Dissertations / Theses on the topic 'Glacial sedimentation'

Thesis advisor: Noah P. Snyder
Land cover and climate changes, attributed to natural and anthropogenic forcings, cause deviations in geomorphic processes that act to deliver sediment from watersheds to lakes. In New England, contradictory evidence exists as to the influence of deforestation associated with EuroAmerican settlement and major flood events on watershed erosion rates over the past ~250 years. Through combining sediment core analysis from Ossipee Lake, New Hampshire with geomorphic analysis of the Ossipee Lake watershed, this study quantifies Holocene through Anthropocene watershed erosion rates, and assesses variations in rates in relation to short-term historic events such as major storm events or deforestation, and long-term variations related to natural climate variability and post-glacial landscape evolution. An 8.63 m core was collected and spans the entire period from deglaciation to present. Bulk composition and age-depth modeling, utilizing both short-lived radioisotopes and radiocarbon dating, are used to quantify changes in deposition and inferred erosion rates over time. Additional insight on sedimentary processes is provided by measurements of magnetic susceptibility and bulk geochemistry. Lake-sediment data suggests clastic sediment mass accumulation rates vary between 0.0032 to 0.5870 g/cm2/yr, with deposits of increased terrestrially derived sediment focused between ~8500 to 7800, ~6500 to 2500, and 1600 cal yr BP to present. Geomorphic analysis is used to identify regions within the watershed that act to deliver sediment to Ossipee Lake. Potential sources of sediment supply include loose, unconsolidated proglacial deposits near Ossipee Lake that transition to primarily till in upland areas. Calculated bed shear stress along rivers highlights areas in the watershed capable of transporting sediment and areas that can serve as traps thus limiting sediment delivery to Ossipee Lake
Thesis (MS) — Boston College, 2019
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences

Undergraduate honors paper--Mount Holyoke College, 2007. Dept. of Earth and Environment.
Includes one CD-Rom appendix of 2005-2006 grain size data. Includes bibliographical references (leaves 125-129).

Windermere, the largest natural lake in England, is a glacial ribbon lake located in the southeast of the Lake District. High resolution geophysical datasets, combined with sediment analysis, geomorphological mapping and historical research have been used to investigate the lake bed environments, recent sediment record of pollution and glacial and post-glacial history of the lake and surrounding catchment. The data are used to generate a present-day landscape map of Windermere, revealing a complex landform record characterised by nine sub-basins, separated by steps, ridges and isolated topographic highs related to the retreat of the British and Irish Ice Sheet (BIIS). Debris flows and anthropogenic features are superimposed on the general bathymetric framework formed since the Last Glacial Maximum. Analysis of sediment cores and correlation with existing seismic data have revealed key stratigraphic facies extend across the lake basin, and consist of a drape of Holocene gyttja overlying glaciolacustrine and lacustrine sediment fill relating to retreat of the BIIS. Analysis of geophysical core properties have identified a peak in magnetic susceptibility and iron which possibly represents a change in relative input from different ice masses. Onshore mapping of Troutbeck Valley identifies a series of depositional environments, including recessional moraines formed by still-stands or small readvances of an outlet glacier. Following deglaciation through disintegration into a number of independent ice caps, major sediment redistribution led to formation of a large fan delta via paraglacial and post-glacial sedimentation. The sedimentology of Windermere is characterised by five distinct lake bed facies showing a dominance of gyttja, representing recent Holocene sedimentation derived from the catchment over the last 10,000 years. Coarser sediments (gravel and fine sand) are found in lake-marginal shallow water. High resolution geochemical data, radiochronology and isotopic analysis have revealed significant increases in lead, zinc and copper in recent lake sediments. The principal sources of anthropogenic lead contamination are gasoline lead, Carboniferous coal (most likely source is coal fired steam ships) and lead derived from Carboniferous Pb-Zn mineralisation (mining activities). A number of up-system sediment traps have limited the amount of mining related heavy metals entering Windermere. As a result, many peaks in heavy metals do not correlate with periods of metal workings, but recent increases are possibly due to flood-induced metal inwash. Elevated concentrations of zinc and filamentous growths on the lake bed are attributed to sewage inputs. Geophysical, physical and visual surveys of twelve demonstrated or putative spawning grounds of Arctic charr (Salvelinus alpinus) suggest suitable spawning habitat in Windermere is limited and siltation by fine sediments has occurred over the past 50 years. The integrated approach used in this study has shown that a catchment analysis, using several datasets and techniques, can be used to inform wider regional and ice sheet wide glacial reconstructions. This approach, which can be applied to other lacustrine environments, is capable of determining modern lake bed habitats and the sediment record of pollution, and further demonstrates the value of lake sediments as a high resolution record of local and regional environmental change.

