Leah E Morgan, Ph.D.
Biography
I joined the 40Ar/39Ar geochronology lab at the USGS in Denver, Colorado as a research geologist in 2015. I was previously a Marie Curie postdoctoral fellow at the Scottish Universities Environmental Research Center and at the Vrije Universiteit Amsterdam. I received a PhD from the University of California at Berkeley in 2009, and a BA from Carleton College in 2004. I was born and raised in Vermont.
I have worked on a range of applications and method development issues in 40Ar/39Ar geochronology. Applications have largely focused on questions in paleoanthropology and the geologic timescale. Method development projects include developing metrologically traceable systems for measuring absolute quantities of 40Ar and 40K, and the design of a mobile neutron source for the future in situ deployment of 40Ar/39Ar capabilities on planetary surfaces.
Education
- Ph.D. Earth & Planetary Science, University of California at Berkeley, 2009
- B.S. Geology, Carleton College, 2004
Professional Experience
- 2015-present, Research Geologist, U.S. Geological Survey
- 2014, Visiting Assistant Professor, Geology Department, Carleton College
- 2011-2014, Marie Curie Postdoctoral Fellow, Scottish Universities Environmental Research Center, University of Glasgow, Scotland
- 2009-2011, Marie Curie Postdoctoral Fellow, Vrije Universiteit Amsterdam, The Netherlands
Affiliations
- 2018-present, Affiliate Faculty, Colorado School of Mines, Golden, CO
Academic and Professional Service
- 2021, co-Chair, Gordon Research Conference on Geochronology
- 2019, vice-Chair, Gordon Research Conference on Geochronology
- 2018-2019, Chair and Founder, Geochronology Division of the Geological Society of America
- 2019-present, Advisory Member, Committee for the Stratigraphy and Chronology Commission, International Union for Quaternary Research
- 2018-present, Steering Committee Member, EarthRates Research Coordination Network
USGS Service
- 2020-present, USGS TRIGA Reactor Operating Committee
- 2017-present, USGS Radiation Safety Committee
- 2016-present, USGS Rocky Mountain Science Seminar Series Convener
- 2018-2020 GGGSC Early Career Advisory Team, GGGSC
Awards
- 2019, USGS Superior Service Award
Science and Products
Argon Geochronology
This project supports the USGS argon geochronology laboratory in Denver. The USGS 40Ar/39Ar geochronology laboratory is a state-of-the-art research facility for determining absolute ages of minerals and rocks. The 40Ar/39Ar laboratory contributes critical geochronology to individual USGS research projects and to partners in academia and other Federal...
Geologic Framework of the Intermountain West
The Geologic Framework of the Intermountain West project was launched with the goal of producing a new digital geologic map database and 3D geologic model of a transect from the Rio Grande rift to the Basin and Range, based on a synthesis of existing geologic maps with new targeted new mapping, subsurface data, and other data sets. This database will integrate disparate map data, resolve...
Serving the U.S. Geological Survey’s geochronological data
Geochronological data provide essential information necessary for understanding the timing of geologic processes and events, as well as quantifying rates and timescales key to geologic mapping, mineral and energy resource and hazard assessments. The USGS’s National Geochronological Database (NGDB) contains over 30,000 radiometric ages, but no formal update has occurred in over 20 years. This...
Argon data for Central Anatolian Ophiolite
This dataset accompanies planned publication 'Conditions, mechanisms, and timing of high-grade metamorphism and ductile deformation of the southern segment of the Central Anatolian Ophiolite'. The Ar/Ar data are for samples that record the metamorphic deformation of the ophiolite. The geochronology provides time constraints for the deformation studied in the manuscript. Samples were col
Argon data for Yellow Pine
This dataset accompanies planned publication 'Timing of Hydrothermal Alteration and Au-Sb-W Mineralization, Stibnite-Yellow Pine District, Idaho'. The Ar/Ar data is for samples that record the mineralization of the area. The geochronology provides time constraints for the mineralization studied in the manuscript. Samples were collected from the Yellow Pine region, and collection was d
Argon data for Central Andes (Domeyko Range, Chile)
This dataset accompanies planned publication 'Gondwanan inheritance on the building of the western Central Andes (Domeyko Range, Chile): Structural and thermochronological approach (U-Pb and 40Ar-39Ar)'. The Ar/Ar data is for samples that record the sedimentation of the area. The geochronology provides time constraints for the sedimentation studied in the manuscript. Samples wer
Argon data for Southern Patagonian Andes
This dataset accompanies planned publication 'Detrital record of the Late Oligocene – Early Miocene mafic volcanic arc in the Southern Patagonian Andes (~51°S) from single-clast geochronology and trace element geochemistry'. The Ar/Ar data is for samples that record the detrital sedimentary record of the basin. The geochronology provides time constraints for the sedimenta
Argon geochronology data for eastern Bhutan
This dataset accompanies publication 'The influence of foreland structures on hinterland cooling: evaluating the drivers of exhumation in the eastern Bhutan Himalaya'. The Ar/Ar data provides time constraints for the cooling of rocks in the study area.
