Digital Commons Network^™

Cambrian Trilobites From The Nounan Dolomite And Lower St. Charles Formation (Upper Marjuman To Lower Sunwaptan; Miaolingian To Furongian Series), Smithfield Canyon, Northern Utah, Frederick A. Sundberg, Hannah R. Cothren, Carol M. Dehler

Geosciences Faculty Publications

The trilobite faunas that occur with the Steptoean Positive Isotope Carbon Excursion (SPICE) at Smithfield Canyon, Utah, have been reported, but not illustrated. Given the importance of the SPICE at this section for international correlations, the trilobites from new collections from the upper Nounan Dolomite to lower St. Charles Formation at Smithfield Canyon are reported herein and integrated with the previously reported taxa. Trilobite assemblages indicate that the upper Cedaria to the Ellipsocephaloides biozones (Miaolingian Series, Guzhangian Stage to Furongian Series, Jiangshanian Stage) are present stratigraphically below or above the SPICE.

Some of the taxa reported herein may represent new …

Contaminant Back Diffusion From Low-Conductivity Matrices: Case Studies Of Remedial Strategies, Julie Blue, Thomas Boving, Mary Ellen Tuccillo, Jonathan Koplos, Jason Rose, Michael Brooks, David Burden

Geosciences Faculty Publications

Recalcitrant groundwater contamination is a common problem at hazardous waste sites worldwide. Groundwater contamination persists despite decades of remediation efforts at many sites because contaminants sorbed or dissolved within low-conductivity zones can back diffuse into high-conductivity zones, and therefore act as a continuing source of contamination to flowing groundwater. A review of the available literature on remediation of plume persistence due to back diffusion was conducted, and four sites were selected as case studies. Remediation at the sites included pump and treat, enhanced bioremediation, and thermal treatment. Our review highlights that a relatively small number of sites have been studied …

Sustainable Water Treatment With Induced Bank Filtration, Miles Schelling, Kavita Patil, Thomas B. Boving

Geosciences Faculty Publications

This study demonstrates that an induced bank filter (IBF) system can treat raw water polluted with Escherichia coli (E. coli) bacteria. Similar to riverbank filtration (RBF), induced or reversed bank filtration relies on natural processes to clean water, including filtration through layers of allochthone alluvial sediments and a bioactive layer that forms on top of the filter after a ripening period. At the study site, located in Southwestern India, villagers rely on a mountain spring for their water supply. Although of generally high quality, the spring water contains E. coli bacteria (up to ~2000 MPN/100 mL). Raw …

Rapid Growth In Late Cretaceous Sea Turtles Reveals Life History Strategies Similar To Extant Leatherbacks, Laura E. Wilson

Geosciences Faculty Publications

Modern sea turtle long bone osteohistology has been surprisingly well-studied, as it is used to understand sea turtle growth and the timing of life history events, thus informing conservation decisions. Previous histologic studies reveal two distinct bone growth patterns in extant sea turtle taxa, with Dermochelys (leatherbacks) growing faster than the cheloniids (all other living sea turtles). Dermochelys also has a unique life history compared to other sea turtles (large size, elevated metabolism, broad biogeographic distribution, etc.) that is likely linked to bone growth strategies. Despite the abundance of data on modern sea turtle bone growth, extinct sea turtle osteohistology …

U-Pb Detrital Zircon Analysis Of Sedimentary Rocks Of The Southeastern New England Avalon Terrane In The U.S. Appalachians: Evidence For A Separate Crustal Block, Yvette D. Kuiper, Daniel P. Murray, Sonia Ellison, James L. Crowley

Geosciences Faculty Publications

The Avalon terrane of southeastern New England is a composite terrane in which various crustal blocks may have different origins and/or tectonic histories. The northern part (west and north of Boston, Massachusetts) correlates well with Avalonian terranes in Newfoundland, Nova Scotia, and New Brunswick, Canada, based on rock types and ages, U-Pb detrital zircon signatures of metasedimentary rocks, and Sm-Nd isotope geochemistry data. In the south, fewer data exist, in part because of poorer rock exposure, and the origins and histories of the rocks are less well constrained. We conducted U-Pb laser ablation-inductively coupled plasma-mass spectrometry analysis on zircon from …

Water Quality Observations From Space: A Review Of Critical Issues And Challenges, Cameron Murray, Albert Larson, Joseph E. Goodwill, Yeqiao Wang, Dawn Cardace, Ali S. Akanda

