Paul Bierman

• University of Vermont

Basal materials in ice cores hold information about paleoclimate conditions, glacial processes, and the timing of past ice-free intervals, all of which aid understanding of ice sheet stability and its contribution to sea level rise in a warming climate. Only a few cores have been drilled through ice sheets into the underlying sediment and bedrock,...

Measurements of multiple cosmogenic nuclides in a single sample are valuable for various applications of cosmogenic nuclide exposure dating and allow for correcting exposure ages for surface weathering and erosion and establishing exposure–burial history. Here we provide advances in the measurement of cosmogenic 10Be in pyroxene and constraints on...

The persistence and size of the Greenland Ice Sheet (GrIS) through the Pleistocene is uncertain. This is important because reconstructing changes in the GrIS determines its contribution to sea level rise during prior warm climate periods and informs future projections. To understand better the history of Greenland’s ice, we analyzed glacial till co...

To understand the erosivity of the eastern portion of the Laurentide Ice Sheet and the isotopic characteristics of the sediment it transported, we sampled buried sand from deglacial features (eskers and deltas) across eastern Canada (n = 10), a landscape repeatedly covered by the Quebec-Labrador Ice Dome. We measured concentrations of 10Be and 26Al...

In 1966, drilling at Camp Century, Greenland, recovered 3.44 meters of sub-glacial material from beneath 1350 meters of ice. Although prior analysis of this material showed that the core includes glacial sediment, ice, and sediment deposited during an interglacial, the sub-glacial material had never been thoroughly studied. To better characterize t...

Rock glaciers are common in alpine landscapes, but their evolution over time and their significance as agents of debris transport are not well‐understood. Here, we assess the movement of an ice‐cemented rock glacier over a range of timescales using GPS surveying, satellite‐based radar, and cosmogenic ¹⁰Be surface‐exposure dating. GPS and InSAR meas...

Measurements of multiple cosmogenic nuclides in a single sample are valuable for various applications of cosmogenic nuclide exposure dating and allow for correcting exposure ages for surface weathering and erosion and establishing exposure-burial history. Here we provide advances in the measurement of cosmogenic 10Be in pyroxene and constraints on...

Basal materials in ice cores contain information about paleoclimate conditions, glacial processes, and the timing of past ice-free intervals, all of which aid understanding of ice-sheet stability and its contribution to sea-level rise in a warming climate. Only a few ice cores have been drilled through ice sheets to the underlying sediment and bedr...

How tectonic forcing, expressed as base level change, is encoded in the stratigraphic and geomorphic records of coupled source-to-sink systems remains uncertain. Using sedimentological, geochronological and geomorphic approaches, we describe the relationship between transient topographic change and sediment deposition for a low-storage system force...

The timing of the Laurentide Ice Sheet's final retreat from North America's Laurentian Great Lakes is relevant to understanding regional meltwater routing, changing proglacial lake levels, and lake-bottom stratigraphy following the Last Glacial Maximum. Recessional moraines on Isle Royale, the largest island in Lake Superior, have been mapped but n...

Glacial and periglacial sediments and landforms record the chronology of glaciation and amount of Pleistocene erosion during colder periods that added substantially to global sediment budgets and contributed to the global CO2 cycle. The now-drained glacial Lake Devlin, dammed in a Front Range tributary valley by a glacier in the North Branch of Bou...

We review geochronological data relating to the timing and rate of Laurentide Ice Sheet recession in the northeastern United States and model ice margin movements in a Bayesian framework using compilations of previously published organic ¹⁴ C ( n = 133) and in situ cosmogenic ¹⁰ Be ( n = 95) ages. We compare the resulting method‐specific chronologi...

Temporal and spatial variations of tectonic rock uplift are generally thought to be the main controls on long-term erosion rates in various landscapes. However, rivers continuously lengthen and capture drainages in strike-slip fault systems due to ongoing motion across the fault, which can induce changes in landscape forms, drainage networks, and l...

Past interglacial climates with smaller ice sheets offer analogs for ice sheet response to future warming and contributions to sea level rise; however, well-dated geologic records from formerly ice-free areas are rare. Here we report that subglacial sediment from the Camp Century ice core preserves direct evidence that northwestern Greenland was ic...

Constraining the timing and rate of Laurentide Ice Sheet (LIS) retreat through the northeastern United States is important for understanding the co-evolution of complex climatic and glaciologic events that characterized the end of the Pleistocene epoch. However, no in situ cosmogenic 10Be exposure age estimates for LIS retreat exist through large p...

10 Be is an important isotope for accelerator mass spectrometry (AMS) because of the demand for cosmogenic radionuclide dating methods in the earth science and paleo-sciences community. At the iThemba Laboratory for Accelerator Based Science (iThemba LABS) we implemented full suppression of the interfering isobar 10 B using a silicon nitride foil-s...

