Robert J Fleck (Former Employee)
Science and Products
Pacific Northwest Geologic Mapping: Northern Pacific Border, Cascades and Columbia
The Pacific Northwest is an area created by active and complex geological processes. On its path to the Pacific Ocean, the Columbia River slices through a chain of active volcanoes located along the western margin of the U.S. in Washington, Oregon, and northern California. These volcanoes rest above the active Cascadia subduction zone, which is the boundary where the oceanic tectonic plate dives...
Tabular geochronologic, geochemical, and isotopic data from igneous rocks in the Lane Mountain area, San Bernardino County, California Tabular geochronologic, geochemical, and isotopic data from igneous rocks in the Lane Mountain area, San Bernardino County, California
This dataset provides geochronologic, geochemical, and isotopic data for selected igneous rock samples collected in the Lane Mountain area about 20 kilometers northeast of Barstow, California. Uranium-lead (U-Pb) zircon geochronologic and whole-rock geochemical data were obtained for 62 samples of which 28 are from Permian to Triassic plutonic rocks and dikes, 24 are from Late Jurassic...
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 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 map of the Beacon Rock quadrangle, Skamania County, Washington Geologic map of the Beacon Rock quadrangle, Skamania County, Washington
The Beacon Rock 7.5′ quadrangle is located approximately 50 km east of Portland, Oregon, on the north side of the Columbia River Gorge, a scenic canyon carved through the axis of the Cascade Range by the Columbia River. Although approximately 75,000 people live within the gorge, much of the region remains little developed and is encompassed by the 292,500-acre Columbia River Gorge...
Geologic map of the Bodie Hills, California and Nevada Geologic map of the Bodie Hills, California and Nevada
The Bodie Hills covers about 1,200 km2 straddling the California-Nevada state boundary just north of Mono Lake in the western part of the Basin and Range Province, about 20 km east of the central Sierra Nevada. The area is mostly underlain by the partly overlapping, middle to late Miocene Bodie Hills volcanic field and Pliocene to late Pleistocene Aurora volcanic field (John and others...
A tunnel runs through it — An inside view of the Tualatin Mountains, Oregon A tunnel runs through it — An inside view of the Tualatin Mountains, Oregon
The Tualatin Mountains form a northwest-striking ridge about 350 m high that separates Portland, Oregon, from the cities of the Tualatin Valley to the west. Known informally as the Portland Hills, the ridge is a late Cenozoic anticline, bounded by reverse faults that dip toward the anticlinal axis. The anticline is a broad, open fold consisting chiefly of Miocene Columbia River Basalt...
Filter Total Items: 43
Geochronologic, isotopic, and geochemical data from pre-Cretaceous plutonic rocks in the Lane Mountain area, San Bernardino County, California Geochronologic, isotopic, and geochemical data from pre-Cretaceous plutonic rocks in the Lane Mountain area, San Bernardino County, California
Pre-Cretaceous, predominantly dioritic plutonic rocks in the Lane Mountain area, California, intrude metasedimentary and metavolcanic rocks considered part of the El Paso terrane. New geochronologic (uranium-lead zircon), geochemical, and isotopic data provide a reliable basis for dividing these pre-Cretaceous plutonic rocks into two mappable suites of Permian–Triassic and Late Jurassic...
Authors
Paul Stone, Howard J. Brown, M. Robinson Cecil, Robert J. Fleck, Jorge A. Vazquez, John A. Fitzpatrick
Characterization of the rhyolite of Bodie Hills and 40Ar/39Ar intercalibration with Ar mineral standards Characterization of the rhyolite of Bodie Hills and 40Ar/39Ar intercalibration with Ar mineral standards
The rhyolite of Bodie Hills (California) is characterized compositionally and the geochronology of selected phases is studied. Sanidine (BHs) from the rhyolite is well suited as a 40Ar/39Ar reference material with high K/Ca and radiogenic yield. Intercalibration with GA1550 biotite from the Dromedary igneous complex (New South Wales, Australia) yields an age of 9.7946 ± 0.0031 Ma for BHs...