Geosciences Faculty Publications

Water is the basis of all life on this planet. Yet, approximately one in seven people in the world do not have access to safe water. Water can become unsafe due to contamination by various organic and inorganic compounds due to various natural and anthropogenic processes. Identifying and monitoring water quality changes in space and time remains a challenge, especially when contamination events occur over large geographic areas. This study investigates recent advances in remote sensing that allow us to detect and monitor the unique spectral characteristics of water quality events over large areas. Based on an extensive literature review, …

Reproducibility And Variability Of Earthquake Subsidence Estimates From Saltmarshes Of A Cascadia Estuary, Jason Scott Padgett, Simon E. Engelhart, Harvey M. Kelsey, Robert C. Witter, Niamh Cahill

Geosciences Faculty Publications

We examine fossil foraminiferal assemblages from 20 sediment cores to assess sudden relative sea-level (RSL) changes across three mud-over-peat contacts at three salt marshes in northern Humboldt Bay, California (~44.8°N, −124.2°W). We use a validated foraminiferal-based Bayesian transfer function to evaluate the variability of subsidence stratigraphy at a range of 30-6000 m across an estuary. We use the consistency in RSL reconstructions to support estimates of coseismic subsidence from megathrust earthquakes. To assess the variability of subsidence estimates, we analyzed: nine examples of the 1700 CE earthquake (average of 0.64 ±0.14 m subsidence; range of 0.24 ± 0.27 to 1.00 …

The Lost And The Found: Memories Of Donald V. Helmberger, Brian K. Savage

Geosciences Faculty Publications

No abstract provided.

Groundwater Quality: Global Challenges, Emerging Threats And Novel Approaches, Dan Lapworth, Thomas B. Boving, Bentje Brauns, Jane Dottridge, Paul Hynds, Seifu Kebede, David Kreamer, Bruce Misstear, Abhijit Mukherjee, Viviana Re, James Sorensen, Claudia Ruz Vargas

Geosciences Faculty Publications

Improving our understanding of groundwater quality threats to human health and the environment is essential to protect and manage groundwater resources effectively. This essay highlights some global groundwater quality challenges, describes key contaminant groups and threats of emerging concern, including antimicrobial resistance, and discusses novel approaches to assessing groundwater quality. Groundwater quality monitoring needs to improve significantly in order to effectively identify and mitigate threats to groundwater from historical, current and future pollution.

Communal Wastewater Treatment Plants’ Effectiveness, Management, And Quality Of Groundwater: A Case Study In Indonesia, Widodo Brontowiyono, Thomas B. Boving, Adelia Anju Asmara, Suphia Rahmawati, Andik Yulianto, Noviani Ima Wantoputri, Annisa Nur Lathifah, Yuli Andriansyah

Geosciences Faculty Publications

The Special Region of Yogyakarta is one of the provinces in Indonesia with a large number of communal wastewater treatment plants (CWWTPs). However, less than 40% of CWWTPS in the province are able to be operated well. This study aims to determine the effectiveness of CWWTPs concerning the quality of the surrounding groundwater. The research location was in Mlati, one of three sub-districts with the highest number of CWWTPs and highest population density in the province. Technical data were analyzed in a laboratory, including water quality of CWWTPs and groundwater quality. This study also analyzed non-technical data related to CWWTP …

Microbial Communities In A Serpentinizing Aquifer Are Assembled Through Strong Concurrent Dispersal Limitation And Selection, Lindsay I. Putman, Mary C. Sabuda, William J. Brazelton, Michael D. Kubo, Tori M. Hoehler, Tom M. Mccollom, Dawn Cardace, Matthew O. Schrenk

Geosciences Faculty Publications

In recent years, our appreciation of the extent of habitable environments in Earth's subsurface has greatly expanded, as has our understanding of the biodiversity contained within. Most studies have relied on single sampling points, rather than considering the long-term dynamics of subsurface environments and their microbial populations. One such habitat are aquifers associated with the aqueous alteration of ultramafic rocks through a process known as serpentinization. Ecological modeling performed on a multiyear time series of microbiology, hydrology, and geochemistry in an ultrabasic aquifer within the Coast Range Ophiolite reveals that community assembly is governed by undominated assembly (i.e., neither stochastic …