A variety of moraine forms were deposited by glaciers during the Loch Lomond Stadial. Study of such moraines and related landforms provides a valuable source of data on patterns of landscape evolution and climatic change. This thesis presents detailed case-studies of moraines in geologically and topographically contrasting areas on the Island of Skye, Scotland. Geomorphological mapping, sedimentological analyses and mathematical modelling techniques were employed to determine the principal controls on moraine morphology, composition and distribution. Particular emphasis was placed on the provenance, transport and deposition of debris, and their spatial variation. The results were used to construct a summary model of glacial landform evolution, which relates different sediment-landform associations to spatial and temporal controls, particularly basin lithology and structure, topography, position of deposition and ice-margin activity. The initial stage of deglaciation in the study area was marked by a series of readvances and/or stillstands. During this stage, the lower-lying glaciers were more sensitive to climatic amelioration than the higher glaciers. The subsequent phase was characterised by more rapid deglaciation. Evidence for one instance of late-stage in situ glacier stagnation is described. The results indicate that landforms hitherto grouped as 'hummocky -moraine' formed by a variety of processes. Such moraines formed by (a) uneven deposition of supraglacially and/or -subglacially-derived debris at active ice margins, (b) deposition at the stagnant margins of otherwise active glaciers, and (c) deposition during uninterrupted glacier retreat or areal stagnation. Differentiation and analysis of so-called 'hummocky moraine' enables glacier behaviour, during the Lateglacial to be interpreted in great detail.

The North Yellow Sea (NYS) and South Yellow Sea (SYS), stretching from the Bohai Sea in the north to the East China Sea (ECS) in the south, represents an end member of modern epicontinental seas. Because of its shallow depths, the Yellow Sea was entirely exposed subaerially during the last glacial maximum. The new post-glacial sea-level curve derived from an extensive local dataset shows a series of rapid flooding events (12--45 mm/y), separated by a series of slow rises (2--6 mm/y). By about 15 ka, sea level had reached -100 m, and seawater entered the SYS. A rapid rise during MWP-1A occurred between 14.7--14.1 ka, sea level jumped from -98 m to -74 m (40 mm/yr). at the end, the sea water had reached the southern edge of the NYS, after which sea level rose again slowly (6 mm/yr) from -72 m to -60 m. Beginning about 11.7 ka, it again jumped, from -60 m to -42 m (MWP-1B), resulting in a rapid westward flooding of the NYS. Sea level then again stagnated (between -42m to -36 m) for about 1.8 ky. Starting about 9.8 ka, the sea-level advanced again from -36m to -16 m at 9.0 ka (MWP-1C), after which most of BS, YS, and ECS had been submerged. Then another slowdown occurred between 9.0--8.0 ka when sea-level rose from -16m to -10m. The last major transgression happened between 8.1 and 7.0 ka (MWP-D), and resulted in Holocene highstand of at least +2 to 4 m along most of Chinese and Korean coastlines. Sequence structures on this epicontinental shelf show strong landward horizontal changes, instead of the vertical changes. The first major deltaic system was developed in the NYS together with the decreased sea-level rise after MWP-1B event, and the intensified summer monsoon and subsequent increased river discharge at about 11 ka. The second subaqueous delta was built in the SYS between 9--7 ka which during another slackened sea-level after MWP-C. The modern subaqueous and subaerial deltas in the west Bahai Gulf have been formed during the sea-level highstand after the last jump of MWP-1D.

Analyses of 13 sediment cores and 2800 km of 3.5 kHz seismic profiles reveal that the majority of the sediments on the Labrador continental slope was deposited by hemipelagic settling and ice-rafting (53%), debris flows (7%) and turbidity currents (34%) during the Wisconsinan Glaciation. Only minor amounts (6%) are attributed to contour current activity and related processes. Eight sedimentary facies were differentiated which include (1) hemipelagic (H); (2) hemipelagic (HI) with ice-rafted detritus (IRD); (3) debris-flow deposits (subfacies D1, D2, D3), spill-over turbidite (T), headspill turbidite (TH), turbidite (TI) alternating with IRD; and (4) contourite (C) and nepheloid-flow deposits (N).
Six major glacial advances were identified in Mid- to Late-Wisconsinan (64-10 ka) slope sediments by 6 very dark hemipelagic units containing abundant sinistral-coiling, cold-water foraminifera. The associated ice-retreat phases are characterized by the occurrence of turbidites, debris-flow deposits, nepheloid-flow deposits, and ice-rafted debris (IRD).

