Glaciology Commons^™

Apparent Glacially Induced Structural Controls On Limestone Conduit Development In Ohio Caverns, United States, Adrienne M. Watts, Ira D. Sasowsky

International Journal of Speleology

Rock discontinuities such as bedding planes and joints are important controls on the form that caves take. We examined structural controls on the development of Ohio Caverns. The cave formed in Devonian limestone underlying a small bedrock knob (Mt. Tabor) within the Interior Lowland province, United States. The area has been overridden by continental glaciation multiple times. The bedrock is pervasively fractured, with many curved and wavy near-vertical fractures showing many different orientations. In the case of Ohio Caverns, it appears that the controlling fractures in map view may not be joints sensu stricto, but rather some combination of …

Climb To The Ice, Richard Vaughan

Richard Vaughan

The article, originally presented as a lecture, discusses George Bird Grinnell's 1887 climb of the Montana glacier that eventually become known as Grinnell Glacier. Grinnell’s efforts to establish Glacier National Park are detailed. Grinnell's previously unpublished descriptions of the glacier and its surrounding area are analyzed by the author. Originally delivered as a lecture at the Montana History Conference, October 2, 2010. Full issue available at: http://issuu.com/um_crown_gye/docs/crownofthecontinent-autumn2012

To The Ice: George Bird Grinnell's 1887 Ascent Of Grinnell Glacier, Richard Vaughan

Richard Vaughan

This article discusses a climbing expedition undertaken by U.S. conservationist George Bird Grinnell to ascend what would come to be known as Grinnell Glacier in Montana. Grinnell’s efforts to establish Glacier National Park are detailed. Grinnell’s previously unpublished descriptions of the glacier and its surrounding area are analyzed by the author.

A College Level Geology Field Trip In Western Connecticut And Vicinity, Stanley Schleifer, Nazrul I. Khandaker, Keshaw Narine, Ezazul Haque, Ratan Dhar

Publications and Research

There are a number of excellent locations for field exposure for college students in, and around Western Connecticut. These are accessible for a one day field trip within striking distance of New York City, Bridgeport and New Haven, CT and other nearby locations. They are also suitable for an expanded weekend field trip. The field locations include; Kent Falls State Park, Kent, CT, Dinosaur State Park, Rocky Hill, CT, the Hubbard Mining Museum, Kent, CT, Bash Bish Falls in Mt. Washington, Massachusetts, Macedonia Brook State Park in Kent, CT and various outcrops exposed along U. S. Route 7 north of …

Effects Of Changes In Moisture Source And The Upstream Rainout On Stable Isotopes In Precipitation – A Case Study In Nanjing, Eastern China, Y. Tang, H. Pang, W. Zhang, Y. Li, Shuang-Ye Wu, S. Hou

Geology Faculty Publications

In the Asian monsoon region, variations in the stable isotopic composition of speleothems have often been attributed to the "amount effect". However, an increasing number of studies suggest that the "amount effect" in local precipitation is insignificant or even non-existent. To explore this issue further, we examined the variability of daily stable isotopic composition (δ18O) in precipitation from September 2011 to November 2014 in Nanjing, eastern China. We found that intra-seasonal variations of δ18O during summer were not significantly correlated with local rainfall amount but could be linked to changes in the moisture source location and rainout processes in the …

Geology Of The Steens Area, Jane Claire Dirks-Edmunds

Jane Claire Dirks-Edmunds Documents

This document is part of a larger discussion in the Dr. Jane Claire Dirks-Edmunds Papers on the geology of Steens Mountain, a large fault-block mountain in Harney County, Oregon. Often confused for a mountain range because of its size and scope, Steens Mountain lies near the Oregon-Nevada border.

For a full-text searchable version of this document, refer to the Additional Files below.

Coastal Ice-Core Record Of Recent Northwest Greenland Temperature And Sea-Ice Concentration, Erich C. Osterberg, Robert L. Hawley, Gifford Wong, Ben Kopec, David Ferris, Jennifer Howley

Dartmouth Scholarship

Coastal ice cores provide an opportunity to investigate regional climate and sea-ice variability in the past to complement hemispheric-scale climate reconstructions from ice-sheet-interior ice cores. Here we describe robust proxies of Baffin Bay temperature and sea-ice concentration from the coastal 2Barrel ice core collected in the Thule region of northwest Greenland. Over the 1990–2010 record, 2Barrel annually averaged methanesulfonic acid (MSA) concentrations are significantly correlated with May–June Baffin Bay sea-ice concentrations and summer temperatures. Higher MSA is observed during warmer years with less sea ice, indicative of enhanced primary productivity in Baffin Bay. Similarly, 2Barrel annually averaged deuterium excess (d-excess) …

