Stephen C. Kuehn

Stephen C. Kuehn
Concord University · Physical Science

Ph.D.

About

119
Publications
13,638
Reads
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786
Citations
Citations since 2016
62 Research Items
543 Citations
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
Additional affiliations
August 2010 - present
Concord University
Position
  • Director of Electron Microprobe and Tephra Laboratory
August 2009 - May 2010
Washington & Lee University
Position
  • Professor (Assistant)
March 2007 - July 2009
University of Alberta
Position
  • PostDoc Position
Education
August 1995 - August 2002
Washington State University
Field of study
  • Geology

Publications

Publications (119)
Article
Full-text available
After decades of debate, the homeland of the First Americans is now generally understood to be northeast Asia; however, the process of Late Pleistocene peopling remains unresolved. As more archaeological sites south of the continental ice sheets are discovered that predate the opening of the interior “ice-free” corridor, interest in a coastal Pacif...
Experiment Findings
Full-text available
A discontinuous black tephra layer of late Holocene age was discovered during excavations at the Nataeł Na’ archaeological site located in the upper Copper River basin in Wrangell-Saint Elias National Park and Preserve, southern Alaska. This dataset includes information on the Nataeł Na’ tephra deposit. The deposit contains brown and clear glass wi...
Article
Full-text available
Tephra is a unique volcanic product with an unparalleled role in understanding past eruptions, long-term behavior of volcanoes, and the effects of volcanism on climate and the environment. Tephra deposits also provide spatially widespread, high-resolution time-stratigraphic markers across a range of sedimentary settings and thus are used in numerou...
Poster
Full-text available
A series of international workshops held in 2014, 2017, 2019, and 2022 focused on improving tephra studies from field collection through publication and encouraging FAIR (findable, accessible, interoperable, reusable) data practices for tephra data and metadata. Two consensus needs for tephra studies emerged from the 2014 and 2017 workshops: (a) st...
Poster
Full-text available
An implementation of the Sparrow data system (https://sparrow-data.org) is currently being developed to support laboratory workflows for sample preparation, geochemical analysis, and SEM imaging in support of tephra research. Tephra, consisting of fragmental material ejected from volcanoes, has a multidisciplinary array of applications from volcano...
Presentation
Full-text available
Electron microscopes can provide an excellent and accessible window into the world of the very small, appropriate for kids and adults alike. Tiny crystals, bits of a feather, or even just an average speck of dust could be the entry point to this micro-world. All sorts of "what is it made of" questions can also be explored. All of this can be done r...
Presentation
Full-text available
Oregon’s northern Great Basin is known for its early archaeological records and dynamic geologic history. A lack of high-resolution paleoenvironmental records from lowland contexts in this region prompted us to conduct sediment coring in the greater Fort Rock Basin, locus of the Connley Caves and Fort Rock Cave sites among others. We collected 5 co...
Poster
Full-text available
Volcanic ash and tuff, or tephra, are critical to geoscientists and archaeologists as widespread time stratigraphic markers and as indicators of past volcanic activity. Research into tephra production, distribution, and characterization supports the use of tephra as a tool for global, interdisciplinary research. These broad uses of tephra will be e...
Presentation
Full-text available
In 2010, Concord University established West Virginia’s first and only electron microprobe analytical laboratory with the intent that it become a statewide resource for education and research. Ready access to instrumentation provides significant advantages, and the Concord microanalytical lab has been a resounding success, supporting innovations in...
Poster
Full-text available
Tephra, or fragmental material ejected from volcanoes, has a unique array of applications in science. Research into tephra production, distribution and characterization supports the use of tephra as a tool for global, interdisciplinary research, and tephra deposits are of critical use to geoscientists as widespread time stratigraphic markers and in...
Poster
Full-text available
Abstract: In 2010, Concord University established an electron microprobe (EPMA) laboratory, the first that we know of at a primarily undergraduate university. Taking on such an effort at a small, state university can certainly be described as "non-traditional." Yet, ready access to on-site instrumentation provides significant advantages, and the C...
Article
Full-text available
This study undertakes an unusual approach to the course-based undergraduate research experience (CURE) by engaging students in an ongoing research project that is embedded across two years of required coursework, including four geology courses and a capstone summer field experience. The authors describe the curriculum, note the importance of scaffo...
Poster
The melting and retreating of the continental ice sheet at the end of the Wisconsin Glacial period influenced the geomorphology and paleoenvironment of much of the Great Lakes Region and northern Indiana, including Appleman Lake, a small kettle-pond in Lagrange County, Indiana. A 2009 paleoecological study of sediment cores retrieved from Appleman...
