Carbonate sedimentology, circumpolar correlation, Paleozoic and Mesozoic stratigraphy of central and northern Alaska
Professional Experience
1979 - Present Research Geologist, USGS, Anchorage AK
Education and Certifications
Ph.D. 1991 University of California, Santa Cruz CA Geology
M.S. 1979 University of Wisconsin, Madison WI Geology
B.S. 1976 University of Wisconsin, Madison WI Geology/Anthropology
Affiliations and Memberships*
Alaskan Geological Society
American Association of Petroleum Geologists
Geological Society of America
International Association of Sedimentologists
SEPM (Society for Sedimentary Geology)
Honors and Awards
Graduate Fellowship, National Science Foundation, 1976
Graduate Training Program Award, USGS, 1985
USGS STAR awards for research and service contributions, 1997, 1999 (2), 2005, 2011
USGS Performance awards: 2010, 2011, 2012, 2013
Science and Products
U-Pb Isotopic Data and Ages of Detrital Zircon from Selected Rocks from northern Yukon, Canada
This data set contains U-Pb isotopic data and associated ages of detrital zircon from sedimentary and metasedimentary rocks collected in northern Yukon, Canada. The samples were originally collected as part of geological mapping and research conducted by the Geological Survey of Canada. They were recovered from archived collections and sent to the U.S. Geological Survey for analysis of detrital zi
Whole Rock Major and Trace Element Chemistry for Igneous Rocks from Tyonek, Lime Hills, Talkeetna, McGrath, and Lake Clark Quadrangles, Western Alaska Range, Alaska
This data release contains whole rock major and trace element data for 69 igneous rock samples collected from the Western Alaska Range between 2011 and 2012. The Series field relates to chronological units discussed in Jones et al. (2021, Geosphere) and Todd et al. (2022 IN PREP). Descriptions are from original collector notebooks and are provided here for informational purposes only.
Geochemical, Geochronologic, Rock-Eval, and Spectral Gamma Ray Data for Selected Triassic Rocks in Northwestern Alaska
This set of data files contains analyses of samples representing the Triassic Shublik and Otuk Formations in Alaska. The samples were collected from the Brontosaurus 1 well and measured stratigraphic sections at Surprise Creek and Cape Lisburne. The data set includes total organic carbon (TOC), Rock-Eval (Tmax) data, geochemical data from inductively coupled plasma-optical emission spectroscopy-ma
Location Data for Petrographic Samples and Isotopic and Age Data from Detrital Zircon Grains from Selected Rock Samples from St. Lawrence Island and the Western Brooks Range, Alaska
This data set contains a list of geologic station localities on St. Lawrence Island, Alaska, from which thin section samples were examined. The data set also contains U-Pb isotopic data and ages of detrital zircon (DZ) from sedimentary rocks collected on St. Lawrence Island and in the western Brooks Range. All St. Lawrence Island samples (DZ and thin sections) were collected by U.S. Geological Sur
Subsurface stratigraphic picks of the Middle-Upper Triassic Shublik Formation, Alaska North Slope
The Middle-Upper Triassic Shublik Formation is the main source rock for Arctic Alaska oil and gas accumulations, including the supergiant Prudhoe Bay field. A revised stratigraphic framework recently has been developed in outcrop for the Shublik and related strata that delineates three large-scale stratigraphic units: 1) the lower clastic (LC) unit, 2) the middle carbonate-chert (MCC) unit, and 3)
U-Pb Isotopic Data and Ages of Detrital Zircon Grains, Whole Rock Major and Trace-element Geochemistry, and Whole Rock Isotopic Data from Selected Rocks from the Western Alaska Range, Medfra area, and Livengood area, Alaska
This data release contains 3 data sets, U-Pb isotopic data and associated ages of detrital zircon grains for 27 sedimentary rocks, whole rock major and trace-element geochemistry for 15 igneous or phosphatic rock samples, and whole rock Sr, Nd, and Pb isotopic data for 6 igneous rock samples. The samples were collected from multiple localities across Alaska as part of geological mapping and resear
Appendices for Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana
