Elmira Wan (Former Employee)
Science and Products
USGS Tephrochronology (Tephra) Project
Tephrochronology is the study of volcanic ash deposits, combining petrology, geochemistry, and isotopic dating methods. We use tephrochronology, along with other chronostratigraphic techniques, to (1) determine the ages of coincident deposits, and, when multiple tephra layers are present, determine the history of geologic events and rates of geologic processes; and (2) correlate sediments from...
Tephra geochemistry of the Ibex Hollow Tuff, a 12-Ma super-eruption Tephra geochemistry of the Ibex Hollow Tuff, a 12-Ma super-eruption
These tables contain geochemical data collected for tephra samples either correlated with or in the same type section with the Ibex Hollow Tuff. Most samples were collected by Andrei Sarna-Wojcicki and Mike Perkins, but some were submitted to the U.S. Geological Survey Tephrochronology Project for analysis by other persons. Electron microprobe analysis (EMA) was performed at the U.S...
Surficial geology and stratigraphy of Pleistocene Lake Manix, San Bernardino County, California Surficial geology and stratigraphy of Pleistocene Lake Manix, San Bernardino County, California
Pluvial Lake Manix and its surrounding drainage basin, in the central Mojave Desert of California, has been a focus of paleoclimate, surficial processes, and neotectonic studies by the U.S. Geological Survey (USGS) since about 2004. The USGS initiated studies of Lake Manix deposits to improve understanding of the paleoclimatic record and the shifts in atmospheric circulation that...
Geologic map and upper Paleozoic stratigraphy of the Marble Canyon area, Cottonwood Canyon quadrangle, Death Valley National Park, Inyo County, California Geologic map and upper Paleozoic stratigraphy of the Marble Canyon area, Cottonwood Canyon quadrangle, Death Valley National Park, Inyo County, California
This geologic map and pamphlet focus on the stratigraphy, depositional history, and paleogeographic significance of upper Paleozoic rocks exposed in the Marble Canyon area in Death Valley National Park, California. Bedrock exposed in this area is composed of Mississippian to lower Permian (Cisuralian) marine sedimentary rocks and the Jurassic Hunter Mountain Quartz Monzonite. These units...
Filter Total Items: 27
Ibex Hollow Tuff from ca. 12 Ma supereruption, southern Idaho, identified across North America, eastern Pacific Ocean, and Gulf of Mexico Ibex Hollow Tuff from ca. 12 Ma supereruption, southern Idaho, identified across North America, eastern Pacific Ocean, and Gulf of Mexico
The Ibex Hollow Tuff, 12.08 ± 0.03 Ma (40Ar/39Ar), is a widespread tephra layer erupted from the Bruneau-Jarbidge volcanic field of southern Idaho. Tephra from this eruption was deposited across much of western and central North America and adjacent ocean areas. We identified the Ibex Hollow Tuff at Trapper Creek, Idaho, near its eruption site, and at 15 distal sites, from the Pacific...
Authors
Andrei M. Sarna-Wojcicki, Jeffrey R. Knott, John A. Westgate, James R. Budahn, John A. Barron, Colin J. Bray, Greg A. Ludvigson, Charles E. Meyer, David M. Miller, Rick E. Otto, Nicholas J.G. Pearce, Charles C. Smith, Laura Walkup, Elmira Wan, James Yount
Tephrochronology of the Miocene Monterey and Modelo Formations, California Tephrochronology of the Miocene Monterey and Modelo Formations, California
Tuff beds have been known in the Miocene Monterey and Modelo Formations since the initial descriptions; however, age control and correlation is predominantly biostratigraphy. Here we combine tephrochronology and biostratigraphy in order to provide numerical age control for eight sedimentary sequences of the Monterey and Modelo Formations from Monterey, California to Orange County...
Authors
Jeffrey R. Knott, Andrei M. Sarna-Wojcicki, John A. Barron, Elmira Wan, Nancy Heizler, Priscilla Martinez
Late Cenozoic tephrochronology of the Mount Diablo area within the evolving plate-tectonic boundary zone of northern California Late Cenozoic tephrochronology of the Mount Diablo area within the evolving plate-tectonic boundary zone of northern California
We present a tephrochronologic/chronostratigraphic database for the Mount Diablo area and greater San Francisco Bay region that provides a spatial and temporal framework for geologic studies in the region, including stratigraphy, paleogeography, tectonics, quantification of earth surface processes, recurrence of natural hazards, and climate change. We identified and correlated 34 tephra...
