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 agencies. This laboratory develops methodology for small and difficult sample analysis often at the limits of existing mass spectrometer technology.
Science Issue and Relevance
The 40Ar/39Ar Method: 40Ar/39Ar geochronology is an experimentally robust and versatile method for constraining the age and thermal history of rocks. Such information is extremely valuable for understanding a variety of geological processes including the formation of ore deposits, mountain building and history of volcanic events, paleo-seismic events, and paleo-climate. The 40Ar/39Ar isotopic dating method has evolved into the most commonly applied geochronological method, and can be applied to many geological problems that require precise and accurate time and temperature control.
Methodology to Address Issue
This project provides partial support for 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 agencies. This facility houses necessary equipment for sample preparation and analysis, including high-sensitivity noble gas mass spectrometers and ultraviolet (UV) and infrared (IR) lasers. The versatility of the 40Ar/39Ar method permits determining the timing of processes and events such as igneous intrusions and extrusions, ore mineralization and hydrothermal fluid circulation, metamorphic cooling and exhumation, mineral formation and recrystallization, and shallow crustal faulting. Scientists are dependent on the geochronologist for data and interpretations to determine these parameters. This laboratory develops methodology for small and difficult sample analysis often at the limits of existing mass spectrometer technology.
Below are other science projects associated with this project.
USGS Geochron: A database of USGS geochronological and thermochronological data
Geologic Framework of the Intermountain West
Serving the U.S. Geological Survey’s geochronological data
Cenozoic Landscape Evolution of the Southern Rocky Mountains
Geochronologic Investigations
Below are data releases associated with this project. Visit USGS Geochron - a database of geochronologic and thermochronologic dates and data.
USGS Geochron: A Database of Geochronological and Thermochronological Dates and Data
Argon data for Hugub Area, Kesem-Kebena-Dulecha, Ethiopia
Argon data for Klamath Mountains
Argon data for Nepal
Argon data for Amazon Craton
Argon data for Central Andes (Domeyko Range, Chile)
Argon data for Yellow Pine
Argon data for Central Anatolian Ophiolite
Argon data for Southern Patagonian Andes
Argon geochronology data for Multiproxy Cretaceous-Paleogene boundary event stratigraphy: an Umbria-Marche basin-wide perspective
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
Argon geochronology data for La Garita caldera
Below are publications associated with this project.
Gondwanic inheritance on the building of the western Central Andes (Domeyko Range, Chile): Structural and thermochronological approach (U-Pb and 40Ar-39Ar)
Age and mantle sources of Quaternary basalts associated with “leaky” transform faults of the migrating Anatolia-Arabia-Africa triple junction
Cenozoic tectonic evolution of the Ecemiş fault zone and adjacent basins, central Anatolia, Turkey during the transition from Arabia - Eurasia collision to escape tectonics
Constraining central Himalayan (Nepal) fault geometry through integrated thermochronology and thermokinematic modeling
Conditions and timing of high-grade metamorphism and ductile deformation of the southern segment of the Central Anatolian Ophiolite
Interpreting and reporting 40Ar/39Ar geochronologic data
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
Multiproxy Cretaceous-Paleogene boundary event stratigraphy: An Umbria-Marche basin-wide perspective
The influence of foreland structures on hinterland cooling: evaluating the drivers of exhumation in the eastern Bhutan Himalaya
Petrology of volcanic rocks associated with silver-gold (Ag-Au) epithermal deposits in the Tonopah, Divide, and Goldfield Mining Districts, Nevada
Petrographic, geochemical, and geochronologic data for cenozoic volcanic rocks of the Tonopah, Divide, and Goldfield Mining Districts, Nevada
Revisiting Herto: New evidence of Homo sapiens from Ethiopia
USGS Geochron Database Explorer
This Web Application is a tool for viewing, exploring, and downloading the "USGS Geochron: A Database of Geochronological and Thermochronological Dates and Data" Data Release.
In addition to the USGS National Cooperative Geologic Mapping Program and the Geosciences and Environmental Change Science Center, below are partners associated with this project.
- Overview
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 agencies. This laboratory develops methodology for small and difficult sample analysis often at the limits of existing mass spectrometer technology.
Science Issue and Relevance
The 40Ar/39Ar Method: 40Ar/39Ar geochronology is an experimentally robust and versatile method for constraining the age and thermal history of rocks. Such information is extremely valuable for understanding a variety of geological processes including the formation of ore deposits, mountain building and history of volcanic events, paleo-seismic events, and paleo-climate. The 40Ar/39Ar isotopic dating method has evolved into the most commonly applied geochronological method, and can be applied to many geological problems that require precise and accurate time and temperature control.