Putting The West Antarctic Ice Sheet Into Context, George H. Denton, Brenda L. Hall

University of Maine Office of Research Administration: Grant Reports

This award supports a project to develop new insights into the cause and pattern of events during the last glacial termination in South America and Antarctica. One emerging view is that a warming Southern Ocean (SO), driven by a chain of events initiated in the Northern Hemisphere (NH) and tied to the interhemispheric climate seesaw of the last termination, was the underlying mechanism that drove the West Antarctic ice sheet (WAIS) from its Late Glacial Maximum (LGM) position back to present-day grounding lines. This ocean thermal forcing would have impacted WAIS by accelerating basal melt rates on fringing floating ice …

Dynamics Of Thermally Induced Ice Streams Simulated With A Higher-Order Flow Model, Douglas Brinkerhoff, Jesse Johnson

Computer Science Faculty Publications

We use a new discretization technique to solve the higher-order thermomechanically coupled equations of glacier evolution. We find that under radially symmetric continuum equations, small perturbations in symmetry due to the discretization are sufficient to produce the initiation of non-symmetric thermomechanical instabilities which we interpret as ice streams, in good agreement with previous studies which have indicated a similar instability. We find that the inclusion of membrane stresses regularizes the size of predicted streams, eliminating the ill-posedness evident in previous investigations of ice stream generation through thermomechanical instability. Ice streams exhibit strongly irregular periodicity which is influenced by neighboring ice …

Glacier Change On The Three Sisters Volcanoes, Oregon: 1900-2010, Justin George Ohlschlager

Dissertations and Theses

A glacier responds to changes in climate by subsequent retreat and advance as a result of changes in snow inputs and outputs. Understanding these changes is important because shrinking glaciers limit and diminish local water resources. They contribute to alpine runoff in the late-summer months by delaying the maximum runoff until late in the melt season. A comprehensive glacier and perennial snowfield inventory has not been completed for the Three Sisters in Central Oregon. Using aerial photography, Digital Elevation Models (DEMs), previous studies, and historical ground based photographs these glacier and perennial snowfields were defined and their surface area change …

Evidence Of Late Quaternary Fires From Charcoal And Siliceous Aggregates In Lake Sediments In The Eastern U.S.A., Joanne P. Ballard

Doctoral Dissertations

The late-glacial transition to the Holocene, 15,000–11,600 cal yr BP, is an enigmatic period of dynamic global changes and a major extinction event in North America. Fire is an agent of disturbance that transforms the environment physically and chemically, and affects plant community composition. To improve understanding of the linkages between fire, vegetation, and climate over the late glacial and Holocene in the eastern U.S., I analyzed lake-sediment cores for charcoal and indicators of wood ash, and compared results to existing pollen records. A new microscopic charcoal record from Anderson Pond, Tennessee revealed high fire activity from 23,000–15,000 cal yr …

Timing And Extent Of The Little Ice Age Glacial Advances In The Eastern Tian Shan, China, Yanan Li

Doctoral Dissertations

Located in Central Asia, one of the most continental regions on Earth, the Tian Shan’s glaciers contribute critical fresh water to populated areas in the lowland. These glaciers are sensitive to climate change, and knowledge of contemporary glaciers and their changes in the past is of critical importance for sustainable development in this region. Constraining glacial fluctuations in recent centuries will fill a gap in numerical constraints on glacial history and paleoclimate information, and provide important evidence on the spatio-temporal changes of the climate systems in the Tian Shan. This doctoral dissertation investigates the timing and extent of Little Ice …

Temperature Distribution And Thermal Anomalies Along A Flowline Of The Greenland Ice Sheet, Joel A. Harrington, Neil F. Humphrey, Joel T. Harper

Geosciences Faculty Publications

Englacial and basal temperature data for the Greenland ice sheet (GrIS) are sparse and mostly limited to deep interior sites and ice streams, providing an incomplete representation of the thermal state of ice within the ablation zone. Here we present 11 temperature profiles at five sites along a 34km east-west transect of West Greenland. These profiles depict ice temperatures along a flowline and local temperature variations between closely spaced boreholes. A temperate basal layer is present in all profiles, increasing in thickness in the flow direction, where it expands from about 3% of ice height furthest inland to 100% at …

