Event Title

Mid-late Holocene glacial history of Manatee Glacier, Upper Lillooet Provincial Park, southern Coast Mountains, British Columbia

Description

Dendroglaciologic evidence exposed by the recent retreat of Manatee Glacier suggests increasing complexity in the glacial record for southern British Columbia Coast Mountain locations, particularly for mid-Holocene aged events. Since ice fronts extended below treeline in this region several times in the Holocene, valley-bottom forests were repeatedly bulldozed into subglacial till deposits. This study uses dendrochronologic and radiometric techniques to develop dates for mid-late Holocene glacial advances from the detrital and in-situ wood samples collected within the forefield of several coalescing glaciers. Evidence from Manatee Glacier, thus far, corroborates with dates obtained from other southern and northern Coast Mountain sites. Long-lived boles recovered from Manatee’s valley, however, suggest that at least two distinct periods of mid-Holocene ice extension occurred at 3430 14C +/- 60 yr BP and 2350 14C +/- 70 yr BP. Nested, lateral moraine sequences flanking the valley walls delineate Little Ice Age glacier positions. Geobotanical dating indicates that moraines stabilized at least 5 times in the late- Holocene, with the maximum glacier extent occurring in 1738 AD. The mid-late Holocene glacial history developed at Manatee Glacier adds to the discussion of pervasive, millennial-scale glacio-climate cycles.

Document Type

Event

Start Date

8-3-2008 8:00 AM

Subject - LCSH

Glaciers--Coast Mountains (B.C. and Alaska); Dendrochronology--Coast Mountains (B.C. and Alaska); Geology, Stratigraphic--Holocene;

End Date

8-3-2008 5:00 PM

Session

Glacial Studies: Coast Mountains / Cascades

Genre/Form

Abstracts

Type

event

Geographic Coverage

Coast Mountains (B.C. and Alaska)

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Language

English

Format

application/pdf

Keywords

dendroglaciology, Coast Mountains, Holocene, glaciers, tree-rings, little ice age

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Mar 8th, 8:00 AM Mar 8th, 5:00 PM

Mid-late Holocene glacial history of Manatee Glacier, Upper Lillooet Provincial Park, southern Coast Mountains, British Columbia

Dendroglaciologic evidence exposed by the recent retreat of Manatee Glacier suggests increasing complexity in the glacial record for southern British Columbia Coast Mountain locations, particularly for mid-Holocene aged events. Since ice fronts extended below treeline in this region several times in the Holocene, valley-bottom forests were repeatedly bulldozed into subglacial till deposits. This study uses dendrochronologic and radiometric techniques to develop dates for mid-late Holocene glacial advances from the detrital and in-situ wood samples collected within the forefield of several coalescing glaciers. Evidence from Manatee Glacier, thus far, corroborates with dates obtained from other southern and northern Coast Mountain sites. Long-lived boles recovered from Manatee’s valley, however, suggest that at least two distinct periods of mid-Holocene ice extension occurred at 3430 14C +/- 60 yr BP and 2350 14C +/- 70 yr BP. Nested, lateral moraine sequences flanking the valley walls delineate Little Ice Age glacier positions. Geobotanical dating indicates that moraines stabilized at least 5 times in the late- Holocene, with the maximum glacier extent occurring in 1738 AD. The mid-late Holocene glacial history developed at Manatee Glacier adds to the discussion of pervasive, millennial-scale glacio-climate cycles.