Keith A. Howard is a Research Geologist Emeritus at the Geology, Minerals, Energy, and Geophysics Science Center in Menlo Park, CA. Since joining the USGS in 1966, he had a diverse geologic career investigating a wide range of geologic processes. Presently, his reasearch includes volcanology, Colorado River evolution, granite, and extensional tectonics.
Keith has conducted lunar and planetary investigations, Apollo astronaut training and mission support (1960s and 1970s), and field studies of volcanic and impact structures. He led a team that made the first national map of active faults and fault provinces of the United States and Puerto Rico. He conceived the USGS climate-research program and led the effort to gain support for the program and its acceptance by Congress (1970s). He led the Pacific to Arizona Crustal Experiment, geologic-geophysical transect across the SW USA (1980s-1990s). He has authored a range of studies of landscape evolution, crustal structure, planetology, and igneous and tectonic processes.
Research Partners:
- Arizona Geological Survey
- National Science Foundation
- University of Wyoming
- University of Oregon
- Queensland Technical Institute
- Texas Tech University
- University of Florida
Professional Experience
2007-current, USGS Scientist Emeritus, Menlo Park, CA
2014, Lecturer, San Jose State University
1966-2006, USGS Research Geologist
1974, Visiting Faculty, University of South Florida
1962, USGS Geologist
1961, Engineering Geologist, McCreary-Koretsky Engineering
1960, Geologic Field Assistant, UC Berkeley
Education and Certifications
PhD, Geology, Yale, 1966
MS, Geological Engineering, University of California, Berkeley, 1962
BS, Geological Engineering, University of California, Berkeley, 1961
Affiliations and Memberships*
Geological Society of America, Elected Fellow, 1972
American Geophysical Union, 1969
Peninsula Geological Society, 1967; President 2008-2009
Geological Society of WA since 1975
Fullbright Asso.
Science and Products
Digital database of geologic units, contacts, and faults for Mineral Resource Potential Map of the Turtle Mountains Wilderness Study Area, San Bernardino County, California (U.S. Geological Survey Bulletin 1713-B, 1988, Plate 1)
This map geodatabase digitally represents the general distribution of bedrock geologic map units in the Turtle Mountains area, California, as portrayed in Plate 1 of USGS Bulletin 1713-B, Mineral resources of the Turtle Mountains Wilderness Study Area, San Bernardino County, California (1988), https://doi.org/10.3133/b1713B. The map covers parts of the Rice, Turtle Mountains, and Savahia Peak 15’
Geologic map of the northern White Hills, Mohave County, Arizona
IntroductionThe northern White Hills map area lies within the Kingman Uplift, a regional structural high in which Tertiary rocks lie directly on Proterozoic rocks as a result of Cretaceous orogenic uplift and erosional stripping of Paleozoic and Mesozoic strata. The Miocene Salt Spring Fault forms the major structural boundary in the map area. This low-angle normal fault separates a footwall (lowe
Geologic map of the Topock 7.5’ quadrangle, Arizona and California
The Topock quadrangle exposes a structurally complex part of the Colorado River extensional corridor and also exposes deposits that record landscape evolution during the history of the Colorado River. Paleoproterozoic gneisses and Mesoproterozoic granitoids and intrusive sheets are exposed through tilted cross-sectional thicknesses of many kilometers. Intruding them are a series of Mesozoic to Ter
Geologic map of the Topock 7.5’ quadrangle, Arizona and California
The Topock quadrangle exposes a structurally complex part of the Colorado River extensional corridor and also exposes deposits that record landscape evolution during the history of the Colorado River. Paleoproterozoic gneisses and Mesoproterozoic granitoids and intrusive sheets are exposed through tilted cross-sectional thicknesses of many kilometers. Intruding them are a series of Mesozoic to Ter
Geologic Map of the Needles 7.5' quadrangle, California and Arizona
The Needles 7.5' quadrangle straddles the Colorado River in the southern part of the Mohave Valley, in Mohave County, Arizona, and San Bernardino County, California. The quadrangle contains part of the Havasu National Wildlife Refuge, sections of the Fort Mojave Indian Reservation, most of the city of Needles, and several major interstate highways and railroads. The quadrangle is underlain by stru
Geologic map of the Verdi Peak Quadrangle, Elko County, Nevada
A 1:24,000-scale, full-color geologic map of the Verdi Peak 7.5-minute quadrangle in Elko County, Nevada, with one cross section and descriptions of 19 rock units. Accompanying text describes the geology of the quadrangle.