Data to accompany U.S. Geological Survey Data Series 1099: Petrographic, geochemical and geochronologic data for Cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
This dataset is the assembled analytical results of geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada. Much of the data presented here for the Tonopah and Divide districts are for samples collected by Bonham and Garside (1979) du
Argon geochronology data forMultiproxy Cretaceous-Paleogene boundary event stratigraphy: an Umbria-Marche basin-wide perspective
This dataset accompanies publication 'Multiproxy Cretaceous-Paleogene boundary event stratigraphy: an Umbria-Marche basin-wide perspective'.
Argon geochronology data for La Garita caldera
This dataset accompanies publication 'A supervolcano and its sidekicks: A 100 ka eruptive chronology of the Fish Canyon Tuff and associated units of the La Garita magmatic system', in review in Geology, which analyzed eruptive products from the La Garita caldera.
Argon and geochemical data for: 40Ar/39Ar geochronology and petrogenesis of the Table Mountain Shoshonites, Golden, CO
This dataset accompanies publication '40Ar/39Ar geochronology and petrogenesis of the Table Mountain Shoshonites, Golden, CO', to be published in Rocky Mountain Geology, which analyzed lava flows on North and South Table Mountain in Golden, CO, for argon geochronology and geochemistry.
Argon data for: Elemental, isotopic, and geochronological variability in Mogollon-Datil Volcanic Province, New Mexico
This dataset accompanies publication 'Elemental, isotopic, and geochronological variability in Mogollon-Datil Volcanic Province archaeological obsidian, Southwestern New Mexico: Solving issues of inter-source discrimination', to be published in Geoarchaeology, which studied the ability of isotopic and argon geochronologic analyses to discriminate between archaeological obsidian so
Data release of geospatial map database, argon geochronology and geochemistry data for: Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado
This dataset accompanies publication "Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado". Data presented here include the digital geologic database, 40Ar/39Ar geochronology and major and trace element chemistry from lava flows and an ignimbrite. The geologic database includes spatial feature classes and non-spatial tables that collectively contain
Argon data for Poncha Pass Map
This dataset accompanies publication 'Geologic Map of the Poncha Pass Area, Chaffee, Fremont, and Saguache Counties, Colorado'.
Constraining central Himalayan (Nepal) fault geometry through integrated thermochronology and thermokinematic modeling
Constraining the subsurface structural geometry of the central Himalaya continues to prove difficult, even after the 2015 Gorkha earthquake and the resulting insights into the trajectory of the Main Himalayan thrust (MHT). To this end, we apply a thermokinematic model to evaluate four possible balanced cross section geometries based on three...
Ghoshal, Surydoy; McQuarrie, Nadine; Robinson, Delores; Adhikari, D.P.; Morgan, Leah E.; Ehlers, Todd A.Conditions and timing of high-grade metamorphism and ductile deformation of the southern segment of the Central Anatolian Ophiolite
Ophiolitic fragments scattered over a wide area of Central Anatolia exhibit varying degrees of metamorphism, from unmetamorphosed to upper amphibolite facies, although geochemical similarities suggest they are all part of the Central Anatolian Ophiolite (CAO). Magmatic crystallization of oceanic crust in the CAO at ~ 91 Ma coincided with high...
Radwany, Molly S.; Morgan, Leah E.; Whitney, Donna L.Interpreting and reporting 40Ar/39Ar geochronologic data
The 40Ar/39Ar dating method is among the most versatile of geochronometers, having the potential to date a broad variety of K-bearing materials spanning from the time of Earth’s formation into the historical realm. Measurements using modern noble-gas mass spectrometers are now producing 40Ar/39Ar dates with analytical uncertainties of ∼0.1%,...
Schaen, Allen J.; Jicha, Brian R.; Hodges, Kip V.; Vermeesch, Pieter; Stelten, Mark E.; Mercer, Cameron M.; Phillips, David; Rivera, Tiffany; Jourdan, Fred; Matchan, Erin L.; Hemming, Sidney R.; Morgan, Leah E.; Kelley, Simon P.; Cassata, William S.; Heizler, Matt T.; Vasconcelos, Paulo M.; Benowitz, Jeff A.; Koppers, Anthony A.P. ; Mark, Darren F.; Niespolo, Elizabeth M.; Courtney J. Sprain; Hames, William E.; Kuiper, Klaudia F.; Turrin, Brent D.; Renne, Paul R.; Ross, Jake; Nomade, Sebastian; Guillou, Hervé; Webb, Laura E.; Cohen, Barbara A.; Calvert, Andrew T.; Joyce, Nancy; Ganderød, Morgan; Wijbrans, Jan; Ishizuka, Osamu; He, Huaiyu; Ramirez, Adán; Pfänder, Jörg; Lopez-Martínez, Margarita; Qiu, Huaning; Singer, Brad S.Detrital record of the late Oligocene – Early Miocene mafic volcanic arc in the southern Patagonian Andes (~51 °S) from single-clast geochronology and trace element geochemistry
Retroarc foreland basins are important archives of continental arc magmatism and upper plate deformational processes that control the evolution of continental lithosphere. However, resolving source areas in foreland basin infill dominated from mixed mafic and recycled sediment using conventional methods such as detrital zircon geochronology poses...