Authors
Andrei Sarna-Wojcicki, Raymond Sullivan, Alan L. Deino, Laura Walkup, J. Ross Wagner, Elmira Wan
Geomorphic history of Lake Manix, Mojave Desert, California: Evolution of a complex terminal lake basin Geomorphic history of Lake Manix, Mojave Desert, California: Evolution of a complex terminal lake basin
The US Environmental Protection Agency's short-term freshwater effluent test methods include a fish (Pimephales promelas), a cladoceran (Ceriodaphnia dubia), and a green alga (Raphidocelis subcapitata). There is a recognized need for additional taxa to accompany the three standard species for effluent testing. An appropriate additional taxon is unionid mussels because mussels are widely
Authors
Marith C. Reheis, David M. Miller, James B. Paces, Charles G. Oviatt, Joanna R. Redwine, Darrell Kaufman, Jordon Bright, Elmira Wan
Lake Andrei: A pliocene pluvial lake in Eureka Valley, Eastern California Lake Andrei: A pliocene pluvial lake in Eureka Valley, Eastern California
We used geologic mapping, tephrochronology and 40Ar/39Ar dating to describe evidence of a ca. 3.5 Ma pluvial lake in Eureka Valley, eastern California, that we informally name herein Lake Andrei. We identified six different tuffs in the Eureka Valley drainage basin including two previously undescribed tuffs: the 3.509 ± 0.009 Ma tuff of Hanging Rock Canyon and the 3.506 ± 0.010 Ma tuff...
Authors
Jeffrey R. Knott, Elmira Wan, Alan L. Deino, Mitch Casteel, Marith C. Reheis, Fred Phillips, Laura Walkup, Kyle McCarty, David N. Manoukian, Ernest Nunez
Pleistocene lakes and paleohydrologic environments of the Tecopa basin, California: Constraints on the drainage integration of the Amargosa River Pleistocene lakes and paleohydrologic environments of the Tecopa basin, California: Constraints on the drainage integration of the Amargosa River
The Tecopa basin in eastern California was a terminal basin that episodically held lakes during most of the Quaternary until the basin and its modern stream, the Amargosa River, became tributary to Death Valley. Although long studied for its sedimentology, diagenesis, and paleomagnetism, the basin’s lacustrine and paleoclimate history has not been well understood, and conflicting...
Authors
Marith C. Reheis, John Caskey, Jordon Bright, James B. Paces, Shannon A. Mahan, Elmira Wan
Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults
Hinkley Valley in the Mojave Desert, near Barstow about 140 km northeast of Los Angeles and midway between Victorville Valley and the Lake Manix basin, contains a thick sedimentary sequence delivered by the Mojave River. Our study of sediment cores drilled in the valley indicates that Hinkley Valley was probably a closed playa basin with stream inflow from four directions prior to Mojave...
Authors
David M. Miller, Elizabeth Haddon, Victoria Langenheim, Andrew J. Cyr, Elmira Wan, Laura Walkup, Scott W. Starratt
Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults
Hinkley Valley in the Mojave Desert, near Barstow about 140 km northeast of Los Angeles and midway between Victorville Valley and the Lake Manix basin, contains a thick sedimentary sequence delivered by the Mojave River. Our study of sediment cores drilled in the valley indicates that Hinkley Valley was probably a closed playa basin with stream inflow from four directions prior to Mojave...
Authors
David M. Miller, Elizabeth Haddon, Victoria E. Langenheim, Andrew J. Cyr, Elmira Wan, Laura Walkup, Scott W. Starratt
Late Neogene–Quaternary tephrochronology, stratigraphy, and paleoclimate of Death Valley, California, USA Late Neogene–Quaternary tephrochronology, stratigraphy, and paleoclimate of Death Valley, California, USA
Sedimentary deposits in midlatitude continental basins often preserve a paleoclimate record complementary to marine-based records. However, deriving that paleoclimate record depends on having well-exposed deposits and establishing a sufficiently robust geochronology. After decades of research, we have been able to correlate 77 tephra beds exposed in multiple stratigraphic sections in the...
Authors
Jeffrey R. Knott, Michael N Machette, Elmira Wan, Ralph E. Klinger, Joseph C Liddicoat, Andrei M. Sarna-Wojcicki, Robert J. Fleck, Alan L. Deino, John W Geissman, Janet L. Slate, David Wahl, Brian P. Wernicke, Stephen G. Wells, John C. Tinsley, Jeffrey C Hathaway, Veva M. Weamer
The story of a Yakima fold and how it informs Late Neogene and Quaternary backarc deformation in the Cascadia subduction zone, Manastash anticline, Washington, USA The story of a Yakima fold and how it informs Late Neogene and Quaternary backarc deformation in the Cascadia subduction zone, Manastash anticline, Washington, USA
The Yakima folds of central Washington, USA, are prominent anticlines that are the primary tectonic features of the backarc of the northern Cascadia subduction zone. What accounts for their topographic expression and how much strain do they accommodate and over what time period? We investigate Manastash anticline, a north vergent fault propagation fold typical of structures in the fold...
