HOLOCENE GLACIER HISTORY OF THE NORTHERN COAST MOUNTAINS, BRITISH COLUMBIA, CANADA

Accelerated glacial recession and downwasting since the end of the Little Ice Age continues to expose subfossil wood remains and laterally contiguous wood mat layers overwhelmed during periods of Holocene glacier expansion. Continuing investigations, including recent dendroglaciological field studies conducted in the Bowser River Watershed, have improved our understanding of the temporal and spatial resolution of mid- to late Holocene advances. A synthesis of dendroglaciology and radiocarbon analyses conducted in the northern Coast Mountains has revealed six intervals of glacial expansion taking place over the Holocene: (1) Late Garibaldi Phase at 5.7-5.1 ka cal. yr BP; (2) the 4200 yr event at 4.3-4.0 ka cal. yr BP; (3) Early Tiedemann at 3.7-3.4 ka cal. yr BP; (4) Late Tiedemann at 2.8-2.2 ka cal. yr BP; (5) two events associated with the First Millennium during 1.7-1.2 ka cal. yr BP; and, (6) at least three advances corresponding to the Little Ice Age during 0.9-0.1 ka cal. yr BP. These results provide new evidence for mid-Holocene glacier activity for northern British Columbia, as well as supporting previous research that Holocene glacier advances were episodic and regionally synchronous.