The timing of the Laurentide Ice Sheet’s final retreat from North America’s Laurentian Great Lakes is relevant to understanding regional meltwater routing, changing proglacial lake levels, and lake-bottom stratigraphy following the Last Glacial Maximum. Recessional moraines on Isle Royale, the largest island in Lake Superior, have been mapped but n...

We present new data from the debris-rich basal ice layers of the NEEM ice core (NW Greenland). Using mineralogical observations, SEM imagery, geochemical data from silicates (meteoric ¹⁰ Be, εNd, ⁸⁷ Sr/ ⁸⁶ Sr) and organic material (C/N, δ ¹³ C), we characterize the source material, succession of previous glaciations and deglaciations and the paleoe...

While there are no ice sheets in the Northern Hemisphere outside of Greenland today, it is uncertain whether this was also the case during most other Quaternary interglacials. We show, using in situ cosmogenic nuclides in ice-rafted debris, that the Laurentide Ice Sheet was likely more persistent during Quaternary interglacials than often thought....

Accurate reconstruction of Laurentide Ice Sheet volume changes following the Last Glacial Maximum is critical for understanding ice sheet contribution to sea-level rise, the resulting influence of meltwater on oceanic circulation, and the spatial and temporal patterns of deglaciation. Here, we provide empirical constraints on Laurentide Ice Sheet t...

River erosion affects the carbon cycle and thus climate by exporting terrigenous carbon to seafloor sediment and by nourishing CO2-consuming marine life. The Yukon River–Bering Sea system preserves rare source-to-sink records of these processes across profound changes in global climate during the past 5 million years (Ma). Here, we expand the terre...

Reference materials are key for assessing inter-laboratory variability and measurement quality, and for placing analytical uncertainty bounds on sample analyses. Here, we investigate four years of data resulting from repeated processing of the CRONUS-N reference material for cosmogenic ¹⁰Be and ²⁶Al analyses. At University of Vermont, we prepared a...

We collected a debris-rich ice core from a buried ice mass in Ong Valley, located in the Transantarctic Mountains in Antarctica. We measured cosmogenic nuclide concentrations in quartz obtained from the ice core to determine the age of the buried ice mass and infer the processes responsible for the emplacement of the debris currently overlaying the...

We use 25 new measurements of in situ produced cosmogenic 26Al and 10Be in river sand, paired with estimates of dissolved load flux in river water, to characterize the processes and pace of landscape change in central Cuba. Long-term erosion rates inferred from 10Be concentrations in quartz extracted from central Cuban river sand range from 3.4–189...

River erosion affects the carbon cycle and thus climate by exporting terrigenous carbon to seafloor sediment and by nourishing CO2-consuming marine life. The Yukon River-Bering Sea system preserves rare source-to-sink records of these processes across profound changes in global climate during the past five million years (Ma). Here, we expand the te...

Geochronology and geochemistry are critical tools in geoscience research and research training, but students and faculty at many institutions have little or no access to the specialized and expensive facilities needed for sample preparation and analysis. Here, we explore whether a community laboratory, dedicated to hosting and training visitors, ca...

Long-term erosion rates in Tasmania, at the southern end of Australia's Great Dividing Range, are poorly known; yet, this knowledge is critical for making informed land-use decisions and improving the ecological health of coastal ecosystems. Here, we present quantitative, geologically relevant estimates of erosion rates for the George River basin,...

Plain Language Summary During ice ages in the past 2.6 million years, mid‐latitude landscapes like central Pennsylvania were shaped by extreme cold and thawing permafrost, conditions that promote fast breakdown and transport of soil. However, the effect of these cold climates and subsequent warming on erosion rates is unclear since we often lack re...

The quantification of rates for the competing forces of tectonic uplift and erosion has important implications for understanding topographic evolution. Here, we quantify the complex interplay between tectonic uplift, topographic development, and erosion recorded in the hanging walls of several active reverse faults in the Ventura basin, southern Ca...

INVENTING AUGR: REFLECTIONS ON DESIGNING AND IMPLEMENTING AN AUTHENTIC UNDERGRADUATE GEOSCIENCE RESEARCH EXPERIENCE BENNETT, Isabella B.1, SOTO-VILLANUEVA, Krizzia2, BIERMAN, Paul R.1, CORBETT, Lee B.1, ACOSTA-COLON, Angel3, HUGHES, K. Stephen4 and WHITTAKER, Joseph A.5, (1)Rubenstein School of Environment and Natural Resources, University of Verm...

Tropical islands, including many in island arcs, are subjected to recurring disturbances from extreme storms such as tropical cyclones. To test whether such storms influence cosmogenic nuclide concentrations such that they do not reflect long-term rates of erosion, we measured meteoric and in situ ¹⁰Be in river sediment samples from Dominica, an an...

We consider measurements of both in situ produced cosmogenic nuclides and dissolved load flux to characterize the processes and pace of landscape change in central Cuba. The tropical landscape of Cuba is losing mass in multiple ways, making it difficult to quantify total denudation rates and thus to assess the impact of agricultural practices on ra...