Conference Paper
In 2010, Concord University established an electron microprobe (EPMA) laboratory, an unusual step for a primarily undergraduate, liberal-arts university. Operating major research instrumentation has many advantages, and the laboratory has been a key tool in supporting innovations in undergraduate teaching and research for the past decade. The core...
Conference Paper
The Three-Sisters–Tumalo volcanic region, located in central Oregon, USA, is associated with a relatively active segment of the Cascade volcanic arc. This region’s potential for future eruptions became especially evident to the public as a result of a period of ground deformation and earthquakes in the 1990s to early 2000s. This region is also asso...
Conference Paper
Full-text available
Pliocene Earth featured a warmer global temperature (+3-4 ° C), little Northern Hemisphere ice cover, and possibly pCO2 of ~400 ppm. During the Pliocene, multiple large perennial lakes existed for several million years in what is now arid and semi-arid Western United States (e.g. Lake Idaho, Idaho; Summer Lake, Oregon; Butte Valley, Tule Lake, Sear...
Conference Paper
Full-text available
At Summer Lake, Oregon, USA, an ~200 kyr outcrop record contains at least 90 tephra beds (Kuehn & Negrini, 2010) yielding an average frequency of one tephra per 2,200 years. Surprisingly, less than one quarter of these beds have been correlated to proximal deposits in the Cascade arc. This indicates that our understanding of the frequency and impac...
Code
This spreadsheet takes (1) X-Y coordinates for three reference positions and multiple sample positions acquired on a source instrument and (2) X-Y coordinates for three reference positions on a second instrument as input. It then transforms the sample coordinates for use on a second instrument and plots the relative positions graphically.
Conference Paper
Full-text available
Recent partnerships between higher education and industry have reconsidered the effectiveness of undergraduate curricula in preparing graduates with workforce-relevant skills and competencies (e.g., Summa et al., 2017, GSA Today; Saxe and Braddy, 2015, Mathematical Assoc. Am.). A common outcome is the realization that the “status quo is unacceptabl...
Poster
Volcanic ash plumes are common phenomena that greatly vary in size and distribution depending on the location, style, and scale of a particular eruption. The resulting fragmental deposits (tephra units) can extend across local regions, countries, oceans, and even multiple continents. Geochemistry, lithostratigraphy, and other parameters can help id...
Conference Paper
Full-text available
The Homestake shear zone (HSZ) and Slide Lake shear zone (SLSZ) both contain a similar suite of tectonites including mutually overprinting mylonite and mylonitic pseudotachylyte (mpt). However, the age relations and pressure-temperature conditions between the two shear zones is unclear. Field mapping and titanium-in-quartz thermometry (TitaniQ) wer...
Conference Paper
Full-text available
During the ice ages, many large lakes existed in the western United States in an area known as the Great Basin. This area includes parts of Nevada, Utah, Oregon, and eastern California; nearly all of this land is desert today. As large ice sheets elsewhere advanced across the continent and then melted away, these lakes expanded and dried up over ti...
Poster
Full-text available
The Three-Sisters–Tumalo volcanic region, located in central Oregon, USA, is associated with a relatively active segment of the Cascade volcanic arc. This region’s potential for future eruptions became especially evident to the public as a result of a period of ground deformation and earthquakes in the 1990s to early 2000s. This region is also asso...
Conference Paper
Full-text available
Course-based undergraduate research experiences (CURE’s) are a common means of delivering high-impact activities to a broader cross section of students. They can even be expanded into multi-semester, curriculum-based research experiences as we have done. However, assessing student learning in CURE’s is complex since the impacts are often highly ind...
Article
The Kos-Nisyros-Yali volcanic region is one of the centers in the South Aegean Volcanic Arc to exhibit Holocene volcanic activity, with poorly dated thin tephra layers on Yali associated with Neolithic artefacts. This paper helps to resolve the age and character of early to mid-Holocene volcanism in the South Aegean Sea. It presents the lithostrati...
Article
The Kos-Nisyros-Yali volcanic region is one of the centers in the South Aegean Volcanic Arc to exhibit Holocene volcanic activity, with poorly dated thin tephra layers on Yali associated with Neolithic artifacts. This paper helps to resolve the age and character of early to mid - Holocene volcanism in the South Aegean Sea. It presents the lithostra...
Poster
Full-text available
As stratigraphic and chronologic markers, tephra layers are a common link across multiple disciplines, including, but not limited to, volcanology, tephrochronology, archaeology, and paleolimnology. Tephra deposits reflect the magmatic, eruptive, dispersal, and depositional processes during their ejection and emplacement and can provide extensive ti...
Article
The middle Tanana River basin has proven to be an important area for investigating the late Pleistocene and Holocene occupations of interior Alaska; however, less research has been reported for the uppermost part of the valley. In 2011, we conducted a reconnaissance cultural-resource survey of land- forms along two upper Tanana River tributaries, t...
