Background As a part of the Mount Edziza volcanic complex, Eve Cone lies within a broad area of volcanoes called the
Northern Cordilleran Volcanic Province, which extends from northwestern British Columbia northwards through
Yukon into easternmost
Alaska. The dominant rocks comprising these volcanoes are
alkali basalts and
hawaiites, but
nephelinite,
basanite and
peralkaline phonolite,
trachyte and
comendite are locally abundant. These rocks were deposited by volcanic eruptions from 20 million years ago to as recently as a few hundred years ago. Volcanism in the Northern Cordilleran Volcanic Province is thought to be due to
rifting of the
North American Cordillera, driven by changes in relative
plate motion between the
North American and
Pacific plates.
Structure cones Eve Cone is a
monogenetic cinder cone, which are simple volcanic edifices that erupted over a single eruptive phase. Such features are typically considered to erupt only once and to be short-lived; they can remain active from days to years but are fed by a relatively small amount of
magma. Eve Cone consists of hawaiite of the
Big Raven Formation and is one of the two youngest eruptive centres in the Desolation Lava Field, the other being Williams Cone about to the southeast. Both cones are of Holocene age but Eve Cone was most likely formed by a towering, vertical
lava fountain due to its symmetrical structure. Loosely
aggregated volcanic
ejecta such as
bombs,
cinders and
ash cover the outer surface of Eve Cone. Relatively fine, dark grey bombs and cinders cover the northern half of Eve Cone whereas coarser, clinkery
spatter is exposed in the more deeply eroded southern half of the cone. Erosion on the southern flank is more extreme due to accelerated
frost wedging and
solifluction which may be caused by greater and more frequent temperature changes. In contrast to Williams Cone, whose surroundings are at least still partially covered with fine ash from its eruption, ash from the Eve Cone eruption has completely eroded away from the surrounding landscape; this suggests Eve Cone is older than Williams Cone.
Lava field Nearly all of the lava erupted from Eve Cone appears to have originated from vents around the base of the volcanic edifice. This is particularly evident on the southeastern side of the cone, where there is a nearly high buttress of overlapping tiers of lava lobes. Streams of lava from these vents merged to form a roughly long
lava field which extends down the northern side of the Big Raven Plateau. It has a maximum width of about , overlies older lava flows from the Triplex Cones and abuts with older lava flows in the northeast from Sidas Cone. The lava flows comprising this field branch out into much narrower
lava channels to the north and northwest, the largest of which is approximately long; it reaches the northeastern end of Buckley Lake. A shorter channel just south of Buckley Lake forms a lava bed with the Triplex Cones lava flows. ==Accessibility==