An Actionable Anti-Racism Plan For Geoscience Organizations, Hendratta N. Ali Ph.D., Sarah L. Sheffield, Jennifer E. Bauer, Rocío P. Caballero-Gill, Nicole M. Gasparini, Julie Libarkin, Kalynda K. Gonzales, Jane Willenbring, Erika Amir-Lin, Julia Cisneros, Dipa Desai, Maitri Erwin, Elisabeth Gallant, Kiara Jeannelle Gomez, Benjamin A. Keisling, Robert Mahon, Erika Marín-Spiotta, Leiaka Welcome, Blair Schneider

Geosciences Faculty Publications

Geoscience organizations shape the discipline. They influence attitudes and expectations, set standards, and provide benefits to their members. Today, racism and discrimination limit the participation of, and promote hostility towards, members of minoritized groups within these critical geoscience spaces. This is particularly harmful for Black, Indigenous, and other people of color in geoscience and is further exacerbated along other axes of marginalization, including disability status and gender identity. Here we present a twenty-point anti-racism plan that organizations can implement to build an inclusive, equitable and accessible geoscience community. Enacting it will combat racism, discrimination, and the harassment of all members.

Diatoms Of The Intertidal Environments Of Willapa Bay, Washington, Usa As A Sea-Level Indicator, Isabel Hong, Benjamin P. Horton, Andrea D. Hawkes, Robert J. O'Donnell Iii, Jason Scott Padgett, Tina Dura, Simon E. Engelhart

Geosciences Faculty Publications

An understanding of the modern relationship between diatom species and elevation is a prerequisite for using fossil diatoms to reconstruct relative sea level (RSL). We described modern diatom distributions from seven transects covering unvegetated subtidal environments to forested uplands from four tidal wetland sites (Smith Creek, Bone River, Niawiakum River, and Naselle River) of Willapa Bay, Washington, USA. We compared our diatom dataset (320 species from 104 samples) to a series of environmental variables (elevation, grain-size, total organic carbon (TOC_SOM), and porewater salinity) using hierarchical clustering and ordination. While no single variable consistently explains variations in diatom …

Surface Runoff Responses To Suburban Growth: An Integration Of Remote Sensing, Gis, And Curve Number, Khurshid Jahan, Soni M. Pradhanang, Md Abu Ehsan Bhuiyan

Geosciences Faculty Publications

Suburban growth and its impacts on surface runoff were investigated using the soil conservation service curve number (SCS-CN) model, compared with the integrated advanced remote sensing and geographic information system (GIS)-based integrated approach, over South Kingston, Rhode Island, USA. This study analyzed and employed the supervised classification method on four Landsat images from 1994, 2004, 2014, and 2020 to detect land-use pattern changes through remote sensing applications. Results showed that 68.6% urban land expansion was reported from 1994 to 2020 in this suburban area. After land-use change detection, a GIS-based SCS-CN model was developed to examine suburban growth and surface …

Induced Bank Filtration: Hydraulic Testing Of Pilot Filters, Miles Schelling, Thomas B. Boving, K. Patil

Geosciences Faculty Publications

Hydraulic tests were performed on two pilot scale filters as part of a water treatment project in the village of Nersa, Karnataka, India. The filters use locally sourced alluvial material to filter E.coli contamination using natural processes that mimic those in Riverbank Filtration (RBF). Two pilot scale filters were tested, one containing locally sourced granular activated carbon (GAC) and one without. A falling head test and tracer test were preformed, and breakthrough curves were used to analyze the hydraulic performance. E.coli data were also collected, and percent removal was calculated to determine the effectiveness of the filters. Relative …

Small Unmanned Aircraft (Suas)-Deployed Thermal Infrared (Tir) Imaging For Environmental Surveys With Implications In Submarine Groundwater Discharge (Sgd): Methods, Challenges, And Novel Opportunities, Kyle S.R. Young, Soni M. Pradhanang

Geosciences Faculty Publications

Submarine Groundwater Discharge (SGD) represents a significant mode of chemical transport to water bodies, making it an important flux to understand. Small Unmanned Aircraft Systems-deployed thermal infrared sensors (sUAS-TIR) provide a financially and logistically inexpensive means of identifying SGD source zones and quantifying SGD thermal infrared (TIR) plume areas over regional scales at high spatial resolutions. sUAS-TIR additionally offers the unique capability of high temporal resolution measurements of SGD. As a developing science application, the use of sUAS-TIR to image SGD requires substantial background knowledge. We present a proposed methodological construct for implementing a sUAS-TIR program for SGD-TIR data gathering, …