Geologic map of the Battle Ground 7.5-minute quadrangle, Clark County, Washington
This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits of the Battle Ground 7.5 minute quadrangle. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of th
Geologic Map of the Sheep Hole Mountains 30' x 60' Quadrangle, San Bernardino and Riverside Counties, California
This data set describes and maps the geology of the Sheep Hole Mountains 30' x 60' quadrangle in southern California. The quadrangle covers an area of the Mojave Desert characterized by desert ranges separated by broad basins. Ranges include parts of the Old Woman, Ship, Iron, Coxcomb, Pinto, Bullion, and Calumet mountains as well as Lead Mountain and the Kilbeck Hills. Basins include part of Ward
Geologic map of the Lamoille Quadrangle, Elko County, Nevada
A 1:24,000-scale, full-color geologic map of the Lamoille 7.5-minute quadrangle in Elko County, Nevada, with one cross section and descriptions of 17 geologic units.
Filter Total Items: 95
Magmatic record of changing Cordilleran plate-boundary conditions—Insights from Lu-Hf isotopes in the Mojave Desert
Belts of Cordilleran arc plutons in the eastern part of the Mojave crustal province, inboard from the southwestern North American plate boundary, record major magmatic pulses at ca. 180–160 and 75 Ma and smaller pulses at ca. 100 and 20 Ma. This cyclic magmatism likely reflects evolving plate-margin processes. Zircon Lu-Hf isotopic characteristics and inherited zircons for different-age plutons ma
Authors
Keith A. Howard, S.E. Shaw, Charlotte M. Allen
Testing models of Laramide orogenic initiation by investigation of Late Cretaceous magmatic-tectonic evolution of the central Mojave sector of the California arc
The Mojave Desert region is in a critical position for assessing models of Laramide orogenesis, which is hypothesized to have initiated as one or more seamounts subducted beneath the Cretaceous continental margin. Geochronological and geochemical characteristics of Late Cretaceous magmatic products provide the opportunity to test the validity of Laramide orogenic models. Laramide-aged plutons are
Authors
R.C Economos, Andrew P. Barth, J.L. Wooden, S. R Paterson, Brody Friesenhahn, B.A Weigand, J.L. Anderson, J.L. Roell, E.F. Palmer, A.J. Ianno, Keith A. Howard
Cryptic evolved melts beneath monotonous basaltic shield volcanoes in the Galápagos Archipelago
Many volcanoes erupt compositionally homogeneous magmas over timescales ranging from decades to millennia. This monotonous activity is thought to reflect a high degree of chemical homogeneity in their magmatic systems, leading to predictable eruptive behaviour. We combine petrological analyses of erupted crystals with new thermodynamic models to characterise the diversity of melts in magmatic syst
Authors
M.J. Stock, D. Geist, DA Neave, M.L.M . Gleason, B. Bernard, Keith A. Howard, I. Buisman, J. Maclennan
The Bouse Formation: A controversial Neogene archive of the evolving Colorado River: A scientific drilling workshop report (Feb. 28-March 3, 2019-Bluewater Resort, Parker, Arizona, USA
Neogene deposits of the lower Colorado River valley, especially the Miocene(?) and early Pliocene Bouse Formation, have been the focus of intense debate regarding the early paleoenvironmental history of this important continental-scale river system in southwestern North America and its integration with the proto-Gulf of California. Fine-grained units within these Neogene deposits also hold a promi
Authors
Andrew S. Cohen, Colleen Cassidy, Ryan S. Crow, Jordon Bright, Laura Crossey, Rebecca Dorsey, Brian F. Gootee, Kyle House, Keith A. Howard, Karl Karlstrom, Philip Pearthree
Insights into post-Miocene uplift of the western margin of the Colorado Plateau from the stratigraphic record of the lower Colorado River
The spatial and temporal distribution of Pliocene to Holocene Colorado River deposits (southwestern USA and northwestern Mexico) form a primary data set that records the evolution of a continental-scale river system and helps to delineate and quantify the magnitude of regional deformation. We focus in particular on the age and distribution of ancestral Colorado River deposits from field observatio
