Dendrochronologic record for mid-late Holocene glacial activity in Manatee

Valley, Upper Lillooet Provincial Park, southern Coast Mountains, BC

Lindsey E. Koehler and Dan J. SmithUniversity of Victoria Tree Ring LaboratoryDepartment of GeographyUniversity of VictoriaVictoria, BC

Outline

Introduction to the research context Study Area Methods Results Discussion Suggestions for future research

Historical Context for Glaciological Research in the B.C. Coast Mountains

1930’s

Early photographic records of glacier extents 1940’s

Post-WWII aerial photography 1950’s

Early applications of dendroglaciology to Little Ice Age moraines (Mathews, 1951; Brink, 1959) 1960’s

Radiometric dating applied to dendroglaciologic samples Beginning of glacier mass balance monitoring at Place Glacier

1980’s

First detailed study of Holocene glacial activity (Ryder and Thomson, 1986) 1990’s

Continued work in the Coast Mountains 2000’s

Detailed glacial reconstructions for entire Holocene Expanding network of glacial chronologies

Study Area Geologic Setting

Coast Mountain Granitic Complex Quaternary volcanics Pleistocene glaciation

Biogeoclimatic Zones ESSF AT

Manatee Valley

Research Methods I

Dendroglaciology Subfossil wood

Detrital In-situ

First Colonizers Moraine crests Distal slopes

Living Trees Lateral margins Tree islands

Research Methods II

Lichenometry Assumptions

Thalli expand at a constant rate Largest thallus on surface is the first colonizer Have surfaces of known age

Temporal Range Uncertainties

Ecesis interval Disturbance of the geomorphic surface Microclimatic factors Life history of lichen species

Results Overview

Mid-Holocene Glacial Events 4270±60 14C years BP 3500±60 14C years BP 3430±60 14C years BP 2350±70 14C years BP

5-6 Little Ice Age moraine-building episodes Late-14th Century Continuous record from 18th-20th centuries

Site 1: Orca Glacier Snout

Site 2: Manatee Glacier Lateral Margin

Site 3: Orca/Beluga Glacier Forefield

Site 4: Manatee Glacier Forefield

Site 5: Orca/Beluga Lateral Moraine

Little Ice Age Moraines

Lichenometry at Manatee Valley

Lichenometric Dates for Moraine

Stabilization

Moraine Dates vs. Tree-Ring-Widths

Discussion: Holocene Advances in Manatee Valley

Mid-Holocene 4200 14C years BP event ‘Early Tiedemann’ Advance ‘Late Tiedemann’ Advance

Little Ice Age 1390’s Mid-1550’s Late-1600’s-early-1700’s Early-1800’s Late-1800’s Early-1900’s

Suggestions for Future Research

Lichenometry More control surfaces from the southern Coast

Mountains Dendroglaciology

Tree-ring chronology development Continued collection of subfossil wood as ice front

recede Mass Balance reconstructions

Acknowledgements