Cynthia Dusel-Bacon (Former Employee)
Science and Products
Filter Total Items: 51
Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in east- and south-central Alaska Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in east- and south-central Alaska
Most of the exposed bedrock in east- and south-central Alaska has been regionally metamorphosed and deformed during Mesozoic and early Cenozoic time. All the regionally metamorphosed rocks are assigned to metamorphic-facies units on the basis of their temperature and pressure conditions and metamorphic age. North of the McKinley and Denali faults, the crystalline rocks of the Yukon-...
Authors
Cynthia Dusel-Bacon, Bela Csejtey, Helen L. Foster, Elizabeth O. Doyle, Warren J. Nokleberg, George Plafker
Geologic studies in Alaska by the U.S. Geological Survey, 1992 Geologic studies in Alaska by the U.S. Geological Survey, 1992
This collection of 19 papers continues the annual series of U.S. Geological Survey reports on the geology of Alaska. The contributions, which include full-length Articles and shorter Geologic Notes, cover a broad range of topics including dune formation, stratigraphy, paleontology, isotopic dating, mineral resources, and tectonics. Articles, grouped under four regional headings, span...
Geologic studies in Alaska by the U.S. Geological Survey, 1991 Geologic studies in Alaska by the U.S. Geological Survey, 1991
This collection of twenty-one papers continues the annual series of U.S. Geological Survey reports on the geology of Alaska. These contributions, which include full-length Articles and shorter Geologic Notes, are grouped under two broad headings: Mineral Resource Studies (ten papers) and Geologic Framework Studies (eleven papers). Reports on mineral resources discuss exploration...
Metamorphic facies map of southeastern Alaska – Distribution, facies, and ages of regionally metamorphosed rocks Metamorphic facies map of southeastern Alaska – Distribution, facies, and ages of regionally metamorphosed rocks
No abstract available.
Authors
Cynthia Dusel-Bacon, D. A. Brew, S. L. Douglass
Metamorphic history of Alaska Metamorphic history of Alaska
No abstract available.
Authors
Cynthia Dusel-Bacon
Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in northern Alaska Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in northern Alaska
Approximately half of the exposed bedrock in northern Alaska has been regionally metamorphosed. The most widespread metamorphic episode that affected northern Alaska occurred under low-grade, initially high-pressure (blueschist-facies) conditions during Mesozoic time. This episode is thought to have been related to the obduction of one or more oceanic terranes onto the continental margin...
Authors
Cynthia Dusel-Bacon, William Peters Brosge, Alison B. Till, Elizabeth O. Doyle, Charles F. Mayfield, Hillard N. Reiser, Thomas P. Miller
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
Geochronology of augen gneiss and related rocks, Yukon-Tanana terrane, east-central Alaska Geochronology of augen gneiss and related rocks, Yukon-Tanana terrane, east-central Alaska
Using several isotopic techniques, we have determined the ages of selected metamorphic rocks in the Yukon-Tanana terrane (YTT) of east-central Alaska. U-Pb zircon data from an augen gneiss body in the Big Delta quadrangle indicate that the granitoid protolith of the gneiss was intruded 341 ± 3 m.y. ago (lower intercept age). An upper intercept age of 2,136 ± 31 m.y. indicates an...
Authors
John N. Aleinikoff, Cynthia Dusel-Bacon, Helen L. Foster
Petrology and tectonic significance of augen gneiss from a belt of Mississippian granitoids in the Yukon-Tanana terrane, east- central Alaska Petrology and tectonic significance of augen gneiss from a belt of Mississippian granitoids in the Yukon-Tanana terrane, east- central Alaska
An approximately E-W-trending belt of porphyritic peraluminous granitic rocks, metamorphosed and deformed to augen gneiss, is exposed for 400 km across the Yukon-Tanana terrain. Chemical, textural, and isotopic data from large augen-gneiss bodies indicate that these bodies originated as early Mississippian granitic rocks that assimilated, or were anatectically derived from, early...
Authors
Cynthia Dusel-Bacon, John N. Aleinikoff
A sillimanite gneiss dome in the Yukon crystalline terrane, east-central Alaska: Petrography and garnet-biotite geothermometry A sillimanite gneiss dome in the Yukon crystalline terrane, east-central Alaska: Petrography and garnet-biotite geothermometry
No abstract available.
Authors
Cynthia Dusel-Bacon, H.L. Foster
Proterozoic zircon from augen gneiss, Yukon-Tanana Upland, east-central Alaska Proterozoic zircon from augen gneiss, Yukon-Tanana Upland, east-central Alaska
U-Th-Pb analyses of zircons from an ortho-augen gneiss body in the Yukon-Tanana Upland of east-central Alaska yield strong evidence for the presence of early Proterozoic material in this area. U-Pb data define a chord that intersects concordia at about 2,300 and 345 m.y. We consider two interpretations: (1) the protolith was intruded during the Proterozoic and was subsequently...
Authors
John N. Aleinikoff, Cynthia Dusel-Bacon, Helen L. Foster, Kiyoto Futa
Preliminary geologic map of the Big Delta quadrangle, Alaska Preliminary geologic map of the Big Delta quadrangle, Alaska
No abstract available.
