John N Aleinikoff
John Aleinikoff is a Scientist Emeritus with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Filter Total Items: 109
Geologic and Geochronologic Studies of the Early Proterozoic Kanektok Metamorphic Complex of Southwestern Alaska Geologic and Geochronologic Studies of the Early Proterozoic Kanektok Metamorphic Complex of Southwestern Alaska
The Kanektok complex of southwestern Alaska appears to be a rootless terrane of early Proterozoic sedimentary, volcanic, and intrusive rocks which were metamorphosed to amphibolite and granulite facies and later underwent a pervasive late Mesozoic thermal event accompanied by granitic plutonism and greenschist facies metamorphism of overlying sediments. The terrane is structurally...
Authors
Donald L. Turner, Robert B. Forbes, John N. Aleinikoff, Ian McDougall, Carl E. Hedge, Frederic H. Wilson, Paul W. Layer, Chad P. Hults
Evolution of crystalline target rocks and impactites in the chesapeake bay impact structure, ICDP-USGS eyreville B core Evolution of crystalline target rocks and impactites in the chesapeake bay impact structure, ICDP-USGS eyreville B core
The 1766-m-deep Eyreville B core from the late Eocene Chesapeake Bay impact structure includes, in ascending order, a lower basement-derived section of schist and pegmatitic granite with impact breccia dikes, polymict impact breccias, and cataclas tic gneiss blocks overlain by suevites and clast-rich impact melt rocks, sand with an amphibolite block and lithic boulders, and a 275-m-thick...
Authors
J. Wright Horton, Michael J. Kunk, Harvey E. Belkin, John N. Aleinikoff, John C. Jackson, I.-M. Chou
Mineral chemistry and shrimp U-Pb Geochronology of mesoproterozoic polycrase-titanite veins in the sullivan Pb-Zn-Ag Deposit, British Columbia Mineral chemistry and shrimp U-Pb Geochronology of mesoproterozoic polycrase-titanite veins in the sullivan Pb-Zn-Ag Deposit, British Columbia
Small polycrase-titanite veins 0.1-2 mm thick cut the tourmalinite feeder zone in the deep footwall of the Sullivan Pb-Zn-Ag deposit, southeastern British Columbia. Unaltered, euhedral crystals of polycrase and titanite 50-100 ??m in diameter are variably replaced by a finer-grained alteration-induced assemblage composed of anhedral polycrase and titanite with local calcite, albite...
Authors
J. F. Slack, J. N. Aleinikoff, H. E. Belkin, C.M. Fanning, P.W. Ransom
Combined EPMA and SHRIMP analyses of xenotime to interpret the geochronological record Combined EPMA and SHRIMP analyses of xenotime to interpret the geochronological record
[No abstract available]
Authors
H.A. Lowers, J. N. Aleinikoff, F.K. Mazdab
On the origin and age of the Great Sand Dunes, Colorado On the origin and age of the Great Sand Dunes, Colorado
Over the past 100??yr, several hypotheses have been proposed for the origin and age of the Great Sand Dunes. These hypotheses differ widely in the descriptions of dune morphometry, the immediate source of eolian sand, and when sand transport occurred. The primary purpose of this paper is to evaluate these hypotheses and, where warranted, to present new ideas about the origin and age of...
Authors
R.F. Madole, J.H. Romig, J. N. Aleinikoff, D.P. VanSistine, E.Y. Yacob
Isotopic evidence for the diversity of late Quaternary loess in Nebraska: Glaciogenic and nonglaciogenic sources Isotopic evidence for the diversity of late Quaternary loess in Nebraska: Glaciogenic and nonglaciogenic sources
Pb isotope compositions of detrital K-feldspars and U-Pb ages of detrital zircons are used as indicators for determining the sources of Peoria Loess deposited during the last glacial period (late Wisconsin, ca. 25–14 ka) in Nebraska and western Iowa. Our new data indicate that only loess adjacent to the Platte River has Pb isotopic characteristics suggesting derivation from this river...