Establishing A Chronology Of Late Quaternary Glacial Advances In The Cordillera De Talamanca, Costa Rica, Rebecca Susan Potter

Masters Theses

Little research has focused on glacial events in the tropics. Providing an absolute glacial chronology in Costa Rica will build a foundation for future glacial chronologies and paleoclimate reconstructions in the highlands of Central America. Evidence of past glaciation, including moraines and glacial lakes, is preserved within formerly glaciated valleys in the Cordillera de Talamanca. Orvis and Horn (2000) constrained deglaciation ages of the most recent glacial event in the Cordillera de Talamanca based on radiocarbon dates of glacial lake sediments. Radiocarbon ages indicated complete deglaciation after 12.4 ka cal BP but before 9.7 ka cal BP (Orvis and Horn, …

The Role Of Damage And Recrystallization In The Elastic Properties Of Columnar Ice, Scott A. Snyder, Erland M. Schulson, Carl E. Renshaw

Dartmouth Scholarship

Effects of damage on elastic properties were studied in columnar-grained specimens of freshwater and saline ice, subjected, at −10°C, to varying levels of inelastic strain. The ice was compressed uniaxially at constant strain rates up to 0.20 strain, which caused localized recrystallization and imparted damage in the form of non-propagating cracks. Damage was quantified in terms of dimensionless crack density, which, along with recrystallized area fraction, was determined from thin sections. The change in porosity due to stress-induced cracks served as another indicator of damage. Elastic properties were derived using P-wave and S-wave ultrasonic transmission velocities measured in across-column directions …

Dramatic Loss Of Glacier Accumulation Area On The Tibetan Plateau Revealed By Ice Core Tritium And Mercury Records, S. Kang, F. Wang, U. Morgenstern, Y. Zhang, B. Grigholm, Susan D. Kaspari, M. Schwikowski, J. Ren, T. Yao, D. Qin, P. A. Mayewski

All Faculty Scholarship for the College of the Sciences

Two ice cores were retrieved from high elevations (~5800 m a.s.l.) at Mt. Nyainqêntanglha and Mt. Geladaindong in the southern and central Tibetan Plateau region. The combined tracer analysis of tritium (³H), ²¹⁰Pb and mercury, along with other chemical records, provided multiple lines of evidence supporting that the two coring sites had not received net ice accumulation since at least the 1950s and 1980s, respectively. These results implied an annual ice loss rate of more than several hundred millimeter water equivalent over the past 30–60 years. Both mass balance modeling at the sites and in situ data …

Roosevelt Island Climate Evolution Project (Rice): Us Deep Ice Core Glaciochemistry Contribution (2011- 2014), Paul Andrew Mayewski, Karl J. Kreutz, Andrei V. Kurbatov

University of Maine Office of Research Administration: Grant Reports

This award supports a project to analyze a deep ice core which will be drilled by a New Zealand research team at Roosevelt Island. The objectives are to process the ice core at very high resolution to (a) better understand phasing sequences in Arctic/Antarctic abrupt climate change, even at the level of individual storm events; (b) determine the impact of changes in the Westerlies and the Amundsen Sea Low on past/present/future climate change; (c) determine how sea ice extent has varied in the area; (d) compare the response of West Antarctica climate to other regions during glacial/interglacial cycles; and (e) …

Dye Tracing To Determine Flow Properties Of Hydrocarbon-Polluted Rabots Glaciär, Kebnekaise, Sweden, Caroline C. Clason, C. Coch, J. Jarsjö, Keith A. Brugger, P. Jansson, G. Rosqvist

Geology Publications

Over 11 000 L of kerosene was deposited on the surface of Rabots glaciär on the Kebnekaise Massif, northern Sweden, following the crash of a Royal Norwegian Air Force aircraft in March 2012. An environmental monitoring programme was subsequently commissioned, including a series of dye tracing experiments during the 2013 melt season, conducted to investigate the transport of pollutants through the glacier hydrological system. This experimental set-up provided a basis from which we could gain new insight into the internal hydrological system of Rabots glaciär. Results of dye tracing experiments reveal a degree of homogeneity in the topology of the …

Interface Friction Parameters For The Mathematical Modeling Of Shell Structures With Infill, Alexander T. Bekker, Nikita Ya. Tsimbelman, Tatiana I. Chernova, Vadim D. Bruss, Ömer Bilgin

