Rock glaciers are tongue-shaped or lobate masses of rock debris which occur below cliffs and talus in many alpine regions. They are best developed in continental alpine climates where it is cold enough to preserve a core or matrix of ice within the rock mass but insufficiently snowy to produce true glaciers. Previous reports have identified and briefly described several rock glaciers in the Olympic Mountains, Washington {Long 1975a, pp. 39-41; Nebert 1984), but no detailed integrative study has been made regarding the geomorphic character, age,and distribution of these features.

This thesis investigated marine isotope stage {MIS) 3-2 glacial sequences in the South Fork Hoh River Valley, Washington and the Lake Hawea Valley, New Zealand. Research objectives were to reconstruct the style and timing of ice advance in both areas and to assess the viability of luminescence dating of glacial sediments in various depositional facies and distances from the ice front. This thesis focused on the sedimentology and stratigraphy of surficial and older glacial sequences in the South Fork Hoh and Lake Hawea areas and used OSL and radiocarbon dating techniques to establish age control for the deposits. Specifically, this research identified, described, and dated the stratigraphy of glacial sequences in order to reconstruct ice dynamics. This work also presents updated geomorphic maps for both study areas as an additional way to show ice advance and retreat events recorded in deposited sediment and geomorphic surfaces. The glacial sequence expressed in the Lake Hawea moraine exposure shows four distinct depositional events that represent retreat from an ice position down -valley, re-advance to the Hawea moraine position, and subsequent retreat and deglaciation broadly spanning -32-18 ka. These results document the terminal glacial advance and subsequent retreat in the Lake Hawea Valley and contribute to the wider swath of research studying the last phase of glacial retreat and its connections to climate on the South Island of New Zealand. The Hawea chronology corresponds to other glacial records and paleoclimate reconstructions from the South Island that collectively suggest the commencement of deglaciation at -13 ka. Three late Pleistocene ice positions are preserved in the South Fork Hoh River Valley, here referred to as South Fork 1-3 (SF 1-3). One of these positions has not previously been recognized in this valley or in the mainstem Hoh River Valley. Optically stimulated luminescence (OSL) and radiocarbon (14C) ages are generally consistent throughout the valley. These finding s advocate for a detailed sedimentologic and stratigraphic approach to glacial depos its and questions whether a similar advance or still -stand occurred in other valleys in the region. If so, this may reveal information regarding climate influences on MIS 2 glaciers in the Olympic Mountains. This research also assesses the applicability of OSL dating to glacial deposits in both field areas. Quartz OSL dating was used in the South Fork Hoh study area; however, quartz produced unreliable results in the Hawea study area, so samples were therefore assessed using feldspar methods. The results advocate for a facies-based sampling approach in glacial settings, where better sorted sandy facies and more distal deposits produce better bleached and more reliable age results than other deposits.

The Olympic Mountains in northwestern Washington, USA are defined by the arcuate shape of the basaltic Crescent Formation (Fm.) that wraps a faulted and folded meta-sedimentary core. This area was developed through accretion and exhumation by subduction-related processes, but how this relates to the deformational history of the area is not fully understood. The region has been mapped geologically, however little focus has been placed on interpreting meso-scale structures. This study investigates structures along a transect where the Hamma Hamma River crosses the Hurricane Ridge Fault, which juxtaposes the meta-sedimentary core (west) and the basaltic Crescent Fm. (east). In the study area, the meta-sedimentary unit is characterized by outcrop scale folding with a calculated fold axis of 69-->342 and a penetrative foliation with a representative orientation of (178, 75). The folds and foliation are crosscut by two fracture populations with representative orientations of (115, 61) and (303, 76). The pillow basalts of the Crescent Fm. are near vertical, N-S striking beds that are cut by four fault groups. Fault Groups A and B have representative orientations of (304, 37) and (207, 59), respectively, and are associated with similarly oriented fracture populations. Fault Group C crosscuts Groups A and B and has a representative orientation of (031, 61). Fault Group D runs subparallel to the outcrop, cuts all other faults, and has a representative orientation of (087, 50). From an interpretation of this data, a deformation model is presented that proposes three distinct periods of deformation under three different states of stress. The first period was dominated by E-W or ENE-WSW oriented compression, followed by a period of N-S or NNW-SSE oriented compression, followed by vertical compression.