Thesis advisor: Noah P. Snyder
Dam-influenced streambank morphology has not been studied extensively in rivers in deglaciated landscapes with high densities of colonial-era milldams. Fluvial restoration in the eastern U.S. often focuses on understanding pre-Colonial floodplain processes. Recent work by Walter and Merritts (2008a) in the Piedmont of the U.S. mid-Atlantic region suggests milldams significantly impact sedimentation by creating surfaces composed of post-dam legacy sediment that are often abandoned by the river and function as fill terraces. I analyze channel morphology and sedimentation patterns upstream of two breached dams on the Sheepscot River in mid-coastal Maine using lidar digital elevation models, historical aerial photographs, radiocarbon dating, and hydraulic modeling. In the past several decades, observable channel morphologic changes occurred at the two study sites: Maxcy's Mills dam (built in 1809, it was 2-m high and breached in the late 1950s), and at Head Tide dam (built in the 1760s, it is 4-m high and was partially breached in 1952). The Sheepscot River has a native population of Atlantic salmon, which is a federally listed endangered species. Understanding the existence and transport of legacy sediment has become an important component of habitat restoration efforts in the region. The goal of this investigation is to determine the extent and morphologic function of legacy sediment in order to better understand how historical dam sites affect channel morphology and sediment transport in a post-glacial, low-gradient river system. Field and remote sensing analyses indicate that surfaces (up to 2.65 m high) composed of mud and sand function as floodplains 1 km upstream from Head Tide dam and surfaces 90 cm high continue 2.5 km upstream from Maxcy's Mills. Analysis of seven radiocarbon dates from pieces of tree bark sampled from the stratigraphy (58-187 cm below the surface) of the two study sites suggest up to 1.8 m of sediment upstream of the two study sites was deposited within the past 300 years and is therefore a legacy of the dams. Quantification of the total volume of stored legacy sediment is on the same scale as volumes observed in the mid-Atlantic Piedmont region, leading to the conclusion that post-glacial rivers in northern New England store milldam sediment in similar fashion to streams analyzed in the Walter and Merritts (2008a) study
Thesis (MS) — Boston College, 2013
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences

