Wayne H. Pollard

McGill University | McGill · Department of Geography

Mega retrogressive thaw slumps (MRTS, >10⁶ m³) are a major threat to Arctic infrastructure, alter regional biogeochemistry, and impact Arctic carbon budgets. However, processes initiating and reactivating MRTS are insufficiently understood. We hypothesize that MRTS preferentially develop a polycyclic behavior because the material is thermally and m...

In the Canadian high Arctic, tabular massive ground ice is found extensively throughout the Eureka Sound Lowlands (ESL). This study evaluates the development of tabular massive ice in raised marine-deltaic sediments of the ESL based on new cryostratigraphic data from sites found between the coastline and the Holocene marine limit. At all sites, mas...

We investigate the water sources for a perennial spring, “Little Black Pond,” located at Expedition Fiord, Axel Heiberg Island in the Canadian High Arctic based on dissolved gases. We measured the dissolved O2 in the likely sources Phantom Lake and Astro Lake and the composition of noble gases (³He/⁴He, ⁴He, Ne,³⁶Ar, ⁴⁰Ar, Kr, Xe), N2, O2, CO2, H2S...

We use the freezing point depressing magnesium and calcium perchlorates in Martian regolith to redistribute ground ice by residual liquid water migration following the initial emplacement of ground ice by vapour deposition. This residual liquid water is moved by forces generated by periodic surface temperatures that decay with depth in conjunction...

We report 3 years of data from one meteorological and three smaller stations in University Valley, a high-elevation (1677 m) site in the Dry Valleys of Antarctica with extensive dry permafrost. Mean air temperature was -23.4°C. Summer air temperatures were virtually always < 0°C and were consistent with the altitude lapse rate and empirical relatio...

Global warming and permafrost degradation are impacting landscapes, ecosystems and the climate-carbon system. Current ground ice and geohazard maps rely on the frost susceptibility of surficial sediments, and substantial areas underestimate ice abundance. Here we use a soil environmental model to show the importance of considering unfrozen water co...

Ice wedges are ubiquitous periglacial features in permafrost terrain. This study investigates the timing of ice wedge formation in the Fosheim Peninsula (Ellesmere and Axel Heiberg Islands). In this region, ice wedge polygons occupy ~50% of the landscape, the majority occurring below the marine limit in the Eureka Sound Lowlands. Numerical simulati...

Arctic coastal infrastructure and cultural and archeological sites are increasingly vulnerable to erosion and flooding due to amplified warming of the Arctic, sea level rise, lengthening of open water periods, and a predicted increase in frequency of major storms. Mitigating these hazards necessitates decision-making tools at an appropriate scale....

We present the basic theory of stable isotopes (δ(18O) and δ(D)) of freezing water solutions in the environment set within a water isotope‐augmented version of FREZCHEM(V15). We validate this model with a couple of examples. The isotope‐capable FREZCHEM is simplified to run much faster using set‐piece initial chemistries to calculate the freezing t...

Warming in the high Arctic is occurring at the fastest rate on the planet, raising concerns over how this global change driver will influence plant community composition, the timing of vegetation phenological events, and the wildlife that rely on them. In this region, as much as 50% of near-surface permafrost is composed of thermally sensitive grou...

Knowledge of the amount of unfrozen water and its migration in permafrost soils is important for understanding physico‐chemical and biological processes. Here, we developed sub‐routines in FREZCHEM and embedded them in the WATEREGO2 soil environmental model to: (a) estimate unfrozen water content under changing soil temperatures and water–ice phase...

Reducing uncertainties about carbon cycling is important in the Arctic where rapid environmental changes contribute to enhanced mobilization of carbon. Here we quantify soil organic carbon (SOC) contents of permafrost soils along the Yukon Coastal Plain and determine the annual fluxes from coastal erosion. Different terrain units were assessed base...

Antarctica is an important region where we can improve our understanding of physico-chemical and biological processes in extreme cold and dry environments. Despite Canada not having a formal Antarctic research program, scientists in Canada have been actively involved in multi-disciplinary Antarctic permafrost research for several decades. Research...

Little is known about the abundance and source of soil organic carbon and biogeochemical cycling in permafrost soils from the ultraxerous environment of the Dry Valleys of Antarctica. Here, we investigate the distribution, source and cycling of organic carbon, total nitrogen and carbonates in the icy permafrost soils of University Valley, Quarterma...

One of the key ingredients for life as we know it is the presence of water and nutrients. Evidence of life in ice-rich Martian permafrost could be found in the form of molecular biomarkers. Currently, the preservation potential of molecular biomarkers in extremely cold ice-bearing permafrost is largely unknown. On Earth, the permafrost in the high...

