David Marchant

Boston University | BU · Department of Earth & Environment

On Earth a transitional phase between glacial and interglacial periods is referred to as the paraglacial period. This period immediately postdates glacial retreat and is characterized by ice removal, glacial unloading, and the exposure of steep slopes and large sediment stores. These responses led to the development of a suite of morphologic units...

The current structure of many undergraduate programs, particularly those at large research universities, requires students to engage with a major or academic emphasis early in their university careers. This oftentimes curbs exploration outside the major and can inhibit interdisciplinary collaboration. The Boston University Research Education and Co...

During the LGM, grounded glacier ice filled the Ross Embayment and deposited glacial drift on volcanic islands and peninsulas in McMurdo Sound, as well as along coastal regions of the Transantarctic Mountains (TAM), including the McMurdo Dry Valleys and Royal Society Range. The flow geometry and retreat history of this ice remains debated, with con...

We report on a decade of fieldwork designed to determine the conditions required for erosion of Mars-like gully channels in the McMurdo Dry Valleys (MDV) of Antarctica. We have outlined the major factors in the morphological evolution of gullies in the Inland Mixed Zone of the MDV: (1) the distribution of ice sources; (2) the temporal aspects of ic...

We report on a decade of fieldwork designed to determine the conditions required for erosion of Mars-like gully channels in the McMurdo Dry Valleys (MDV) of Antarctica. We have outlined the major factors in the morphological evolution of gullies in the Inland Mixed Zone of the MDV: (1) the distribution of ice sources; (2) the temporal aspects of ic...

Antarctica’s recent glacial history provides important geologic constraints on potential sea level rise (SLR) from the burning of fossil fuels. However, as almost 98% of the continent is covered with glacial ice, terrestrial archives for ice advance and retreat are rare. The ice-free oasis of the McMurdo region (78°S) offers a unique terrestrial re...

During the Last Glacial Maximum (LGM), grounded glacier ice filled the Ross Embayment and deposited glacial drift on volcanic islands and peninsulas in McMurdo Sound, as well as along coastal regions of the Transantarctic Mountains (TAM), including the McMurdo Dry Valleys and Royal Society Range. The flow geometry and retreat history of this ice, h...

The observed darkening of water tracks near Don Juan Pond (DJP) as well as the formation of wet patches elsewhere in the McMurdo Dry Valleys is attributed at least partially to deliquescence, a process by which salts absorb atmospheric water vapor and form brine, coupled with liquid-phase growth when the atmospheric relative humidity exceeds the wa...

We utilize an environmental chamber capable of recreating the extreme polar conditions of the McMurdo Dry Valleys (MDV) of Antarctica to investigate the sublimation rate of the Mullins Valley debris-covered glacier (hereafter Mullins Glacier), reportedly one of the oldest debris-covered alpine glaciers in the world. We measure ice loss via sublimat...

The degree to which debris-covered glaciers record past environmental conditions is debated.Here we describe a novel palaeoclimate archive derived from the surface morphology and internal debris within cold-based debris-covered glaciers in Antarctica. Results show that subtle changes in mass balance impart major changes in the concentration of engl...

Supplementary Figures and Supplementary References.

We mapped six distinct glacial moraines alongside Stocking Glacier in the McMurdo Dry Valleys, Antarctica. Stocking Glacier is one of several alpine glaciers in the Dry Valleys fringed by multiple cold-based drop moraines. To determine the age of the outermost moraine, we collected 10 boulders of Ferrar Dolerite along the crest of the moraine and a...

Using in-situ field measurements, laboratory analyses, and numerical modeling, we test the potential efficacy of thermal stress weathering in the flaking of mm-thick alteration rinds observed on cobbles and boulders of Ferrar Dolerite on Mullins Glacier, McMurdo Dry Valleys (MDV). In particular, we examine whether low magnitude stresses, arising fr...

The McMurdo Dry Valleys (MDV) are home to one of the longest terrestrial records of glaciation in Antarctica. However, the record is discontinuous and spatially variable due to glacial reworking and erosion. Exposure dating of moraines and drifts indicates advance of East Antarctic outlet glaciers during the penultimate interglacial, Marine Isotope...