The South Westland Continental Margin (SWCM) is incised by two major active canyon channels, the Hokitika and Cook canyons, which export large volumes of terrigenous sediment from the active New Zealand landmass to the deep ocean basins. This thesis examines modern sediment textures and compositions of shelf and canyon heads, to interpret depositional and transport processes in shelf-canyon interactions and the dispersal and provenance of SWCM surface sediments. This is the first detailed study of modern sediments south of the Whataroa River which focuses on both shelf and canyon head sediments. Submarine canyons that incise active continental shelves are major conduits for sediment transfer. The frequency and magnitude of this transfer has important implications for ocean nutrient cycling (i.e. organic carbon), the stratigraphy and morphology of continental shelves, and the development of economic mineral deposits. Grain size analysis, petrology, geochemistry, detrital magnetite analysis (microprobe), swath bathymetry, and wave hindcast data are used to interpret the spatial distribution, dispersal, and provenance of surface grab samples, canyon cores, and beach and river samples on the SWCM. Four main surficial facies are defined from textural and compositional results, primarily reflecting the supply and storm dominated nature of the SWCM. Facies 1 is comprised of inner shelf very fine to medium sand sized quartz, metamorphic lithics, and feldspar. This facies occurs above the mean Hsig wave base (48 m) where silts, clays, and sand sized micas are bypassed further offshore. Facies 2 is a transitional sand to mud facies between 40 -70 m depth where increasing clay, silt, and mica reflect a decrease in the frequency and magnitude of wave orbital remobilisation. Facies 3 is a mud dominated (80-90%), clay rich (7-9%) facies with the highest mica and Al₂O₃ content of all the SWCM facies. The shelves south of the Hokitika canyon are blanketed beyond the inner shelf in facies 3 towards the shelf break. Facies 4 is restricted to the canyon head north rims and is characterised by mixed relict and modern terrigenous sediments and glaucony. Net transport on the SWCM shelf is to the north, particularly during south-westerly storms where wind drift and storm swells may stir and transport the deeper Facies 2 and 3 sediments. The SWCM has an energetic wave climate and numerous high yield mountainous rivers. As a result the shelf has an extensive coverage of silts and clays with sediment transport most likely dominated by nepheloid layers and fluid mud flows during wet storms. North of the Hokitika canyon, shelf width increases as fluvial supply falls, resulting in a more storm dominated shelf as the prevailing hydraulic conditions prevent modern silts and clays from blanketing the outer shelf. Narrower shelf widths and higher fluvial supply between the Hokitika canyon and the Haast region results in more fluvial dominated shelves. Contrasting canyon rim textures and compositions reflect the major influence the Hokitika and Cook canyon heads impose on the SWCM by intercepting modern net northward shelf transport paths. This interception creates a leeward sediment deficit on the canyon north rims where low sedimentation rates prevail and relict sediments are partially exposed. The south and east rims of both canyons are characterised by modern fine grained terrigenous textures and compositions similar to the SWCM middle to outer shelf facies 3. The build-up and storage of these unconsolidated sediments at the south and east rims provides favourable environments for sediment gravity flows that feed into the canyon systems. Wave orbitals can resuspend fine sands up to 50 m below the canyon rims during large storms. This resuspension will be a main driver of canyon head sedimentation in the form of fluid mud flows. Gully networks along the south and east rims of the Hokitika and Cook canyons indicate active submarine erosion, unconfined fluid flow, and sediment gravity flows operate here. ii In contrast, the north canyon rims are characterised by gravels and coarse sands out of equilibrium with the prevailing modern hydraulic regime. Relict gravels are particularly prevalent on the Hokitika canyon north rim between 90 – 150 m depth. A lack of active gully networks and the presence of relict terraces and cuspate channels provide further evidence for a relict origin of HCH north rim sediments and little influx of modern fine sediments. North rim sediments on the Hokitika canyon between 90 – 125 m have features characteristic of relict beach and littoral environments. These features include pebble and coarse sand sized siliciclastics, high heavy mineral percentages (i.e. garnet), high Zr and Y levels, elevated SiO₂/Al₂O₃ ratios, and relict shell fragments. Mature glaucony is common on the north rims of both canyons, especially between 180 -200 m depth providing further evidence for extended periods of little to no modern sediment deposition in the canyon lee. Glaucony grains have experienced limited transport and are probably parautochthonous. The bulk composition of SWCM shelf, canyon, river, and beach sediments is controlled mainly by the hydrodynamic sorting of Alpine Schist derived material. Regional changes in catchment geology are identified in modern SWCM shelf sediments. Ultramafic signals (i.e. enriched trace element patterns and Cr/V and Ni/Y ratios) from the Pounamu Ultramafics and Dun Mountain Ultramafics were identified on the North and Cascade shelves respectively. The contribution of other lithologies to the bulk composition of SWCM sediments is localised due to rapid dilution with Alpine Schist detritus. The low carbonate and skeletal content on the SWCM is due to the energetic wave climate and high fluvial supply on the shelves. A variety of Cr-rich spinels and magnetites are supplied to the SWCM shelves and vary with regional changes in catchment geology. The Cascade shelf is rich in chromites (containing up to 215,000 ppm Cr) and Cr – rich magnetites sourced from the Dun Mountain Ultramafics via the Cascade River. Shelf, beach, and river samples between the Haast River and Waitaha River are dominated by low-Cr magnetite grains which represent the ‘background’ magnetite composition sourced from rivers draining the Alpine Schist dominated catchments. The dispersal of Cr-rich spinels is limited due to the dilution with low Cr-magnetites from rivers and littoral sediments. Glacio-eustatic lowstands such as the Last Glacial Cold Period (LGCP), represented periods of robust connection of local rivers with the Hokitika and Cook canyon heads, increased interception of littoral transport paths, and compartmentalisation of inter-canyon shelves. Hokitika canyon cores reflect these changes with textural and compositional ‘spikes’ indicating higher terrigenous input during the LGCP. The geochemistry of the terrigenous fraction in the Hokitika canyon provides evidence for enrichment in ferromagnesian and Cr-rich minerals during the LGCP. This is due to the increased connectivity of the Cr-spinel bearing Hokitika River to the canyon head. The Cr/V ratio in particular demonstrates its effectiveness as a proxy for interglacial – glacial change in submarine canyon stratigraphy. Increases and decreases in the connectivity of Cr-bearing fluvial systems during lowstands and highstands respectively can be observed with this ratio.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1985.
Microfiche copy available in Archives and Science.
Includes bibliographies.
by Stephanie Louise Pfirman.
Ph.D.