The preservation of cosmogenic nuclides that accumulated during periods of prior exposure but were not subsequently removed by erosion or radioactive decay complicates interpretation of exposure, erosion, and burial ages used for a variety of geomorphological applications. In glacial settings, cold-based, non-erosive glacier ice may fail to remove...

Outlet glaciers that flow through the Transantarctic Mountains (TAM) experienced changes in ice thickness greater than other coastal regions of Antarctica during glacial maxima. As a result, ice-free areas that are currently exposed may have been covered by ice at various points during the Cenozoic, complicating our understanding of ecological succ...

We assess if variations in the in situ cosmogenic 26Al/10Be production ratio expected from nuclear physics are consistent with empirical data, knowledge critical for two-isotope studies. We do this using 313 samples from glacially transported boulders or scoured bedrock with presumed simple exposure histories in the Informal Cosmogenic-nuclide Expo...

Long-term erosion rates in Tasmania, at the southern end of Australia’s Great Dividing Range, are poorly known, yet such knowledge is critical for making informed land-use decisions and improving ecological health of coastal ecosystems. Here, we present the first quantitative, geologically-relevant estimates of erosion rates for the George River ba...

The preservation of cosmogenic nuclides that accumulated during periods of prior exposure but were not subsequently removed by erosion or radioactive decay, complicates interpretation of exposure, erosion, and burial ages used for a variety of geomorphological applications. In glacial settings, cold-based, non-erosive glacier ice may fail to remove...

Accurately inferring erosion rates from cosmogenic isotope concentrations in river sand assumes temporally steady concentrations; few studies test this assumption. Following Hurricane María in Puerto Rico, we quantified temporal variability in meteoric and in situ ¹⁰Be (¹⁰Bem, ¹⁰Bei) on sand-sized grains of riverine transported material in landslid...

Significance Understanding Greenland Ice Sheet history is critical for predicting its response to future climate warming and contribution to sea-level rise. We analyzed sediment at the bottom of the Camp Century ice core, collected 120 km from the coast in northwestern Greenland. The sediment, frozen under nearly 1.4 km of ice, contains well-preser...

The behavior of the Greenland Ice Sheet during the Pleistocene remains uncertain due to the paucity of evidence predating the Last Glacial Maximum. Here, we employ a novel approach, cosmogenic nuclide analysis of individual subglacially-derived cobbles, which allows us to make inferences about ice sheet processes and subglacial erosion. From three...

We attempt to synchronize the North American Varve Chronology (NAVC) with ice core and calendar year timescales by comparing records of atmospherically produced 10Be fallout in the NAVC and in ice cores. The North American Varve Chronology (NAVC) is a sequence of 5659 varves deposited in a series of proglacial lakes adjacent to the southeast margin...

Measuring the cosmogenic isotope, beryllium 10 (10Be) in stream sand is increasingly used for inferring erosion rates at watershed scales. We assume that 10Be integrates through rare, large magnitude events like floods or mass movements, thus providing geologically-meaningful average rates of landscape change. This assumption has been assessed for...

Stephen C. Porter was an international leader in Quaternary science for several decades, having worked on most of the world’s continents and having led international organizations and a prominent interdisciplinary journal. His work influenced many individuals, and he played an essential role in linking Chinese Quaternary science with the broader in...

Late Cenozoic cooling and changes in glacial–interglacial cycle tempo are thought to increase global rates of erosion starting ~3 million years ago (Ma). Bedrock rivers set rates and patterns of erosion in most landscapes, but constraints on river response to late Cenozoic climate change remain elusive. Here, we determine cosmogenic isotope and lum...

Modeling studies and field mapping show that increases in ice thickness during glacial periods were not uniform across Antarctica. Rather, outlet glaciers that flow through the Transantarctic Mountains (TAM) experienced the greatest changes in ice thickness. As a result, ice-free areas that are currently exposed may have been covered by ice at vari...

We attempt to synchronize the North American Varve Chronology (NAVC) with the calendar year time scale by comparing records of atmospherically produced Be-10 fallout in the NAVC and in ice cores. The North American Varve Chronology (NAVC) is a sequence of 5659 varves deposited in a series of proglacial lakes adjacent to the southeast margin of the...

The multi‐million year history of the Greenland Ice Sheet remains poorly known. Ice‐proximal glacial marine diamict provides a direct but discontinuous record of ice sheet behavior; it is underutilized as a climate archive. Here, we present a novel multiproxy analysis of an Early Pleistocene marine diamict from northwestern Greenland. Low cosmogeni...

Since the 1990s, cosmogenic nuclides have revolutionized the study of Earth surface processes, particularly the understanding of rates and dates. These nuclides, including ³He, ¹⁰Be, ¹⁴C, ²¹Ne, ²⁶Al, and ³⁶Cl, enable dating of landforms and the measurement of erosion rates both at the scale of drainage basins and at specific locations on Earth's su...