Based on exposure dating of moraines and drifts, East Antarctic outlet glaciers in the McMurdo Dry Valleys (MDV) advanced during the mid-Pliocene and/or early-Pleistocene. However, significant scatter in exposure ages is common for these deposits (and other glacial drifts throughout Antarctica), making it difficult to tie glacial advances to specif...

We develop a modeling framework to describe the accumulation of terrestrial cosmogenic 3He in Antarctic debris-covered glaciers. The framework helps quantify the expected range in cosmogenic-nuclide inventories for measured clasts at the surface of supraglacial debris. We first delineate the physical factors that impact clast movement within, and o...

The tropical mountain glacial fan-shaped deposit (FSD) to the northwest of the Arsia Mons volcano on Mars contains numerous glacial and volcanic landforms. While most of the glacial landforms are interpreted to have formed by cold-based glacial processes, several glacial landforms near glaciovolcanic edifices are more consistent with localized wet-...

The fan-shaped deposit (FSD) on the western and northwestern flanks of Arsia Mons is the remnant of tropical mountain glaciers, deposited several tens to hundreds of millions of years ago during periods of high spin-axis obliquity. Previous workers have argued that the Smooth Facies in the FSD contains a core of ancient glacial ice. Here, we find e...

Observations from mid-latitude martian glaciated craters can constrain the timing and duration of deglaciation and the transition into a post-glacial climate.

We review previously undescribed landforms in the Arsia Mons FSD whose morphology indicates that they may still contain remnant tropical mountain glacier ice.

The early climate of Mars (Noachian Period, the first ~20% of its history) is thought to differ significantly from that of its more recent history (Amazonian Period, the last ~66%) which is characterized by hyperarid, hypothermal conditions that result in mean annual air temperatures (MAAT) well below 0°C, a global cryosphere, minimal melting on th...

The guest editors wish to express thanks to all of the authors involved in the manuscripts submitted to this special volume of Antarctic Science, celebrating the award of The Seligman Crystal to Professor David Sugden from the International Glaciological Society. The response from the international Antarctic geoscience community to our request for...

We describe the morphology and internal structure of Mullins and Friedman Glaciers, two cold-based, debris-covered alpine glaciers that occur in neighboring valleys in the McMurdo Dry Valleys, Antarctica. Both glaciers are overlain by a single, dry supraglacial debris layer (8-75 cm thick); each mantling debris layer is marked with near-identical p...

The high-elevation western Olympus Range in Antarctica contains a terrestrial record of cold-based glaciation that extends to the mid-Miocene. Within adjacent, ~2-km wide cirque valleys, a suite of stratigraphically-correlated drifts and moraines record recent fluctuations of cold-based alpine glaciers. We measured helium isotopes from pyroxenes in...

Fan-shaped deposits (FSD) superposed on the sides of the Tharsis Montes volcanic edifices are widely interpreted to have been formed by cold-based glaciation during the Late Amazonian, a period when the Tharsis Montes were volcanically active. We survey the ∼166,000 km2 Arsia Mons FSD using new, high-resolution image and topography data and describ...

We review terrestrial paraglacial processes and geomorphology as an analog for young features found in martian craters associated with glaciation.

Several regions of the Arsia Mons Fan-Shaped Deposit show that volcano-ice interactions induced local wet-based behavior in the otherwise cold-based glacier.

We apply paraglacial geomorpholgy to martian craters bearing evidence of glaciation to suggest young geologic features form in a post-glacial environment.

Lobate debris aprons (LDA) are lobate-shaped aprons surrounding scarps and isolated massifs that are concentrated in the vicinity of the northern Dichotomy Boundary on Mars. LDAs have been interpreted as (1) ice-cemented talus aprons undergoing viscous flow, (2) local debris-covered alpine-like glaciers, or (3) remnants of the collapse of a regiona...