At head of title: National Centre for Petroleum Geology and Geophysics. CD-ROM contains Appendices (1-10) in PDF. Includes copies of papers co-authored by the author. Includes bibliographical references (leaves [471]-499 in vol. 2) Studies the provenance and diagenesis of the Merrimelia Formation in South Australia and Queensland; a complex mosaic of glacial facies in which the Tirrawarra Sandstone and Merrimelia Formation exhibit an interfingering relationship, and defines the relationship further. Indicates that the Tirrawarra Sandstone should be included in the Merrimelia Formation as a "facies type" as both the Merrimelia and Tirrawarra sediments form an integrated suite of sediments. System requirements for accompanying CD-ROM: Macintosh or IBM compatible computer with Windows NT. Other requirements: Adobe Acrobat Reader.

De par sa position, le Golfe du Lion est un site idéal pour l’investigation des changements paléo-environnementaux et des processus affectant le dépôt sédimentaire. Les travaux antérieurs ont permis de mettre en évidence les impacts de la variabilité climatique et glacioeustatique sur l’organisation stratigraphique de la marge, mais également sur les exports terrestres de matière organique.L’étude isotopique du carbone organique et de l’azote de la matière organique dans les sédiments du forage PRGL1-4 nous a permis de mettre en évidence de forts exports fluviaux lors des interstades survenus au cours des 200 000 derniers milles ans. La mise en regard de cette découverte avec les enregistrements paléo-climatologiques terrestre et marin disponibles dans la région indique que ces forts exports fluviaux résultent d’une augmentation des précipitations le long de la bordure Nord Méditerranéenne. Grâce à la position dePRGL1-4, nous proposons que ces pluies soient le résultat d’une augmentation du passage de dépressions Nord Atlantique dans le bassin Ouest Méditerranéen.Une caractérisation des isotopes du soufre préservés dans la pyrite sédimentaire a été réalisée. Les résultats obtenus ont permis de mettre en évidence une variation isotopique insoupçonnée, l’une des plus grandes observées de nos jours, dont la cyclicité semble indiquer un fort contrôle climatique. Nous proposons deux mécanismes influençant le fractionnement isotopique: une modulation de l’activité bactérienne par le climat, et/ou (ii) une modulation locale liée la nature des sédiments impliqués dans la formation des pyrites en lien avec les variations eustatiques
By its position, the Gulf of Lion is an ideal location for investigation of past ecological changes and processes affecting the sedimentary deposition. Previous work has highlighted the impacts of climatic and glacio-eustatic changes on the GoL stratigraphic organization, but also on terrestrial exports of organic matter.This isotopic study based on the organic carbon and nitrogen preserved in PRGL1-4 sediments highlights important rivers runoff during warm periods of the last 200 000 years.Regional intercomparison with terrestrial and marine records indicates that these river exports resulting from an increase of precipitation over the North Mediterranean borderland.Using PRGL1-4 location, out of Mediterranean cyclogenetic area, we suggest that these pluvial events occurred in response to enhance passage of North Atlantic atmospheric perturbation into the Western Mediterranean basin.Pyrite sulfur isotopes investigations over the last 500 kyr have also been done. The stratigraphic variations (up to 76‰) in the isotopic data reported here are among the largest ever observed in pyrite, and are in phase with glacial-interglacial sea level. These results suggest that there exist important but previously overlooked depositional controls on sedimentary sulfur isotope records. Two different mechanisms influencing the isotopic fractionation can explain the observed dataset: a climatic modulation of the bacterial activity, and / or (ii) a local sedimentary modulation involve during early diagenetic formation of pyrite in relation with the eustatic variations

Piston cores from the western Ross Sea reveal a stratigraphy consisting of basal tills overlain by glacial-marine sediments, succeeded seaward by glacial-marine deposits with abundant microfossils and IRD. The glacigenic sediments are succeeded at the shelf margin by coarse bioclastic sands and gravels. Seismic and core data indicate that the grounding line for the late Wisconsinan glacial maximum was just north of Coulman Island. Carbonate sediments from the outer shelf were grouped into four distinct facies. Radiocarbon dates indicate that carbonate deposition was occurring during much of the late Wisconsin. The pre-mid Miocene unconformity identified in DSDP Site 273 (Hayes and Frakes, 1975) was tied to the seismic data in the western Ross Sea. The data suggests that this event was responsible for the general physiography of the western shelf. Turbidites, including calcarenites, litharenites and quartz arenites, were recovered from the slope and the data suggests that outer shelf banks are the source for these deposits.