A morphological model for estimating ground-ice contents of various landscape units is presented to address the gap between large-scale, general studies and small-scale, site-specific case histories. The model considers different ground-ice types and cryostratigraphic relations between ice bodies within a terrain unit. Input parameters needed for t...

The cryostratigraphy of permafrost in ultraxerous environments is poorly known. In this study, icy permafrost cores from University Valley (McMurdo Dry Valleys, Antarctica) were analysed for sediment properties, ground-ice content, types and distribution of cryostructures, and presence of unconformities. No active layer exists in the valley, but th...

Perennial springs at the Gypsum Hill site on Axel Heiberg Island in the Canadian Arctic (79° 24’ N, 90° 44’ W) represent a high-fidelity analogue to hydrothermal systems that might exist on Mars. The springs were surveyed using electromagnetic induction sounding (EMIS) and ground penetrating radar (GPR). Both instruments probed the subsurface to a...

Ground ice is one of the most important and dynamic geologic components of permafrost; however, few studies have investigated the distribution and origin of ground ice in the McMurdo Dry Valleys of Antarctica. In this study, ice-bearing permafrost cores were collected from 18 sites in University Valley, a small hanging glacial valley in the Quarter...

In the upper McMurdo Dry Valleys, 90% of the measured ice table depths range from 0 to 80 cm; however numerical models predict that the ice table is not in equilibrium with current climate conditions and should be deeper than measured. This study explored the effects of boundary conditions (air vs ground surface temperature and humidity), ground te...

Ice-rich permafrost coasts often undergo rapid erosion, which results in land loss and release of considerable amounts of sediment, organic carbon and nutrients, impacting the near-shore ecosystems. Because of the lack of volumetric erosion data, Arctic coastal erosion studies typically report on planimetric erosion. Our aim is to explore the relat...

This study compares the relations between solar radiation and air and ground temperatures in the Quartermain Mountains of the McMurdo Dry Valleys of Antarctica with those in ice-free Victoria Land and Arctic Canada. The surface offset is near 0°C at all sites in the Quartermain Mountains and other sites in coastal Victoria Land, whereas the thermal...

The high Arctic is the world's fasting warming biome, allowing access to sections of previously inaccessible land for resource extraction. Starting in 2011, exploration of one of the Earth's largest undeveloped coal seams was initiated in a relatively pristine, polar desert environment in the Canadian high Arctic. Due to the relative lack of histor...

The salt fraction in permafrost soils/sediments of the McMurdo Dry Valleys (MDV) of Antarctica can be used as a proxy for cold desert geochemical processes and paleoclimate reconstruction. Previous analyses of the salt fraction in permafrost soils have largely been conducted in coastal regions where permafrost soils are variably affected by aqueous...

Some of the coldest and driest permafrost soils on Earth are located in the high-elevation McMurdo Dry Valleys (MDVs) of Antarctica, but little is known about the permafrost microbial communities other than that microorganisms are present in these valleys. Here, we describe the microbiology and habitable conditions of highly unique dry and ice-ceme...

The polar desert biome of the Canadian high Arctic Archipelago is currently experiencing some of the greatest mean annual air temperature increases on the planet, threatening the stability of ecosystems residing above temperature‐sensitive permafrost. Ice wedges are the most widespread form of ground ice, occurring in up to 25% of the world's terre...

Arctic coastal infrastructure and cultural and archeological sites are increasingly vulnerable to erosion and flooding due to amplified warming of the Arctic, sea level rise, lengthening of open water periods, and a predicted increase in frequency of major storms. Mitigating these hazards necessitates decision-making tools at an appropriate scale....

Block failure is considered to be an important component of coastal retreat in permafrost regions. A comprehensive model is developed to study the effects of thermoerosional niche and ice wedge morphology on the stability of permafrost dominated coastal cliff against block failure. The model is formulated by coupling slope stability analysis with a...

The presence and origin of ground ice in cold and hyper-arid regions defies the conventional understanding of ground ice forming processes. This study investigates the amount, distribution and origin of ground ice in a sand-wedge polygon in University Valley, McMurdo Dry Valleys of Antarctica. Analysis of computed tomodensitometric scans revealed t...

With future warming and resource extraction activities, the presence and areal extent of thaw subsidence in the circumpolar Arctic are predicted to increase. In the context of restoration, this presents unique challenges for mitigating ecosystem change and developing effective restoration strategies for environmentally sensitive areas and derelict...

Methane (CH4) emission by carbon-rich cryosols at the high latitudes in Northern Hemisphere has been studied extensively. In contrast, data on the CH4 emission potential of carbon-poor cryosols is limited, despite their spatial predominance. This work employs CH4 flux measurements in the field and under laboratory conditions to show that the minera...