This set of data files are the appendices for paper titled Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana. The dataset consists of 8 appendices, including a histogram of solid bitumen and vitrinite Ro values, gas chromatograms, isotopic data, organic and inorganic geochemical analyses, and x-ray diffraction mineralogy
Bedrock geologic map of the Seward Peninsula, Alaska, and accompanying conodont data
This 1:500,000-scale geologic map depicts the bedrock geology of Seward Peninsula, western Alaska, on the North American side of the Bering Strait. The map encompasses all of the Teller, Nome, Solomon, and Bendeleben 1:250,000-scale quadrangles, and parts of the Shishmaref, Kotzebue, Candle, and Norton Bay 1:250,000-scale quadrangles (sh. 1; sh. 2). The geologic map is presented on Sheet 1. The p
Geologic and Fossil Locality Maps of the West-Central Part of the Howard Pass Quadrangle and Part of the Adjacent Misheguk Mountain Quadrangle, Western Brooks Range, Alaska
The map depicts the field distribution and contact relations between stratigraphic units, the tectonic relations between major stratigraphic sequences, and the detailed internal structure of these sequences. The stratigraphic sequences formed in a variety of continental margin depositional environments, and subsequently underwent a complexde formational history of imbricate thrust faulting
Filter Total Items: 97
Ordovician geology of Alaska
Ordovician rocks, found in northern, east-central, interior and southern Alaska, formed in a variety of depositional and palaeogeographic settings. Shallow- and deep-water strata deposited along the northwestern Laurentian margin occur in east-central Alaska (Yukon River area) and probably correlative rocks crop out to the north in the Porcupine River area. Ordovician strata elsewhere in Alaska ar
Biosiliceous, organic-rich, and phosphatic facies of Triassic strata of northwest Alaska: Transect across a high-latitude, low-angle continental margin
The Shublik Formation (Middle and Upper Triassic) is a mixed siliciclastic-carbonate-phosphatic unit in northern Alaska. It generated oil found in Prudhoe Bay and other accumulations and is a prospective self-sourced resource play on Alaska’s North Slope. Its distal, deeper-water equivalent—the Otuk Formation—consists largely of radiolarian chert, mudstone, and limestone and contains potential gas
Detrital zircon ages from upper Paleozoic–Triassic clastic strata on St. Lawrence Island, Alaska: An enigmatic component of the Arctic Alaska–Chukotka microplate
New lithologic and detrital zircon (DZ) U-Pb data from Devonian–Triassic strata on St. Lawrence Island in the Bering Sea and from the western Brooks Range of Alaska suggest affinities between these two areas. The Brooks Range constitutes part of the Arctic Alaska–Chukotka microplate, but the tectonic and paleogeographic affinities of St. Lawrence Island are unknown or at best speculative. Strata o
Integration of microfacies analysis, inorganic geochemical data, and hyperspectral imaging to unravel mudstone depositional and diagenetic processes in two cores from the Triassic Shublik Formation, Northern Alaska
The Middle – Upper Triassic Shublik Formation is an organic-rich heterogeneous carbonate-siliciclastic-phosphatic unit that generated much of the oil in the Prudhoe Bay field and other hydrocarbon accumulations in northern Alaska. A large dataset, including total organic carbon (TOC), X-ray diffraction (XRD), X-ray fluorescence (XRF) and inductively coupled plasma – mass spectrometry (ICP-MS) meas
The Sedimentary Geochemistry and Paleoenvironments Project
Geobiology explores how Earth's system has changed over the course of geologic history and how living organisms on this planet are impacted by or are indeed causing these changes. For decades, geologists, paleontologists, and geochemists have generated data to investigate these topics. Foundational efforts in sedimentary geochemistry utilized spreadsheets for data storage and analysis, suitable fo
Assessment of undiscovered gas resources in Upper Devonian to Lower Cretaceous strata of the western North Slope, Alaska, 2021
Using a geology-based assessment methodology, the U.S. Geological Survey estimated a mean of 1,407 billion (1.4 trillion) cubic feet of gas in conventional accumulations in Upper Devonian to Lower Cretaceous strata of the western North Slope, Alaska.