Authors
John N. Aleinikoff, Daniel R. Muhs, E. Arthur Bettis, William C. Johnson, C. Mark Fanning, Rachel Benton
Science and Products
Filter Total Items: 109
Geologic and Geochronologic Studies of the Early Proterozoic Kanektok Metamorphic Complex of Southwestern Alaska Geologic and Geochronologic Studies of the Early Proterozoic Kanektok Metamorphic Complex of Southwestern Alaska
The Kanektok complex of southwestern Alaska appears to be a rootless terrane of early Proterozoic sedimentary, volcanic, and intrusive rocks which were metamorphosed to amphibolite and granulite facies and later underwent a pervasive late Mesozoic thermal event accompanied by granitic plutonism and greenschist facies metamorphism of overlying sediments. The terrane is structurally...
Authors
Donald L. Turner, Robert B. Forbes, John N. Aleinikoff, Ian McDougall, Carl E. Hedge, Frederic H. Wilson, Paul W. Layer, Chad P. Hults
Evolution of crystalline target rocks and impactites in the chesapeake bay impact structure, ICDP-USGS eyreville B core Evolution of crystalline target rocks and impactites in the chesapeake bay impact structure, ICDP-USGS eyreville B core
The 1766-m-deep Eyreville B core from the late Eocene Chesapeake Bay impact structure includes, in ascending order, a lower basement-derived section of schist and pegmatitic granite with impact breccia dikes, polymict impact breccias, and cataclas tic gneiss blocks overlain by suevites and clast-rich impact melt rocks, sand with an amphibolite block and lithic boulders, and a 275-m-thick...
Authors
J. Wright Horton, Michael J. Kunk, Harvey E. Belkin, John N. Aleinikoff, John C. Jackson, I.-M. Chou
Mineral chemistry and shrimp U-Pb Geochronology of mesoproterozoic polycrase-titanite veins in the sullivan Pb-Zn-Ag Deposit, British Columbia Mineral chemistry and shrimp U-Pb Geochronology of mesoproterozoic polycrase-titanite veins in the sullivan Pb-Zn-Ag Deposit, British Columbia
Small polycrase-titanite veins 0.1-2 mm thick cut the tourmalinite feeder zone in the deep footwall of the Sullivan Pb-Zn-Ag deposit, southeastern British Columbia. Unaltered, euhedral crystals of polycrase and titanite 50-100 ??m in diameter are variably replaced by a finer-grained alteration-induced assemblage composed of anhedral polycrase and titanite with local calcite, albite...
Authors
J. F. Slack, J. N. Aleinikoff, H. E. Belkin, C.M. Fanning, P.W. Ransom
Combined EPMA and SHRIMP analyses of xenotime to interpret the geochronological record Combined EPMA and SHRIMP analyses of xenotime to interpret the geochronological record
[No abstract available]
Authors
H.A. Lowers, J. N. Aleinikoff, F.K. Mazdab
On the origin and age of the Great Sand Dunes, Colorado On the origin and age of the Great Sand Dunes, Colorado
Over the past 100??yr, several hypotheses have been proposed for the origin and age of the Great Sand Dunes. These hypotheses differ widely in the descriptions of dune morphometry, the immediate source of eolian sand, and when sand transport occurred. The primary purpose of this paper is to evaluate these hypotheses and, where warranted, to present new ideas about the origin and age of...
Authors
R.F. Madole, J.H. Romig, J. N. Aleinikoff, D.P. VanSistine, E.Y. Yacob
Isotopic evidence for the diversity of late Quaternary loess in Nebraska: Glaciogenic and nonglaciogenic sources Isotopic evidence for the diversity of late Quaternary loess in Nebraska: Glaciogenic and nonglaciogenic sources
Pb isotope compositions of detrital K-feldspars and U-Pb ages of detrital zircons are used as indicators for determining the sources of Peoria Loess deposited during the last glacial period (late Wisconsin, ca. 25–14 ka) in Nebraska and western Iowa. Our new data indicate that only loess adjacent to the Platte River has Pb isotopic characteristics suggesting derivation from this river...
Authors
John N. Aleinikoff, Daniel R. Muhs, E. Arthur Bettis, William C. Johnson, C. Mark Fanning, Rachel Benton