The Dry Valleys are subdivided into three microclimate zones on the basis of summertime measurements of atmospheric temperature, soil moisture, relative humidity and wind-speed/direction. Subtle variations in these climate parameters result in considerable differences in process geomorphology and in the development of unique landforms within each z...

Alteration of fresh rock surfaces proceeds very rapidly in most terrestrial environments so that initial stages of modification of newly exposed surfaces are quickly masked by subsequent aqueous weathering processes. The hyper-arid and hypo-thermal environment of Beacon Valley, Antarctica, is limited in terms of available liquid water and energy av...

Thermokarst is a land surface lowered and disrupted by melting ground ice. Thermokarst is a major driver of landscape change in the Arctic, but has been considered to be a minor process in Antarctica. Here, we use ground-based and airborne LiDAR coupled with timelapse imaging and meteorological data to show that 1) thermokarst formation has acceler...

Recent climate models suggest that Noachian Mars may have been characterized by a "cold and icy", rather than a "warm and wet" climate. Noachian valley networks and open basin lakes have been cited as key evidence for a "warm and wet" early Mars. We investigate fluvial and lacustrine processes in the Mars-like Antarctic McMurdo Dry Valleys (MDV) to...

The discovery on Mars of recurring slope lineae (RSL), thought to represent seasonal brines, has sparked interest in analogous environments on Earth. We report on new studies of Don Juan Pond (DJP), which exists at the upper limit of ephemeral water in the McMurdo Dry Valleys (MDV) of Antarctica, and is adjacent to several steep-sloped water tracks...

Oxidative weathering products are modeled at high abundances across the martian surface, implying cold and dry alteration processes during the Amazonian epoch.

Orbital spectroscopy and laboratory analyses are utilized to identify major geochemical variations throughout the Ferrar Dolerite exposed in the McMurdo Dry Valleys (MDV) of Antarctica. Our laboratory results highlight the range of primary and secondary chemical and spectral variations observed throughout the dolerite, and provide the necessary cal...

The discovery on Mars of recurring slope lineae (RSL), thought to represent seasonal brines, has sparked interest in analogous environments on Earth. We report on new studies of Don Juan Pond (DJP), which exists at the upper limit of ephemeral water in the McMurdo Dry Valleys (MDV) of Antarctica, and is adjacent to several steep-sloped water tracks...

Fan-shaped deposits (FSDs) extending to the northwest of the Tharsis Montes on Mars are the remnants of Amazonian-aged, cold-based, tropical mountain glaciers. We use high-resolution images to perform new impact crater size-frequency distribution (CSFD) analyses on these deposits in an effort to constrain the timing and duration of ice accumulation...

Currently, and throughout much of the Amazonian, the mean annual surface temperatures of Mars are so cold that basal melting does not occur in ice sheets and glaciers and they are cold-based. The documented evidence for extensive and well-developed eskers (sediment-filled former sub-glacial meltwater channels) in the south circumpolar Dorsa Argente...

The Antarctic Dry Valleys (ADV) are characterized by mean annual temperatures (MAT) well below the freezing point of water and are among the coldest and driest environments on Earth. In spite of these extreme conditions, seasonal temperatures (ST) and peak daytime temperatures (PDT) can locally exceed the melting point of water in certain settings...

Primary igneous and secondary alteration signatures can be resolved using orbital spectroscopy over mafic regions of the McMurdo Dry Valleys. We assess the nature of these signatures and their link to surface stability and regional microclimates.

The chemical, mineralogical, and spectral products of oxidation are characterized using a variety of laboratory techniques. Orbital and in situ observations of the martian surface suggest that this process is widespread and spectrally significant.

To assess the role of thermal contraction-crack polygons (sublimation polygons) in modulating sublimation of buried glacier ice in Antarctica, we applied a 2D numerical model using COMSOL Multiphysics that calculates the rate and spatial variability of vapour diffusion through porous media. Specifically, we examined vapour transport through Granite...

