John N Aleinikoff
John Aleinikoff is a Scientist Emeritus with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 109
SHRIMP U-Pb ages of xenotime and monazite from the Spar Lake red bed-associated Cu-Ag deposit, western Montana: Implications for ore genesis SHRIMP U-Pb ages of xenotime and monazite from the Spar Lake red bed-associated Cu-Ag deposit, western Montana: Implications for ore genesis
Xenotime occurs as epitaxial overgrowths on detrital zircons in the Mesoproterozoic Revett Formation (Belt Supergroup) at the Spar Lake red bed-associated Cu-Ag deposit, western Montana. The deposit formed during diagenesis of Revett strata, where oxidizing metal-bearing hydrothermal fluids encountered a reducing zone. Samples for geochronology were collected from several mineral zones...
Authors
John N. Aleinikoff, Timothy S. Hayes, Karl V. Evans, Frank K. Mazdab, Renee M. Pillers, C. Mark Fanning
Constraints on the timing of Co-Cu ± Au mineralization in the Blackbird district, Idaho, using SHRIMP U-Pb ages of monazite and xenotime plus zircon ages of related Mesoproterozoic orthogneisses and metasedimentary rocks Constraints on the timing of Co-Cu ± Au mineralization in the Blackbird district, Idaho, using SHRIMP U-Pb ages of monazite and xenotime plus zircon ages of related Mesoproterozoic orthogneisses and metasedimentary rocks
The Blackbird district, east-central Idaho, contains the largest known Co reserves in the United States. The origin of strata-hosted Co-Cu ± Au mineralization at Blackbird has been a matter of controversy for decades. In order to differentiate among possible genetic models for the deposits, including various combinations of volcanic, sedimentary, magmatic, and metamorphic processes, we...
Authors
John N. Aleinikoff, John F. Slack, Karen Lund, Karl V. Evans, C. Mark Fanning, Frank K. Mazdab, Joseph L. Wooden, Renee M. Pillers
The Edwardsburg Formation and related rocks, Windermere Supergroup, central Idaho, USA The Edwardsburg Formation and related rocks, Windermere Supergroup, central Idaho, USA
In central Idaho, Neoproterozoic stratified rocks are engulfed by the Late Cretaceous Idaho batholith and by Eocene volcanic and plutonic rocks of the Challis event. Studied sections in the Gospel Peaks and Big Creek areas of west-central Idaho are in roof pendants of the Idaho batholith. A drill core section studied from near Challis, east-central Idaho, lies beneath the Challis...
Authors
Karen Lund, John N. Aleinikoff, Karl V. Evans
Provisional zircon and monazite uranium-lead geochronology for selected rocks from Vermont Provisional zircon and monazite uranium-lead geochronology for selected rocks from Vermont
This report presents the results of zircon and monazite uranium-lead (U-Pb) geochronologic analyses of 24 rock samples. The samples in this study were collected from mapped exposures identified while conducting either new, detailed (1:24,000-scale) geologic quadrangle mapping or reconnaissance mapping, both of which were used for compilation of the bedrock geologic map of Vermont. All of...
Authors
John N. Aleinikoff, Nicholas M. Ratcliffe, Gregory J. Walsh
U-Pb SHRIMP-RG zircon ages and Nd signature of lower Paleozoic rifting-related magmatism in the Variscan basement of the Eastern Pyrenees U-Pb SHRIMP-RG zircon ages and Nd signature of lower Paleozoic rifting-related magmatism in the Variscan basement of the Eastern Pyrenees
The ages of orthogneisses exposed in massifs of the Variscan chain can determine whether they are part of a pre-Neoproterozoic basement, a Neoproterozoic, Panafrican arc, or are, in fact, lower Paleozoic, and their isotopic compositions can be used to probe the nature of their source rocks, adding to the understanding of the types, distribution, and tectonic evolution of peri-Gondwanan...
Authors
F.J. Martinez, A. Iriondo, C. Dietsch, J. N. Aleinikoff, J.J. Peucat, J. Cires, J. Reche, R. Capdevila
The tectono-thermal evolution of the Waterbury dome, western Connecticut, based on U-Pb and 40Ar/39Ar ages The tectono-thermal evolution of the Waterbury dome, western Connecticut, based on U-Pb and 40Ar/39Ar ages
The Waterbury dome, located in the Rowe-Hawley zone in western Connecticut, is a triple window exposing three terranes: parautochthonous or allochthonous peri-Laurentian rocks in its lowest level 1, allochthonous rocks of the Rowe-Hawley zone in its middle level 2, and allochthonous cover rocks, including Silurian-Devonian rocks of the Connecticut Valley Gaspé trough, in its highest...