VanderLeest, Rebecca A; Fosdick, Julie C; Leonard, Joel S; Morgan, Leah E.Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado
This report presents a 1:24,000-scale geologic map, cross sections, and descriptive and interpretative text for the Poncha Pass area in central Colorado. The map area is irregular in shape, covering all of one 7 ½' quadrangle (Poncha Pass) and parts of five others (Mount Ouray, Maysville, Salida West, Salida East, and Wellsville). The map...
Minor, Scott A.; Caine, Jonathan Saul; Ruleman, Chester A.; Fridrich, Christopher J.; Chan, Christine F.; Brandt, Theodore R.; Holm-Denoma, Christopher S.; Morgan, Leah E.; Cosca, Michael A.; Grauch, V. J.Multiproxy Cretaceous-Paleogene boundary event stratigraphy: An Umbria-Marche basin-wide perspective
The complete and well-studied pelagic carbonate successions from the Umbria-Marche Basin (Italy) permit the study of the event-rich stratigraphical interval around the Cretaceous-Paleogene (K-Pg) boundary (e.g., Deccan volcanism, boundary impact, Paleocene recovery and climate). To test the robustness of various proxy records (bulk carbonate δ13C...
Sinnesael, Matthias; Montanari, Alessandro; Frontalini, Fabrizio; Coccioni, Rodolfo; Gattacceca, Jerome; Snoeck, Christophe; Wegner, Wencke; Koeberl, Christian; Morgan, Leah E.; de Winter, Niels; DePaolo, Donald J.; Claeys, PhilippeThe influence of foreland structures on hinterland cooling: evaluating the drivers of exhumation in the eastern Bhutan Himalaya
Understanding, and ideally quantifying, the relative roles of climatic and tectonic processes during orogenic exhumation is critical to resolving the dynamics of mountain building. However, vastly differing opinions regarding proposed drivers often complicate how thermochronometric ages are interpreted, particularly from the hinterland portions of...
McQuarrie, Nadine; Eizenhofer, Paul R.; Long, Sean P.; Tobgay, Tobgay; Ehlers, Todd A.; Blythe, Ann; Morgan, Leah E.; Gilmore, Michelle; Dering, Gregory M.Petrology of volcanic rocks associated with silver-gold (Ag-Au) epithermal deposits in the Tonopah, Divide, and Goldfield Mining Districts, Nevada
Miocene calc-alkaline volcanic rocks, part of the southern segment of the ancestral Cascades magmatic arc, are spatially, temporally, and likely genetically associated with precious metal epithermal deposits in the Tonopah, Divide, and Goldfield Districts of west-central Nevada. In the Tonopah mining district, volcanic rocks include the Mizpah...
du Bray, Edward A.; John, David A.; Colgan, Joseph P.; Vikre, Peter G.; Cosca, Michael A.; Morgan, Leah E.Petrographic, geochemical, and geochronologic data for cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
The purpose of this report is to summarize geochemical, petrographic, and geochronologic data for samples, principally those of unmineralized Tertiary volcanic rocks, from the Tonopah, Divide, and Goldfield mining districts of west-central Nevada (fig. 1). Much of the data presented here for the Tonopah and Divide districts are for samples...
du Bray, Edward A.; John, David A.; Vikre, Peter G.; Colgan, Joseph P.; Cosca, Michael A.; Morgan, Leah E.; Fleck, Robert J.; Premo, Wayne R.; Holm-Denoma, Christopher S.Revisiting Herto: New evidence of Homo sapiens from Ethiopia
Localities in the radiometrically dated Upper Herto Member of Ethiopia’s Bouri Formation continue to produce new data that complement and extend initial reports of fossils and artifacts published in 2003. Results of these revisits are reported here and include the in situ recovery of artifacts from the same sediments containing hominid fossils. We...
Sahle, Yonatan; Beyene, Yonas; Defleur, Alban; Asfaw, Berhane; WoldeGabriel, Giday; Hart, William K; Morgan, Leah E.; Renne, Paul R.; Carlson, Joshua; White, Tim DA supervolcano and its sidekicks: A 100 ka eruptive chronology of the Fish Canyon Tuff and associated units of the La Garita magmatic system
Establishing temporal constrains on major volcanic eruptions is limited by the precision of existing geochronometers. Prior work on the La Garita caldera, created by the eruption of the Fish Canyon Tuff, failed to resolve temporal differences between pre-, syn-, and post-collapse eruptive units. Here, we report 40Ar/39Ar geochronologic data...
Morgan, Leah E.; Johnstone, Samuel A.; Gilmer, Amy K.; Cosca, Michael A.; Thompson, Ren A.Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado
The geologic map of the San Antonio Mountain area in northern New Mexico and southern Colorado is located along the west-central part of the San Luis Valley. The San Luis Valley is the geomorphic expression of the San Luis Basin, an extensional basin associated with the northern Rio Grande rift. Deposits within the map area record volcanic,...
Turner, Kenzie J.; Thompson, Ren A.; Cosca, Michael A.; Shroba, Ralph R.; Chan, Christine F.; Morgan, Leah E.