Piston cores, bottom grabs, and single-channel seismic data acquired during Deep Freeze/USARP cruises have been used to examine sedimentation and recent climatic history in the bays and fjords of the Gerlache Strait region (Antarctic Pensinsula). The local climate and glacial setting exhibit profound influences on sedimentation via the processes associated with subglacial water. Visible sediment plumes are rare, and glacial ice above sea level is pristine white, indicating that debris is entering the water from the glaciers that are grounded below sea level. In the relatively warm and wet Palmer Archipelago, terrigenous muds and sands with a variable IRD component are ponding in every available bathymetric depression, and sediment gravity flow processes are common. Along the colder and drier Danco Coast, diatomaceous sediments drape uniformly across the rugged basement topography, rather than ponding, and resedimentation is rare. In both areas, sedimentation occurs in quiescent water.

A marine sedimentologic investigation was conducted on the northern Antarctic Peninsula continental margin. The data base included piston cores, surficial sediments, and high resolution seismic reflection profiles. The objectives of this study were three-fold: examine sedimentation patterns in the Bransfield Basin, a high-latitude, actively spreading back-arc basin; relate sedimentation processes to lithofacies patterns in bays and fjords of the South Shetland Islands, Palmer Archipelago, and Danco Coast; and interpret the recent glacial-climatic history of this region. As a back-arc basin in a polar latitude, the Bransfield Basin represents a unique sedimentary environment. Fluvial discharge systems are lacking and the Bransfield Basin receives only minor amounts of continentally-derived sediment. The South Shetland arc is inactive, and the locus of recent volcanic activity is the axis of back-arc spreading. The sediments accumulating in the Bransfield Basin represent the input of terrigenous, biogenic, and volcaniclastic phases. Sediment distribution reflects the interplay of marine currents, primary production, and volcanic activity. At water depths $<$250 m, marine currents actively redistribute sediment, and residual deposits blanket the shelf between the northern tip of the Antarctic Peninsula and Tower Island. A transition from residual deposits to deposits with increased mud content west of Tower Island indicates a decrease in the intensity of marine currents as they flow east to west along the shelf. Lower energy conditions characterize the Bransfield Basin, permitting the suspension settling of fine terrigenous and biogenic phases. These predominantly fine-grained deposits record episodic pulses of increased volcaniclastic input. The normally graded volcanic ash layers represent both air fall deposits and sediment gravity flow deposits (turbidites). The distribution and composition of lithofacies recovered in bays and fjords appear to be regulated by the proximity to ice margins and to discharging meltwater systems. Where terrigenous sediment input is less pronounced, a biogenic lithofacies is present. Seismic records show that the thickness of the meltwater facies increases from south to north in the study area. It appears that initiation of meltwater production occurred relatively recently in bays of the Danco Coast. In contrast, sedimentation in bays of the Palmer Archipelago and South Shetland Islands is meltwater-dominated, and terrigenous sediments are rapidly accumulating. (Abstract shortened with permission of author.)

At head of title: National Centre for Petroleum Geology and Geophysics.
CD-ROM contains Appendices (1-10) in PDF.
Includes copies of papers co-authored by the author.
Includes bibliographical references (leaves [471]-499 in vol. 2)
System requirements for accompanying CD-ROM: Macintosh or IBM compatible computer with Windows NT. Other requirements: Adobe Acrobat Reader.
2 v. (various pagings) : ill. (some col.), maps, ports. ; 30 cm. + 1 CD-ROM (4 3/4 in.)
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Studies the provenance and diagenesis of the Merrimelia Formation in South Australia and Queensland; a complex mosaic of glacial facies in which the Tirrawarra Sandstone and Merrimelia Formation exhibit an interfingering relationship, and defines the relationship further. Indicates that the Tirrawarra Sandstone should be included in the Merrimelia Formation as a "facies type" as both the Merrimelia and Tirrawarra sediments form an integrated suite of sediments.
Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 2000?