Methodology to Address Issue
This project provides partial support for 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 agencies. This facility houses necessary equipment for sample preparation and analysis, including high-sensitivity noble gas mass spectrometers and ultraviolet (UV) and infrared (IR) lasers. The versatility of the 40Ar/39Ar method permits determining the timing of processes and events such as igneous intrusions and extrusions, ore mineralization and hydrothermal fluid circulation, metamorphic cooling and exhumation, mineral formation and recrystallization, and shallow crustal faulting. Scientists are dependent on the geochronologist for data and interpretations to determine these parameters. This laboratory develops methodology for small and difficult sample analysis often at the limits of existing mass spectrometer technology.
- Science
Below are other science projects associated with this project.
USGS Geochron: A database of USGS geochronological and thermochronological data
The U.S. Geological Survey (USGS) has developed an updated geochronology database (USGS Geochron) to include geochronology summary and analytical data created or funded by the USGS.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 projCenozoic Landscape Evolution of the Southern Rocky Mountains
The Cenozoic Landscape Evolution of the Southern Rocky Mountains Project is a multi-year investigation funded by the National Cooperative Geologic Mapping Program. This project utilizes a combination of geologic mapping, geophysical surveys, basin modeling, and structural, neotectonic, geomorphic, volcanic, stratigraphic, and geochronologic studies to better understand the geologic landscape of...Geochronologic Investigations
The present landscape of the Southern Rocky Mountains and surrounding physiographic areas results from time-integrated interaction between the asthenosphere, lithosphere, and hydrosphere. Large-scale phenomena, such as asthenospheric upwelling directly or indirectly affect lithospheric thinning, faulting, basin development, and igneous activity sometimes associated with ore deposits. During the... - Data
Below are data releases associated with this project. Visit USGS Geochron - a database of geochronologic and thermochronologic dates and data.
Filter Total Items: 18USGS Geochron: A Database of Geochronological and Thermochronological Dates and Data
USGS Geochron is a database of geochronological and thermochronological dates and data. The data set contains published ages, dates, analytical information, sample metadata including location, and source citations. The following analytical techniques are represented in the data set: 40Ar/39Ar, K-Ar, U-Th-Pb, Sm-Nd, Rb-Sr, Lu-Hf, fission track, and luminescence. This data set incorporates data prevArgon data for Hugub Area, Kesem-Kebena-Dulecha, Ethiopia
Tephra samples were collected by Leah Morgan (now at the U.S. Geological Survey (USGS)) from the Hugub Area, Kesem-Kebena-Dulecha, Afar, Ethiopia. Sanidine grains were separated from the bulk sample and analyzed by argon geochronology at the Scottish Universities Environmental Research Centre, Scotland. The data indicate that the age of the Hugub Bed, which is rich in archarological artifacts, isArgon data for Klamath Mountains
This dataset accompanies planned publication '40Ar/39Ar geochronology of hydrothermal activity related to orogenic gold mineralization in the Klamath Mountains, California, U.S.A.'. The Ar/Ar data are 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 Klamath MountainsArgon data for Nepal
This dataset accompanies planned publication 'Determining fault geometry through the transport-parallel distribution of thermochronometer cooling ages'. The Ar/Ar data is for samples that record the thermal history of the area. The geochronology provides time constraints for the thermal histories studied in the manuscript. Samples were collected from Nepal, overseen by Nadine McQuarrie (UniversityArgon data for Amazon Craton
This dataset accompanies planned publication 'Genesis of early Neoproterozoic gold deposits, southwestern Amazon Craton, western Brazil'. 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 Amazon Craton region, and collection was done by Rodrigo PrudeArgon 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 were collected from thArgon 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 done by numeroArgon 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 collected fromArgon 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 (~51S) 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 sedimentation studied in the manuscrArgon geochronology data for Multiproxy 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'.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) during geologic mapArgon 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. - Publications
Below are publications associated with this project.
