The Significance of Volcanism in the Prehistory of Subarctic Northwest North America

Workman, William B.

doi:10.1016/b978-0-12-639120-6.50016-9

Cited by 26 publications

(36 citation statements)

References 21 publications

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“…Churchill eruption approximately 300-350 yr ago and the MTR 146 tephra may record a further midHolocene eruption, suggesting at least four Holocene eruptions have occurred. There is evidence that the WRA eruptions may have had significant impacts on human occupation of the region (Workman, 1979;Moodie et al, 1992). It is possible that these previously unidentified eruptions may also have had significant impacts on the physical and human environment of the region.…”

Section: Implications For Volcano Hazard Assessmentmentioning

confidence: 99%

Using cryptotephras to extend regional tephrochronologies: An example from southeast Alaska and implications for hazard assessment

2008

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Cryptotephrochronology, the use of hidden, diminutive volcanic ash layers to date sediments, has rarely been applied outside western Europe but has the potential to improve the tephrochronology of other regions of the world. Here we present the first comprehensive cryptotephra study in Alaska. Cores were extracted from five peatland sites, with cryptotephras located by ashing and microscopy and their glass geochemistry examined using electron probe microanalysis. Glass geochemical data from nine tephras were compared between sites and with data from previous Alaskan tephra studies. One tephra present in all the cores is believed to represent a previously unidentified eruption of Mt. Churchill and is named here as the ‘Lena tephra’. A mid-Holocene tephra in one site is very similar to Aniakchak tephra and most likely represents a previously unidentified Aniakchak eruption, ca. 5300–5030 cal yr BP. Other tephras are from the late Holocene White River eruption, a mid-Holocene Mt. Churchill eruption, and possibly eruptions of Redoubt and Augustine volcanoes. These results show the potential of cryptotephras to expand the geographic limits of tephrochronology and demonstrate that Mt. Churchill has been more active in the Holocene than previously appreciated. This finding may necessitate reassessment of volcanic hazards in the region.

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Section: Implications For Volcano Hazard Assessmentmentioning

confidence: 99%

Using cryptotephras to extend regional tephrochronologies: An example from southeast Alaska and implications for hazard assessment

2008

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“…Detailed radiocarbon dating suggests an age of 1147 calendar years before 1950 (a date of A.D. 803) for this lobe (Clague et al, 1995). Workman (1979) and Moodie et al (1992) suggest that the ashfall from the eastern lobe triggered human population displacements that led to Athapaskan migrations eastward into the Mackenzie Valley and southward into northern British Columbia.…”

Section: The White River Ashmentioning

confidence: 99%

“…Denton and Karlén (1977) used both lobes of the White River ash to examine the timing of glacier fluctuations and moraine development in southwestern Yukon Territory, although their interpretations resulted in some controversy (Rampton, 1978). The ash has also been used as a marker in several palaeoecological studies (e.g., MacDonald, 1983;Slater, 1985) and in anthropological and archaeological studies (Workman, 1979).…”

Section: The White River Ash As a Chronostratigraphic Markermentioning

confidence: 99%

Extending the Late Holocene White River Ash Distribution, Northwestern Canada

Robinson¹

2001

ARCTIC

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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.

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“…Volcanism and tectonic activity are endemic in the Aleutian arc, although shifting wind patterns and the segmentation of rupture zones mean that individual events are unlikely to affect several areas at the same time (Workman, 1979). The wide distribution and high density of Aleut settlements at contact suggest that volcanic eruptions and sporadic earthquakes may have had minimal cultural-historical impact on a region-wide basis (McCartney, 1975;Workman, 1979), but there is increasing evidence that high magnitude seismic events and volcanism in the eastern Aleutian arc were locally devastating to intertidal resources and prehistoric inhabitants on several occasions during the Holocene (Black, 1976;Smith, 1977, 1987;Waythomas et al, 1996;Mann et al, 1998).…”

Section: Discussionmentioning

confidence: 99%