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Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu 2016 University of Chinese Academy of Sciences

Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu

Shuang-ye Wu

Reconstruction of the Hirnantian (Late Ordovician) palaeotopography in South China is important for understanding the distribution pattern of the Hirnantian marine depositional environment. In this study, we reconstructed the Hirnantian palaeotopography in the Upper Yangtze region based on the rankings of the palaeo-water depths, which were inferred according to the lithofacies and biofacies characteristics of the sections. Data from 374 Hirnantian sections were collected and standardized through the online Geobiodiversity Database. The Ordinary Kriging interpolation method in the ArcGIS software was applied to create the continuous surface of the palaeo-water depths, i.e. the Hirnantian palaeotopography. Meanwhile, the line transect ...


Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. McGrew, Kenneth A. Foland 2016 Yale University

Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. Mcgrew, Kenneth A. Foland

Allen J. McGrew

New mapping, structural analysis, and 40Ar/39Ar dating reveal an unusually well‐constrained history of Late Eocene extension in the Copper Mountains of the northern Basin and Range province. In this area, the northeast‐trending Copper Creek normal fault juxtaposes a distinctive sequence of metacarbonate and granitoid rocks against a footwall of Upper Precambrian to Lower Cambrian quartzite and phyllite. Correlation of the hanging wall with footwall rocks to the northwest provides an approximate piercing point that requires 8–12 km displacement in an ESE direction. This displaced fault slice is itself bounded above by another normal fault (the Meadow ...


Prevailing Weather Conditions During Summer Seasons Around Gangotri Glacier, Pratap Singh, Umesh K. Haritashya, K. S. Ramasastri, Naresh Kumar 2016 Hydro Tasmania Consulting

Prevailing Weather Conditions During Summer Seasons Around Gangotri Glacier, Pratap Singh, Umesh K. Haritashya, K. S. Ramasastri, Naresh Kumar

Umesh K. Haritashya

Meteorological data collected near the snout of the Gangotri Glacier suggest that the study area receives less rainfall. The average seasonal rainfall is observed to be about 260 mm. The rainfall distribution does not show any monsoon impact. Amount of seasonal rainfall is highly variable (131.4-368.8 mm) from year to year, but, in general, August had the maximum rainfall. A verage daily maximum and minimum temperatures were 14.7 and 4.1°C respectively, whereas average mean temperature was 9.4°C. July was recorded as the warmest month. During daytime, wind speed was four times higher than ...


Multispectral Image Analysis Of Glaciers And Glacier Lakes In The Chugach Mountains, Alaska, Jeffrey Kargel, Matthew Beedle, Andrew Bush, Francisco Carreño, Elena Castellanos, Umesh Haritashya, Gregory Leonard, Javier Lillo, Ivan Lopez, Mark Pleasants, Edward Pollock, David Wolfe 2016 University of Colorado

Multispectral Image Analysis Of Glaciers And Glacier Lakes In The Chugach Mountains, Alaska, Jeffrey Kargel, Matthew Beedle, Andrew Bush, Francisco Carreño, Elena Castellanos, Umesh Haritashya, Gregory Leonard, Javier Lillo, Ivan Lopez, Mark Pleasants, Edward Pollock, David Wolfe

Umesh Haritashya

The Chugach Mountains contain the largest nonpolar alpine glaciers in the world and include a wide variety of glacier types: some are land terminating; some calve variously into tidewater, lakes, and rivers; some are heavily debris covered; some are surge-type, whereas others are neither debris covered nor surge type. Nearly all are retreating, thinning, or both, though some rare ones are advancing, and some are thickening at high elevations. To assist the further documentation of changes, we establish an inventory of glaciers in the eastern Chugach Mountains. Several case studies of diverse glacier types showcase remotesensing applications and are used ...


Iceland: Extreme Learning In The Land Of Fire And Ice, Jason Polk, Leslie North 2016 Western Kentucky University Hoffman Institute

Iceland: Extreme Learning In The Land Of Fire And Ice, Jason Polk, Leslie North

Leslie North

WKU Libraries kicked off the spring season of "Far Away Places" with Dr. Jason Polk and Dr. Leslie North, Asstant Professors from the Department of Geography and Geology at WKU, who talked about leading a study abroad group to Iceland in the summer of 2015. WKU Libraries kicks off the spring season of Far Away Places with Jason Polk and Leslie North, Asst. Professors from the Department of Geography and Geology at WKU, who will be talking about leading a study abroad group to Iceland in the summer of 2015. Dr. Polk and Dr. North co-taught this course with faculty ...