Conference Paper
Full-text available
Analysis of natural and synthetic glasses is a common application of electron probe microanalysis (EPMA). Since the late 1960s, EPMA has remained at the forefront of tephra glass analysis because of the technique’s high spatial resolution, analytical sensitivity, rapidity, cost-effectiveness, and potential for high precision. These attributes make...
Conference Paper
Full-text available
As chronostratigraphic markers and as records of volcanic events, tephra layers are a common link across multiple disciplines, including volcanology, tephrochronology, archaeology, and paleolimnology among many others. Tephra deposits reflect the magmatic, eruptive, dispersal, and depositional processes that contribute to their formation. They are...
Article
Full-text available
Tephra deposits correlated between nearby lakes provide the opportunity to improve age estimates of the sediment sequences, even if the ages of the tephras are previously unknown. We explore this potential using cryptotephras and visible tephra deposits in sediment cores from Upper and Lower Whitshed Lakes near Cordova, Alaska. Each tephra was desc...
Code
Spreadsheet which calculates temperatures using the general form TitaniQ equation from Thomas et al., 2010, TitaniQ Under Pressure
Preprint
The INternational focus group on Tephrochronology And Volcanism (INTAV) of the International Union for Quaternary Research (INQUA) has conducted an intercomparison of tephrochronology laboratories with electron-beam microanalytical data on volcanic glasses submitted from 27 instruments at 24 institutions in 9 countries. This assessment includes mos...
Conference Paper
Short-term undergraduate research experiences (URE’s) provide skill and confidence enhancement to students, but it is unclear how effective they are in comparison to a dedicated, longer-term URE. This study examines the impact of a long-term URE embedded in a sequence of five courses in the geology curriculum. It begins with a sophomore course in e...
Article
We define tephras and cryptotephras and their components (mainly ash-sized particles of glass ± crystals in distal deposits) and summarize the basis of tephrochronology as a chronostratigraphic correlational and dating tool for palaeoenvironmental, geological, and archaeological research. We then document and appraise recent advances in analytical...
Conference Paper
Full-text available
The Three-Sisters–Tumalo volcanic region, located in central Oregon, USA, is associated with one of the more active segments of the Cascade volcanic arc. This region’s potential for future eruptions was thrust into public consciousness by a period of ground deformation and earthquakes during the late 1990s to early 2000s. The region is also a known...
Conference Paper
Full-text available
Short-term undergraduate research experiences (URE’s) provide skill and confidence enhancement to students, but it is unclear how effective they are in comparison to a dedicated, longer-term URE. This study examines the impact of a long-term URE embedded in a sequence of five courses in the geology curriculum. It begins with a sophomore course in e...
Article
The ‘Lateglacial’ period (~14.7 – 11.7 cal ka BP) eruptions of Mount St Helens and Glacier Peak in the Cascade Range deposited ash layers (tephras) within a short time span across much of western North America where they form event-stratigraphic marker layers or isochrons. They were deposited at a time which has long been of interest because it rep...
Conference Paper
Full-text available
In 2010, Concord University, a 2800-student, predominantly undergraduate institution in West Virginia, installed an ARL SEMQ microprobe as the first stage of a plan to establish a microanalytical facility that emphasizes undergraduate teaching and research while also supporting other uses. This facility has now operated successfully for six years a...
Conference Paper
Full-text available
Analysis of natural and synthetic glasses is a common application of electron probe microanalysis (EPMA). In the geosciences, this includes the analysis of volcanic ash and pumice (tephra) and of melt inclusions in mineral grains to support a wide range of research objectives. Key among these are understanding volcanic gas emissions and magma proce...
Article
The ‘Lateglacial’ period (~14.7-11.7 cal ka BP) eruptions of Mount St Helens and Glacier Peak in the Cascade Range deposited ash layers (tephras) within a short time span across much of western North America where they form event-stratigraphic marker layers or isochrons. They were deposited at a time which has long been of interest because it repre...
Conference Paper
Volcanic ash and pumice (tephra) deposits provide important records of past volcanism. By understanding the eruption history and processes of volcanoes, better estimates can be made about eruptions. Volcanic ash beds can also provide important time-markers or studies including archeology, earthquake hazards, and long-term environmental change. Lake...
Conference Paper
Full-text available
The Tephra 2014 Workshop (3-7 August 2014) discussed major developments, best practices, future directions, and critical needs in tephra studies from both volcanological and tephrochronological perspectives. In a consensus-seeking session held at the end of the workshop, the international group of over 70 tephra scientists focused on two complement...