Authors
Ryan S. Crow, Keith A. Howard, L. Sue Beard, Phil Pearthree, Kyle House, Karl Karlstrom, Lisa Peters, William C. McIntosh, Colleen Cassidy, Tracey J. Felger, Debra Block
A river is born: Highlights of the geologic evolution of the Colorado River extensional corridor and its river: A field guide honoring the life and legacy of Warren Hamilton
The Colorado River extensional corridor, which stretched by a factor of 2 in the Miocene, left a series of lowland basins and intervening bedrock ranges that, at the dawn of the Pliocene, were flooded by Colorado River water newly diverted from the Colorado Plateau through Grand Canyon. This water and subsequent sediment gave birth, through a series of overflowing lakes, to an integrated Colorado
Authors
Keith A. Howard, Kyle House, Barbara E John, Ryan S. Crow, Philip A Pearthree
Detrital K-feldspar Pb isotopic evaluation of extraregional sediment transported through an Eocene tectonic breach of southern California's Cretaceous batholith
Sedimentary provenance studies have come to be overwhelmingly based upon U–Pb geochronologic measurements performed with detrital zircon while alternative and potentially complementary approaches such as conglomerate clast studies and heavy mineral analysis have faded in importance. Measurement of Pb isotopic compositions in detrital K-feldspar is among the under-utilized approaches available to a
Authors
Danielle Ziva Shulaker, Marty Grove, Jeremy K. Hourigan, Nicholas Van Buer, Glenn R. Sharman, Keith A. Howard, Jonathan Miller, Andrew P. Barth
Large hydromagmatic eruption related to Fernandina Volcano’s 1968 caldera collapse—Deposits, landforms, and ecosystem recovery
The hydromagmatic eruption that immediately preceded the 1968 caldera collapse of Fernandina Volcano, Galápagos, which had a volcano explosivity index (VEI) of 4, offers a case study of powerful eruptions where basaltic magma interacts with caldera-ponded water. The 4-d-long hydromagmatic eruption sequence records an early stage and a small fraction of the volume of magmatic withdrawal that led th
Authors
Keith A. Howard, Tom Simkin, Dennis J. Geist, Godfrey Merlen, Bruce Nolf
The Colorado River and its deposits downstream from Grand Canyon in Arizona, California, and Nevada
Understanding the evolution of the Colorado River system has direct implications for (1) the processes and timing of continental-scale river system integration, (2) the formation of iconic landscapes like those in and around Grand Canyon, and (3) the availability of groundwater resources. Spatial patterns in the position and type of Colorado River deposits, only discernible through geologic mappin
Authors
Ryan S. Crow, Debra L. Block, Tracey J. Felger, Kyle House, Philip A. Pearthree, Brian F. Gootee, Ann M. Youberg, Keith A. Howard, L. Sue Beard
Regional and temporal variability of melts during a Cordilleran magma pulse: Age and chemical evolution of the jurassic arc, eastern mojave desert, California
Intrusive rock sequences in the central and eastern Mojave Desert segment of the Jurassic Cordilleran arc of the western United States record regional and temporal variations in magmas generated during the second prominent pulse of Mesozoic continental arc magmatism. U/Pb zircon ages provide temporal control for describing variations in rock and zircon geochemistry that reflect differences in magm
Authors
A.P. Barth, J.L. Wooden, David M. Miller, Keith A. Howard, Lydia Fox, Elizabeth R. Schermer, C.E. Jacobson
River-evolution and tectonic implications of a major Pliocene aggradation on the lower Colorado River: The Bullhead Alluvium
The ∼200-m-thick riverlaid Bullhead Alluvium along the lower Colorado River downstream of Grand Canyon records massive early Pliocene sediment aggradation following the integration of the upper and lower Colorado River basins. The distribution and extent of the aggraded sediments record (1) evolving longitudinal profiles of the river valley with implications for changing positions of the river’s m
Authors
Keith A. Howard, Kyle House, Rebecca J. Dorsey, Phillip A. Pearthree