The potential long-term effects of thaw slump disturbances on tundra ecosystems include a significant reorganization of tundra plant communities. In this study, vegetation sucession of stabilized retrogressive thaw slumps was investigated using four age classes: 10, 20, and 250 years old, and undisturbed areas. While still active, slumps are charac...

Beringian climate and environmental history are poorly characterized at its easternmost edge. Lake sediments from the northern Yukon Territory have recorded sedimentation, vegetation, summer temperature and precipitation changes since ~16 cal ka BP. Herb-dominated tundra persisted until ~14.7 cal ka BP with mean July air temperatures less than or e...

Ground-penetrating radar (GPR) is the leading geophysical candidate technology for future lunar missions aimed at mapping shallow stratigraphy (<5 m). The instrument's exploration depth and resolution capabilities in lunar materials, as well as its small size and lightweight components, make it a very attractive option from both a scientific and en...

VNIR reflectance spectra of several chloride salts and ices are presented that will enable CRISM analyses of the martian chloride units at low-albedo sites.

The high elevation valleys of the McMurdo Dry Valleys of Antarctica are the only locations on Earth known to contain dry permafrost. The Dry Valleys are a hyper-arid polar desert environment and above 1500 m elevation, air temperatures do not exceed 0 °C and thus, similarly to Mars, liquid water is largely absent and instead the hydrologic cycle is...

This study investigates the origin and age of ground ice in the uppermost 1 m of permafrost in University Valley, one of the upper valleys in the McMurdo Dry Valleys of Antarctica. In contrast to other regions in the MDV, mean daily air and soil temperatures at the coring sites are always below 0 �C, which allows for unique cryogenic processes to o...

We report on 475 measurements of depth to ice-cemented ground in four high-elevation valleys of the Quartermain Mountains, McMurdo Dry Valleys, Antarctica. These valleys have pervasive ice-cemented ground, and the depth to ice-cemented ground and the ice composition may be indicators of climate change. In University Valley, the measured depth to ic...

Here we provide geologic and geomorphologic evidence of Hesperian glacial activity along the Martian topographic dichotomy in Aeolis Mensae. Our geologic investigation focuses on a fretted plateau unit with networks of deep, flat-bottomed valleys, some of which extend from cirque-like scarps. Based on cross-sectional elevation profiles of the valle...

Abstract The search for evidence of life on Mars is the primary motivation for the exploration of that planet. The results from previous missions, and the Phoenix mission in particular, indicate that the ice-cemented ground in the north polar plains is likely to be the most recently habitable place that is currently known on Mars. The near-surface...

Retrogressive thaw slump are among the most important carbon emitters along the Arctic coastline. Significant increases in their activity in the last 50 years has been demonstrated at multiple locations including Herschel Island. While distribution, size of retrogressive thaw slump and their respective change over time are assessed in a number of p...

We provide evidence that the development of two separate surface features are intrinsically linked, demonstrating that the landscape is a co-evolving system.

Capacitively-coupled resistivity and ground-penetrating radar surveys were performed in an area of ice-rich permafrost at Parsons Lake 55 km southwest of Tuktoyaktuk in the Northwest Territories. The Parsons Lake area has been identified as a possible staging site for future hydrocarbon development. Since ground ice is an important factor affecting...

Future exploration of the Moon will require access to the subsurface and acquisition of samples for scientific analysis and ground truthing of water-ice and mineral reserves for in situ resource utilization purposes. The LunarVader drill described in this paper is a 1-m class drill and cuttings acquisition system enabling subsurface exploration of...

Ice-rich permafrost landscapes are sensitive to climate and environmental change due to the melt-out of ground ice during thermokarst development. Thermokarst processes in the northern Yukon Territory are currently not well-documented. Lake sediments from Herschel Island (69°36'N; 139°04'W) in the western Canadian Arctic provide a record of thermok...

Beringian climate and environmental history are poorly characterized at its easternmost edge. Lake sediments from the northern Yukon Territory have recorded sedimentation, vegetation, summer temperature and precipitation changes since ~ 16 cal ka BP. Herb-dominated tundra persisted until ~ 14.7 cal ka BP with mean July air temperatures ≤ 5°C colder...

This contribution describes a series of science instruments built by MDA together with other Canadian companies, ranging from sensors for navigation and workspace characterization, to chemical analysis, to subsurface and atmospheric investigations.

Exploration of the polar ice caps and apparent glacial and periglacial landforms on Mars will aid our understanding of its ancient climate conditions and the history of water on the planet. Given that ground-penetrating radar (GPR) is likely to be used to understand these features, we investigated the real component of the complex dielectric permit...