Authors
Harvey M. Kelsey, Tyler C. Ladinsky, Lydia M. Staisch, Brian L. Sherrod, Richard J. Blakely, Thomas L. Pratt, William J. Stephenson, Jackson K. Odum, Elmira Wan
Holocene environmental changes inferred from biological and sedimentological proxies in a high elevation Great Basin lake in the northern Ruby Mountains, Nevada, USA Holocene environmental changes inferred from biological and sedimentological proxies in a high elevation Great Basin lake in the northern Ruby Mountains, Nevada, USA
Multi-proxy analyses were conducted on a sediment core from Favre Lake, a high elevation cirque lake in the northern Ruby Mountains, Nevada, and provide a ca. 7600 year record of local and regional environmental change. Data indicate that lake levels were lower from 7600-5750 cal yr BP, when local climate was warmer and/or drier than today. Effective moisture increased after 5750 cal yr...
Authors
David B. Wahl, Scott W. Starratt, Lysanna Anderson, Jennifer E. Kusler, Christopher C. Fuller, Jason A. Addison, Elmira Wan
Quaternary tephrochronology and deposition in the subsurface Sacramento–San Joaquin Delta, California, U.S.A. Quaternary tephrochronology and deposition in the subsurface Sacramento–San Joaquin Delta, California, U.S.A.
We document characteristics of tephra, including facies and geochemistry, from 27 subsurface sites in the Sacramento-San Joaquin Delta, California, to obtain stratigraphic constraints in a complex setting. Analyzed discrete tephra deposits are correlative with: 1) an unnamed tephra from the Carlotta Formation near Ferndale, California, herein informally named the ash of Wildcat Grade (~0...
Authors
Katherine L. Maier, Emma Gatti, Elmira Wan, Daniel J. Ponti, Mark Pagenkopp, Scott W. Starratt, Holly A. Olson, John Tinsley
Science and Products
USGS Tephrochronology (Tephra) Project
Tephrochronology is the study of volcanic ash deposits, combining petrology, geochemistry, and isotopic dating methods. We use tephrochronology, along with other chronostratigraphic techniques, to (1) determine the ages of coincident deposits, and, when multiple tephra layers are present, determine the history of geologic events and rates of geologic processes; and (2) correlate sediments from...
Tephra geochemistry of the Ibex Hollow Tuff, a 12-Ma super-eruption Tephra geochemistry of the Ibex Hollow Tuff, a 12-Ma super-eruption
These tables contain geochemical data collected for tephra samples either correlated with or in the same type section with the Ibex Hollow Tuff. Most samples were collected by Andrei Sarna-Wojcicki and Mike Perkins, but some were submitted to the U.S. Geological Survey Tephrochronology Project for analysis by other persons. Electron microprobe analysis (EMA) was performed at the U.S...
Surficial geology and stratigraphy of Pleistocene Lake Manix, San Bernardino County, California Surficial geology and stratigraphy of Pleistocene Lake Manix, San Bernardino County, California
Pluvial Lake Manix and its surrounding drainage basin, in the central Mojave Desert of California, has been a focus of paleoclimate, surficial processes, and neotectonic studies by the U.S. Geological Survey (USGS) since about 2004. The USGS initiated studies of Lake Manix deposits to improve understanding of the paleoclimatic record and the shifts in atmospheric circulation that...
Geologic map and upper Paleozoic stratigraphy of the Marble Canyon area, Cottonwood Canyon quadrangle, Death Valley National Park, Inyo County, California Geologic map and upper Paleozoic stratigraphy of the Marble Canyon area, Cottonwood Canyon quadrangle, Death Valley National Park, Inyo County, California
This geologic map and pamphlet focus on the stratigraphy, depositional history, and paleogeographic significance of upper Paleozoic rocks exposed in the Marble Canyon area in Death Valley National Park, California. Bedrock exposed in this area is composed of Mississippian to lower Permian (Cisuralian) marine sedimentary rocks and the Jurassic Hunter Mountain Quartz Monzonite. These units...