Authors
Craig Dietsch, Michael J. Kunk, John Aleinikoff, John F. Sutter
Science and Products
Filter Total Items: 109
SHRIMP U-Pb ages of xenotime and monazite from the Spar Lake red bed-associated Cu-Ag deposit, western Montana: Implications for ore genesis SHRIMP U-Pb ages of xenotime and monazite from the Spar Lake red bed-associated Cu-Ag deposit, western Montana: Implications for ore genesis
Xenotime occurs as epitaxial overgrowths on detrital zircons in the Mesoproterozoic Revett Formation (Belt Supergroup) at the Spar Lake red bed-associated Cu-Ag deposit, western Montana. The deposit formed during diagenesis of Revett strata, where oxidizing metal-bearing hydrothermal fluids encountered a reducing zone. Samples for geochronology were collected from several mineral zones...
Authors
John N. Aleinikoff, Timothy S. Hayes, Karl V. Evans, Frank K. Mazdab, Renee M. Pillers, C. Mark Fanning
Constraints on the timing of Co-Cu ± Au mineralization in the Blackbird district, Idaho, using SHRIMP U-Pb ages of monazite and xenotime plus zircon ages of related Mesoproterozoic orthogneisses and metasedimentary rocks Constraints on the timing of Co-Cu ± Au mineralization in the Blackbird district, Idaho, using SHRIMP U-Pb ages of monazite and xenotime plus zircon ages of related Mesoproterozoic orthogneisses and metasedimentary rocks
The Blackbird district, east-central Idaho, contains the largest known Co reserves in the United States. The origin of strata-hosted Co-Cu ± Au mineralization at Blackbird has been a matter of controversy for decades. In order to differentiate among possible genetic models for the deposits, including various combinations of volcanic, sedimentary, magmatic, and metamorphic processes, we...
Authors
John N. Aleinikoff, John F. Slack, Karen Lund, Karl V. Evans, C. Mark Fanning, Frank K. Mazdab, Joseph L. Wooden, Renee M. Pillers
The Edwardsburg Formation and related rocks, Windermere Supergroup, central Idaho, USA The Edwardsburg Formation and related rocks, Windermere Supergroup, central Idaho, USA
In central Idaho, Neoproterozoic stratified rocks are engulfed by the Late Cretaceous Idaho batholith and by Eocene volcanic and plutonic rocks of the Challis event. Studied sections in the Gospel Peaks and Big Creek areas of west-central Idaho are in roof pendants of the Idaho batholith. A drill core section studied from near Challis, east-central Idaho, lies beneath the Challis...
Authors
Karen Lund, John N. Aleinikoff, Karl V. Evans
Provisional zircon and monazite uranium-lead geochronology for selected rocks from Vermont Provisional zircon and monazite uranium-lead geochronology for selected rocks from Vermont
This report presents the results of zircon and monazite uranium-lead (U-Pb) geochronologic analyses of 24 rock samples. The samples in this study were collected from mapped exposures identified while conducting either new, detailed (1:24,000-scale) geologic quadrangle mapping or reconnaissance mapping, both of which were used for compilation of the bedrock geologic map of Vermont. All of...
Authors
John N. Aleinikoff, Nicholas M. Ratcliffe, Gregory J. Walsh
U-Pb SHRIMP-RG zircon ages and Nd signature of lower Paleozoic rifting-related magmatism in the Variscan basement of the Eastern Pyrenees U-Pb SHRIMP-RG zircon ages and Nd signature of lower Paleozoic rifting-related magmatism in the Variscan basement of the Eastern Pyrenees
The ages of orthogneisses exposed in massifs of the Variscan chain can determine whether they are part of a pre-Neoproterozoic basement, a Neoproterozoic, Panafrican arc, or are, in fact, lower Paleozoic, and their isotopic compositions can be used to probe the nature of their source rocks, adding to the understanding of the types, distribution, and tectonic evolution of peri-Gondwanan...
Authors
F.J. Martinez, A. Iriondo, C. Dietsch, J. N. Aleinikoff, J.J. Peucat, J. Cires, J. Reche, R. Capdevila
The tectono-thermal evolution of the Waterbury dome, western Connecticut, based on U-Pb and 40Ar/39Ar ages The tectono-thermal evolution of the Waterbury dome, western Connecticut, based on U-Pb and 40Ar/39Ar ages
The Waterbury dome, located in the Rowe-Hawley zone in western Connecticut, is a triple window exposing three terranes: parautochthonous or allochthonous peri-Laurentian rocks in its lowest level 1, allochthonous rocks of the Rowe-Hawley zone in its middle level 2, and allochthonous cover rocks, including Silurian-Devonian rocks of the Connecticut Valley Gaspé trough, in its highest...
Authors
Craig Dietsch, Michael J. Kunk, John Aleinikoff, John F. Sutter