This paper presents preliminary observations on the distribution and nature of ground ice in University Valley located in the Quartermain Mountains of the McMurdo Dry Valleys. University Valley lies in the ultraxerous soil zone characterized by extreme cold and aridity. Shallow coring and excavations in 2009 and 2010 documented widespread ice-cemen...

Polygon networks are usually described qualitatively as becoming more regular through time, but such a concept has yet to be demonstrated numerically. The aim of this study is to address this question quantitatively in order to determine if polygonal terrain networks actually become more regular as they develop. Spatial point pattern analysis (SPPA...

Buried snowpack deposits are found within the McMurdo Dry Valleys of Antarctica, which offers the opportunity to study these layered structures of sand and ice within a polar desert environment. Four discrete buried snowpacks are studied within Pearse Valley, Antarctica, through in situ observations, sample analyses, O-H isotope measurements and nu...

Arctic landscapes underlain by massive ground ice and ice-rich permafrost are inherently unstable and often display surficial evidence of past thaw subsidence. Retrogressive thaw slumps are permafrost thaw features that are progressively backwasting and result in dramatic changes to the landscape. The cyclic pattern of disturbance and stabilization...

Four retrogressive thaw slumps (RTS) located on Herschel Island and the Yukon coast (King Point) in the western Canadian Arctic were investigated to compare the environmental, sedimentological and geochemical setting and characteristics of zones in active and stabilised slumps and at undisturbed sites. In general, the slope, sedimentology and bioge...

Arctic permafrost coasts are sensitive to changing climate. The lengthening open water season and the increasing open water area are likely to induce greater erosion and threaten community and industry infrastructure as well as dramatically change nutrient pathways in the near-shore zone. The shallow, mediterranean Arctic Ocean is likely to be stro...

In this paper we report on the development of a rotary-percussive sampling drill, LunarVader. The purpose of the drill is to penetrate at least 1 meter in icy-regolith and acquire sub-surface sample for science analysis and for the In Situ Resource Utilization (ISRU). The drill was tested in a lunar analog site of the Ross Island, in the Antarctic...

This project provides various quantitative analyses of polygonal and scalloped terrain morphologies in Utopia Planitia, demonstrating that these two landforms interact as they evolve.

In Arctic wet tundra, microbial controls on organic matter decomposition are likely to be altered as a result of climatic disruption. Here, we present a study on the activity, diversity and vertical distribution of methane-cycling microbial communities in the active layer of wet polygonal tundra on Herschel Island. We recorded potential methane pro...

Terrestrial permafrost archives along the Yukon Coastal Plain (northwest Canada) have recorded landscape development and environmental change since the Late Wisconsinan at the interface of unglaciated Beringia (i.e. Komakuk Beach) and the northwestern limit of the Laurentide Ice Sheet (i.e. Herschel Island). The objective of this paper is to compar...

Four retrogressive thaw slumps (RTS) located on Herschel Island and the Yukon coast (King Point) in the western Canadian Arctic were investigated to compare the environmental, sedimentological and geochemical setting and characteristics of zones in active and stabilised slumps and at undisturbed sites. In general, the slope, sedimentology and bioge...

Buried snowpack deposits are found within the McMurdo Dry Valleys of Antarctica, which offers the opportunity to study these layered structures of sand and ice within a polar desert environment. Four discrete buried snowpacks are studied within Pearse Valley, Antarctica, through in situ observations, sample analyses, O-H isotope measurements and nu...

Terrestrial permafrost archives along the Yukon Coastal Plain (northwest Canada) have recorded landscape development and environmental change since the Late Wisconsinan at the interface of unglaciated Beringia (i.e. Komakuk Beach) and the northwestern limit of the Laurentide Ice Sheet (i.e. Herschel Island). The objective of this paper is to compar...

The high elevation Dry Valleys of Antarctica provide a unique location for the study of permafrost distribution and stability. In particular, the extremely arid and cold conditions preclude the presence of liquid water, and the exchange of water between the ice-cemented ground and the atmosphere is through vapour transport (diffusion). In addition,...

Polygonal features in the Canadian High Arctic are found in many areas, have diverse appearances, and occur in a variety of surface materials. As part of a larger project using geophysical methods to study ice wedge depth, width, and thickness, ground penetrating radar (GPR) data were collected across polygonal surface features on Devon Island. As...

Arctic permafrost coasts are sensitive to changing climate. The lengthening open-water season and the increasing open-water area are likely to induce greater erosion and threaten community and industry infrastructure as well as dramatically change organic carbon and nutrient pathways in the nearshore zone. The shallow, mediterranean Arctic Ocean is...