Filter Total Items: 66Gondwanic inheritance on the building of the western Central Andes (Domeyko Range, Chile): Structural and thermochronological approach (U-Pb and 40Ar-39Ar)
Tectonics inheritance controls the evolution of many orogens. To unravel the role of the Gondwanan heritage (late Paleozoic to Triassic) over the building of the Central Andes in northern Chile (Domeyko Range), we performed detrital U‐Pb zircon and 40Ar/39Ar muscovite geochronology along with structural analyses (kinematics and structural balancing). 40Ar/39Ar dating of detrital muscovite revealsAuthorsMauricio Espinoza, Veronica Oliveros, Paulina Vasquez, Laura Giambiagi, Leah E. Morgan, Rodrigo Gonzalez, Luigi Solari, Florencia BechisAge and mantle sources of Quaternary basalts associated with “leaky” transform faults of the migrating Anatolia-Arabia-Africa triple junction
The Anatolia (Eurasia), Arabia, and Africa tectonic plates intersect in southeast Turkey, near the Gulf of İskenderun, forming a tectonically active and unstable triple junction (the A3 triple junction). The plate boundaries are marked by broad zones of major, dominantly left-lateral transform faults including the East Anatolian fault zone (the Anatolia-Arabia boundary) and the Dead Sea fault zoAuthorsMichael Cosca, Mary Reid, Jonathan Delph, Gonca Gençalioğlu Kuşcu, Janne Blichert-Toft, Wayne R. Premo, Donna Whitney, Christian Teyssier, Bora RojayCenozoic tectonic evolution of the Ecemiş fault zone and adjacent basins, central Anatolia, Turkey during the transition from Arabia - Eurasia collision to escape tectonics
The effects of Arabia-Eurasia collision are recorded in faults, basins, and exhumed metamorphic massifs across eastern and central Anatolia. These faults and basins also preserve evidence of major changes in deformation and associated sedimentary processes along major suture zones including the Inner Tauride suture where it lies along the southern (Ecemiş) segment of the Central Anatolian fault zoAuthorsPaul J. Umhoefer, Stuart Thompson, Come Lefebre, Michael Cosca, Christian Teyssier, Donna L. WhitneyConstraining 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 estimates of the MHT in central Nepal. We compare the efAuthorsSurydoy Ghoshal, Nadine McQuarrie, Delores Robinson, D.P. Adhikari, Leah E. Morgan, Todd A. EhlersConditions 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-grade metamorphism of rocks that underlie the southern,AuthorsMolly S. Radwany, Leah E. Morgan, Donna L. WhitneyInterpreting 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%, thereby providing precise time constraints for a wide raAuthorsAllen J. Schaen, Brian R. Jicha, Kip V. Hodges, Pieter Vermeesch, Mark E. Stelten, Cameron M. Mercer, David Phillips, Tiffany Rivera, Fred Jourdan, Erin L. Matchan, Sidney R. Hemming, Leah E. Morgan, Simon P. Kelley, William S. Cassata, Matt T. Heizler, Paulo M. Vasconcelos, Jeff A. Benowitz, Anthony A.P. Koppers, Darren F. Mark, Elizabeth M. Niespolo, Courtney J. Sprain, William E. Hames, Klaudia F. Kuiper, Brent D. Turrin, Paul R. Renne, Jake Ross, Sebastian Nomade, Hervé Guillou, Laura E. Webb, Barbara A. Cohen, Andrew T. Calvert, Nancy Joyce, Morgan Ganderød, Jan Wijbrans, Osamu Ishizuka, Huaiyu He, Adán Ramirez, Jörg Pfänder, Margarita Lopez-Martínez, Huaning Qiu, Brad S. SingerDetrital 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 a challenge to thorough analysis due to lower zircoAuthorsRebecca A. VanderLeest, Julie C Fosdick, Joel S Leonard, Leah E. MorganMultiproxy 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, δ18O, 87Sr/86Sr and Ca, Fe, Sr and Mn concentratioAuthorsMatthias Sinnesael, Alessandro Montanari, Fabrizio Frontalini, Rodolfo Coccioni, Jerome Gattacceca, Christophe Snoeck, Wencke Wegner, Christian Koeberl, Leah E. Morgan, Niels de Winter, Donald J. DePaolo, Philippe ClaeysThe 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 thrust belts. Here we integrate three possible croAuthorsNadine McQuarrie, Paul R. Eizenhofer, Sean P. Long, Tobgay Tobgay, Todd A. Ehlers, Ann Blythe, Leah E. Morgan, Michelle Gilmore, Gregory M. DeringPetrology 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 Trachyte, Fraction Tuff, and Oddie Rhyolite; in the DiAuthorsEdward A. du Bray, David A. John, Joseph Colgan, Peter G. Vikre, Michael A. Cosca, Leah E. MorganPetrographic, 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 collected by Bonham and Garside (1979) during geologic mapAuthorsEdward A. du Bray, David A. John, Peter G. Vikre, Joseph Colgan, Michael A. Cosca, Leah E. Morgan, Robert J. Fleck, Wayne R. Premo, Christopher S. Holm-DenomaRevisiting 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 evaluate the absolute and relative temporal placemAuthorsYonatan Sahle, Yonas Beyene, Alban Defleur, Berhane Asfaw, Giday WoldeGabriel, William K Hart, Leah E. Morgan, Paul R. Renne, Joshua Carlson, Tim D White - Web Tools
USGS Geochron Database Explorer
This Web Application is a tool for viewing, exploring, and downloading the "USGS Geochron: A Database of Geochronological and Thermochronological Dates and Data" Data Release.
- News
- Partners
In addition to the USGS National Cooperative Geologic Mapping Program and the Geosciences and Environmental Change Science Center, below are partners associated with this project.