page_title: Level Mountain
section_title: Background
hierarchical_section_title: Level Mountain / Geology / Background
caption_attribution_description: English: cross section of a general rift
context_page_description: Level Mountain is a massive complex volcano in the Northern Interior of British Columbia, Canada. It is located 50 km north-northwest of Telegraph Creek and 60 km west of Dease Lake on the Nahlin Plateau. With a maximum elevation of 2,166 m, it is the third highest of five large complexes in an extensive north-south trending volcanic zone. Much of the mountain is gently-sloping; when measured from its base, Level Mountain is about 1,100 m tall, slightly taller than its neighbour to the northwest, Heart Peaks. The lower broader half of Level Mountain consists of a shield-like edifice while its upper half has a more steep, jagged profile. Its large summit is dominated by the Level Mountain Range, a small mountain range with prominent peaks cut by deep valleys. These valleys serve as a radial drainage for several small streams that flow from the volcano. Meszah Peak is the only named peak in the Level Mountain Range.
  The mountain began forming about 15 million years ago, with volcanism continuing up until geologically recent times. There have been four stages of activity throughout the long volcanic history of Level Mountain.
context_section_description: Level Mountain is part of the Northern Cordilleran Volcanic Province (NCVP), a broad area of volcanoes extending from northwestern British Columbia northwards through Yukon into easternmost Alaska. Volcanism in this geologic province can be traced as far back as 20 million years ago with the emplacement of alkali basalt in western Yukon. Several types of volcanic eruptions have since created different landforms across the NCVP, including shield volcanoes, lava domes, stratovolcanoes and cinder cones. Other volcanic formations, notably subglacial volcanoes, take their shape from the environment they formed, regardless of the type of magma they produced. The NCVP contains over 100 volcanoes and is the most volcanically active area in Canada, with eruptions expected to occur roughly every 100 years.
  The NCVP is underlain by four large crustal fragments, namely Stikinia, Yukon–Tanana, Cassiar and Cache Creek. Stikinia comprises volcanic, plutonic and sedimentary rocks that were created in an island arc environment during the Paleozoic and Mesozoic eras. Mélange and abyssal peridotites, formed largely in an ancient oceanic basin, are the primary rocks of the Cache Creek Terrane. These are also Paleozoic to Mesozoic in age and are intersected by younger granitic intrusions. Yukon–Tanana and Cassiar consist of sedimentary and metamorphic rocks derived from the North American continent. The rocks of these two terranes are displaced and autochthonous in nature.
  A number of mechanisms have been proposed to interpret the origin of volcanism in the NCVP. This includes slab windows, mantle plumes, crustal extension and deglaciation. The most common and best mechanism used to explain NCVP volcanic activity is incipient rifting of the North American Plate caused by crustal extension. As the continental crust stretches, the near surface rocks fracture along steeply dipping cracks parallel to the rift known as faults. Mafic magma rises along these fractures to create fluid lava flows, although more viscous felsic magma also makes its way to the surface and can produce explosive eruptions. Two major structural features, the Tintina and Denali-Coast fault systems, run parallel with the NCVP. Both structures have had strike-slip motions since the Cretaceous period, which has resulted in several hundred kilometres of crustal displacement.
caption: Cross section of a general rift
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