Editorial: Deep Carbon Science, Dawn Cardace, Dan J. Bower, Isabelle Daniel, Artur Ionescu, Sami Mikhail, Mattia Pistone, Sabin Zahirovic

Geosciences Faculty Publications

Our understanding of the slow, deep carbon cycle, key to Earth’s habitability is examined here. Because the carbon cycle links Earth’s reservoirs on nano- to mega-scales, we must integrate geological, physical, chemical, biological, and mathematical methods to understand objects and processes so small and yet so vast. Here, we profile current research in the physical chemistry of carbon in natural and model systems, processes ongoing in the deepest portions of planets, and observations of carbon utilization by the deep biosphere. The relationships between the carbon cycle and planetary habitability are undeniable, forming a conceptual anchor to all work in deep …

Fire Suppression Impacts On Fuels And Fire Intensity In The Western U.S.: Insights From Archaeological Luminescence Dating In Northern New Mexico, Christopher I. Roos, Tammy M. Rittenour, Thomas W. Swetnam, Rachel A. Loehman, Kacy L. Hollenback, Matthew J. Liebmann, Dana Drake Rosenstein

Geosciences Faculty Publications

Here, we show that the last century of fire suppression in the western U.S. has resulted in fire intensities that are unique over more than 900 years of record in ponderosa pine forests (Pinus ponderosa). Specifically, we use the heat-sensitive luminescence signal of archaeological ceramics and tree-ring fire histories to show that a recent fire during mild weather conditions was more intense than anything experienced in centuries of frequent wildfires. We support this with a particularly robust set of optically stimulated luminescence measurements on pottery from an archaeological site in northern New Mexico. The heating effects of an October 2012 …

Structural Controls On Crustal Fluid Circulation And Hot Spring Geochemistry Above A Flat‐Slab Subduction Zone, Peru, Brandt E. Scott, Dennis L. Newell, M. J. Jessup, T. A. Grambling, C. A. Shaw

Geosciences Faculty Publications

Hot spring geochemistry from the Cordillera Blanca and Cordillera Huayhuash, Peru, reveal the influence of crustal‐scale structures on geothermal fluid circulation in an amagmatic region located above a flat‐slab subduction zone. To test the influence of contrasting modes of faulting in these regions, springs were targeted along the Cordillera Blanca detachment fault, within its hanging wall, in the footwall of the detachment, and in the Cordillera Huayhuash. Hot springs along the Cordillera Blanca detachment fault zone are associated with recent extension and normal faulting, and those in its footwall and the Cordillera Huayhuash are located in the Marañon fold and …

Hematite (U-Th)/He Thermochronometry Detects Asperity Flash Heating During Laboratory Earthquakes, Melissa S. Chapot, Alexis K. Ault, Greg Hirth, Robert G. Mcdermott

Geosciences Faculty Publications

Evidence for coseismic temperature rise that induces dynamic weakening is challenging to directly observe and quantify in natural and experimental fault rocks. Hematite (U-Th)/He (hematite He) thermochronometry may serve as a fault-slip thermometer, sensitive to transient high temperatures associated with earthquakes. We test this hypothesis with hematite deformation experiments at seismic slip rates, using a rotary-shear geometry with an annular ring of silicon carbide (SiC) sliding against a specular hematite slab. Hematite is characterized before and after sliding via textural and hematite He analyses to quantify He loss over variable experimental conditions. Experiments yield slip surfaces localized in an ∼5–30-µm-thick …

Carbon Assimilation Strategies In Ultrabasic Groundwater: Clues From The Integrated Study Of A Serpentinization-Influenced Aquifer, Lauren M. Seyler, William J. Brazelton, Craig Mclean, Lindsay I. Putman, Alex Hyer, Michael Dy Kubo, Tory Hoehler, Dawn Cardace, Matthew O. Schrenk

