,known as Flourmill Cone and Pointed Stick Cone, whereas
lava flows from the two cones lie on glaciated bedrock,
their makeup suggesting an early Holocene age (12,000 years ago to present).
Eruptions near Ray Lake created Dragon Cone, finishing with an approximate 9.9
miles lava flow known as the Dragon Tongue and has been dated to be at least
7,600 years old, it damned the southern end of Clearwater Lake. The latest
volcanic eruption created Kostal Cone, a small tree-covered basaltic cone at the
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east end of Kostal Lake as recent as 400-years-ago, making it one of the youngest
volcanic actions in Canada based on tree-growth information.
More recent, but not conclusive, studies by volcanologist have indicated that the
sub-ducted extension of the Nootka Fault may be the primary cause of the alkali
structure of the Wells Gray-Clearwater Volcanic Field, mostly being generated by
asthenospheric24
upwelling by the displacement along the transformer fault.
Canim Falls and lava flows
The Nazko Cone is another small potentially active cinder cone, located 46.6
miles from Quesnel in central British Columbia, about 93 miles southwest of Prince
George. It is considered the easternmost volcano in the Anahim Volcanic Belt.
The small tree covered Nazko Cone rises some 394 feet above the Chilcotin-
Nechako Plateau and sits atop glacial tillIt was formed in three episodes of
activity, the 1st of which took place during the Pleistocene inter-glacial stage about
340,000 years ago. The 2nd stage produced a large hyaloclastic scoria mound that
erupted from beneath the Cordilleran Ice Sheet during the Pleistocene, its 3rd and
last eruption produced two small lava flows that traveled 0.62 miles to the west,
24http://en.wikipedia.org/wiki/Asthenosphere
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along with a blanket of volcanic ash that extends several miles to the north and
east of the cone.
The Nazko Cone resides at the eastern end of the Anahim Volcanic Belt and is the
youngest of the Anahim volcanoes the belt overall has had three magmatic
episodes, 15-13 mya, 9-6 mya and 3-1 mya, and it is apparent that these major
events happened over a hot-spot in the earths crust and as the North AmericanPlate slides west at a rate of 0.8 inches to 1.3 inches a year the earth above it from
time-to-time builds a volcano, this hot-spot is considered to be similar to the one
that has created the Hawaiian Islands.
Beginning on Oct 9th, 2007 and ending Oct 20th, 2007, a series of 1,000 small
earthquake swarms of 4.0 M or less hit the region, with their epicenters near the
Baezaeko River, 19 miles west of the Nazko Cone a swarm of earthquakes that are
unique in the fact that they are the only recorded seismicity in the Canadian
Cordillera away from the British Coast. Their origination is said to be some 15.5
miles below the surface, and their seismic waves suggest that they originated from
a magmatic source, and it is believed to be linked to the hypothesized hot-spot
albeit hypothesized, volcanologists point west to the previously created shield
volcanoes the Rainbow, Ilgachuz, and ItchaTheir suggestions point to the fact that
the earthquakes are an indication of a future earthquake in the Nazko region are a
bit further to the east extending the now 370 mile Anahim Volcanic Belt.
Nazko Cone
In recent history recorded earthquakes at other regions such a Mount Meager (17events), Mount Cayley (four events), Mount Garibaldi (3 events), SilverthroneCaldera (2 events), Castle Rock (2 events), Hoodoo Mountain (8-events), CrowLagoon (four events), The Volcano (five events), and the Mount Edziza VolcanicComplex (8-events) signifies that these regions still contain active magmachambers, and could possibly erupt in the near future how near is anyones guess,as the data available does not allow anyone to draw any concrete conclusions butsufficiently clear enough to indicated the volcanoes are still active and represent a
future risk to the land around them. Especiallyworrisome are the records that indicate HoodooMountain and the Mount Edziza Volcanic Complexand their explosive nature.
The Boundary Ranges, shown as outline in red
on the map are the largest and most northerly
sub-range of the Coast Mountains. One cannot
help but imagine the force behind the formation
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of all the mountains and thousands of Islands between Puget Sound in the south to
the Mt St Elias range in the north, when you look at the topography of the interior.
