Extending the Late Holocene White River Ash Distribution, Northwestern Canada

Abstract

ABSTRACT. Peatlands are a particularly good medium for trapping and preserving tephra, as their surfaces are wet and well vegetated. The extent of tephra-depositing events can often be greatly expanded through the observation of ash in peatlands. This paper uses the presence of the White River tephra layer (1200 B.P.) in peatlands to extend the known distribution of this late Holocene tephra into the Mackenzie Valley, northwestern Canada. The ash has been noted almost to the western shore of Great Slave Lake, over 1300 km from the source in southeastern Alaska. This new distribution covers approximately 540 000 km 2 with a tephra volume of 27 km 3 . The short time span and constrained timing of volcanic ash deposition, combined with unique physical and chemical parameters, make tephra layers ideal for use as chronostratigraphic markers.

Secondary mineral formation in the White River tephra in grassland and forest soils in central Yukon Territory

“…1). The White River tephra is the most likely origin of the tephra considered in this study based on the distribution pattern documented by Lerbekmo and Campbell (1969), Richter et al (1995), Clague et al (1995) and Robinson (2001). The White River tephra is distributed over an area of ~ 540 000 km 2 with a plume volume of 27 km 3 (Robinson 2001).…”

“…The White River tephra is the most likely origin of the tephra considered in this study based on the distribution pattern documented by Lerbekmo and Campbell (1969), Richter et al (1995), Clague et al (1995) and Robinson (2001). The White River tephra is distributed over an area of ~ 540 000 km 2 with a plume volume of 27 km 3 (Robinson 2001). There are two separate lobes of volcanic ejecta (Lerbekmo and Campbell 1969) consisting of a northern deposit (1900-1500 14 C yr BP) along the Alaska/Yukon border and the eastern deposit (1147 14 C yr BP) (Clague et al 1995).…”

Carbon accumulation in peatlands, southwestern Northwest Territories, Canada

“…Five short cores (selected from a series of over 100 cores; Robinson and Moore 1999) were collected from peat landforms representative of the peatland as a whole, including rich fen, poor fen, bog, peat plateau, and collapse fen. Each of the short cores were collected using the methods described in Robinson and Moore (1999) to the level of the White River ash, a 1200-yr-old tephra used as a chronostratigraphic marker (Robinson 2001 content, and loss-on-ignition were measured on 2-cm slices of each core, and peat material was described based upon primary botanical composition.…”

Soil formation on supraglacial tephra deposits, Klutlan Glacier, Yukon Territory

“…From its source in eastern Alaska, the eastern lobe of the White River tephra (1147 cal years BP; Clague et al 1995) extends across southern Yukon and into the Northwest Territories (Robinson 2001). The older northern lobe (ca.…”