Mullins Valley Glacier in the Dry Valleys, Antarctica contains some of the oldest ice on earth, with overlying volcanic ash having been K-Ar dated to a maximum of ~8 Ma (Marchant et al., 2007; Kowalewski et al., 2011). Geochemical analysis and dating of trapped gases within the glacial ice provides context for understanding the processes preserving...

The hyper-arid and hypo-thermal conditions that are pervasive throughout the McMurdo Dry Valleys (MDV) result in slow, immature chemical alteration that is often shadowed by physical erosion and mass wasting processes. Beacon Valley is an exception to this model in that its surface is extremely stable and has been for at least several million years...

The Antarctic Dry Valleys (ADV) are generally classified as a hyper-arid, cold-polar desert. The region has long been considered an important terrestrial analog for Mars because of its cold and dry climate and because it contains a suite of landforms at macro-, meso-, and microscales that closely resemble those occurring on the martian surface. The...

A fretted valley system on Mars located at the northern mid-latitude dichotomy boundary contains lineated valley fill (LVF) with extensive flow-like features interpreted to be glacial in origin. We have modeled this deposit using glacial flow models linked to atmospheric general circulation models (GCM) for conditions consistent with the deposition...

Pits in rocks on the surface of Mars have been observed at several locations. Similar pits are observed in rocks in the Mars-like hyperarid, hypothermal stable upland zone of the Antarctic Dry Valleys; these form by very localized chemical weathering due to transient melting of small amounts of snow on dark dolerite boulders preferentially heated a...

A range of cold desert landforms are found on the Martian surface that have been interpreted to indicate prevailing frozen and hyperarid conditions for at least the past several million years. These cold desert conditions are punctuated by brief periods of localized surficial liquid water flow. Sediment transport pathways operate under these condit...

We modeled water–vapor diffusion within Mullins till, a relatively dry supraglacial till in southern Victoria Land, Antarctica, that rests directly on Mullins Glacier, purportedly one of the oldest alpine glaciers in the world. Like most supraglacial tills in cold-desert environments, Mullins till contains three characteristic facies: a weathered f...

The extensive geological record of Mars' most recent ice age and the current interglacial period offer unprecedented and accessible opportunities to explore and characterize systematic effects of individual periods of spin-axis/orbital variation.

New observations of ice-rich lobate debris aprons and an adjacent plains unit in Deuteronilus Mensae, Mars, including similar crater retention ages and complex marginal textures, suggest modification of the plains unit by regional glaciation.

Dorsa Argentea Formation (Noachian-Hesperian) eskers are evidence for basal melting. Ice-flow models show that the mean annual south polar temperature must be raised to -50° to -75°C, providing an independent estimate of elevated lower latitude surface temperature.

We use a flowband model to assess development of lobate debris apron sublimation lag thickness and lateral extent beneath scarps. We obtain estimates of the climate in place as the LDAs were forming during collapse of a larger, regional ice sheet.

The Amazonian period of Mars has been described as static, cold, and dry. Recent analysis of high-resolution imagery of equatorial and mid-latitude regions has revealed an array of young landforms produced in association with ice and liquid water; because near-surface ice in these regions is currently unstable, these ice-and-water-related landforms...

We describe a landscape in the Dry Valleys area consisting of channels, potholes, plunge pools, stripped bedrock, and scabland created by subglacial outburst floods on a scale similar to that of the massive outbursts of Lake Missoula in Washington, United States. The features are dated to the mid-Miocene and occurred when a thicker East Antarctic i...

We describe the geomorphic record preserved within the highly degraded 80 km diameter Asimov impact crater located within Noachis Terra. The crater has been significantly in-filled since its formation in the Noachian, presumably by sedimentary materials similar to units identified elsewhere in Noachian aged craters. In this case the fill is unusual...

A recent theme in geomorphological research is to understand the age, origin, and modification of buried-ice deposits in polar latitudes. One application of these investigations has been to understand the climatic significance of debris-covered glaciers in Antarctica, some of which may contain ice of late Miocene age. A related inquiry, presented h...

