No description available.

No description available.

Five periods of ice advance in the North Klondike-upper Blackstone basins of the Ogilvie Mountains are recognized by the downvalley sequence of progressively older moraines. The youngest occurred during the last millennium and is represented by glacierets and fresh moraines. The other advances are of the Pleistocene Epoch; from youngest to oldest they are: Age I (valley glacier stage), Age II (transection glacier), Age IIA (transection glacier with piedmont) and Age III (mountain ice cap). Evidence for Age III is limited to the north slope of the ranges. Age IIA was recognized only on the north slope and may represent a slightly older pulse of the Age II. This chronosequence is tentatively correlated with those elsewhere in the northern Cordillera. Within the region an array of surficial elements indicates that a continuous and discontinuous mosaic of processes have operated interdependently during the Quaternary. A product of these processes is mapped under one of eight facies - attention being directed to the varieties of features associated with the glacial and periglacial cycles. Of the latter, active, inactive and degradational forms exist. Strong correlations between the distribution of some types of surficial features and the underlying bedrock geology are recognized. No changes in morphology, permafrost distribution, pebble weathering, pedogenesis and floral succession could be related to the ages of the Pleistocene moraines. The influence of permafrost on all ages of moraines, the variability in their environment of deposition, and an edaphic and climatic discontinuity produce greater differences than does the age factor. In the northern half of the study area, permafrost and associated phenomena were observed to greatly retard chemical alteration; on the other hand, they permit the development of only a vegetational and pedological "polyclimax", rather than a single mesic climax, in a time span of less than 11,000-15,000 years. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Sediments from the northern end of Juan de Fuca Ridge are Late Quaternary in age and contain widely correlatable cycles of turbidity current and hemipelagic sedimentation. Sediments from the Ridge were examined for their mineralogy, structure, components of the sand fraction, rates of sedimentation and grain size distribution to establish processes of sedimentation, stratigraphy, correlation and local hydrothermal relationships. Ten gravity and Phleger core sites along two profiles of the Ridge were examined in detail, one section was perpendicular to West Valley, the main spreading centre, and one section was within and parallel to West Valley. Sediment from Cascadia Basin was compared to the results of the Ridge study. Changes in sedimentation defined by core X-radiograph structure, components of the sand fraction and grain size distribution, indicated cycles of relatively coarse sediment overlain by finer bioturbated sediment with a repeated stratigraphic relationship in all but one Juan de Fuca Ridge core. Changes in sediment composition are attributed to brief, episodic, continent derived turbidity current deposition followed by lengthy periods of hemipelagic sedimentation for each cycle. Differences in composition exist between sediment of ridges and valleys, with a greater winnowed foraminiferal-hemipelagic and a lesser turbidity current influence in the former area. Radiocarbon dated foraminiferal-rich intervals from ridge sediments were exclusively Late Pleistocene with Middle Ridge sediment having an inferred 9000-9500 B.P. Late Pleistocene-Holocene boundary. Similar sedimentation cycles between Middle Ridge and valley localities enabled correlation of ridge and valley stratigraphy and the Late Pleistocene-Holocene boundary. A stratigraphic relationship based on the episodic deposition of continent derived turbidites exists between the northern end of Juan de Fuca Ridge and the continental Pacific Northwest. Pulses of turbidity current sedimentation coincide with initial interglacial warming trends during the Late Pleistocene. Holocene sedimentation for Juan de Fuca Ridge is of hemipelagic origin with rare local turbidity current deposition. Hydrothermal minerals were not detected. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No description available.

No description available.

published_or_final_version / abstract / Earth Sciences / Master / Master of Philosophy

published_or_final_version / Applied Geosciences / Master / Master of Science

published_or_final_version / Applied Geosciences / Master / Master of Science

A complex late Quaternary alluvial sequence is exposed in Whitewater Draw arroyo, Cochise County, Arizona. The alluvial history is characterized by: (1) sand and gravel deposition in a through-flowing stream between 15,000-8,000 yr B.P. and 6,700-5,500 yr B.P. and (2) cycles of erosion and clay-and-silt deposition in large wet meadows or cienegas between 8,000-6,700 yr B.P. and 5,500 yr B.P.-historic period. Modern arroyo entrenchment began after A.D. 1885 and was largely completed before 1910. The alluvial sequence of the Douglas basin differs in timing, character, and number of degradational and aggradational events, with the exception of the arroyo cutting and filling episode between 6,700 and 5,500 yr B.P., when compared to the alluvial sequence of the adjacent San Pedro Valley and the generalized alluvial chronology for the West. Megafaunal extinction occurred in the Douglas basin no later than 10,400 yr B.P. as evidenced by the occurrence of articulated camel and mammoth remains in sediments of this age. Mammoth, horse, camel, and dire wolf remains from deposits dating 10,400 to 7,000 yr B.P. are in secondary contexts, redeposited from older units. Archaeological remains of the Cochise Culture occur in nearly all the Upper Quaternary deposits of Whitewater Draw. Artifacts of the Sulphur Spring phase, the earliest phase of the Cochise Culture, are found at four sites in Whitewater Draw and at the Lehner site, where they overlie the Clovis horizon. Ground-stone artifacts are the most common element of the Sulphur Spring artifact assemblage and indicate that the Douglas basin was the site of specialized plant gathering and processing. Flaked-stone artifacts are poorly represented and are primarily unifacially retouched flake tools but also include bifacially flaked projectile points. The Sulphur Spring phase dates from 8,000 to 10,000 yr B.P. and probably to 10,500 yr B.P. Evidence suggests that the Sulphur Spring people may have temporally overlapped with relict populations of Pleistocene megafauna during the onset of the Holocene. The Sulphur Spring and western San Dieguito I complex are considered to be temporal equivalents. The Cazador phase is no longer considered a valid phase of the Cochise Culture. Cazador artifacts at the type site occur in deposits equivalent in age to sediments containing Sulphur Spring remains.