Surface to subsurface correlation of the Middle-Upper Triassic Shublik Formation within a revised sequence stratigraphic framework
Recent work on cores and outcrops of the Middle-Upper Triassic Shublik Formation has facilitated surface to subsurface correlation of depositional sequences across the Alaska North Slope. Five transgressive-regressive depositional sequences have been defined within three large-scale stratigraphic units. Outcrop spectral gamma-ray (GR) profiles were used to correlate observed stacking patterns with
Assessment of undiscovered oil and gas resources in the Central North Slope of Alaska, 2020
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 3.6 billion barrels of oil and 8.9 trillion cubic feet of natural gas (associated and nonassociated) in conventional accumulations in Mississippian through Paleogene strata in the central North Slope of Alaska.
Element cycling in the Middle-Late Triassic Shublik Formation: Mineralization vs. recycling of biolimiting nutrients in an unconventional resource play
The Triassic Shublik Formation in northern Alaska is one of the major source rocks in North America, having generated much of the petroleum in Prudhoe Bay and associated fields. The middle Shublik Formation, the focus of this study, is a highly phosphatic, organic-rich carbonate mudstone interval. Apatite cements can occur as phosphatic peloids, steinkerns, elongate or angular nodules, and shells
U-Pb geochronology and tectonic implications of a Silurian ash in the Farewell Terrane, Alaska
The Farewell terrane is an exotic continental fragment in interior Alaska that during the early Paleozoic was the site of a passive margin. We report a 238U/206Pb zircon age of 432.9±3.0 Ma from a Farewell terrane ash in Mt. McKinley quadrangle, Alaska. This age overlaps with prominent detrital zircon age maxima reported from Silurian and Devonian strata from the Farewell, Arctic Alaska-Chukotka,
Studies by the U.S. Geological Survey in Alaska, 2010
The collection of papers that follows continues the series of U.S. Geological Survey (USGS) investigative reports in Alaska under the broad umbrella of the geologic sciences. This series represents new and sometimes-preliminary findings that are of interest to Earth scientists in academia, government, and industry; to land and resource managers; and to the general public. The reports presented in
A revised Triassic stratigraphic framework for the Arctic Alaska Basin
The Triassic Shublik Formation and the Triassic–Jurassic Otuk Formation are partially age-equivalent lithostratigraphic units that were deposited in the Arctic Alaska Basin (AAB). The Shublik Formation represents proximal deposition within the basin, with episodic siliciclastic input, whereas the Otuk Formation was deposited in the distal part of the basin, with significant intervals of mudstone a
Science and Products
- Data
U-Pb Isotopic Data and Ages of Detrital Zircon from Selected Rocks from northern Yukon, Canada
This data set contains U-Pb isotopic data and associated ages of detrital zircon from sedimentary and metasedimentary rocks collected in northern Yukon, Canada. The samples were originally collected as part of geological mapping and research conducted by the Geological Survey of Canada. They were recovered from archived collections and sent to the U.S. Geological Survey for analysis of detrital ziWhole Rock Major and Trace Element Chemistry for Igneous Rocks from Tyonek, Lime Hills, Talkeetna, McGrath, and Lake Clark Quadrangles, Western Alaska Range, Alaska
This data release contains whole rock major and trace element data for 69 igneous rock samples collected from the Western Alaska Range between 2011 and 2012. The Series field relates to chronological units discussed in Jones et al. (2021, Geosphere) and Todd et al. (2022 IN PREP). Descriptions are from original collector notebooks and are provided here for informational purposes only.Geochemical, Geochronologic, Rock-Eval, and Spectral Gamma Ray Data for Selected Triassic Rocks in Northwestern Alaska
This set of data files contains analyses of samples representing the Triassic Shublik and Otuk Formations in Alaska. The samples were collected from the Brontosaurus 1 well and measured stratigraphic sections at Surprise Creek and Cape Lisburne. The data set includes total organic carbon (TOC), Rock-Eval (Tmax) data, geochemical data from inductively coupled plasma-optical emission spectroscopy-maLocation Data for Petrographic Samples and Isotopic and Age Data from Detrital Zircon Grains from Selected Rock Samples from St. Lawrence Island and the Western Brooks Range, Alaska