Filter Total Items: 27
Ibex Hollow Tuff from ca. 12 Ma supereruption, southern Idaho, identified across North America, eastern Pacific Ocean, and Gulf of Mexico Ibex Hollow Tuff from ca. 12 Ma supereruption, southern Idaho, identified across North America, eastern Pacific Ocean, and Gulf of Mexico
The Ibex Hollow Tuff, 12.08 ± 0.03 Ma (40Ar/39Ar), is a widespread tephra layer erupted from the Bruneau-Jarbidge volcanic field of southern Idaho. Tephra from this eruption was deposited across much of western and central North America and adjacent ocean areas. We identified the Ibex Hollow Tuff at Trapper Creek, Idaho, near its eruption site, and at 15 distal sites, from the Pacific...
Authors
Andrei M. Sarna-Wojcicki, Jeffrey R. Knott, John A. Westgate, James R. Budahn, John A. Barron, Colin J. Bray, Greg A. Ludvigson, Charles E. Meyer, David M. Miller, Rick E. Otto, Nicholas J.G. Pearce, Charles C. Smith, Laura Walkup, Elmira Wan, James Yount
Tephrochronology of the Miocene Monterey and Modelo Formations, California Tephrochronology of the Miocene Monterey and Modelo Formations, California
Tuff beds have been known in the Miocene Monterey and Modelo Formations since the initial descriptions; however, age control and correlation is predominantly biostratigraphy. Here we combine tephrochronology and biostratigraphy in order to provide numerical age control for eight sedimentary sequences of the Monterey and Modelo Formations from Monterey, California to Orange County...
Authors
Jeffrey R. Knott, Andrei M. Sarna-Wojcicki, John A. Barron, Elmira Wan, Nancy Heizler, Priscilla Martinez
Late Cenozoic tephrochronology of the Mount Diablo area within the evolving plate-tectonic boundary zone of northern California Late Cenozoic tephrochronology of the Mount Diablo area within the evolving plate-tectonic boundary zone of northern California
We present a tephrochronologic/chronostratigraphic database for the Mount Diablo area and greater San Francisco Bay region that provides a spatial and temporal framework for geologic studies in the region, including stratigraphy, paleogeography, tectonics, quantification of earth surface processes, recurrence of natural hazards, and climate change. We identified and correlated 34 tephra...
Authors
Andrei Sarna-Wojcicki, Raymond Sullivan, Alan L. Deino, Laura Walkup, J. Ross Wagner, Elmira Wan
Geomorphic history of Lake Manix, Mojave Desert, California: Evolution of a complex terminal lake basin Geomorphic history of Lake Manix, Mojave Desert, California: Evolution of a complex terminal lake basin
The US Environmental Protection Agency's short-term freshwater effluent test methods include a fish (Pimephales promelas), a cladoceran (Ceriodaphnia dubia), and a green alga (Raphidocelis subcapitata). There is a recognized need for additional taxa to accompany the three standard species for effluent testing. An appropriate additional taxon is unionid mussels because mussels are widely
Authors
Marith C. Reheis, David M. Miller, James B. Paces, Charles G. Oviatt, Joanna R. Redwine, Darrell Kaufman, Jordon Bright, Elmira Wan
Lake Andrei: A pliocene pluvial lake in Eureka Valley, Eastern California Lake Andrei: A pliocene pluvial lake in Eureka Valley, Eastern California
We used geologic mapping, tephrochronology and 40Ar/39Ar dating to describe evidence of a ca. 3.5 Ma pluvial lake in Eureka Valley, eastern California, that we informally name herein Lake Andrei. We identified six different tuffs in the Eureka Valley drainage basin including two previously undescribed tuffs: the 3.509 ± 0.009 Ma tuff of Hanging Rock Canyon and the 3.506 ± 0.010 Ma tuff...
Authors
Jeffrey R. Knott, Elmira Wan, Alan L. Deino, Mitch Casteel, Marith C. Reheis, Fred Phillips, Laura Walkup, Kyle McCarty, David N. Manoukian, Ernest Nunez
Pleistocene lakes and paleohydrologic environments of the Tecopa basin, California: Constraints on the drainage integration of the Amargosa River Pleistocene lakes and paleohydrologic environments of the Tecopa basin, California: Constraints on the drainage integration of the Amargosa River
The Tecopa basin in eastern California was a terminal basin that episodically held lakes during most of the Quaternary until the basin and its modern stream, the Amargosa River, became tributary to Death Valley. Although long studied for its sedimentology, diagenesis, and paleomagnetism, the basin’s lacustrine and paleoclimate history has not been well understood, and conflicting...
