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Many deglaciated watersheds possess complex longitudinal profiles and spatially variable sediment sources derived from the last glaciation. Accordingly, downstream patterns in fluvial forms and characteristics of the channel and floodplain may diverge from conventional ‘graded’ watershed models where channel slope decreases downstream. Within a small, deglaciated watershed, five distinct fluvial forms were identified and it was found that the watershed is organized in a spatially variable, but generally inverted arrangement with stable, low-energy forms dominating the upper watershed and more dynamic, high-energy forms in the lower watershed. As a consequence of this inverted and variable downstream succession, and the spatially erratic organization of glacial sediment sources, downstream trends in channel and floodplain characteristics are poorly defined, and in many cases, deviate from expected trends. This is most true for sedimentological variables where multiple co-dominant controls exist, while morphological and hydrological variables better conform to expected downstream trends.

Many deglaciated watersheds possess complex longitudinal profiles and spatially variable sediment sources derived from the last glaciation. Accordingly, downstream patterns in fluvial forms and characteristics of the channel and floodplain may diverge from conventional ‘graded’ watershed models where channel slope decreases downstream. Within a small, deglaciated watershed, five distinct fluvial forms were identified and it was found that the watershed is organized in a spatially variable, but generally inverted arrangement with stable, low-energy forms dominating the upper watershed and more dynamic, high-energy forms in the lower watershed. As a consequence of this inverted and variable downstream succession, and the spatially erratic organization of glacial sediment sources, downstream trends in channel and floodplain characteristics are poorly defined, and in many cases, deviate from expected trends. This is most true for sedimentological variables where multiple co-dominant controls exist, while morphological and hydrological variables better conform to expected downstream trends.