Distributed Modeling Of Ablation (1996–2011) And Climate Sensitivity On The Glaciers Of Taylor Valley, Antarctica, Matthew J. Hoffman, Andrew G. Fountain, Glen E. Liston 2016 Los Alamos National Laboratory

Distributed Modeling Of Ablation (1996–2011) And Climate Sensitivity On The Glaciers Of Taylor Valley, Antarctica, Matthew J. Hoffman, Andrew G. Fountain, Glen E. Liston

Geology Faculty Publications and Presentations

The McMurdo Dry Valleys of Antarctica host the coldest and driest ecosystem on Earth, which is acutely sensitive to the availability of water coming from glacial runoff. We modeled the spatial variability in ablation and assessed climate sensitivity of the glacier ablation zones using 16 years of meteorological and surface mass-balance observations collected in Taylor Valley. Sublimation was the primary form of mass loss over much of the ablation zones, except for near the termini where melt, primarily below the surface, dominated. Microclimates in ~10 m scale topographic basins generated melt rates up to ten times higher than over smooth ...


Processes Controlling Carbon Cycling In Antarctic Glacier Surface Ecosystems, Elizabeth A. Bagshaw, Martyn Tranter, Jemma L. Wadham, Andrew G. Fountain, A. Dubnick, S. Fitzsimons 2016 Cardiff University

Processes Controlling Carbon Cycling In Antarctic Glacier Surface Ecosystems, Elizabeth A. Bagshaw, Martyn Tranter, Jemma L. Wadham, Andrew G. Fountain, A. Dubnick, S. Fitzsimons

Geology Faculty Publications and Presentations

Glacier surface ecosystems, including cryoconite holes and cryolakes, are significant contributors to regional carbon cycles. Incubation experiments to determine the net production (NEP) of organic matter in cryoconite typically have durations of 6-24 hours, and produce a wide range of results, many of which indicate that the system is net heterotrophic. We employ longer term incubations to examine the temporal variation of NEP in cryoconite from the McMurdo Dry Valleys, Antarctica to examine the effect of sediment disturbance on system production, and to understand processes controlling production over the lifetimes of glacier surface ecosystems. The shorter-term incubations have durations of ...


Estimating Supraglacial Lake Depth In West Greenland Using Landsat 8 And Comparison With Other Multispectral Methods, Allen Pope, T A. Scambos, M Moussavi, M Tedesco, M Willis, D Shean, S Grigsby 2016 University of Colorado Boulder

Estimating Supraglacial Lake Depth In West Greenland Using Landsat 8 And Comparison With Other Multispectral Methods, Allen Pope, T A. Scambos, M Moussavi, M Tedesco, M Willis, D Shean, S Grigsby

University Libraries Open Access Fund Supported Publications

Liquid water stored on the surface of ice sheets and glaciers impacts surface mass balance, ice dynamics, and heat transport. Multispectral remote sensing can be used to detect supraglacial lakes and estimate their depth and area. In this study, we use in situ spectral and bathymetric data to assess lake depth retrieval using the recently launched Landsat 8 Operational Land Imager (OLI). We also extend our analysis to other multispectral sensors to evaluate their performance with similar methods. Digital elevation models derived from WorldView stereo imagery (pre-lake filling and post-drainage) are used to validate spectrally derived depths, combined with a ...


Large Ensemble Modeling Of The Last Deglacial Retreat Of The West Antarctic Ice Sheet: Comparison Of Simple And Advanced Statistical Techniques, David Pollard, Won Chang, Murali Haran, Patrick Applegate, Robert DeConto 2016 The Pennsylvania State University

Large Ensemble Modeling Of The Last Deglacial Retreat Of The West Antarctic Ice Sheet: Comparison Of Simple And Advanced Statistical Techniques, David Pollard, Won Chang, Murali Haran, Patrick Applegate, Robert Deconto

Geosciences Department Faculty Publication Series

A 3-D hybrid ice-sheet model is applied to the last deglacial retreat of the West Antarctic Ice Sheet over the last  ∼  20 000 yr. A large ensemble of 625 model runs is used to calibrate the model to modern and geologic data, including reconstructed grounding lines, relative sea-level records, elevation–age data and uplift rates, with an aggregate score computed for each run that measures overall model–data misfit. Two types of statistical methods are used to analyze the large-ensemble results: simple averaging weighted by the aggregate score, and more advanced Bayesian techniques involving Gaussian process-based emulation and calibration, and ...