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Thin metal or reinforced concrete shells with granular infill structures are considered in this article. These structures are massive and they are used as support for the construction of berthing quays, piers, artificial islands, shore protection, and other structures of coastal infrastructure. It is more convenient to use the thin shell structures during the development of the Arctic shelf, because it is possible to install them from the ice side. In addition, it is possible to enhance the technology and install thin shells with infill on deeper solid foundation layers. A mathematical model for the stresses on a compressible foundation …

Threshold Behavior Of A Marine‐Based Sector Of The East Antarctic Ice Sheet In Response To Early Pliocene Ocean Warming, Melissa A. Hansen, Sandra Passchier, Boo‐Keun Khim, Buhan Song, Trevor Williams

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

We investigate the stability of the East Antarctic Ice Sheet (EAIS) on the Wilkes Land continental margin, Antarctica, utilizing a high‐resolution record of ice‐rafted debris (IRD) mass accumulation rates (MAR) from Integrated Ocean Drilling Program Site U1359. The relationship between orbital variations in the IRD record and climate drivers was evaluated to capture changes in the dynamics of a marine‐based ice sheet in response to early Pliocene warming. Three IRD MAR excursions were observed and confirmed via scanning electron microscope microtextural analysis of sand grains. Time series analysis of the IRD MAR reveals obliquity‐paced expansions of the ice sheet to …

Reconstructing Thermal Properties Of Firn At Summit, Greenland, From A Temperature Profile Time Series, Alexandra L. Giese, Robert L. Hawley

Dartmouth Scholarship

We have constrained the value for thermal diffusivity of near-surface snow and firn at Summit Station, Greenland, using a Fourier-type analysis applied to hourly temperature measurements collected from eight thermistors in a closed-off, air-filled borehole between May 2004 and July 2008. An implicit, finite-difference method suggests that a bulk diffusivity of ∼25 ± 3m2 a−1 is the most reasonable for representing macroscale heat transport in the top 30 m of firn and snow. This value represents an average diffusivity and, in a conduction-only model, generates temperature series whose phase shifts with depth most closely match those of the Summit borehole …

Accelerated Glacier Melt On Snow Dome, Mount Olympus, Washington, Usa, Due To Deposition Of Black Carbon And Mineral Dust From Wildfire, Susan D. Kaspari, S. Mckenzie Skiles, Ian Delaney, Daniel Dixon, Thomas H. Painter

All Faculty Scholarship for the College of the Sciences

Assessing the potential for black carbon (BC) and dust deposition to reduce albedo and accelerate glacier melt is of interest in Washington because snow and glacier melt are an important source of water resources, and glaciers are retreating. In August 2012 on Snow Dome, Mount Olympus, Washington, we measured snow surface spectral albedo and collected surface snow samples and a 7 m ice core. The snow and ice samples were analyzed for iron (Fe, used as a dust proxy) via inductively coupled plasma sector field mass spectrometry, total impurity content gravimetrically, BC using a single-particle soot photometer (SP2), and charcoal …

Glacial Till Prospecting In Southwest Ohio: Implications For Improved Sampling, Dylan J. Mckevitt

The Research and Scholarship Symposium (2013-2019)

Glacial till (drift) prospecting has served a major role in corporate mineral exploration, especially for gold and diamond during the past 30 years. It involves analyzing heavy indicator minerals from bulk sampling of various glacial deposits in order to track up ice flow direction to the potential orebody (such as a kimberlite pipe or Cu-Ni deposit), a technique commonly used in Canada but not in the U.S. Heavy minerals including diamond, gold, and native copper have been found in Ohio glacial till; the provenance of these heavy minerals is the Precambrian bedrock north of Ohio. This study utilized standard procedures …

Determining Provenance Of Glacial Material In Southwestern Ohio, Jorian Krob

The Research and Scholarship Symposium (2013-2019)

During the last glacial maximum, ice moved south from Canada to cover much of the northern United States. This included the northern and western portions of Ohio. As the ice migrated it picked up Canadian bedrock which it transported and then left in Ohio when the ice retreated. The goal of this project was to determine the provenance (the source of origin) of the glacial material that is located in Greene, Clark, Montgomery, Logan, and Champaign Counties in Ohio. To determine where in southern Canada the material in these counties came from, this project included literature review into the glacial …

Early Miocene Antarctic Glacial History: New Insights From Heavy Mineral Analysis From Andrill And–2a Drill Core Sediments, Francesco Iacoviello, Giovanna Giorgetti, Isabella Turbanti Memmi, Sandra Passchier

