Dori J. Kovanen

Decadal variability in climate and glacier fluctuations on Mt Baker, Washington, USA

Abstract Climate variability in the Pacific basin has been attributed to large‐scale oceanic‐atmospheric modulations (e.g. the El Niño‐Southern Oscillation (ENSO)) that dominate the weather of adjacent land areas. The Pacific Decadal Oscillation (PDO) and north Pacific index are thought to be indicators of modulations and events in the northeast Pacific. In this study we find that variations in the PDO are reflected in the terminus position of glaciers on Mt Baker, in the northern Cascade Range, Washington. The initiation of retreat and advance phases of six glaciers persisted for 20–30 years, which relate to PDO regime shifts. The result of this study agrees with previous studies that link glacier mass balance changes to local precipitation anomalies and processes in the Pacific. However, the use of mass balance changes and glacier terminus variation for identification of regime shifts in climate indices is complicated by the lack of standardized measuring techniques, differing response times of individual glaciers to changes in climate, geographic and morphometric factors, and the use of assorted climate indices with different domains and time‐scales in the Pacific for comparison.

Relict shorelines and ice flow patterns of the Northern Puget lowland from lidar data and digital terrain modelling

Abstract Airborne lidar data from the northern Puget Lowland provide information on the spatial variability and amplitude of raised postglacial shorelines, marine deltaic features and glaciomarine sediments deposited between approximately c. 12 920 and 11 050 14C yr BP (15 960‐12 364 cal yr BP). Relict shorelines preserved in embayments on Whidbey and Camano islands (between 47°54′N and 48°24′N) are found up to an altitude of c. 90 m and record glacio‐isostatic movements attributed to postglacial rebound. The tilt of the regional minimum highstand sea level surface to the north of 0.80 m km−1, with local variability from 0.25 m km−1 to 0.77 m km−1, is consistent with previous studies (Thorson 1989; Dethier et al. 1995). The local variability is related to the uncertainty in the depth of the water column above these features at the time of deposition and probable tectonic deformation. The information generated by these lidar data is most valuable in posing new research questions, generating alternative research hypotheses to those already formulated in the northern Puget Lowland.

The Fraser Lowland: A Polygenetic Paraglacial Landsystem

The Fraser Lowland is a landsystem that has been modified in its entirety by non-glacial processes conditioned by glaciation. The Late Pleistocene and Holocene paraglacial processes of landform modification include slope erosion, glacimarine, marine, glacifluvial, fluvial, glacilacustrine, lacustrine, organic, mass movement, and aeolian. This complex paraglacial landsystem has transitioned from proglacial through marine to its present dominantly fluvial character. Landforms representative of each sediment redistribution process are described, and a conceptual model is developed with relative sea level and sediment source changes as the primary drivers. Accelerated anthropogenic modification during the past two centuries (the Anthropocene) has complicated the paraglacial story and is shown to impact the incidence of natural hazards, especially in the context of hydroclimate change.

Geomorphological Landscapes and Geoconservation

The intrinsic value of geomorphological landscapes is considered in the context of aesthetics, culture, socio-economics, and ecology as well as geoscience. Geoconservation has become more urgent as geodiversity, biodiversity, and cultural diversity have declined. The evolution of western Canada’s parks and natural heritage sites is a story of alternating successes and failures to achieve geoconservation in the face of hostile economic and political visions. The recent emergence of tribal parks and geoparks is yet further evidence of the lively debate that continues. The common element in these debates is the increasing awareness of the intrinsic value of the geoheritage of which geomorphological landscapes are a central part.

Long-Term Geomorphic History of Western Canada

Geological timescales and large spatial landscape units of Canada are introduced. The tectonic framework of western Canada is sketched with specific attention to the north–northwest to south–southeast orientation of western Canadian mountain landscapes and the east–west grain of much of the western arctic islands. Structural, physiographic, and geomorphological landscape units of western Canada are defined, and the distinctive landscape impact of volcanic and carbonate lithologies is discussed. A descriptive account of each of the geomorphological landscape units of western Canada provides a general background for the individual case studies reported in Chaps. 4– 28.

Pleistocene Landscapes of Western Canada

A brief summary of western Canada’s late Quaternary history emphasizes the period from the Last Glacial Maximum to the start of the Holocene Epoch. Almost all of Canada was covered by ice at the Last Glacial Maximum. Canada’s contemporary landscapes are deeply imprinted with the Quaternary legacy. The general concept of a glacial landsystem is the prism through which western Canadian landscapes are seen. The concept recognizes three glacial landsystems: the Shield terrain, the sedimentary lowlands and the glacial valley terrain. Within the glacial landsystems, individual landscapes and landform assemblages subject to supraglacial, englacial and subglacial processes are described. Glacivolcanic landscapes are exceptionally important in western Canada and are discussed separately. The 5 % of western Canada that was not glaciated in the Quaternary has distinctive landscapes. The increasing importance of fluvial and proglacial lake processes towards the end of the Pleistocene requires separate treatment.

Holocene and Anthropocene Landscapes of Western Canada

A brief review of Holocene history of western Canada is followed by a description of the deglaciation of the western Canadian landscape within the framework of the paraglacial model. The landforms and landform assemblages of the Holocene are more localized than those of the previous chapters and include landscapes impacted by volcanism, periglaciation, aeolian, mass movement, fluvial and coastal processes. The proposed Anthropocene epoch is discussed under landscapes modified by human activity, climate change and associated hazards and risks.