Conference Paper
Full-text available
Evidence-based research continues to affirm that participation in undergraduate research results in numerous cognitive, personal, and professional gains among STEM students. However, emergent research suggests that longer engagement as an undergraduate advances these benefits and is necessary for independent scientific thought to mature. This prese...
Conference Paper
Full-text available
The Summer Lake sub-basin of pluvial lake Chewaucan has been a locus of research for decades, yielding important records of environmental conditions and climate in the northwestern Great Basin for the late Pleistocene. Lithostratigraphic, ostracode, pollen, and geochemical indicators obtained from cores and outcrop provide evidence for vegetation c...
Conference Paper
Full-text available
Se presentan aquí nuevos antecedentes geocronológicos y estratigráficos para el Cuaternario del Valle del Elqui (Región IV, Chile) entre Vicuña y Huanta. Los depósitos cuaternarios están dominados por la secuencia aluvial proveniente de quebradas tributarias de los ríos Claro, Turbio y Elqui, interestratificados con depósitos fluviales. Se han iden...
Conference Paper
Full-text available
The Summer Lake sub-basin of pluvial Lake Chewaucan contains excellent Holocent to Pleistocene (Pliocene?) records of environmental change, paleomagnetism, Basin and Range fault movements, and volcanism (e.g. Cohen et al., 2000; Kuehn and Negrini, 2010; Negrini et al., 2014; Weldon et al., 2009). Numerous tephra layers present in the lake sediments...
Conference Paper
Sediment cores from Upper and Lower Whitshed Lakes located near Cordova, Alaska were used to create a tephrochronology and to reconstruct environmental and climatic change during the past 15,000 years. Independent age models were developed for both lakes using radiocarbon dates, and profiles of short-lived radioisotopes for the surface of the cores...
Poster
Full-text available
In the complex marine setting around the upper Quaternary volcanic islands of the southeast Aegean Sea, the Marine Geological Unit of Athens University, Greece, recently recovered 43 cores. This project focuses on characterizing tephra from selected portions of 11 cores (PAG-12-8, PAG-12-9, PAG-12-10, PAG-12-11, PAG-12-13, M-22-103, M-15-150, LC-21...
Conference Paper
Full-text available
In the complex marine setting around the upper Quaternary volcanic islands of the southeast Aegean Sea, the Marine Geological Unit of Athens University, Greece, recently recovered 43 cores. This project focuses on characterizing tephra from selected portions of 11 cores (PAG-12-8, PAG-12-9, PAG-12-10, PAG-12-11, PAG-12-13, M-22-103, M-15-150, LC-21...
Conference Paper
Full-text available
Tephra deposits provide key information for documenting volcano eruptive histories, and to understand volcanic processes and hazards. Widespread tephra layers from major eruptions are used around the world for correlation and dating in geology and archaeology. Applications include earth surface processes, past environmental/climate changes, and hum...
Conference Paper
Full-text available
The Tephra 2014 Workshop was convened 3-7 August, 2014, to discuss major developments, best practices, and future directions/needs in tephra studies from both volcanological and tephrochronological perspectives. By bringing together an international group of over 70 scientists with a variety of backgrounds who study tephra for different purposes, o...
Conference Paper
Full-text available
In the complex marine setting around the volcanic islands of the southeast Aegean Sea, Athens University has recently recovered 43 cores. a tephra identified interbedded within the uppermost East Mediterranean sapropel S1 prompted a high resolution study of 11 cores retrieved from around the islands of Nisyros, Yali, Pyrgousa and Kos. This research...
Conference Paper
Full-text available
Consistent usage of terminology and detailed documentation of sample and deposit characteristics are critical for successful integration of studies that utilize tephra. The multiple scientific communities that study tephra have developed their own terminologies, techniques and knowledge-bases through time, based on differences in research foci. Thi...
Poster
Full-text available
Lacustrine sediments preserved near Summer Lake, which occupies a portion of the northwestern sub-basin of Pluvial Lake Chewaucan contain an exceptional long-term record of Cascade arc pyroclastic volcanism and is therefore a key reference locality for tephrochronology. Multiple studies have also examined paleoclimate, paleomagnetic, and paleoseism...
Conference Paper
Full-text available
Tephra deposits form a common thread which connects diverse, multidisciplinary research directions that share overlapping data needs. Tephra beds reflect the magmatic, eruptive, dispersal, and depositional processes involved in their generation as well as the tectonic environment from which they originate. Therefore, they are globally important for...
Article
Marked changes in sediment types deposited in Cabin Lake, near Cordova, Alaska, represent environmental shifts during the early and late Holocene, including fluctuations in the terminal position of Sheridan Glacier. Cabin Lake is situated to receive meltwater during periods when the outwash plain of the advancing Sheridan Glacier had aggraded. A br...