Authors
Florence R. Weber, H.L. Foster, T. E. Keith, Cynthia Dusel-Bacon
Science and Products
Filter Total Items: 51
Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in east- and south-central Alaska Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in east- and south-central Alaska
Most of the exposed bedrock in east- and south-central Alaska has been regionally metamorphosed and deformed during Mesozoic and early Cenozoic time. All the regionally metamorphosed rocks are assigned to metamorphic-facies units on the basis of their temperature and pressure conditions and metamorphic age. North of the McKinley and Denali faults, the crystalline rocks of the Yukon-...
Authors
Cynthia Dusel-Bacon, Bela Csejtey, Helen L. Foster, Elizabeth O. Doyle, Warren J. Nokleberg, George Plafker
Geologic studies in Alaska by the U.S. Geological Survey, 1992 Geologic studies in Alaska by the U.S. Geological Survey, 1992
This collection of 19 papers continues the annual series of U.S. Geological Survey reports on the geology of Alaska. The contributions, which include full-length Articles and shorter Geologic Notes, cover a broad range of topics including dune formation, stratigraphy, paleontology, isotopic dating, mineral resources, and tectonics. Articles, grouped under four regional headings, span...
Geologic studies in Alaska by the U.S. Geological Survey, 1991 Geologic studies in Alaska by the U.S. Geological Survey, 1991
This collection of twenty-one papers continues the annual series of U.S. Geological Survey reports on the geology of Alaska. These contributions, which include full-length Articles and shorter Geologic Notes, are grouped under two broad headings: Mineral Resource Studies (ten papers) and Geologic Framework Studies (eleven papers). Reports on mineral resources discuss exploration...
Metamorphic facies map of southeastern Alaska – Distribution, facies, and ages of regionally metamorphosed rocks Metamorphic facies map of southeastern Alaska – Distribution, facies, and ages of regionally metamorphosed rocks
No abstract available.
Authors
Cynthia Dusel-Bacon, D. A. Brew, S. L. Douglass
Metamorphic history of Alaska Metamorphic history of Alaska
No abstract available.
Authors
Cynthia Dusel-Bacon
Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in northern Alaska Distribution, facies, ages, and proposed tectonic associations of regionally metamorphosed rocks in northern Alaska
Approximately half of the exposed bedrock in northern Alaska has been regionally metamorphosed. The most widespread metamorphic episode that affected northern Alaska occurred under low-grade, initially high-pressure (blueschist-facies) conditions during Mesozoic time. This episode is thought to have been related to the obduction of one or more oceanic terranes onto the continental margin...
Authors
Cynthia Dusel-Bacon, William Peters Brosge, Alison B. Till, Elizabeth O. Doyle, Charles F. Mayfield, Hillard N. Reiser, Thomas P. Miller
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
Geochronology of augen gneiss and related rocks, Yukon-Tanana terrane, east-central Alaska Geochronology of augen gneiss and related rocks, Yukon-Tanana terrane, east-central Alaska
Using several isotopic techniques, we have determined the ages of selected metamorphic rocks in the Yukon-Tanana terrane (YTT) of east-central Alaska. U-Pb zircon data from an augen gneiss body in the Big Delta quadrangle indicate that the granitoid protolith of the gneiss was intruded 341 ± 3 m.y. ago (lower intercept age). An upper intercept age of 2,136 ± 31 m.y. indicates an...
Authors
John N. Aleinikoff, Cynthia Dusel-Bacon, Helen L. Foster
Petrology and tectonic significance of augen gneiss from a belt of Mississippian granitoids in the Yukon-Tanana terrane, east- central Alaska Petrology and tectonic significance of augen gneiss from a belt of Mississippian granitoids in the Yukon-Tanana terrane, east- central Alaska
An approximately E-W-trending belt of porphyritic peraluminous granitic rocks, metamorphosed and deformed to augen gneiss, is exposed for 400 km across the Yukon-Tanana terrain. Chemical, textural, and isotopic data from large augen-gneiss bodies indicate that these bodies originated as early Mississippian granitic rocks that assimilated, or were anatectically derived from, early...
Authors
Cynthia Dusel-Bacon, John N. Aleinikoff
A sillimanite gneiss dome in the Yukon crystalline terrane, east-central Alaska: Petrography and garnet-biotite geothermometry A sillimanite gneiss dome in the Yukon crystalline terrane, east-central Alaska: Petrography and garnet-biotite geothermometry
No abstract available.
Authors
Cynthia Dusel-Bacon, H.L. Foster
Proterozoic zircon from augen gneiss, Yukon-Tanana Upland, east-central Alaska Proterozoic zircon from augen gneiss, Yukon-Tanana Upland, east-central Alaska
U-Th-Pb analyses of zircons from an ortho-augen gneiss body in the Yukon-Tanana Upland of east-central Alaska yield strong evidence for the presence of early Proterozoic material in this area. U-Pb data define a chord that intersects concordia at about 2,300 and 345 m.y. We consider two interpretations: (1) the protolith was intruded during the Proterozoic and was subsequently...
Authors
John N. Aleinikoff, Cynthia Dusel-Bacon, Helen L. Foster, Kiyoto Futa
Preliminary geologic map of the Big Delta quadrangle, Alaska Preliminary geologic map of the Big Delta quadrangle, Alaska
No abstract available.
Authors
Florence R. Weber, H.L. Foster, T. E. Keith, Cynthia Dusel-Bacon