We examine the spatial variability of sublimation rates and associated net annual ice loss across a buried alpine glacier in the McMurdo Dry Valleys of Antarctica, purportedly one of the oldest active alpine glaciers in the world. Sublimation of Mullins Glacier is controlled by rates of vapor diffusion through Mullins till, a dry supraglacial till...

Hypotheses accounting for the formation of concentric crater fill (CCF) on Mars range from ice-free processes (e.g., aeolian fill), to ice-assisted talus creep, to debris-covered glaciers. Based on analysis of new CTX and HiRISE data, we find that concentric crater fill (CCF) is a significant component of Amazonian-aged glacial landsystems on Mars....

Viscous flow lobes are common throughout the McMurdo Dry Valleys (MDV) of Antarctica. These features have been described as rock glaciers, gelifluction lobes, solifluction lobes, talus mobilized by pore ice and/or segregation ice, and debris-covered glaciers. We investigate the origin, modification, and flow of a 2-km-long lobe (East Stocking Lobe...

Abundant evidence exists for glaciation being an important geomorphic process in the mid-latitude regions of both hemispheres of Mars, as well as in specific environments at near-equatorial latitudes, such as along the western flanks of the major Tharsis volcanoes. Detailed analyses of glacial landforms (lobate-debris aprons, lineated valley fill,...

Lobate debris aprons (LDA) and lineated valley fill (LVF) have been known to characterize the mid-latitude regions of Mars since documented by Viking; their flow-like character suggested that deposition of ice in talus pile pore space caused lubrication and flow during an earlier climatic regime. A number of factors have remained uncertain, however...

Amazonian non-polar ice deposits on Mars record periods and events when the climate differed substantially from that of today. Particularly evident are examples of ice-rich deposits in the martian mid-latitudes (lobate debris aprons, lineated valley fill, and concentric crater fill). Uncertain, however, is the amount of ice remaining in these depos...

A variety of Late Amazonian landforms on Mars have been attributed to the dynamics of ice-related processes. Evidence for large-scale, mid-latitude glacial episodes existing within the last 100 million to 1 billion years on Mars has been presented from analyses of lobate debris aprons (LDA) and lineated valley fill (LVF) in the northern and souther...

We present results from ground-penetrating radar (GPR) and seismic surveys for the Mullins Valley debris-covered glacier (Mullins Glacier), Antarctica, that yield local ice-thickness estimates of 80–110 m in upper Mullins Valley and 150 m in upper Beacon Valley. Englacial debris in upper Mullins Glacier occurs as scattered cobbles and as discrete l...

Martian debris-covered glaciers should be considered as landing sites in the search for biosignatures, as they represent large volumes of non-polar ice, with a wide regional distribution, unique bio-preservation potential, and intermediate age.

The Antarctic Dry Valleys are an ideal location to examine links between surface compositions and climate variables in a Mars-like, hyper-arid, cold-polar desert. We report results from ongoing field work and laboratory and orbital spectroscopy.

Spectroscopic studies of Beacon Valley, Antarctica, reveal a range of secondary alteration minerals that have developed in a cold, dry, and stable environment. These results have implications for the development of similar minerals on Mars.

We test theories of Mars gully formation by examining gullies found superposed on glacial deposits on Mars and Earth. Many gullies form in environments favoring long-term snow/ice accumulation; stratigraphic relations favor top-down melting during warming climatic periods.

Our results suggest that variations in both englacial-debris concentration and local environmental conditions impart first-order changes in the surface morphology of Mullins Glacier. Results can be applied toward understanding the distribution of debris in LDA and LVF.

Models help interpret observed glacial deposits and test formation scenarios. We examine a lobate debris apron recently proven to contain pure water ice. Two hypotheses are tested: alcove-only and collapse from a larger ice sheet driven by a GCM.

Analyses suggest that glacial ice in the northern mid-latitudes of Mars was more extensive in the recent past. Plains units and textures surrounding lobate debris aprons in Deuteronilus Mensae are examined in search of former glacial maxima.

New data on the structure, accumulation zone, talus contributions, debris cover, terminal and lateral moraines, ages and volcano-ice interactions of the Late Amazonian tropical mountain glaciers along the western scarp of Olympus Mons are reported.