At head of title: National Centre for Petroleum Geology and Geophysics.
CD-ROM contains Appendices (1-10) in PDF.
Includes copies of papers co-authored by the author.
Includes bibliographical references (leaves [471]-499 in vol. 2)
System requirements for accompanying CD-ROM: Macintosh or IBM compatible computer with Windows NT. Other requirements: Adobe Acrobat Reader.
2 v. (various pagings) : ill. (some col.), maps, ports. ; 30 cm. + 1 CD-ROM (4 3/4 in.)
Studies the provenance and diagenesis of the Merrimelia Formation in South Australia and Queensland; a complex mosaic of glacial facies in which the Tirrawarra Sandstone and Merrimelia Formation exhibit an interfingering relationship, and defines the relationship further. Indicates that the Tirrawarra Sandstone should be included in the Merrimelia Formation as a "facies type" as both the Merrimelia and Tirrawarra sediments form an integrated suite of sediments.
Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 2000?

Shallowly-buried channel systems have been imaged on the New Jersey Shelf with high-resolution seismic imaging. These channels formed as riverine systems that occupied the exposed shelf during the Last Glacial Maximum, ~18 ka. Subsequent sea level rise ~15-12 ka modified the valleys, forming estuaries and filling the channels with estuarine sediments. The infill sediments within the channel provide evidence for the response of the shelf to the Late Pleistocene glacio-eustatic sea level rise, but little work has been done on samples from these strata. This study aids in the ground-truthing of previous stratigraphic results by analyzing the cores collected within the infill sediments. The seismic stratigraphy of fill sediments from the mid-shelf and outer-shelf channels are structurally dissimilar. The mid-shelf channel fill stratigraphy is dominated by finely-laminated U-shaped reflectors throughout the section, with cut and fill geometries. In contrast, the outer shelf channel fill stratigraphy is a well-ordered sequence of 4 identifiable, primarily flat-lying seismic units. We collected five cores in mid-shelf channels (~30 m water depth), one in an outer shelf channel (~80 m of water depth) and one core in the trangressive ravinement surface. Cores were logged for density and seismic velocity. Grain size analysis was conducted by settling column and laser particle size analyzer. Radiocarbon analysis of the stratigraphy was conducted with the shell fragments and organic mud within the samples. The foraminiferal assemblages aided in determining the depositional environment. Using these data I investigated the differences in depositional environment of the mid- and outer-shelf channels systems, and consider these results in the context of sedimentary models for estuarine processes. The radiocarbon dates and foraminiferal are consistent with channel infill in an estuarine environment. Grain size and density log data indicate that the mid-shelf channel fills are sandier than the outer-shelf channel fills, which leads me to infer that the sediment from the mid-shelf channels was deposited in a higher energy environment than that of the sediment in the outer shelf channels. The stratigraphic differences and locations of the channel systems are similar to the Zaitlin (1994) model of incised valley infill, but infill of the mid-shelf channel system could possibly be the result of a catastrophic meltwater flood event occurring ~14 ka as glacial lakes to the north broke their dams and flooded the mid-shelf.
text

Indiana University-Purdue University Indianapolis (IUPUI)
U/Pb and (U-Th)/He (ZHe) dating of detrital zircons from glacial till samples in the Ross Embayment, Antarctica records cooling after the Ross/Pan-African orogeny (450-625 Ma) followed by a mid-Jurassic to mid-Cretaceous heating event in the Beacon basin. Zircons were extracted from till samples from heads of major outlet glaciers in East Antarctica, one sample at the mouth of Scott Glacier, and from beneath three West Antarctic ice streams. The Ross/Pan-African U/Pb population is ubiquitous in these Antarctic tills and many Beacon Supergroup sandstones, thus 83 grains were analyzed for ZHe to subdivide this population. Two ZHe age populations are evident in East Antarctic tills, with 64% of grains 115-200 Ma and 35% between 200-650 Ma. The older population is interpreted to be associated with the Ross/Pan-African orogeny including cooling of the Granite Harbour Intrusives and/or exhumation of the older basement rocks to form the Kukri Peneplain. The lag time between zircon U/Pb, ZHe and 40Ar/39Ar ages from K-bearing minerals show cooling over 200 My. Grains in East Antarctic tills with a ZHe age of 115-200 Ma likely reflects regional heating following the breakup of Gondwana from the Ferrar dolerite intrusions, subsidence within the rift basin, and a higher geothermal gradient. Subsequent cooling and/or exhumation of the Transantarctic Mountains brought grains below the closure temperature over a span of 80 My. This population may also provide a Beacon Supergroup signature as most of the tills with this age are adjacent to nunataks mapped as Beacon Supergroup and contain an abundance of vi Beacon pebbles within the moraine. Nine zircons grains from three Beacon Supergroup sandstones collected from moraines across the Transantarctic Mountains yield ages from 125-180 Ma. West Antarctic tills contain a range of ZHe ages from 75-450 Ma reflecting the diverse provenance of basin fill from East Antarctica and Marie Byrd Land. ZHe and U/Pb ages <105 Ma appear to be distinctive of West Antarctic tills. The combination of U/Pb, ZHe and 40Ar/39Ar analyses demonstrates that these techniques can be used to better constrain the tectonic evolution and cooling of the inaccessible subglacial source terrains beneath the Antarctic Ice Sheet.