Bering Sea Surface Water Conditions During Marine Isotope Stages 12 To 10 At Navarin Canyon (Iodp Site U1345), Beth E. Caissie, Julie Brigham-Grette, Mea S. Cook, Elena Colmenero-Hidalgo 2016 Iowa State University

Bering Sea Surface Water Conditions During Marine Isotope Stages 12 To 10 At Navarin Canyon (Iodp Site U1345), Beth E. Caissie, Julie Brigham-Grette, Mea S. Cook, Elena Colmenero-Hidalgo

Geological and Atmospheric Sciences Publications

Records of past warm periods are essential for understanding interglacial climate system dynamics. Marine Isotope Stage 11 occurred from 425 to 394 ka, when global ice volume was the lowest, sea level was the highest, and terrestrial temperatures were the warmest of the last 500 kyr. Because of its extreme character, this interval has been considered an analog for the next century of climate change. The Bering Sea is ideally situated to record how opening or closing of the Pacific–Arctic Ocean gateway (Bering Strait) impacted primary productivity, sea ice, and sediment transport in the past; however, little is known ...


Mechanism Of Seasonal Arctic Sea Ice Evolution And Arctic Amplification, Kwang-Yul Kim, Benjamin D. Hamlington, Hanna Na, Jinju Kim 2016 Old Dominion University

Mechanism Of Seasonal Arctic Sea Ice Evolution And Arctic Amplification, Kwang-Yul Kim, Benjamin D. Hamlington, Hanna Na, Jinju Kim

CCPO Publications

Sea ice loss is proposed as a primary reason for the Arctic amplification, although the physical mechanism of the Arctic amplification and its connection with sea ice melting is still in debate. In the present study, monthly ERA-Interim reanalysis data are analyzed via cyclostationary empirical orthogonal function analysis to understand the seasonal mechanism of sea ice loss in the Arctic Ocean and the Arctic amplification. While sea ice loss is widespread over much of the perimeter of the Arctic Ocean in summer, sea ice remains thin in winter only in the Barents-Kara seas. Excessive turbulent heat flux through the sea ...


Lateral Variations In Sediment Provenance And Grain Size Along The Baffin Island Slope, Anna Klein 2016 University of Colorado, Boulder

Lateral Variations In Sediment Provenance And Grain Size Along The Baffin Island Slope, Anna Klein

Undergraduate Honors Theses

Baffin Bay is a 689,000 km­­2 basin linking the Arctic and the North Atlantic oceans. Nearby ice sheets and their ice streams are responsible for eroding, transporting, and depositing sediment of various size fractions on the sea floor. For over thirty years, geologists have known of the presence of detrital carbonate-rich (DC-) facies in the Baffin Bay Quaternary sediment sequence. It has been demonstrated that the distribution of marine carbonate facies, carbonate sources on land, and carbonate on the floors of the large Canadian Arctic Channels can reveal a relationship between land and sea records. This thesis aims ...


Late Pleistocene Glaciations And Catastrophic Glacial Floods Of Central Colorado, Cole C. Pazar 2016 University of Colorado Boulder, Department of Geological Sciences

Late Pleistocene Glaciations And Catastrophic Glacial Floods Of Central Colorado, Cole C. Pazar

Undergraduate Honors Theses

Late Pleistocene glaciations of the Sawatch and Elk Mountain Ranges of Central Colorado at ~130 and ~20 ka left behind glacial features in the topography, ideal for constraining the local climactic variability. In the northern end of the Sawatch Range, distinct lateral and terminal moraines reveal strong geologic evidence that multiple large glaciers drained eastward. Two of these appear to have dammed the Arkansas River. Very fine-grained lacustrine sediments, ‘ice-rafted’ boulders, and catastrophic glacial flood boulders down-valley, show at least two glacial-ice dammed lakes that catastrophically drained. We report flood discharge calculations consistent with previous estimates, on the order of ...