Detrital zircon U-Pb provenance of the Colorado River: A 5 m.y. record of incision into cover strata overlying the Colorado Plateau and adjacent regions
New detrital zircon U-Pb age distributions from 49 late Cenozoic sandstones and Holocene sands (49 samples, n = 3922) record the arrival of extra-regional early Pliocene Colorado River sediment at Grand Wash (western USA) and downstream locations ca. 5.3 Ma and the subsequent evolution of the river’s provenance signature. We define reference age distributions for the early Pliocene Colorado River
Authors
David L. Kimbrough, Marty Grove, George E. Gehrels, Rebecca J. Dorsey, Keith A. Howard, Oscar Lovera, Andres Aslan, Kyle House, Philip A. Pearthree
Science and Products
- Data
Digital database of geologic units, contacts, and faults for Mineral Resource Potential Map of the Turtle Mountains Wilderness Study Area, San Bernardino County, California (U.S. Geological Survey Bulletin 1713-B, 1988, Plate 1)
This map geodatabase digitally represents the general distribution of bedrock geologic map units in the Turtle Mountains area, California, as portrayed in Plate 1 of USGS Bulletin 1713-B, Mineral resources of the Turtle Mountains Wilderness Study Area, San Bernardino County, California (1988), https://doi.org/10.3133/b1713B. The map covers parts of the Rice, Turtle Mountains, and Savahia Peak 15’ - Maps
Geologic map of the northern White Hills, Mohave County, Arizona
IntroductionThe northern White Hills map area lies within the Kingman Uplift, a regional structural high in which Tertiary rocks lie directly on Proterozoic rocks as a result of Cretaceous orogenic uplift and erosional stripping of Paleozoic and Mesozoic strata. The Miocene Salt Spring Fault forms the major structural boundary in the map area. This low-angle normal fault separates a footwall (loweGeologic map of the Topock 7.5’ quadrangle, Arizona and California
The Topock quadrangle exposes a structurally complex part of the Colorado River extensional corridor and also exposes deposits that record landscape evolution during the history of the Colorado River. Paleoproterozoic gneisses and Mesoproterozoic granitoids and intrusive sheets are exposed through tilted cross-sectional thicknesses of many kilometers. Intruding them are a series of Mesozoic to TerGeologic map of the Topock 7.5’ quadrangle, Arizona and California
The Topock quadrangle exposes a structurally complex part of the Colorado River extensional corridor and also exposes deposits that record landscape evolution during the history of the Colorado River. Paleoproterozoic gneisses and Mesoproterozoic granitoids and intrusive sheets are exposed through tilted cross-sectional thicknesses of many kilometers. Intruding them are a series of Mesozoic to TerGeologic Map of the Needles 7.5' quadrangle, California and Arizona
The Needles 7.5' quadrangle straddles the Colorado River in the southern part of the Mohave Valley, in Mohave County, Arizona, and San Bernardino County, California. The quadrangle contains part of the Havasu National Wildlife Refuge, sections of the Fort Mojave Indian Reservation, most of the city of Needles, and several major interstate highways and railroads. The quadrangle is underlain by struGeologic map of the Verdi Peak Quadrangle, Elko County, Nevada
A 1:24,000-scale, full-color geologic map of the Verdi Peak 7.5-minute quadrangle in Elko County, Nevada, with one cross section and descriptions of 19 rock units. Accompanying text describes the geology of the quadrangle.Geologic map of the Battle Ground 7.5-minute quadrangle, Clark County, Washington
This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits of the Battle Ground 7.5 minute quadrangle. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of thGeologic Map of the Sheep Hole Mountains 30' x 60' Quadrangle, San Bernardino and Riverside Counties, California
This data set describes and maps the geology of the Sheep Hole Mountains 30' x 60' quadrangle in southern California. The quadrangle covers an area of the Mojave Desert characterized by desert ranges separated by broad basins. Ranges include parts of the Old Woman, Ship, Iron, Coxcomb, Pinto, Bullion, and Calumet mountains as well as Lead Mountain and the Kilbeck Hills. Basins include part of WardGeologic map of the Lamoille Quadrangle, Elko County, Nevada