This data set contains a list of geologic station localities on St. Lawrence Island, Alaska, from which thin section samples were examined. The data set also contains U-Pb isotopic data and ages of detrital zircon (DZ) from sedimentary rocks collected on St. Lawrence Island and in the western Brooks Range. All St. Lawrence Island samples (DZ and thin sections) were collected by U.S. Geological SurSubsurface stratigraphic picks of the Middle-Upper Triassic Shublik Formation, Alaska North Slope
The Middle-Upper Triassic Shublik Formation is the main source rock for Arctic Alaska oil and gas accumulations, including the supergiant Prudhoe Bay field. A revised stratigraphic framework recently has been developed in outcrop for the Shublik and related strata that delineates three large-scale stratigraphic units: 1) the lower clastic (LC) unit, 2) the middle carbonate-chert (MCC) unit, and 3)U-Pb Isotopic Data and Ages of Detrital Zircon Grains, Whole Rock Major and Trace-element Geochemistry, and Whole Rock Isotopic Data from Selected Rocks from the Western Alaska Range, Medfra area, and Livengood area, Alaska
This data release contains 3 data sets, U-Pb isotopic data and associated ages of detrital zircon grains for 27 sedimentary rocks, whole rock major and trace-element geochemistry for 15 igneous or phosphatic rock samples, and whole rock Sr, Nd, and Pb isotopic data for 6 igneous rock samples. The samples were collected from multiple localities across Alaska as part of geological mapping and researAppendices for Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana
This set of data files are the appendices for paper titled Transgressive-regressive cycles in the metalliferous, oil shale-bearing Heath Formation (Upper Mississippian), central Montana. The dataset consists of 8 appendices, including a histogram of solid bitumen and vitrinite Ro values, gas chromatograms, isotopic data, organic and inorganic geochemical analyses, and x-ray diffraction mineralogy - Maps
Bedrock geologic map of the Seward Peninsula, Alaska, and accompanying conodont data
This 1:500,000-scale geologic map depicts the bedrock geology of Seward Peninsula, western Alaska, on the North American side of the Bering Strait. The map encompasses all of the Teller, Nome, Solomon, and Bendeleben 1:250,000-scale quadrangles, and parts of the Shishmaref, Kotzebue, Candle, and Norton Bay 1:250,000-scale quadrangles (sh. 1; sh. 2). The geologic map is presented on Sheet 1. The pGeologic and Fossil Locality Maps of the West-Central Part of the Howard Pass Quadrangle and Part of the Adjacent Misheguk Mountain Quadrangle, Western Brooks Range, Alaska
The map depicts the field distribution and contact relations between stratigraphic units, the tectonic relations between major stratigraphic sequences, and the detailed internal structure of these sequences. The stratigraphic sequences formed in a variety of continental margin depositional environments, and subsequently underwent a complexde formational history of imbricate thrust faulting - Publications
Filter Total Items: 97
Ordovician geology of Alaska
Ordovician rocks, found in northern, east-central, interior and southern Alaska, formed in a variety of depositional and palaeogeographic settings. Shallow- and deep-water strata deposited along the northwestern Laurentian margin occur in east-central Alaska (Yukon River area) and probably correlative rocks crop out to the north in the Porcupine River area. Ordovician strata elsewhere in Alaska arBiosiliceous, organic-rich, and phosphatic facies of Triassic strata of northwest Alaska: Transect across a high-latitude, low-angle continental margin
The Shublik Formation (Middle and Upper Triassic) is a mixed siliciclastic-carbonate-phosphatic unit in northern Alaska. It generated oil found in Prudhoe Bay and other accumulations and is a prospective self-sourced resource play on Alaska’s North Slope. Its distal, deeper-water equivalent—the Otuk Formation—consists largely of radiolarian chert, mudstone, and limestone and contains potential gasDetrital zircon ages from upper Paleozoic–Triassic clastic strata on St. Lawrence Island, Alaska: An enigmatic component of the Arctic Alaska–Chukotka microplate