Geosciences Faculty Publications

Serpentinization is a low-temperature metamorphic process by which ultramafic rock chemically reacts with water. Such reactions provide energy and materials that may be harnessed by chemosynthetic microbial communities at hydrothermal springs and in the subsurface. However, the biogeochemistry mediated by microbial populations that inhabit these environments is understudied and complicated by overlapping biotic and abiotic processes. We applied metagenomics, metatranscriptomics, and untargeted metabolomics techniques to environmental samples taken from the Coast Range Ophiolite Microbial Observatory (CROMO), a subsurface observatory consisting of 12 wells drilled into the ultramafic and serpentinite mélange of the Coast Range Ophiolite in California. Using a combination …

Crustal Composition And Moho Variations Of The Central And Eastern United States: Improving Resolutionand Geologic Interpretation Of Earthscope Usarray Seismic Images Using Gravity, H. L. Zhang, D. Ravat, Anthony R. Lowry

Geosciences Faculty Publications

EarthScope's USArray Transportable Array has shortcomings for the purpose of interpreting geologic features of wavelengths less than the Transportable Array station spacing, but these can be overcome by using higher spatial resolution gravity data. In this study, we exploit USArray receiver functions to reduce nonuniqueness in the interpretation of gravity anomalies. We model gravity anomalies from previously derived density variations of sedimentary basins, crustal V_p/V_s variation, Moho variation, and upper mantle density variation derived from body wave imaging informed by surface wave tomography to estimate V_p/V_s. Although average densities and density contrasts for …

What Can We Learn From X‐Ray Fluorescence Core Scanning Data? A Paleomonsoon Case Study, Daniel Gebregiorgis, Liviu Giosan, Edmund Hathorne, Pallavi Anand, Katrina Nilsson-Kerr, Anna Plaß, Andreas Lückge, Steven Clemens, Martin Frank

Geosciences Faculty Publications

X‐ray fluorescence (XRF) core scanning of marine and lake sediments has been extensively used to study changes in past environmental and climatic processes over a range of timescales. The interpretation of XRF‐derived element ratios in paleoclimatic and paleoceanographic studies primarily considers differences in the relative abundances of particular elements. Here we present new XRF core scanning data from two long sediment cores in the Andaman Sea in the northern Indian Ocean and show that sea level related processes influence terrigenous inputs based proxies such as Ti/Ca, Fe/Ca, and elemental concentrations of the transition metals (e.g., Mn). Zr/Rb ratios are mainly …

Mariana Serpentinite Mud Volcanism Exhumes Subducted Seamount Materials: Implications For The Origin Of Life., Patricia Fryer, C. Geoffrey Wheat, Trevor Williams, Christopher Kelley, Kevin Johnson, Jeffrey Ryan, Walter Kurz, John W. Shervais, Elmar Albers, Barbara Bekins, Baptiste Debret, Jianghong Deng, Yanhui Dong, Philip Eickenbusch, Emanuelle Frery, Yuji Ichiyama, Richard Kevorkian, Et Al.

Geosciences Faculty Publications

The subduction of seamounts and ridge features at convergent plate boundaries plays an important role in the deformation of the overriding plate and influences geochemical cycling and associated biological processes. Active serpentinization of forearc mantle and serpentinite mud volcanism on the Mariana forearc (between the trench and active volcanic arc) provides windows on subduction processes.  Here, we present (1) the first observation of an extensive exposure of an undeformed Cretaceous seamount currently being subducted at the Mariana Trench inner slope; (2) vertical deformation of the forearc region related to subduction of Pacific Plate seamounts and thickened crust; (3) recovered Ocean …

Oxygen Isotopes In Authigenic Clay Minerals: Toward Building A Reliable Salinity Proxy, Daniel Gebregiorgis, Daniel M. Deocampo, Fred Longstaffe, A. Simpson, Gail M. Ashley, Emily Beverly, Jeremy Delaney, Javier Cuadros

Geosciences Faculty Publications

Most clay minerals in sedimentary environments have traditionally been considered to be of detrital origin, but under certain conditions, authigenic clay minerals can form at low temperature through the transformation of precursor clays or as direct precipitates from lake water. Such clay minerals can hold important information about the prevailing climatic conditions during the time of deposition. We present the first quantitative reconstruction of salinity in paleolake Olduvai based on the oxygen‐isotope composition of authigenic clay minerals. We provide a framework illustrating that the isotopic signature of authigenic lacustrine clay minerals is related to the isotopic composition of paleo‐waters, and …

Development Of Ceramic Water Filter Clay Selection Criteria, Zachary J. Shepard, Yichen Zhang, Nelson M. Anaya, Dawn Cardace, Vinka Oyanedel-Craver

