John N Aleinikoff
John Aleinikoff is a Scientist Emeritus with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 109
U-Pb geochronologic constraints on the origin of a unique monazite- xenotime gneiss, Hudson Highlands, New York U-Pb geochronologic constraints on the origin of a unique monazite- xenotime gneiss, Hudson Highlands, New York
No abstract available.
Authors
John N. Aleinikoff, Richard I. Grauch
Evidence for an Early Archean component in the Middle to Late Archean gneisses of the Wind River Range, west-central Wyoming: conventional and ion microprobe U-Pb data Evidence for an Early Archean component in the Middle to Late Archean gneisses of the Wind River Range, west-central Wyoming: conventional and ion microprobe U-Pb data
Gneissic rocks that are basement to the Late Archean granites comprising much of the Wind River Range, west-central Wyoming, have been dated by the zircon U-Pb method using both conventional and ion microprobe techniques. A foliated hornblende granite gneiss member from the southern border of the Bridger batholith is 2670??13 Ma. Zircons from a granulite just north of the Bridger...
Authors
J. N. Aleinikoff, I.S. Williams, W. Compston, J. S. Stuckless, R. G. Worl
Zircon morphology and U-Pb geochronology of seven metaluminous and peralkaline post-orogenic granite complexes of the Arabian Shield, Kingdom of Saudi Arabia Zircon morphology and U-Pb geochronology of seven metaluminous and peralkaline post-orogenic granite complexes of the Arabian Shield, Kingdom of Saudi Arabia
The U-Pb zircon method was used to determine the ages of seven metaluminous-to-peralkaline post-orogenic granites located throughout the Late Proterozoic Arabian Shield of Saudi Arabia. Zircons from the metaluminous rocks are prismatic, with length-to-width ratios of about 2-4:1 and small pyramidal terminations. In contrast, zircons from three of the four peralkaline complexes either...
Authors
John Nicholas Aleinikoff, D. B. Stoeser
Evolution of the Early Proterozoic Colorado province: Constraints from U-Pb geochronology Evolution of the Early Proterozoic Colorado province: Constraints from U-Pb geochronology
The Colorado province represents an addition of a belt of rocks more than 500 km wide to the southern margin of the Archean Wyoming craton during the Early Proterozoic, between about 1790 and 1660 Ma. Correspondence in ages between metamorphism, deformation, and plutonism; association of volcanic rocks with comagmatic calc-alkalic plutons; and lack of older basement are all consistent...
Authors
John C. Reed, M. E. Bickford, Wayne R. Premo, John N. Aleinikoff, John S. Pallister
Lead isotopic fingerprinting of tectono-stratigraphic terranes, east-central Alaska Lead isotopic fingerprinting of tectono-stratigraphic terranes, east-central Alaska
Common lead isotopic compositions have been determined on feldspars from meta-igneous rocks from nine tectono-stratigraphic terranes or subterranes in east-central Alaska. Most of the terranes have distinct and well-defined signatures in terms of isotopic composition; thus, most can be distinguished on conventional lead isotopic diagrams. Lead isotopic ratios provide evidence for (1)...
Authors
John N. Aleinikoff, Cynthia Dusel-Bacon, Helen Laura Foster, Warren J. Nokleberg
Observations and controls on the occurrence of inherited zircon in Concord-type granitoids, New Hampshire Observations and controls on the occurrence of inherited zircon in Concord-type granitoids, New Hampshire
U-Pb analyses of zircons separated from two Concord-type plutons near Sunapee and Dixville Notch, New Hampshire, reveal differences in the pattern and magnitude of zircon inheritance which are related to differences in melt chemistry. The Sunapee pluton contains only slightly more Zr than required to saturate the melt at the peak temperature of 700 ± 30°C. Traces of inherited zircon in...
Authors
T.M. Harrison, J. N. Aleinikoff, W. Compston
Science and Products
Filter Total Items: 109
U-Pb geochronologic constraints on the origin of a unique monazite- xenotime gneiss, Hudson Highlands, New York U-Pb geochronologic constraints on the origin of a unique monazite- xenotime gneiss, Hudson Highlands, New York
No abstract available.
Authors
John N. Aleinikoff, Richard I. Grauch
Evidence for an Early Archean component in the Middle to Late Archean gneisses of the Wind River Range, west-central Wyoming: conventional and ion microprobe U-Pb data Evidence for an Early Archean component in the Middle to Late Archean gneisses of the Wind River Range, west-central Wyoming: conventional and ion microprobe U-Pb data
Gneissic rocks that are basement to the Late Archean granites comprising much of the Wind River Range, west-central Wyoming, have been dated by the zircon U-Pb method using both conventional and ion microprobe techniques. A foliated hornblende granite gneiss member from the southern border of the Bridger batholith is 2670??13 Ma. Zircons from a granulite just north of the Bridger...
Authors
J. N. Aleinikoff, I.S. Williams, W. Compston, J. S. Stuckless, R. G. Worl
Zircon morphology and U-Pb geochronology of seven metaluminous and peralkaline post-orogenic granite complexes of the Arabian Shield, Kingdom of Saudi Arabia Zircon morphology and U-Pb geochronology of seven metaluminous and peralkaline post-orogenic granite complexes of the Arabian Shield, Kingdom of Saudi Arabia
The U-Pb zircon method was used to determine the ages of seven metaluminous-to-peralkaline post-orogenic granites located throughout the Late Proterozoic Arabian Shield of Saudi Arabia. Zircons from the metaluminous rocks are prismatic, with length-to-width ratios of about 2-4:1 and small pyramidal terminations. In contrast, zircons from three of the four peralkaline complexes either...
Authors
John Nicholas Aleinikoff, D. B. Stoeser
Evolution of the Early Proterozoic Colorado province: Constraints from U-Pb geochronology Evolution of the Early Proterozoic Colorado province: Constraints from U-Pb geochronology
The Colorado province represents an addition of a belt of rocks more than 500 km wide to the southern margin of the Archean Wyoming craton during the Early Proterozoic, between about 1790 and 1660 Ma. Correspondence in ages between metamorphism, deformation, and plutonism; association of volcanic rocks with comagmatic calc-alkalic plutons; and lack of older basement are all consistent...
Authors
John C. Reed, M. E. Bickford, Wayne R. Premo, John N. Aleinikoff, John S. Pallister
Lead isotopic fingerprinting of tectono-stratigraphic terranes, east-central Alaska Lead isotopic fingerprinting of tectono-stratigraphic terranes, east-central Alaska
Common lead isotopic compositions have been determined on feldspars from meta-igneous rocks from nine tectono-stratigraphic terranes or subterranes in east-central Alaska. Most of the terranes have distinct and well-defined signatures in terms of isotopic composition; thus, most can be distinguished on conventional lead isotopic diagrams. Lead isotopic ratios provide evidence for (1)...
Authors
John N. Aleinikoff, Cynthia Dusel-Bacon, Helen Laura Foster, Warren J. Nokleberg
Observations and controls on the occurrence of inherited zircon in Concord-type granitoids, New Hampshire Observations and controls on the occurrence of inherited zircon in Concord-type granitoids, New Hampshire
U-Pb analyses of zircons separated from two Concord-type plutons near Sunapee and Dixville Notch, New Hampshire, reveal differences in the pattern and magnitude of zircon inheritance which are related to differences in melt chemistry. The Sunapee pluton contains only slightly more Zr than required to saturate the melt at the peak temperature of 700 ± 30°C. Traces of inherited zircon in...
Authors
T.M. Harrison, J. N. Aleinikoff, W. Compston