New lithologic and detrital zircon (DZ) U-Pb data from Devonian–Triassic strata on St. Lawrence Island in the Bering Sea and from the western Brooks Range of Alaska suggest affinities between these two areas. The Brooks Range constitutes part of the Arctic Alaska–Chukotka microplate, but the tectonic and paleogeographic affinities of St. Lawrence Island are unknown or at best speculative. Strata oIntegration of microfacies analysis, inorganic geochemical data, and hyperspectral imaging to unravel mudstone depositional and diagenetic processes in two cores from the Triassic Shublik Formation, Northern Alaska
The Middle – Upper Triassic Shublik Formation is an organic-rich heterogeneous carbonate-siliciclastic-phosphatic unit that generated much of the oil in the Prudhoe Bay field and other hydrocarbon accumulations in northern Alaska. A large dataset, including total organic carbon (TOC), X-ray diffraction (XRD), X-ray fluorescence (XRF) and inductively coupled plasma – mass spectrometry (ICP-MS) measThe Sedimentary Geochemistry and Paleoenvironments Project
Geobiology explores how Earth's system has changed over the course of geologic history and how living organisms on this planet are impacted by or are indeed causing these changes. For decades, geologists, paleontologists, and geochemists have generated data to investigate these topics. Foundational efforts in sedimentary geochemistry utilized spreadsheets for data storage and analysis, suitable foAssessment of undiscovered gas resources in Upper Devonian to Lower Cretaceous strata of the western North Slope, Alaska, 2021
Using a geology-based assessment methodology, the U.S. Geological Survey estimated a mean of 1,407 billion (1.4 trillion) cubic feet of gas in conventional accumulations in Upper Devonian to Lower Cretaceous strata of the western North Slope, Alaska.Surface to subsurface correlation of the Middle-Upper Triassic Shublik Formation within a revised sequence stratigraphic framework
Recent work on cores and outcrops of the Middle-Upper Triassic Shublik Formation has facilitated surface to subsurface correlation of depositional sequences across the Alaska North Slope. Five transgressive-regressive depositional sequences have been defined within three large-scale stratigraphic units. Outcrop spectral gamma-ray (GR) profiles were used to correlate observed stacking patterns withAssessment of undiscovered oil and gas resources in the Central North Slope of Alaska, 2020
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 3.6 billion barrels of oil and 8.9 trillion cubic feet of natural gas (associated and nonassociated) in conventional accumulations in Mississippian through Paleogene strata in the central North Slope of Alaska.Element cycling in the Middle-Late Triassic Shublik Formation: Mineralization vs. recycling of biolimiting nutrients in an unconventional resource play
The Triassic Shublik Formation in northern Alaska is one of the major source rocks in North America, having generated much of the petroleum in Prudhoe Bay and associated fields. The middle Shublik Formation, the focus of this study, is a highly phosphatic, organic-rich carbonate mudstone interval. Apatite cements can occur as phosphatic peloids, steinkerns, elongate or angular nodules, and shellsU-Pb geochronology and tectonic implications of a Silurian ash in the Farewell Terrane, Alaska
The Farewell terrane is an exotic continental fragment in interior Alaska that during the early Paleozoic was the site of a passive margin. We report a 238U/206Pb zircon age of 432.9±3.0 Ma from a Farewell terrane ash in Mt. McKinley quadrangle, Alaska. This age overlaps with prominent detrital zircon age maxima reported from Silurian and Devonian strata from the Farewell, Arctic Alaska-Chukotka,Studies by the U.S. Geological Survey in Alaska, 2010
The collection of papers that follows continues the series of U.S. Geological Survey (USGS) investigative reports in Alaska under the broad umbrella of the geologic sciences. This series represents new and sometimes-preliminary findings that are of interest to Earth scientists in academia, government, and industry; to land and resource managers; and to the general public. The reports presented inA revised Triassic stratigraphic framework for the Arctic Alaska Basin
The Triassic Shublik Formation and the Triassic–Jurassic Otuk Formation are partially age-equivalent lithostratigraphic units that were deposited in the Arctic Alaska Basin (AAB). The Shublik Formation represents proximal deposition within the basin, with episodic siliciclastic input, whereas the Otuk Formation was deposited in the distal part of the basin, with significant intervals of mudstone a
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government