A 1:24,000-scale, full-color geologic map of the Lamoille 7.5-minute quadrangle in Elko County, Nevada, with one cross section and descriptions of 17 geologic units. - Publications
Filter Total Items: 95
Magmatic record of changing Cordilleran plate-boundary conditions—Insights from Lu-Hf isotopes in the Mojave Desert
Belts of Cordilleran arc plutons in the eastern part of the Mojave crustal province, inboard from the southwestern North American plate boundary, record major magmatic pulses at ca. 180–160 and 75 Ma and smaller pulses at ca. 100 and 20 Ma. This cyclic magmatism likely reflects evolving plate-margin processes. Zircon Lu-Hf isotopic characteristics and inherited zircons for different-age plutons maAuthorsKeith A. Howard, S.E. Shaw, Charlotte M. AllenTesting models of Laramide orogenic initiation by investigation of Late Cretaceous magmatic-tectonic evolution of the central Mojave sector of the California arc
The Mojave Desert region is in a critical position for assessing models of Laramide orogenesis, which is hypothesized to have initiated as one or more seamounts subducted beneath the Cretaceous continental margin. Geochronological and geochemical characteristics of Late Cretaceous magmatic products provide the opportunity to test the validity of Laramide orogenic models. Laramide-aged plutons areAuthorsR.C Economos, Andrew P. Barth, J.L. Wooden, S. R Paterson, Brody Friesenhahn, B.A Weigand, J.L. Anderson, J.L. Roell, E.F. Palmer, A.J. Ianno, Keith A. HowardCryptic evolved melts beneath monotonous basaltic shield volcanoes in the Galápagos Archipelago
Many volcanoes erupt compositionally homogeneous magmas over timescales ranging from decades to millennia. This monotonous activity is thought to reflect a high degree of chemical homogeneity in their magmatic systems, leading to predictable eruptive behaviour. We combine petrological analyses of erupted crystals with new thermodynamic models to characterise the diversity of melts in magmatic systAuthorsM.J. Stock, D. Geist, DA Neave, M.L.M . Gleason, B. Bernard, Keith A. Howard, I. Buisman, J. MaclennanThe Bouse Formation: A controversial Neogene archive of the evolving Colorado River: A scientific drilling workshop report (Feb. 28-March 3, 2019-Bluewater Resort, Parker, Arizona, USA
Neogene deposits of the lower Colorado River valley, especially the Miocene(?) and early Pliocene Bouse Formation, have been the focus of intense debate regarding the early paleoenvironmental history of this important continental-scale river system in southwestern North America and its integration with the proto-Gulf of California. Fine-grained units within these Neogene deposits also hold a promiAuthorsAndrew S. Cohen, Colleen Cassidy, Ryan S. Crow, Jordon Bright, Laura Crossey, Rebecca Dorsey, Brian F. Gootee, Kyle House, Keith A. Howard, Karl Karlstrom, Philip PearthreeInsights into post-Miocene uplift of the western margin of the Colorado Plateau from the stratigraphic record of the lower Colorado River
The spatial and temporal distribution of Pliocene to Holocene Colorado River deposits (southwestern USA and northwestern Mexico) form a primary data set that records the evolution of a continental-scale river system and helps to delineate and quantify the magnitude of regional deformation. We focus in particular on the age and distribution of ancestral Colorado River deposits from field observatioAuthorsRyan S. Crow, Keith A. Howard, L. Sue Beard, Phil Pearthree, Kyle House, Karl Karlstrom, Lisa Peters, William C. McIntosh, Colleen Cassidy, Tracey J. Felger, Debra BlockA river is born: Highlights of the geologic evolution of the Colorado River extensional corridor and its river: A field guide honoring the life and legacy of Warren Hamilton
