John (Jack) Hillhouse (Former Employee)
Science and Products
Filter Total Items: 36
Fission-track age (400,000 yr) of the Rockland tephra, based on inclusion of zirco grains lacking fossil fission tracks Fission-track age (400,000 yr) of the Rockland tephra, based on inclusion of zirco grains lacking fossil fission tracks
A zircon fission-track age of about 400,000 yr B.P. has been determined for the Rockland tephra, a widespread pyroclastic layer in northern California and western Nevada. New ages of zircon separates from both proximal and distal exposures of this layer range from 370,000 to 460,000 yr; ages of the best material provide a narrower range, from 370,000 yr for unwelded ash-flow tuff to 420...
Authors
C.E. Meyer, A.M. Sarna-Wojcicki, John Hillhouse, M.J. Woodward, J. Slate, D. Sorg
Paleomagnetism and tectonic rotation of the lower Miocene Peach Springs Tuff: Colorado Plateau, Arizona, to Barstow, California Paleomagnetism and tectonic rotation of the lower Miocene Peach Springs Tuff: Colorado Plateau, Arizona, to Barstow, California
We have determined remanent magnetization directions of the lower Miocene Peach Springs Tuff at 41 localities in western Arizona and southeastern California. An unusual northeast and shallow magnetization direction confirms the proposed geologic correlation of isolated outcrops of the tuff from the Colorado Plateau to Barstow, California, a distance of 350 km. The Peach Springs Tuff was...
Authors
Ray E. Wells, John Hillhouse
Early Cretaceous paleolatitude of the Yukon-Koyukuk province, Alaska Early Cretaceous paleolatitude of the Yukon-Koyukuk province, Alaska
We report results from a paleomagnetic study of the Yukon-Koyukuk province, a key region for reconstructing the Cretaceous paleogeography of northern Alaska and northeastern Asia. The province lies between the displaced continental fragment of Arctic Alaska and the accreted terranes of southern Alaska. Although Lower Cretaceous volcanogenic rocks of the Yukon-Koyukuk province preserve...
Authors
John Hillhouse, C. S. Grommé
Accretion of southern Alaska Accretion of southern Alaska
Paleomagnetic data from southern Alaska indicate that the Wrangellia and Peninsular terranes collided with central Alaska probably by 65 Ma ago and certainly no later than 55 Ma ago. The accretion of these terranes to the mainland was followed by the arrival of the Ghost Rocks volcanic assemblage at the southern margin of Kodiak Island. Poleward movement of these terranes can be...
Authors
John Hillhouse
Late Cenozoic Arctic Ocean sea ice and terrestrial paleoclimate Late Cenozoic Arctic Ocean sea ice and terrestrial paleoclimate
Sea otter remains found in deposits of two marine transgressions (Bigbendian and Fishcreekian) of the Alaskan Arctic Coastal Plain which occurred between 2.4 and 3 Ma suggest that during these two events the southern limit of seasonal sea ice was at least 1600 km farther north than at present in Alaskan waters. Perennial sea ice must have been severely restricted or absent, and winters...
Authors
L. Carter, J. Brigham-Grette, L. Marincovich, V.L. Pease, John Hillhouse
Cenozoic rocks in the Barstow basin area of southern California: Stratigraphic relations, radiometric ages, and paleomagnetism Cenozoic rocks in the Barstow basin area of southern California: Stratigraphic relations, radiometric ages, and paleomagnetism
No abstract available.
Authors
D. Burke, John Hillhouse, E.H. McKee, S. Miller, J. Morton
Limits to northward drift of the Paleocene Cantwell Formation, central Alaska Limits to northward drift of the Paleocene Cantwell Formation, central Alaska
Volcanic rocks of the Paleocene Cantwell Formation in central Alaska apparently originated at a paleolatitude of 83°N (α95 = 9.7°), as indicated by paleomagnetic results. When compared with the Paleocene pole for the North American craton, the 95% confidence limits of the results suggest that terranes north of the Denali fault have moved no more than 550 km northward relative to the...
