Pliocene and pleistocene volcanic interaction with cordilleran ice sheets, damming of the Yukon River and vertebrate palaeontology, Fort Selkirk volcanic group, west-central Yukon, Canada
Date
2012
Authors
Jackson, L.E.
Nelson, F.E.
Huscroft, C.A.
Villeneuve, M.
Barendregt, René W.
Storer, J.E.
Ward, B.C.
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Neogene volcanism in the Fort Selkirk area began with eruptions in the Wolverine Creek basin ca. 4.3 Ma
and persisted to ca. 3.0 Ma filling the ancestral Yukon River valley with at least 40 m of lava flows.
Activity at the Ne Ch’e Ddhäwa eruptive center overlapped with the last stages of the Wolverine Creek
eruptive centers. Hyaloclastic tuff was erupted between ca. 3.21 and 3.05 Ma. This eruption caused or
was coincident with damming of Yukon River. The first demonstrable incursion of a Cordilleran ice sheet
into the Fort Selkirk area was coincident with a second eruption of the Ne Ch’e Ddhäwa eruptive center
ca. 2.1 Ma. The Ne Ch’e Ddhäwa subglacial mound was erupted beneath at least 300 m of glacial ice (Ne
Ch’e Ddhäwa Glaciation). The Eruption of the Fort Selkirk center occurred between the last eruption of
Ne Ch’e Ddhäwa and Fort Selkirk Glaciation (ca. 2.1e1.5 Ma). Till and outwash from Fort Selkirk Glaciation
are conformably overlain by nonglacial sediments that contain the Fort Selkirk tephra (fission track
dated at ca. 1.5 Ma). These nonglacial sediments also preserve a short magnetic reversal (reversed to
normal) identified as the Gilsá polarity excursion. Temporal control and sedimentology constrain Fort
Selkirk Glaciation and the Fort Selkirk Local Fauna to marine isotope stage 54. Rapid and extensive
eruption of the Pelly eruptive center filled the Yukon River valley with 70 m of lava which buried these
glacial and nonglacial sediments and dammed Yukon River. Local striations and erratic pebbles occur on
the last of these lava flows. They document a subsequent incursion of glacial ice during the last 500 ka of
the Matuyama Chron (Forks Glaciation). The last major eruption of mafic lava occurred in the middle
Pleistocene west of (early Holocene) Volcano Mountain in basin of Black Creek: lava flowed down the
valley presently occupied by Black Creek and dammed Yukon River in the area of the Black Creek
confluence. This eruption predated the middle Pleistocene Reid Glaciation. Minor volcanism has
continued in this area since the middle Pleistocene at Volcano Mountain.
Description
Accepted author manuscript
Keywords
Volcanism , Fort Selkirk , Yukon River , Pliocene , Pleistocene , Cordilleran ice sheets , Lava flows
Citation
Jackson, L.E., Nelson, F.E., Huscroft, C.A., Villeneuve, M., Barendregt, R.W., Storer, J.E. & Ward, B.C. (2012). Pliocene and pleistocene volcanic interaction with cordilleran ice sheets, damming of the Yukon River and vertebrate palaeontology, Fort Selkirk volanic group, west-central Yukon, Canada. Quaternary International, 260, 3-20. doi:10.1016/j.quaint.2011.08.033