A Comparison Between Mass Balance Of The Taku And Lemon Creek Glaciers Derived From Glaciological Methods And Grace, Danielle Beaty 2016 University of Colorado, Boulder

A Comparison Between Mass Balance Of The Taku And Lemon Creek Glaciers Derived From Glaciological Methods And Grace, Danielle Beaty

Undergraduate Honors Theses

Glacier mass balance is of increasing concern due to climate change, and for this reason it is important to determine and refine the best methodology for obtaining mass balance data. The present study compares the use of in situ field measurements with gravimetric mass measurements obtained by the satellite GRACE. Field mass balance data from both the Taku and Lemon Creek glaciers in southeast Alaska was compared to GRACE data for the years 2003­2014, and a linear regression analysis was performed to determine the correlation between these two data types. GRACE and field data show similar long term trends ...


Pinedale Glaciation At Longs Peak And Glacier Gorge, Selena Neale 2016 University of Colorado, Boulder

Pinedale Glaciation At Longs Peak And Glacier Gorge, Selena Neale

Undergraduate Honors Theses

Little is known about the Longs Peak and Glacier Gorge Glaciers, located in the Front Range in Rocky Mountain National Park, because, as of this thesis, they had yet to be studied. An understanding of the degree to which these glaciers shaped the landscape around them and what kind of climate could have created these glaciers was the goal of the thesis. I calculate the rate of backwearing of the glacier headwall in order to document the influence of these glaciers on the surrounding alpine landscape. I also created 1D models of the glaciers using Matlab to estimate a range ...


Response Of Antarctic Cryoconite Microbial Communities To Light, Elizabeth A. Bagshaw, Jemma L. Wadham, Martyn Tranter, Rupert Perkins, Alistair Morgan, Christopher J. Williamson, Andrew G. Fountain, Sean Fitzsimons, Ashley Dubnick 2016 Cardiff University

Response Of Antarctic Cryoconite Microbial Communities To Light, Elizabeth A. Bagshaw, Jemma L. Wadham, Martyn Tranter, Rupert Perkins, Alistair Morgan, Christopher J. Williamson, Andrew G. Fountain, Sean Fitzsimons, Ashley Dubnick

Geology Faculty Publications and Presentations

Microbial communities on polar glacier surfaces are found dispersed on the ice surface, or concentrated in cryoconite holes and cryolakes, which are accumulations of debris covered by a layer of ice for some or all of the year. The ice lid limits the penetration of photosynthetically available radiation (PAR) to the sediment layer, since the ice attenuates up to 99% of incoming radiation. This suite of field and laboratory experiments demonstrates that PAR is an important control on primary production in cryoconite and cryolake ecosystems. Increased light intensity increased efficiency of primary production in controlled laboratory incubations of debris from ...


High-Resolution Ground-Penetrating Radar Profiles Of Perennial Lake Ice In The Mcmurdo Dry Valleys, Antarctica: Horizon Attributes, Unconformities, And Subbottom, Hilary A. Dugan, Steven A. Arcone, Maciej K. Obryk, Peter T. Doran 2016 University of Wisconsin - Madison

High-Resolution Ground-Penetrating Radar Profiles Of Perennial Lake Ice In The Mcmurdo Dry Valleys, Antarctica: Horizon Attributes, Unconformities, And Subbottom, Hilary A. Dugan, Steven A. Arcone, Maciej K. Obryk, Peter T. Doran

Geology Faculty Publications and Presentations

Ground-penetrating radar (GPR) is not commonly used to study lake ice, and in general, the ground-based use of radar frequencies greater than 500 MHz in cryosphere geophysics is rare, due to a general interest in deeper stratigraphy and the difficulty of extensive profiling over rough snow surfaces. Our goal was to find further information on the origin of the deposition and formation of intra-ice layers, bottom topography, and subbottom deposits using GPR with pulses centered near 850 MHz on two permanently ice-covered lakes in the Mc- Murdo Dry Valleys, Antarctica. The profiles were obtained using a one-person sled operation over ...


Apparent Glacially Induced Structural Controls On Limestone Conduit Development In Ohio Caverns, United States, Adrienne M. Watts, Ira D. Sasowsky 2015 University Of Akron

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 tensile ...


Climb To The Ice, Richard Vaughan 2015 Indiana University Maurer School of Law

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 2015 Indiana University Maurer School of Law

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.


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