Debris flows, which occur in mountain settings worldwide, have been particularly damaging in the glaciated basins flanking the stratovolcanoes in the Cascade Range of the northwestern United States. This thesis contains two manuscripts that respectively investigate the (1) initiation processes of debris flows in these glaciated catchments, and (2) debris flow occurrence and its effect on valley bottoms over the last thousand years. In a 2006 storm, seven debris flows initiated from proglacial gullies of separate basins on the flanks of Mount Rainier. Gully heads at glacier termini and distributed collapse of gully walls imply that clear water was transformed to debris flow through progressive addition of sediment along gully lengths. In the first study, we analyze gully changes, reconstruct runoff conditions, and assess spatial distributions of debris flows to infer the processes and conditions necessary for debris flow initiation in glaciated catchments. Gully measurements suggest that sediment bulking requires steep gradients, abundant unstable material, and sufficient gully length. Reconstruction of runoff generated during the storm suggests that glaciers are important for generating the runoff necessary for debris flow initiation, particularly because infiltration capacities on glacial till covered surfaces well exceed measured rainfall rates. Runoff generation from glaciers and abundant loose debris at their termini explain why all debris flows in the storm initiated from proglacial areas. Proglacial areas that produced debris flows have steeper drainage networks with significantly higher elevations and lower drainage areas, suggesting that debris flows are associated with high elevation glaciers with relatively steep proglacial areas. This correlation reflects positive slope-elevation trends for the Mount Rainier volcano. An indirect effect of glacier change is thus the change in the distribution of ice-free slopes, which influence a basin’s debris flow potential. These findings have implications for projections of debris flow activity in basins experiencing glacier change. The second study uses a variety of dating techniques to reconstruct a chronology of debris flows in the Kautz Creek valley on the southwest flank of Mount Rainier (Washington). Dendrochronologic dating of growth disturbances combined with lichenometric techniques constrained five debris flow ages from 1712 to 1915 AD. We also estimated ages of three debris flows ranging in age from ca. 970 to 1661. Run-out distances served as a proxy for debris flow magnitude, and indicate that at least 11, 2, and 1 debris flow(s) have traveled at least 1, 3, and 5 km from the valley head, respectively since ca. 1650. Valley form reflects the frequency-magnitude relationship indicated by the chronology. In the upper, relatively steep valley, discrete debris flow snouts and secondary channels are abundant, suggesting a process of debris flow conveyance, channel plugging, and channel avulsion. The lower valley is characterized by relatively smooth surfaces, an absence of bouldery debris flow snouts, few secondary channels, and relatively old surface ages inferred from the presence of tephra layers. We infer that the lower valley is deposited on by relatively infrequent, large magnitude, low-yield strength debris flows like an event in 1947, which deposited wide, tabular lobes of debris outside of the main channel. Debris flows during the Little Ice Age (LIA) predominantly traveled no further than the upper valley. Stratigraphic evidence suggests that the main Kautz Creek channel was filled during the LIA, enhancing debris flow deposition on the valley surface and perhaps reducing run-out lengths. Diminished areas and gradients in front of glaciers during the LIA also likely contributed to decreased run-out lengths. These findings suggest that changes in debris flow source and depositional zones resulting from temperature and glacier cycles influence the magnitude and run-out distances of debris flows, and the dynamics of deposition in valley bottoms.
Graduation date: 2013