Authors
John Hillhouse, C. S. Grommé
Paleomagnetism of Triassic red beds and basalt in the Chulitna Terrane, south-central Alaska Paleomagnetism of Triassic red beds and basalt in the Chulitna Terrane, south-central Alaska
No abstract available.
Authors
John Hillhouse, C. S. Grommé
Additional results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east of Lake Turkana (Lake Rudolf), Kenya Additional results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east of Lake Turkana (Lake Rudolf), Kenya
The magnetostratigraphy of the hominid-bearing sediments exposed east of Lake Turkana has been strengthened by new palaeomagnetic results. Ages obtained from several tuffs by the 40Ar/39Ar method suggest an approxmate match between the observed magnetozones and the geomagnetic polarity time scale; however, the palaeomagnetic results are also compatible with a younger chronology suggested...
Authors
John Hillhouse, J.W.M. Ndombi, A. Cox, A. Brock
Paleomagnetic investigation of late Quaternary sediments of south San Francisco Bay, California Paleomagnetic investigation of late Quaternary sediments of south San Francisco Bay, California
Paleomagnetic inclinations of the Late Quaternary sediments of South San Francisco Bay were determined from bore hole samples collected near Dumbarton Bridge. The sediments consist of estuarine muds and nonmarine sand deposits, floored by bedrock of the Mesozoic Franciscan Formation. - Beneath Dumbarton Bridge the entire sedimentary fill is normally polarized; therefore, the fill...
Authors
John Hillhouse
Paleomagnetism of the Plio-Pleistocene sediments of Lake Tecopa, California, and East Rudolf, Kenya; magnetic stratigraphy and polarity transitions Paleomagnetism of the Plio-Pleistocene sediments of Lake Tecopa, California, and East Rudolf, Kenya; magnetic stratigraphy and polarity transitions
No abstract available.
Authors
John Hillhouse
Science and Products
Filter Total Items: 36
Fission-track age (400,000 yr) of the Rockland tephra, based on inclusion of zirco grains lacking fossil fission tracks Fission-track age (400,000 yr) of the Rockland tephra, based on inclusion of zirco grains lacking fossil fission tracks
A zircon fission-track age of about 400,000 yr B.P. has been determined for the Rockland tephra, a widespread pyroclastic layer in northern California and western Nevada. New ages of zircon separates from both proximal and distal exposures of this layer range from 370,000 to 460,000 yr; ages of the best material provide a narrower range, from 370,000 yr for unwelded ash-flow tuff to 420...
Authors
C.E. Meyer, A.M. Sarna-Wojcicki, John Hillhouse, M.J. Woodward, J. Slate, D. Sorg
Paleomagnetism and tectonic rotation of the lower Miocene Peach Springs Tuff: Colorado Plateau, Arizona, to Barstow, California Paleomagnetism and tectonic rotation of the lower Miocene Peach Springs Tuff: Colorado Plateau, Arizona, to Barstow, California
We have determined remanent magnetization directions of the lower Miocene Peach Springs Tuff at 41 localities in western Arizona and southeastern California. An unusual northeast and shallow magnetization direction confirms the proposed geologic correlation of isolated outcrops of the tuff from the Colorado Plateau to Barstow, California, a distance of 350 km. The Peach Springs Tuff was...
Authors
Ray E. Wells, John Hillhouse
Early Cretaceous paleolatitude of the Yukon-Koyukuk province, Alaska Early Cretaceous paleolatitude of the Yukon-Koyukuk province, Alaska
We report results from a paleomagnetic study of the Yukon-Koyukuk province, a key region for reconstructing the Cretaceous paleogeography of northern Alaska and northeastern Asia. The province lies between the displaced continental fragment of Arctic Alaska and the accreted terranes of southern Alaska. Although Lower Cretaceous volcanogenic rocks of the Yukon-Koyukuk province preserve...