The Colorado River extensional corridor, which stretched by a factor of 2 in the Miocene, left a series of lowland basins and intervening bedrock ranges that, at the dawn of the Pliocene, were flooded by Colorado River water newly diverted from the Colorado Plateau through Grand Canyon. This water and subsequent sediment gave birth, through a series of overflowing lakes, to an integrated ColoradoAuthorsKeith A. Howard, Kyle House, Barbara E John, Ryan S. Crow, Philip A PearthreeDetrital K-feldspar Pb isotopic evaluation of extraregional sediment transported through an Eocene tectonic breach of southern California's Cretaceous batholith
Sedimentary provenance studies have come to be overwhelmingly based upon U–Pb geochronologic measurements performed with detrital zircon while alternative and potentially complementary approaches such as conglomerate clast studies and heavy mineral analysis have faded in importance. Measurement of Pb isotopic compositions in detrital K-feldspar is among the under-utilized approaches available to aAuthorsDanielle Ziva Shulaker, Marty Grove, Jeremy K. Hourigan, Nicholas Van Buer, Glenn R. Sharman, Keith A. Howard, Jonathan Miller, Andrew P. BarthLarge hydromagmatic eruption related to Fernandina Volcano’s 1968 caldera collapse—Deposits, landforms, and ecosystem recovery
The hydromagmatic eruption that immediately preceded the 1968 caldera collapse of Fernandina Volcano, Galápagos, which had a volcano explosivity index (VEI) of 4, offers a case study of powerful eruptions where basaltic magma interacts with caldera-ponded water. The 4-d-long hydromagmatic eruption sequence records an early stage and a small fraction of the volume of magmatic withdrawal that led thAuthorsKeith A. Howard, Tom Simkin, Dennis J. Geist, Godfrey Merlen, Bruce NolfThe Colorado River and its deposits downstream from Grand Canyon in Arizona, California, and Nevada
Understanding the evolution of the Colorado River system has direct implications for (1) the processes and timing of continental-scale river system integration, (2) the formation of iconic landscapes like those in and around Grand Canyon, and (3) the availability of groundwater resources. Spatial patterns in the position and type of Colorado River deposits, only discernible through geologic mappinAuthorsRyan S. Crow, Debra L. Block, Tracey J. Felger, Kyle House, Philip A. Pearthree, Brian F. Gootee, Ann M. Youberg, Keith A. Howard, L. Sue BeardRegional and temporal variability of melts during a Cordilleran magma pulse: Age and chemical evolution of the jurassic arc, eastern mojave desert, California
Intrusive rock sequences in the central and eastern Mojave Desert segment of the Jurassic Cordilleran arc of the western United States record regional and temporal variations in magmas generated during the second prominent pulse of Mesozoic continental arc magmatism. U/Pb zircon ages provide temporal control for describing variations in rock and zircon geochemistry that reflect differences in magmAuthorsA.P. Barth, J.L. Wooden, David M. Miller, Keith A. Howard, Lydia Fox, Elizabeth R. Schermer, C.E. JacobsonRiver-evolution and tectonic implications of a major Pliocene aggradation on the lower Colorado River: The Bullhead Alluvium
The ∼200-m-thick riverlaid Bullhead Alluvium along the lower Colorado River downstream of Grand Canyon records massive early Pliocene sediment aggradation following the integration of the upper and lower Colorado River basins. The distribution and extent of the aggraded sediments record (1) evolving longitudinal profiles of the river valley with implications for changing positions of the river’s mAuthorsKeith A. Howard, Kyle House, Rebecca J. Dorsey, Phillip A. PearthreeDetrital zircon U-Pb provenance of the Colorado River: A 5 m.y. record of incision into cover strata overlying the Colorado Plateau and adjacent regions
New detrital zircon U-Pb age distributions from 49 late Cenozoic sandstones and Holocene sands (49 samples, n = 3922) record the arrival of extra-regional early Pliocene Colorado River sediment at Grand Wash (western USA) and downstream locations ca. 5.3 Ma and the subsequent evolution of the river’s provenance signature. We define reference age distributions for the early Pliocene Colorado RiverAuthorsDavid L. Kimbrough, Marty Grove, George E. Gehrels, Rebecca J. Dorsey, Keith A. Howard, Oscar Lovera, Andres Aslan, Kyle House, Philip A. Pearthree
*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