A history of soil erosion, alluvial and colluvial deposition is presented for a small catchment in NW Greece. The role of climatic events, tectonics and human disturbance of the landscape are examined. A major valley aggradation, named the Syndendron alluvium, was deposited in the valley floor during the close of the last glaciation. The 15,000 – 10,000 cal yr BP period was a time of dramatic climate fluctuations and associated changes in vegetation, fluctuating between steppe and oak woodland. The Syndendron alluvial deposit is associated with significant fires in the mid and upper catchment, as indicated by ash layers and charcoal in soils dated from this time. Regular fires were clearly an important part of landscape modification in sediments and soil deposited after about 15,000 cal yrs BP. The deposition of the Syndendron alluvium may have began as early as 14,200 cal yr BP but more likely was deposited between ca 12,250 and 9,300 cal yr BP (sites C11, C12, C13 and P37). The alluvium buries distinctive charcoal-rich paleosols dated between 14,700 and 14,200 cal yr BP (sites C6, C9 and C19). Debris flow deposits and slope wash from adjacent hill slopes provided the sediment source for the alluvium and slope wash has buried several distinctive late Pleistocene hill soils (sites C11, C12, C19). Alluvial sedimentation and hill slope erosion continued until at least 11,000 cal yrs BP, as indicated by an eroded hill soil at C11 that is buried by the aggrading Syndendron alluvium. Deposition had, however,ceased by ca. 9,300, as indicated by distinct alluvial soils that developed on the deposit (sites C12 and P37). Several colluvial soils dated to about 8,000 cal yr BP (C9 and C17) also cap the alluvium. The Syndendron alluvial event may in part relate to the arrival of humans during the climatic amelioration associated with the late glacial interstadial (Bolling-Allerod interstadials). Certainly there is increased burning of the catchment after about 15,000 cal yrs BP. Palaeolithic stone tools have been found in the catchment and along with others in the Grevena and Epirus regions, indicating humans were present. This period is also associated with colluvial soil deposition on lower slopes (sites C6 and C19). However, after about 12,250 cal yr BP there is a dramatic acceleration in the erosion rate and associated deposition on the valley floor and lower slopes. While fire appears to be important, a change to drier and cooler conditions, recorded in the Greenland ice cores as the Younger Dryas phase, may have caused denudation between 12,800 and 11, 600 cal yrs BP. The climate change toward wetter conditions after 10,000 cal yr BP and increasing tree cover appears to have led to a more stable landscape indicated by soil development and associated soil creep. However, there have been no Mesolithic sites identified in Grevena, and it is generally a period of low human activity in Greece. Following the hill slope erosion and deposition of the Syndendron alluvium the catchment seems to have become relatively stable as indicated by the development of moderately deep and well structured fertile black silty clay loam soils on the Syndendron alluvium. This is also supported in the upper catchment, as soil colluvium caps the Syndendron alluvium after 10,000 cal yr BP (site C12), and the stream re-incised the alluvium before 7,500 cal yr BP (site C11). The stream incision and also the arrival of Neolithic farmers in the valley are associated with a series of landslides and debris flow deposits between 7,500 and 6,500 cal yrs BP. In the lower catchment 2 m of fine-textured alluvium buries well-developed dark soils formed on the Syndendron alluvium sometime after 9,300 cal yrs BP. The landslide deposits dating between about 7,500 and 6,500 cal yr BP in the upper catchment contain large (4 x 1 m), intact pieces of highly weathered soil similar in chemical composition to those preserved on the upper slopes and catchment divide. The renewed incision of the Syndendron alluvium may have over-steepened some slopes and triggered land sliding at this time. The large size of the landslides and paucity of charcoal within them may implicate increased seismic activity as a trigger, as occurred during the 1995 Grevena earthquake. Fault displacements have been noted in both the Tertiary bedrock and the upper Plio-Pleistocene sediments within the catchment, although no active (Holocene) fault scarps were noted. Work in the base of the catchment indicates that the Neolithic impact was generally minor, with 1.5 m of alluvial deposition occurring between 5,900 and about 4,700 cal yrs BP. However, this alluvium was then abruptly buried by over 2 m of slope deposits derived from erosion of adjacent hills at after about 4,400 cal yrs BP. Thin,0.2m, A/C soils formed on the alluvial sediments during two stable periods each of about 500 years duration, indicating topsoils can develop rapidly in this environment. Other dark, loamy soil-like colluvial materials begin to be transported down-slope at about 5,000 through to 2,750 cal yrs BP. However, between 2,200 and 1,300 cal yr BP dark greyish-brown calcareous colluvium containing bedrock debris was deposited in depressions and gullies. This hill slope erosion and deposition was associated with the latter phase of the Sirini alluvium, which is the second major Holocene alluvial valley fill. This alluvium is dated near its base to ca. 4,150 cal yrs BP, but the major deposition occurs after 3,100 cal yr BP with 5 m of sediment being deposited after this date. At another site more than 6 m of fine-textured alluvium is deposited after 2,450 cal yrs BP. Sheep/goat vertebrae and bovine teeth (male) were located in two of the alluvial sections and suggest agricultural grazing practises were very well established after about 3,100 cal yrs BP. The Sirini alluvial deposition continues until at least 2,000 cal yr BP as indicated at one site and 1,700 cal yr BP at another. The Sirini alluvial deposition coincides with a series of colluvial deposits on the valley sides dated between 2,750 and 1,390 cal yrs BP. This Sirini alluvial filling appears to be staggered. At one site a distinct alluvial soil separates the alluvium into two phases Sirini A and Sirini B. Re-incision of the Sirini alluvium occurred sometime after about 1,700 cal yrs BP. Thin and incipient A/C soils form on the top of this alluvium supporting its youthfulness. In the modern valley floor a very young alluvial deposit named the Leipsokouki alluvium occurs 1 - 4 m above the modern flood plain. This alluvial fill has very weakly expressed topsoil development and is largely composed of raw weakly weathered alluvium. It is dated as modern (140 + 130 cal yr BP Wk 9926) on charcoal taken from the upper fine-textured alluvium in the mid catchment, but elsewhere it contains Ottoman sherds.

This thesis presents the findings of a combined geomorphological, sedimentological and geochronological investigation into the glacial history of the Clearwater Basin, Mid Canterbury, New Zealand. The study demonstrates that a thick wedge of glacial and paraglacial sediments are preserved in the valley. These are >100m thick and preserve evidence of at least 3 glacial phases (>180ka). The study presents a new and detailed geomorphology map for the Clearwater valley and adjacent areas and has added 17 new recessional positions to the local glacial record. Surface Exposure Dating (SED) has been used to directly date the moraines of the Clearwater Basin providing the first detailed chronology for glacial moraine in this area. In total 31 cosmogenic ages from 9 separate moraines are presented. The results demonstrate that the LGM advance is the Trinity moraine of Mabin (1980) and not the Hakatere moraine as previously assumed and that the LGM was achieved at or about 23ka. The Clearwater glacier receded up valley between 23 and 13ka with some indication of accelerated retreat after c.16ka. The correlation to the adjacent Lake Heron Valley is also revised.