Authors
Marith C. Reheis, John Caskey, Jordon Bright, James B. Paces, Shannon A. Mahan, Elmira Wan
Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults
Hinkley Valley in the Mojave Desert, near Barstow about 140 km northeast of Los Angeles and midway between Victorville Valley and the Lake Manix basin, contains a thick sedimentary sequence delivered by the Mojave River. Our study of sediment cores drilled in the valley indicates that Hinkley Valley was probably a closed playa basin with stream inflow from four directions prior to Mojave...
Authors
David M. Miller, Elizabeth Haddon, Victoria Langenheim, Andrew J. Cyr, Elmira Wan, Laura Walkup, Scott W. Starratt
Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults Middle Pleistocene infill of Hinkley Valley by Mojave River sediment and associated lake sediment: Depositional architecture and deformation by strike-slip faults
Hinkley Valley in the Mojave Desert, near Barstow about 140 km northeast of Los Angeles and midway between Victorville Valley and the Lake Manix basin, contains a thick sedimentary sequence delivered by the Mojave River. Our study of sediment cores drilled in the valley indicates that Hinkley Valley was probably a closed playa basin with stream inflow from four directions prior to Mojave...
Authors
David M. Miller, Elizabeth Haddon, Victoria E. Langenheim, Andrew J. Cyr, Elmira Wan, Laura Walkup, Scott W. Starratt
Late Neogene–Quaternary tephrochronology, stratigraphy, and paleoclimate of Death Valley, California, USA Late Neogene–Quaternary tephrochronology, stratigraphy, and paleoclimate of Death Valley, California, USA
Sedimentary deposits in midlatitude continental basins often preserve a paleoclimate record complementary to marine-based records. However, deriving that paleoclimate record depends on having well-exposed deposits and establishing a sufficiently robust geochronology. After decades of research, we have been able to correlate 77 tephra beds exposed in multiple stratigraphic sections in the...
Authors
Jeffrey R. Knott, Michael N Machette, Elmira Wan, Ralph E. Klinger, Joseph C Liddicoat, Andrei M. Sarna-Wojcicki, Robert J. Fleck, Alan L. Deino, John W Geissman, Janet L. Slate, David Wahl, Brian P. Wernicke, Stephen G. Wells, John C. Tinsley, Jeffrey C Hathaway, Veva M. Weamer
The story of a Yakima fold and how it informs Late Neogene and Quaternary backarc deformation in the Cascadia subduction zone, Manastash anticline, Washington, USA The story of a Yakima fold and how it informs Late Neogene and Quaternary backarc deformation in the Cascadia subduction zone, Manastash anticline, Washington, USA
The Yakima folds of central Washington, USA, are prominent anticlines that are the primary tectonic features of the backarc of the northern Cascadia subduction zone. What accounts for their topographic expression and how much strain do they accommodate and over what time period? We investigate Manastash anticline, a north vergent fault propagation fold typical of structures in the fold...
Authors
Harvey M. Kelsey, Tyler C. Ladinsky, Lydia M. Staisch, Brian L. Sherrod, Richard J. Blakely, Thomas L. Pratt, William J. Stephenson, Jackson K. Odum, Elmira Wan
Holocene environmental changes inferred from biological and sedimentological proxies in a high elevation Great Basin lake in the northern Ruby Mountains, Nevada, USA Holocene environmental changes inferred from biological and sedimentological proxies in a high elevation Great Basin lake in the northern Ruby Mountains, Nevada, USA
Multi-proxy analyses were conducted on a sediment core from Favre Lake, a high elevation cirque lake in the northern Ruby Mountains, Nevada, and provide a ca. 7600 year record of local and regional environmental change. Data indicate that lake levels were lower from 7600-5750 cal yr BP, when local climate was warmer and/or drier than today. Effective moisture increased after 5750 cal yr...
Authors
David B. Wahl, Scott W. Starratt, Lysanna Anderson, Jennifer E. Kusler, Christopher C. Fuller, Jason A. Addison, Elmira Wan
Quaternary tephrochronology and deposition in the subsurface Sacramento–San Joaquin Delta, California, U.S.A. Quaternary tephrochronology and deposition in the subsurface Sacramento–San Joaquin Delta, California, U.S.A.
We document characteristics of tephra, including facies and geochemistry, from 27 subsurface sites in the Sacramento-San Joaquin Delta, California, to obtain stratigraphic constraints in a complex setting. Analyzed discrete tephra deposits are correlative with: 1) an unnamed tephra from the Carlotta Formation near Ferndale, California, herein informally named the ash of Wildcat Grade (~0...
Authors
Katherine L. Maier, Emma Gatti, Elmira Wan, Daniel J. Ponti, Mark Pagenkopp, Scott W. Starratt, Holly A. Olson, John Tinsley