ANDRILL Research and Publications

The present study deals with heavy mineral analysis of late Early Miocene marine sediments recovered in the McMurdo Sound region (Ross Sea, Antarctica) during the ANDRILL— SMS Project in 2007. The main objective is to investigate how heavy mineral assemblages reflect different source rocks and hence different provenance areas. These data contribute to a better understanding of East Antarctica ice dynamics in the Ross Sea sector during the Early Miocene (17.6–20.2 Ma), a time of long-term global warming and sea level rise. The AND-2A drill core recovered several stratigraphic intervals that span from Early Miocene to Pleistocene and it collected …

Heat Sources Within The Greenland Ice Sheet: Dissipation, Temperate Paleo-Firn And Cryo-Hydrologic Warming, M. P. Lüthi, C. Ryser, L. C. Andrews, G. A. Catania, M. Funk, R. L. Hawley

Dartmouth Scholarship

Ice temperature profiles from the Greenland Ice Sheet contain information on the deformation history, past climates and recent warming. We present full-depth temperature profiles from two drill sites on a flow line passing through Swiss Camp, West Greenland. Numerical modeling reveals that ice temperatures are considerably higher than would be expected from heat diffusion and dissipation alone. The possible causes for this extra heat are evaluated using a Lagrangian heat flow model. The model results reveal that the observations can be explained with a combination of different processes: enhanced dissipation (strain heating) in ice-age ice, temperate paleo-firn, and cryo-hydrologic warming …

Collaborative Research: Byrd Glacier Flow Dynamics, Gordon S. Hamilton

University of Maine Office of Research Administration: Grant Reports

This award supports a project to understand the flow dynamics of large, fast-moving outlet glaciers that drain the East Antarctic Ice Sheet. The project includes an integrated field, remote sensing and modeling study of Byrd Glacier which is a major pathway for the discharge of mass from the East Antarctic Ice Sheet (EAIS) to the ocean. Recent work has shown that the glacier can undergo short-lived but significant changes in flow speed in response to perturbations in its boundary conditions. Because outlet glacier speeds exert a major control on ice sheet mass balance and modulate the ice sheet contribution to …

Collaborative Research: Glacier-Ocean Coupling In A Large East Greenland Fjord, Gordon S. Hamilton

University of Maine Office of Research Administration: Grant Reports

This award will support a study of glacier-fjord interactions in east Greenland. The 'Intellectual Merit' of the proposed study lies in the current understanding that the contribution of the Greenland Ice Sheet to sea level rise more than doubled in the last seven years, mostly because of a widespread and nearly simultaneous acceleration of many glaciers that terminate at tidewater in deep fjords. Understanding the causes of changes in glacier dynamics, and predicting their future trajectories is a topic of enormous scientific and societal importance. The Greenland fjords provide an intimate connection between the ice sheet and the ocean and, …

Glacier Status And Contribution To Streamflow In The Olympic Mountains, Usa, Jon L. Riedel, Steve Wilson, William Baccus, Michael Larrabee, T.J. Fudge, Andrew G. Fountain

Geology Faculty Publications and Presentations

The Olympic Peninsula, Washington, USA, currently holds 184 alpine glaciers larger than 0.01 km² and their combined area is 30.2 ± 0.95km². Only four glaciers are >1km² and 120 of the others are -¹ (1900–80) to 0.54 km² a^-¹ (1980–2009). Thinning rates on four of the largest glaciers averaged nearly 1ma^-¹ from 1987 to 2010, resulting in estimated volume losses of 17–24%. Combined glacial snow, firn and ice melt in the Hoh watershed is in the range 63–79 ± 7 × 10⁶m³, or 9–15% of total May–September streamflow. In the critical August–September …

Geologic Map Of The Welcome Quadrangle And An Adjacent Part Of The Wells Quadrangle, Elko County, Nevada, Allen J. Mcgrew, Arthur W. Snoke

Geology Faculty Publications

Located in central Elko County, the Welcome and adjacent part of the Wells quadrangles expose a remarkable array of critical relationships for understanding the geologic history of the State of Nevada and the interior of the southwestern U.S. Cordillera. Covering the northern end of the East Humboldt Range and adjacent Clover Valley and Clover Hill, this map includes the northern terminus of the Ruby Mountains-East Humboldt Range metamorphic core complex. The oldest rocks in the State of Nevada (the gneiss complex of Angel Lake), and Nevada’s only exposures of Archean rock, form the core of a multikilometer scale, southward-closing recumbent …