Authors
John Hillhouse, C. S. Grommé
Accretion of southern Alaska Accretion of southern Alaska
Paleomagnetic data from southern Alaska indicate that the Wrangellia and Peninsular terranes collided with central Alaska probably by 65 Ma ago and certainly no later than 55 Ma ago. The accretion of these terranes to the mainland was followed by the arrival of the Ghost Rocks volcanic assemblage at the southern margin of Kodiak Island. Poleward movement of these terranes can be...
Authors
John Hillhouse
Late Cenozoic Arctic Ocean sea ice and terrestrial paleoclimate Late Cenozoic Arctic Ocean sea ice and terrestrial paleoclimate
Sea otter remains found in deposits of two marine transgressions (Bigbendian and Fishcreekian) of the Alaskan Arctic Coastal Plain which occurred between 2.4 and 3 Ma suggest that during these two events the southern limit of seasonal sea ice was at least 1600 km farther north than at present in Alaskan waters. Perennial sea ice must have been severely restricted or absent, and winters...
Authors
L. Carter, J. Brigham-Grette, L. Marincovich, V.L. Pease, John Hillhouse
Cenozoic rocks in the Barstow basin area of southern California: Stratigraphic relations, radiometric ages, and paleomagnetism Cenozoic rocks in the Barstow basin area of southern California: Stratigraphic relations, radiometric ages, and paleomagnetism
No abstract available.
Authors
D. Burke, John Hillhouse, E.H. McKee, S. Miller, J. Morton
Limits to northward drift of the Paleocene Cantwell Formation, central Alaska Limits to northward drift of the Paleocene Cantwell Formation, central Alaska
Volcanic rocks of the Paleocene Cantwell Formation in central Alaska apparently originated at a paleolatitude of 83°N (α95 = 9.7°), as indicated by paleomagnetic results. When compared with the Paleocene pole for the North American craton, the 95% confidence limits of the results suggest that terranes north of the Denali fault have moved no more than 550 km northward relative to the...
Authors
John Hillhouse, C. S. Grommé
Paleomagnetism of Triassic red beds and basalt in the Chulitna Terrane, south-central Alaska Paleomagnetism of Triassic red beds and basalt in the Chulitna Terrane, south-central Alaska
No abstract available.
Authors
John Hillhouse, C. S. Grommé
Additional results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east of Lake Turkana (Lake Rudolf), Kenya Additional results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east of Lake Turkana (Lake Rudolf), Kenya
The magnetostratigraphy of the hominid-bearing sediments exposed east of Lake Turkana has been strengthened by new palaeomagnetic results. Ages obtained from several tuffs by the 40Ar/39Ar method suggest an approxmate match between the observed magnetozones and the geomagnetic polarity time scale; however, the palaeomagnetic results are also compatible with a younger chronology suggested...
Authors
John Hillhouse, J.W.M. Ndombi, A. Cox, A. Brock
Paleomagnetic investigation of late Quaternary sediments of south San Francisco Bay, California Paleomagnetic investigation of late Quaternary sediments of south San Francisco Bay, California
Paleomagnetic inclinations of the Late Quaternary sediments of South San Francisco Bay were determined from bore hole samples collected near Dumbarton Bridge. The sediments consist of estuarine muds and nonmarine sand deposits, floored by bedrock of the Mesozoic Franciscan Formation. - Beneath Dumbarton Bridge the entire sedimentary fill is normally polarized; therefore, the fill...
Authors
John Hillhouse
Paleomagnetism of the Plio-Pleistocene sediments of Lake Tecopa, California, and East Rudolf, Kenya; magnetic stratigraphy and polarity transitions Paleomagnetism of the Plio-Pleistocene sediments of Lake Tecopa, California, and East Rudolf, Kenya; magnetic stratigraphy and polarity transitions
No abstract available.
Authors
John Hillhouse
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