A5002470859- Geology and Paleoclimatology Research
- Hydrology and Sediment Transport Processes
- Geological formations and processes
- Archaeology and Natural History
- Landslides and related hazards
- Aeolian processes and effects
- Soil erosion and sediment transport
- American Environmental and Regional History
- Rangeland and Wildlife Management
- Tree-ring climate responses
- Hydrology and Watershed Management Studies
- Geological Modeling and Analysis
- Marine and environmental studies
- Cryospheric studies and observations
- earthquake and tectonic studies
- Energy and Environment Impacts
- Botany, Ecology, and Taxonomy Studies
- Geological Studies and Exploration
- Pleistocene-Era Hominins and Archaeology
- Methane Hydrates and Related Phenomena
- Radioactive contamination and transfer
- Building materials and conservation
- Conservation Techniques and Studies
- Mexican Socioeconomic and Environmental Dynamics
- Geophysical Methods and Applications
Minnesota State University, Mankato
2014-2025
University of Minnesota, Duluth
2020
Minnesota State Colleges and Universities System
2015-2019
Arizona State University
2010-2012
As rivers sculpt their valleys and floodplains, they transport sediments – primarily quartz feldspar from source regions to the sea. These complex sediment-transport processes, difficult study even over short time scales, can eventually build systems of river terraces, which in turn record impacts past climate on Earth-surface systems. To both landform-building we focus deglacial fluvial stored upper Mississippi valley.We collected terrace sediment samples for luminescence dating...
Historical accounts suggest that Euro-American agricultural practices (post−1850 CE) accelerated soil erosion in the Paleozoic Plateau of Upper Mississippi River Valley (USA). However, magnitude this change compared to longer-term Late Pleistocene rates is poorly constrained. Such context necessary assess how under natural, high-magnitude climate and eco-geomorphic compare against rates. We pair cosmogenic 10Be analyses optically stimulated luminescence (OSL) ages from samples alluvium build...
Alluvial fans and fluvial terraces occur in nearly all climatic settings often coexist within the same drainage basin. These landforms play an important role understanding geomorphic, hydrologic, sedimentologic erosional histories of a The juxtaposition terraces, some instances, can lead to misinterpretation distinguishing traditional from truncated toe tributary alluvial fans. This becomes particularly troublesome for those attempting interpret results published field studies where fan-cut...
Abstract Our study adds to the Quaternary history of eolian systems and deposits in western Wisconsin, USA, primarily within lower Chippewa River valley. Thickness textural patterns loess region indicate transport by west-northwesterly westerly winds. Loess is thickest coarsest on southeastern flanks large bedrock ridges uplands, similar some ways shadow dunes. In many areas, sand was transported up onto as ramps, presumably deposited their lee. Long, linear dunes, common sandy lowlands...
AbstractThe Sonoran Desert portion of the Basin and Range physiographic province contains a number streams that now flow across once-closed basins. We explore here research questions if how granitic rock pediments respond to transition from rimming endorheic basins bordering through-flowing streams. Granitic northern Usery eastern McDowell Mountains once graded closed Miocene–Pliocene Pemberton basin occupied present-day location confluence Salt Verde Rivers. The process lake overflow, which...
Pediments of the Sonoran Desert in United States have intrigued physical geographers and geomorphologists for nearly a century. These gently sloping bedrock landforms are staple desert landscape that millions visit each year. Despite long-lived scientific curiosity, an understanding processes operating on pediment has remained elusive. In this study we revisit extensive history research. We then apply geospatial, field, laboratory cosmogenic 10Be nuclide dating back-scattered electron...
Stream terraces of the Salt River form interpretive backbone Plio-Pleistocene landscape evolution central Arizona, because they represent base level all tributary streams. This paper presents a new addition to T.L. Péwé' s Terrace sequence (in decreasing topographic position and age: Sawik, Mesa, Blue Point, Lehi) that has been unrefined for last 30 years. The existence an older, higher terrace was predicted by research suggesting lower originated lake overflow from ancestral Pliocene in...
Although mountains represent a barrier to the flow of liquid water across our planet and an Earth impenetrable would have produced very different geography, many rivers do cross mountain ranges. These transverse drainages through one four general mechanisms: antecedence—the river maintains its course during building (orogeny); superimposition—a erodes buried bedrock atop erodible sediment or sedimentary rock, providing route what later becomes exhumed range; piracy capture—where steeper...
Analyses of ephemeral granitic drainages \<5 km^2^ at South Mountain metamorphic core complex, central Arizona, reveal a previously undocumented process bedrock strath formation in this setting. Granitic channel banks experience higher degree mineral decay than that floors. Electron microscope observations show grussification along the occurs through abiotic processes biotite oxidation and biotic associated with mycorrhizal fungi roots plants preferentially growing banks. Digital image...
No prior research has documented the different types of rock coatings in Yosemite Valley, despite evident black streaks down Falls, light granitic exposed by recent falls contrasting with dark coatings, and millions visitors who have photographed coated rocks Yosemite. This paper identifies found on Half Dome, assesses hypothesis that are consistent landscape geochemical model coating formation, considers relevance equifinality. Eight were identified: case-hardened surfaces, heavy metal...
Talus flatirons (TFs) are morphostratigraphic markers of prior talus deposition that now disconnected from the active hillslope. Three generations TFs (TF1, TF2, TF3) exist flanking a Sonoran Desert inselberg, Rock Peak, in welded tuff caprocks-controlled landscape bounded by pediments. at Peak enable estimation slope retreat rates through application cosmogenic 10Be, optically stimulated luminescence dating, and catchment-wide denudation (CWDR). We estimate disconnection TF1 on 88.9 ± 7.8...
Large parts of the upper Midwest, USA were impacted by permafrost during Last Glacial Maximum (LGM). Even though persisted as Laurentide Ice Sheet began to recede, direct age control this interval is largely lacking. To better temporally constrain in western Wisconsin, we identified two sites, outside Late Wisconsin (MIS 2) glacial limit, that contain relict, ice‐wedge pseudomorphs, initially interpreted be sand wedges, hosted within well‐drained outwash deposits. The pre‐Wisconsin (>MIS...
Abstract Sand stringers are subtle, aeolian landforms that reach hundreds to thousands of metres in length and lack a slipface. While sand exist beyond the Last Glacial Maximum margin Upper Midwest, USA, little is known about timing nature their formation. This research characterizes morphology stratigraphy provides geochronological data from two upper Mississippi River basin Minnesota Wisconsin. The investigated have similar west–northwest east–southeast orientations located ~100 km each...
Preliminary observations of three trains dune-like landforms, just south the shore Lake Superior, near Christmas, MI, USA, reveal presence large and imbricated boulder clasts on their surface 20&#8211;33 m deep bedrock canyons in close proximity. These characteristics suggest an ambiguous episode high-magnitude discharge across this landscape before modern physical geography Superior basin was established. Understanding formation these landforms is important reconstructing regional...
A burgeoning theme of research has focused on overflow and outburst flood events in reorganizing drainage basins, creating new fluvial landscapes transverse drainages. Generalized conceptual ideas may not fully grasp the complexity real proglacial deglacial landscapes, making these important to examine. The St. Croix River valley (SCRV), MN/WI, USA, its basin contain well understood glacial geology, complex evolution SCRV is largely result dyssynchronous advance retreat Superior Lobe...