Geosciences Faculty Publications

Ceramic water filters (CWFs) are point-of-use drinking water treatment systems that are manufactured and used in under-served communities around the world. The clayey material (CM) used to manufacture CWFs is a locally sourced mixture of clay, sand, slit and amorphous material (usually dug near the CWF factory). CM varies in composition and purity depending on the geographical location and geological setting. In this study, a set of 13 CM samples collected from around the world were analyzed using grain size analysis, as well as liquid and plastic limit tests. Mineralogical composition was determined using X-ray diffraction. A selection of three …

Predicting Runoff Chloride Concentrations In Suburban Watersheds Using An Artificial Neural Network (Ann), Khurshid Jahan, Soni M. Pradhanang

Geosciences Faculty Publications

Road salts in stormwater runoff, from both urban and suburban areas, are of concern to many. Chloride-based deicers [i.e., sodium chloride (NaCl), magnesium chloride (MgCl₂), and calcium chloride (CaCl₂)], dissolve in runoff, travel downstream in the aqueous phase, percolate into soils, and leach into groundwater. In this study, data obtained from stormwater runoff events were used to predict chloride concentrations and seasonal impacts at different sites within a suburban watershed. Water quality data for 42 rainfall events (2016–2019) greater than 12.7 mm (0.5 inches) were used. An artificial neural network (ANN) model was developed, using measured …

Use Of Α-Cyclodextrin To Promote Clean And Environmentally Friendly Disinfection Of Phenolic Substrates Via Chlorine Dioxide Treatment, Sauradip Chaudhuri, Dana J. Discenza, Thomas B. Boving, Alan Burke, Mindy Levine

Geosciences Faculty Publications

The use of chlorine dioxide to disinfect drinking water and ameliorate toxic components of wastewater has significant advantages in terms of providing safe water. Nonetheless, significant drawbacks toward such usage remain. These drawbacks include the fact that toxic byproducts of the disinfection agents are often formed, and the complete removal of such agents can be challenging. Reported herein is one approach to solving this problem: the use of α-cyclodextrin to affect the product distribution in chlorine dioxide-mediated decomposition of organic pollutants. The presence of α-cyclodextrin leads to markedly more oxidation and less aromatic chlorination, in a manner that is highly …

Evaluation Of Annagnps Model For Runoff Simulation On Watersheds From Glaciated Landscape Of Usa Midwest And Northeast, Marzia Tamanna, Soni M. Pradhanang, Arthur Gold, Kelly Addy, Philippe G. Vidon, Ronald L. Bingner

Geosciences Faculty Publications

Runoff modeling of glaciated watersheds is required to predict runoff for water supply, aquatic ecosystem management and flood prediction, and to deal with questions concerning the impact of climate and land use change on the hydrological system and watershed export of contaminants of glaciated watersheds. A widely used pollutant loading model, Annualized Agricultural Non-Point Source Pollution (AnnAGNPS) was applied to simulate runoff from three watersheds in glaciated geomorphic settings. The objective of this study was to evaluate the suitability of the AnnAGNPS model in glaciated landscapes for the prediction of runoff volume. The study area included Sugar Creek watershed, Indiana; …

Paleoenvironments, Taphonomy, And Stable Isotopic Content Of The Terrestrial, Fossil-Vertebrate–Bearing Sequence Of The El Disecado Member, El Gallo Formation, Upper Cretaceous, Baja California, México, David Fastovsky, Marisol Montellano-Ballesteros, Henry C. Fricke, Jahandar Ramezani, Kaori Tsukui, Gregory P. Wilson, Paul Hall, Rene Hernandez-Rivera, Geraldo Alvarez

Geosciences Faculty Publications

The Late Campanian (Late Cretaceous), upper part of the El Disecado Member, El Gallo Formation, Baja California, México, preserves a rich fossil assemblage of microvertebrates and macrovertebrates, silicified logs, macroscopic plant remains, and pollen that was likely deposited as the distal part of a subaerial fan. The unit was episodic and high energy, with its salient features deriving from active river channels and sheet, debris-flow deposits. Landscape stability is indicated by the presence of compound paleosol horizons, containing Fe₂O₃ mottling in B horizons, cutans, and calcium carbonate concretions. All of these features indicate wet/dry cyclicity in subsurface …