From a distance, you see ripples of land, but it only becomes apparent when you
walk across the landscape in a valley and see the towering mountains on each side
of you framed by the clear deep blue sky. Awesome and frightening at the same
time.The Boundary Ranges (Alaska Boundary Ranges) begins at the Nass River in
northern British Columbia, and flows through the Coast Mountains for 235 miles
terminating in Nass Bay, a bay that joins Portland Inlet just south of Observatory
Inlet. The English word Nass is a derivative a Tlingit Nation name Naas which
loosely translated means intestines or guts in reference to the rivers large
capacity of fish, namely the candle fish, the NIsgas name for the river is Kalii
Aksim Lisims, the Gitxsan name is Git-Txaemsim meaning People of Txeemsim
(Raven or Trickster). The Boundary Ranges end near the Kelsall River near the
Chilkook Pass, beyond which is the Alsek Ranges of the Saint Elias Mountains, and
north the Yukon Territory flanking the west side of the Yukon River drainage as far
as Champagne Pass, north of which is the Yukon Ranges. To the east are the
Skeena Mountains, and the Stikine Plateau with the immediate adjoining sub-
region the Tahltan Highlands. To the northeast is the Tagish Highland, which is a
sub-region of the Yukon Plateau both highlands are considered in some
descriptions as part of the Coast Mountains. The Alexander Archipelago lies
offshore and is entirely within the State of Alaska.
The Boundary Ranges have within its region several large icefields, such as the
Juneau Icefield, which is the 5th largest icefield in the western hemisphere,
encompassing 1,506 square miles and home to many glaciers like the Mendenhall
and the Taku, and you will find over 40 large valley glaciers and 100 smaller ones.
It reached its maximum glaciation around 1700 and has been in retreat since, as amatter of fact, of its 19 notable glaciers only the Taku Glacier is the only one
advancing whereas the Mendenhall Glacier since 1946 have retreated some 2,300
feet. In addition some 5 miles to the north Herbert Glacier has retreated some
1,775 feet, while Eagle Glacier has retreated like the Mendenhall 2,300 feet, Gilkey
Glacier over 2.17 miles and Llewellyn Glacier 1.75 miles. While on the south side
the Norris Glacier has retreated over 1.07 miles, the East Twin Glacier some 3,600
feet, and the West Twin Glacier over 1,850 feet. A notable peak in the icefield is
Devils Paw, at 8,584 feet and the highest in the Juneau Icefield, locally along with
several smaller peaks the group is called the Mendenhall Towers.
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Juneau Icefield
The Stikine Icecap is the another very large Ice-Field, straddling the border
between SouthEast Alaska and British Columbia, lying smack dab in the middle of
the Boundary Ranges. This extremely large field is the home of the majority of
water for both the Taku and Stikine Rivers and one notable tributary of the Stikine
the Chutine (Clearwater River) the name Chutine is translated as in the Tahltan
language Half-people, Tahltan & Tlingit.
The icecap is the also the home of the LeConte and Sawyer Glaciers on the Alaska
side, and the Great Glacier on the BC side and entering the land on the lower
Stikine the Mud and Flood Glaciers which form the boundaries of the Boundary
Range. It is also known for some of the most dangerous mountain peaks and spires
of granite in the Pacific Northwest, with one such peak being the Devils Thumb.
Devils Thumb
The most famous feature on the Devils Thumb is its unclimbed Northwest Face,
which rises 6,700 ft (2,042 m) from the Witches Cauldron at its base to the summit,
at an average angle of 67 degrees. This is unparalleled steepness for a face this size
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in North America. Unfortunately, the conditions prevalent on this face make it into
perhaps the most dangerous climbing proposition on the continent as well.
There are 1,000 peaks on the Alaska Canadian Border that make up the
boundary peaks, and where accessible each peak during the survey had a bronze
marker placed on the peak, whereas from one peak you could see the previous
peak and the next peak.http://en.wikipedia.org/wiki/List_of_Boundary_Peaks_of_the_Alaska-
British_Columbia_border
One of the most remote regions on this planet, and the least explored is the
mountain range that spans the Pacific Northwest Coast, a mountain range that is
over 995 miles long and 186 miles wide, extending from virtually all the coast of
British Columbia, up through the Alaskan Panhandle and terminating in
southwestern Yukon. It includes volcanic and non-volcanic giants of nature and
huge icefields that are remnants of the Ice Ages.
If youre so inclined and have an un-limited budget, pack up your digital camera
and assorted lens in your 4-wheel drive vehicle and spend the rest of your natural
life exploring the un-explored. Noting the stories from the local indigenous, native
and non-native, and taking snaps, Im sure youd find enough to keep you busy and
productive for at least 50 yearsand what an account that would be.
In the meantime, if your budget prohibits you from doing so, hop on the Internet
and begin your search of the mountains that God build for his entertainment and a
place to spend a weekend from time-to-time visiting the animals and what few
friends of his living in the wilds of North America.
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As John Muir commented in one of his famous writings,
came straight from the hand of God, uncorrupted by civilization and domestication.
This is the Pacific Northwest Coastal Ranges.