Glaciation is schematically considered as a perturbation of "normal" fluvial conditions. Drift is unstable in a proglacial or postglacial fluvial environment, resulting in heightened sediment movement that continues as long as drift material remains easily accessible for fluvial erosion and transportation. Sediment yield bears no relation to concurrent primary production of weathered debris. Examples of such "paraglacial" denudation and sedimentation are reported from two contrasting areas. Postglacial valley alluvial deposits are widespread in central Baffin Island where rapid sedimentation continues today; estimated denudation rates are an order of magnitude higher than in comparable unperturbed areas. In south-central British Columbia, rapid sedimentation during the paraglacial period contrasts sharply with present-day conditions. DEFINITION The term "paraglacial" is introduced to define nonglacial processes that are directly conditioned by glaciation. It refers both to proglacial processes, and to those occurring around and within the margins of a former glacier that are the direct result of the earlier presence of the ice. It is specifically contrasted with the term "periglacial," which does not imply the necessity of glacial events occurring (see the discussion by Tricart in Fairbridge, 1968, p. 829). The term "paraglacial" has previously been introduced by Ryder (1971a, 1971b), but was not critically defined there. In this paper the term is used, additionally, as an adjective of time; such as, "paraglacial period," to define the time during which paraglacial processes occur.

Moraine stratigraphy and morphology, radiocarbon dates from Klinaklini, Franklin, Tiedemann, Gilbert, and Bridge glaciers, and related information from elsewhere in the Coast Mountains are used to construct a chronology for glacier fluctuations. The Garibaldi phase of glacier expansion, 6000–5000 14C years BP, at the end of the early Holocene xerothermic interval, is indicated by overridden tree stumps. The mid-Neoglacial Tiedemann advance, 3300–1900 14C years BP, is represented by moraines, till, and meltwater sediments at three glaciers, but only Tiedemann Glacier attained its greatest Holocene extent at this time. Late Neoglacial expansion commenced before 900 14C years BP and continued without notable interruption until glaciers achieved their maximum post-Pleistocene expansion during the eighteenth and nineteenth centuries. Evidence for the Garibaldi and Tiedemann events is scarce within the Coast Mountains because of the more extensive late Neoglacial advance. However, correlative advances have been recognized in adjacent mountains within British Columbia, Washington, and Alaska.

Alluvial fan construction within the interior valleys of southern British Columbia was dependent upon temporary conditions resulting from deglaciation. Glacial drift was reworked by streams and mudflows to form fans whose composition is dependent upon the nature of the drift supply and the hydrologic character of the parent basin.Stratigraphic evidence suggests that fan building commenced soon after valley floors became ice-free, continued during post-glacial aggradation by major rivers and for some time after wards. Most recently, fans were built upon degradational river terraces. Mazama volcanic ash within fans indicates that their construction continued until after 6600 years B.P. After deposition ceased many fans were dissected either as local base-levels were lowered under the control of degrading major rivers or by fan-head trenching initiated as the debris supply declined. Where fan building persisted during degradation, multi-level fans were constructed.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. INSTAAR, University of Colorado andThe Regents of the University of Colorado, a body corporate, contracting on behalf of the University of Colorado at Boulder for the benefit of INSTAAR are collaborating with JSTOR to digitize, preserve and extend access to Arctic and Alpine Research. ABSTRACTObservations are reported of the morphology and processes on debris slopes in Home Bay and northern Cumberland Peninsula regions of east Baffin Island. The area is blockfaulted, heavily glaciated Precambrian gneiss and migmatite. The climate is marine Arctic.Accumulations range from debris mantles on bedding plane slopes, through conical and sheet talus, to slopes on which snow avalanche or water flow has modified features. The classification of Rapp is extended to encompass these forms. Other features include protalus debris accumulations, and "talus rock glaciers." Most slopes are planar-concave, with mean unconstrained angles in the range 30 to 38? (mode at 32 to 33?): few slopes appear to be near failure. Size gradation of material occurs downslope: size distribution of material also changes, with Rosin-type distributions near the top and log-normal distributions farther down. Below the surface is a matrix of fines. Size distributions of rock lichens suggest that activity on these debris slopes has been greater in the recent past than at present.Observations of material delivery and slope stability at Ekalugad Fiord reveal that rockfall is the primary rock delivery mechanism, though dirty snow avalanches are also significant. Rock release appears to be associated principally with the seasonal "freeze-burstthaw" cycle in water-filled joints and fractures. Material is transferred and rearranged on the slope by impact scattering, creep and settlement, and minor slumps and slides.A concluding discussion compares observations from east Baffin Island with the assumptions and results of models for debris glope development. process on glacially bared surfaces in the eastern mountains. In this paper, "debris slope" means any slope upon which rock clasts have accumulated by mass-wasting processes.The paper describes debris slopes in several areas of east-central Baffin Island (see Figure 1) and provides a summary of their morphometric and sedimentological variability. Attention is then given to a more detailed study of debris accumulation near the head of Ekalugad Fiord (68052'N, 69030'W). Finally, a discussion is presented of the significance of the field results in the light of recently proposed modes of debris slope formation. M. CHURCH ETAL. / 371This content downloaded from 195.78.The character and extent of debris accumulation depend upon the efficacy of a set of rock release mechanisms, and...

The maximum Holocene extent of glaciers in the study area is marked by late Neoglacial (Little Ice Age) terminal moraines. Moraine stratigraphy and 14C dates from a small number of sites suggest that glacier advance, almost as extensive as that of the late Neoglacial, occurred about 2500 14C years BP, and that late Neoglacial advance began well before 770 14C years BP (or the thirteenth century A.D.); glacier termini then stood close to the position of the climax moraines for several centuries. Dates of stabilization of end moraines at 16 glaciers were determined by dendrochronology, with tree-ring counts corrected for sampling errors and ecesis. Most terminal moraines date from 1860 to 1900. Many recessional moraines were formed between 1900 and 1940, coincident with a regionally documented phase of cooler and wetter climate. The proposed chronology is similar to results from elsewhere in the Canadian Cordillera.