Authors
Robert J. Fleck, Andrew T. Calvert, Matthew Coble, Joseph L. Wooden, Kip V. Hodges, Leslie A. Hayden, Matthijs C. van Soest, Edward A. du Bray, David A. John
Geochronologic, isotopic, and geochemical data from igneous rocks in the Lane Mountain area, San Bernardino County, California Geochronologic, isotopic, and geochemical data from igneous rocks in the Lane Mountain area, San Bernardino County, California
We present new geochronologic, isotopic, and geochemical data for selected igneous rocks in the Lane Mountain area, California. We determined SHRIMP-RG U-Pb zircon ages for the following units: (1) Larrea complex (~253 Ma and ~149–146 Ma); (2) Daisy granodiorite (~151 Ma); (3) Jack Spring quartz monzonite (~85–82 Ma); (4) unnamed porphyritic dikes and stocks (~80–73 Ma); and (5) Lane...
Authors
Paul Stone, Howard J. Brown, M. Robinson Cecil, Robert J. Fleck, Jorge A. Vazquez, John A. Fitzpatrick, Jose J. Rosario
Petrographic, geochemical, and geochronologic data for cenozoic volcanic rocks of 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
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...
Authors
Edward A. du Bray, David A. John, Peter G. Vikre, Joseph P. Colgan, Michael A. Cosca, Leah E. Morgan, Robert J. Fleck, Wayne R. Premo, Christopher S. Holm-Denoma
Geology and paleontology of the late Miocene Wilson Grove Formation at Bloomfield Quarry, Sonoma County, California Geology and paleontology of the late Miocene Wilson Grove Formation at Bloomfield Quarry, Sonoma County, California
An extensive fauna of at least 77 taxa is reported from the basal Wilson Grove Formation in a small quarry just north of the town of Bloomfield, Sonoma County, California. The fauna represents intertidal to shallow subtidal water depths and water temperatures interpreted from the fauna, consistent with the latitude of the fossil locality (37° north) during the late Miocene. The fauna...
Authors
Charles L. Powell, Robert W. Boessenecker, N. Adam Smith, Robert J. Fleck, Sandra J. Carlson, James R. Allen, Douglas J. Long, Andrei M. Sarna-Wojcicki, Raj B. Guruswami-Naidu
Exploring ends of eras in the eastern Mojave Desert: The road log Exploring ends of eras in the eastern Mojave Desert: The road log
No abstract available.
Authors
David M. Miller, G.A. Spaulding, R.E. Reynolds, James Calzia, M.E. Wells, Robert J. Fleck, S. Baltzer
Science and Products
Pacific Northwest Geologic Mapping: Northern Pacific Border, Cascades and Columbia
The Pacific Northwest is an area created by active and complex geological processes. On its path to the Pacific Ocean, the Columbia River slices through a chain of active volcanoes located along the western margin of the U.S. in Washington, Oregon, and northern California. These volcanoes rest above the active Cascadia subduction zone, which is the boundary where the oceanic tectonic plate dives...
Tabular geochronologic, geochemical, and isotopic data from igneous rocks in the Lane Mountain area, San Bernardino County, California Tabular geochronologic, geochemical, and isotopic data from igneous rocks in the Lane Mountain area, San Bernardino County, California
This dataset provides geochronologic, geochemical, and isotopic data for selected igneous rock samples collected in the Lane Mountain area about 20 kilometers northeast of Barstow, California. Uranium-lead (U-Pb) zircon geochronologic and whole-rock geochemical data were obtained for 62 samples of which 28 are from Permian to Triassic plutonic rocks and dikes, 24 are from Late Jurassic...
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 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 map of the Beacon Rock quadrangle, Skamania County, Washington Geologic map of the Beacon Rock quadrangle, Skamania County, Washington
The Beacon Rock 7.5′ quadrangle is located approximately 50 km east of Portland, Oregon, on the north side of the Columbia River Gorge, a scenic canyon carved through the axis of the Cascade Range by the Columbia River. Although approximately 75,000 people live within the gorge, much of the region remains little developed and is encompassed by the 292,500-acre Columbia River Gorge...
Geologic map of the Bodie Hills, California and Nevada Geologic map of the Bodie Hills, California and Nevada
The Bodie Hills covers about 1,200 km2 straddling the California-Nevada state boundary just north of Mono Lake in the western part of the Basin and Range Province, about 20 km east of the central Sierra Nevada. The area is mostly underlain by the partly overlapping, middle to late Miocene Bodie Hills volcanic field and Pliocene to late Pleistocene Aurora volcanic field (John and others...