We present new analyses of the hydrological, chemical, and morphologic properties of permafrost in Taylor Valley, Antarctica, as basis for analysis of near-surface water and nutrient cycling in ancient and geologically-recent Martian terrains.

Our vapor diffusion modeling suggests surface textures, topography, and the presence of salt layers demonstrably alter sublimation rates in the McMurdo Dry Valleys and offer insight into similar environments in the hyper-arid cold climate of Mars.

We study Mars gully analogs in the Antarctic Dry Valleys and report on the differences in precipitation, temperature profiles, meltwater sources, and level of fluvial activity in the gullies over a four year period, and discuss application to Mars.

We present new observations of small valleys associated with glacial features in the Martian mid-latitudes, based on a survey of images from the Context Camera (CTX) on the Mars Reconnaissance Orbiter. These valleys are small (~50-400 m wide) and short (

The Friis Hills, located at the head of Taylor Valley in the the McMurdo Dry Valleys, hold a sequence of stacked tills at least Early Miocene in age. Sedimentology, clast lithology and bedrock striations indicate these tills were deposited from wet-based glaciers that flowed southeastward down a shallow paleovalley toward the Ferrar trough. Interbe...

The discovery of several locations in the Transantarctic Mountains that contain macrofossils and pollen is transforming our understanding of late Cenozoic Antarctica. The most southerly location is on the Beardmore Glacier (85.1°S) about 500 km from the South Pole. The environment was an active glacial margin in which plants, insects and freshwater...

PolarTREC is an educational research experience in which K-14 teachers participate in polar research with scientists as a pathway to improving science education. The program is funded by the National Science Foundation and managed by the Arctic Research Consortium of the United States. Teachers share their experiences with scientists, educators, co...

We analyze Surface Stereo Imager observations of rocks, sediments, and permafrost-related landforms in the vicinity of the Phoenix lander, comparing the imaged features to analogous examples of physical weathering and periglacial processes observed in the Antarctic Dry Valleys. Observations at the Phoenix landing site of pitted rocks, ``puzzle rock...

a b s t r a c t Thermal contraction crack polygons are complex landforms that have begun to be deciphered on Earth and Mars by the combined investigative efforts of geomorphology, environmental monitoring, physical models, paleoclimate reconstruction, and geochemistry. Thermal contraction crack polygons are excel-lent indicators of the current or p...

A fundamental question in Antarctic science is the inception of the present, polar East Antarctic Ice Sheet. The ice sheet, including its associated girdle of sea ice, has been described as the most prominent physical feature on Earth. Ocean and atmospheric processes that link low-latitude regions with Antarctica as a major heat sink are critical f...

At martian mid-to-high latitudes, the surfaces of potentially ice-rich features, including concentric crater fill, lobate debris aprons, and lineated valley fill, typically display a complex texture known as “brain terrain,” due to its resemblance to the complex patterns on brain surfaces. In order to determine the structure and developmental histo...

In order to assess the nature, degradational processes and history of the dichotomy boundary on Mars, we conducted a detailed morphological analysis of a 70,000 km2 region of its northern portion (north-central Deuteronilus Mensae, south of Lyot, in the vicinity of Sinton Crater). This region is characterized by the distinctive sinuous ∼2 km-high p...

We describe the morphology and spatial relationships between composite-wedge polygons and Mars-like gullies (consisting of alcoves, channels, and fans) in the hyper-arid Antarctic Dry Valleys (ADV), as a basis for understanding possible origins for martian gullies that also occur in association with polygonally patterned ground. Gullies in the ADV...

We estimate the total water abundance on Mars and the nature and magnitude of sources and sinks throughout its history by starting with the present environment, when climate conditions are more well-known, and working backward in time, using the geologic record as a measure of the presence, location, and state of water. We identify elements of the...

Recent climatic change on Mars has been recorded in a series of equilibrium landform assemblages located in Noachis Terra. We explore these features through the detailed mapping of terrestrial analogs in the Antarctic Dry Valleys.