This thesis investigates the assertion by many early and more recent New Zealand glacial workers, that the high catchment rainfall and low seasonality in New Zealand create unique glacial sedimentary and geomorphic processes. Specifically the thesis examines the nature of glacial sedimentology and geomorphology in South Island, New Zealand focussing on the Rakaia Valley, as most of the early studies that suggested a distinct New Zealand process environment were based on South Island, East Coast glacial valleys. The thesis provides insights into glacial processes operating at glacial termini of late Quaternary glaciers in this region. The primary findings are as follows: Glacial terminus landforms (moraines) and sediments are described in two eastern (Rakaia and Ashburton Lakes) and one western (Waiho) valley of South Island. There are three main types of landforms 1) outwash head, 2) push moraines and 3) ice-contact fans. Outwash heads and push moraines have been identified before in New Zealand, but ice-contact fans have not. The spatial relationships between the three landforms can be complex especially where there is a fluctuating glacier terminus. Outwash heads are the dominant landform, with ice-contact fans deposited at a stationary terminus with channelised meltwater and push moraines preserved during retreat accompanied with outwash head incision. Both ice-contact fans and push moraines are prone to reworking into the outwash head. Supraglacial material comprises a small cap on the moraines and is usually insignificant in this system. The nature of past glacier termini can be gained from detailed study of these three landform relationships and their sediment record. The dominance of glacifluvial processes at the glacier terminus is a reflection of the low seasonality, abundant catchment rainfall, coupled with a large sediment supply. Preservation and deposition of the push moraines and ice-contact fans are controlled by glacifluvial processes on an outwash head, which in turn are controlled by the mass balance of the glacier. Sedimentology, stratigraphy and facies architecture were examined in the lower Rakaia Valley and elsewhere. The main environments recorded by these sediments are largely proglacial lacustrine and fluvial including 1) outwash gravels, with deposition of a sequence of glacier-fed, Gilbert-type deltas deposited over buried ice at Bayfield Cliff, 2) lacustrine silts and sands, 3) sub-aqueous ice-contact fans, 4) sub-aqueous mass flow deposits, and 5) supraglacial melt out material. These glacilacustrine facies are widespread during both retreats and advances. Sub-aqueous deltas are the primary ice terminus form, in this mid-valley lacustrine setting, which record termini advance and retreats. Syn- and postdepositional deformation of lacustine facies are also common as a result of pushing and overriding from the fluctuating glacier termini. Buried ice is also widespread and many of these deposits display evidence of disruption of sedimentation by its meltout. This implies that stagnant tongues of ice were often buried by outwash and lacustrine sediments. From the sediments and geomorphology described in this thesis, two main glacier terminus settings in New Zealand valleys are apparent A) when the glacier terminus is on or abutting its outwash fan-head, or B) when the glacier terminus is within its trough. Both the geomorphic and edimentological findings allow a better understanding of New Zealand glacial chronologies. Firstly, the sedimentology permits the identification of many more advances and retreats than are recorded in surface sediments. At Rakaia Valley, facies record six significant advances and retreats and many more small oscillations over the last 200 000 years. The geomorphic understanding and high resolution mapping has identified many more ice termini in the valleys than were previously recognised and allow the insights into ice margin behaviour through time. This includes the changing location of outwash heads and glacial troughs, with a migration up-valley since the OIS 6 advance/s, in the Rakaia Valley. The glacier overran its outwash head to reach its LGM position, and subsequently retreated slowly over about 10,000 years, back to its outwash head. It then changed to a calving margin and continued retreating but with no terminal moraines preserved, only lateral features. The research in this thesis has contributed to greater understanding of the New Zealand glacial system. Although low seasonality and large volumes of meltwater do play a role, and equally important control in New Zealand valleys is that of tectonics in terms of delivering huge sediment supply. This sediment supply enables large outwash head and fans to accumulate, which allow large stable lakes to form during glacier recession. The data and interpretations from this thesis will underpin the development of a New Zealand glacial land system, of which other valleys such as the Himalayas have. This land system development is important for understanding the temperate, high sediment yield glacial environment end member.

Thesis (Ph.D. ) - James Cook University, 2006. / Appendices 1-7 contained on CD-ROM. Typescript (photocopy) Bibliography: leaves 7-1 to 7-19 (vol. 1.)

Thesis (Ph.D.) - Carleton University, 2005. / Includes bibliographical references (p. 177-211). Also available in electronic format on the Internet.

Mémoire (M.Sc.A.)-- Université du Québec à Chicoutimi, 1986. / "Mémoire présenté en vue de l'obtention de la maîtrise en sciences appliquées en géologie" Page 157 manquante. CaQCU CaQCU Bibliogr.: ff. 99-110. Document électronique également accessible en format PDF. CaQCU