A tunnel runs through it — An inside view of the Tualatin Mountains, Oregon A tunnel runs through it — An inside view of the Tualatin Mountains, Oregon
The Tualatin Mountains form a northwest-striking ridge about 350 m high that separates Portland, Oregon, from the cities of the Tualatin Valley to the west. Known informally as the Portland Hills, the ridge is a late Cenozoic anticline, bounded by reverse faults that dip toward the anticlinal axis. The anticline is a broad, open fold consisting chiefly of Miocene Columbia River Basalt...
Filter Total Items: 43
Geochronologic, isotopic, and geochemical data from pre-Cretaceous plutonic rocks in the Lane Mountain area, San Bernardino County, California Geochronologic, isotopic, and geochemical data from pre-Cretaceous plutonic rocks in the Lane Mountain area, San Bernardino County, California
Pre-Cretaceous, predominantly dioritic plutonic rocks in the Lane Mountain area, California, intrude metasedimentary and metavolcanic rocks considered part of the El Paso terrane. New geochronologic (uranium-lead zircon), geochemical, and isotopic data provide a reliable basis for dividing these pre-Cretaceous plutonic rocks into two mappable suites of Permian–Triassic and Late Jurassic...
Authors
Paul Stone, Howard J. Brown, M. Robinson Cecil, Robert J. Fleck, Jorge A. Vazquez, John A. Fitzpatrick
Characterization of the rhyolite of Bodie Hills and 40Ar/39Ar intercalibration with Ar mineral standards Characterization of the rhyolite of Bodie Hills and 40Ar/39Ar intercalibration with Ar mineral standards
The rhyolite of Bodie Hills (California) is characterized compositionally and the geochronology of selected phases is studied. Sanidine (BHs) from the rhyolite is well suited as a 40Ar/39Ar reference material with high K/Ca and radiogenic yield. Intercalibration with GA1550 biotite from the Dromedary igneous complex (New South Wales, Australia) yields an age of 9.7946 ± 0.0031 Ma for BHs...
Authors
Robert J. Fleck, Andrew T. Calvert, Matthew Coble, Joseph L. Wooden, Kip V. Hodges, Leslie A. Hayden, Matthijs C. van Soest, Edward A. du Bray, David A. John
Geochronologic, isotopic, and geochemical data from igneous rocks in the Lane Mountain area, San Bernardino County, California Geochronologic, isotopic, and geochemical data from igneous rocks in the Lane Mountain area, San Bernardino County, California
We present new geochronologic, isotopic, and geochemical data for selected igneous rocks in the Lane Mountain area, California. We determined SHRIMP-RG U-Pb zircon ages for the following units: (1) Larrea complex (~253 Ma and ~149–146 Ma); (2) Daisy granodiorite (~151 Ma); (3) Jack Spring quartz monzonite (~85–82 Ma); (4) unnamed porphyritic dikes and stocks (~80–73 Ma); and (5) Lane...
Authors
Paul Stone, Howard J. Brown, M. Robinson Cecil, Robert J. Fleck, Jorge A. Vazquez, John A. Fitzpatrick, Jose J. Rosario
Petrographic, geochemical, and geochronologic data for cenozoic volcanic rocks of 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
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...
Authors
Edward A. du Bray, David A. John, Peter G. Vikre, Joseph P. Colgan, Michael A. Cosca, Leah E. Morgan, Robert J. Fleck, Wayne R. Premo, Christopher S. Holm-Denoma
Geology and paleontology of the late Miocene Wilson Grove Formation at Bloomfield Quarry, Sonoma County, California Geology and paleontology of the late Miocene Wilson Grove Formation at Bloomfield Quarry, Sonoma County, California
An extensive fauna of at least 77 taxa is reported from the basal Wilson Grove Formation in a small quarry just north of the town of Bloomfield, Sonoma County, California. The fauna represents intertidal to shallow subtidal water depths and water temperatures interpreted from the fauna, consistent with the latitude of the fossil locality (37° north) during the late Miocene. The fauna...
Authors
Charles L. Powell, Robert W. Boessenecker, N. Adam Smith, Robert J. Fleck, Sandra J. Carlson, James R. Allen, Douglas J. Long, Andrei M. Sarna-Wojcicki, Raj B. Guruswami-Naidu
Exploring ends of eras in the eastern Mojave Desert: The road log Exploring ends of eras in the eastern Mojave Desert: The road log
No abstract available.
Authors
David M. Miller, G.A. Spaulding, R.E. Reynolds, James Calzia, M.E. Wells, Robert J. Fleck, S. Baltzer
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government