Date of Award
Doctor of Philosophy
The Sunwapta Pass area contains environmental records extending back to the late glacial/early Holocene. The records obtained by pollen analysis of one alpine and five subalpine sites were examined to establish if a consistent pattern of environmental change occurred.;Chronologic control was provided by radiocarbon dates and tephrostratigraphy. The oldest date, 9600(TURN)350 (GX-8785), came from near the base of the alpine Wilcox Pass Core. Tephra identification, using titanomagnetite composition determined by electronprobe microanalysis, was hampered by the difficulty of distinguishing analytically between Mazama and Bridge River tephras. Characterization based on differences in glass shard morphology was useful in this case.;The alpine site provided the most complete regional environmental record. The basal zone (WP1), dominated by Artemisia pollen, represented the initial vegetation after deglaciation and is the earliest assemblage yet described from this area of the middle Canadian Rockies. In Zone WP2, a lodgepole pine forest was present. Small amounts of Arceuthobium pollen indicated a probable higher-than-present treeline. Zone WP3 contained substantial amounts of haploxylon (whitebark) pine. Increasing Picea and Abies pollen implied that subalpine forest was now established. This has persisted to the present (Zones WP4 and WP5). The Hypsithermal is not well-marked. Picea/Pinus ratios, by comparison with contemporary pollen samples, showed timberline higher-than-present for most of the Holocene with a substantial retreat beginning c. 1800 yr B.P. marking the onset of Neoglacial conditions.;In contrast to this continuous record, subalpine bogs from the Sunwapta Pass valley floor were greatly influenced by episodic sedimentation from large alluvial fans. However, three records extended to the early Holocene. In general, the records showed a similar pattern to that from Wilcox Pass. Abundant charcoal in all records indicated that fire has been an important environmental influence throughout the Holocene. The incomplete and equivocal environmental history provided by the subalpine bogs in Sunwapta Pass emphasises the role of data from relatively undisturbed alpine sites as a basis for calibration and comparison.
Beaudoin, Alwynne Bowyer, "Holocene Environmental Change In The Sunwapta Pass Area, Jasper National Park" (1984). Digitized Theses. 1361.