Browsing Geology by Issue Date
Now showing items 1-20 of 35
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Magnetic Stratigraphy of the Eocene-Oligocene Transition in Northwestern Oregon
(1998-01-01)The Keasey Formation in Northwestern Oregon contains one of the most complete geologic records of the Eocene-Oligocene transition in the Pacific Northwest. Samples from this sequence of sedimentary rocks were collected in ... -
Magnetostratigraphy of the Lower Miocene Sespe-Vaqueros Formations, Santa Ana Mountains, Orange County, California L.L. Donohoo
(1998-01-01)The nonmarine redbeds of the Sespe Formation and the overlying gray marine sandstones of the Vaqueros Formation are widespread in southern California, and in most places yield Eocene and Oligocene mammals and molluscs. ... -
Paleointensities of Late Miocene Intrusions from Paiute Ridge, Nevada
(1998-01-01)Shallow intrusive rocks from Paiute Ridge, Nevada, record what is interpreted to be a relatively complete record of a reversal of Earth's magnetic field that occurred approximately 8.65 million years ago. We attempt to ... -
Paleomagnetism and Deformation of the Quottoon Pluton, British Columbia
(1998-01-01)In this study, we are using directions of magnetization to determine how the 60 my old Quottoon pluton (Coast Mountains, British Columbia) has deformed. In May 1998, 119 oriented core samples from 17 sites were collected. ... -
Magnetic Stratigraphy and Tectonic Rotation of the Lower Miocene Rincon Shale (Saucesian Foraminiferal Stage), Santa Barbara County, California
(1999-01-01)The foraminifera from the Rincon Shale in Ventura and Santa Barbara counties, California, were the original basis for the Saucesian Stage of Kleinpell (1938). The Saucesian was originally correlated with the early Miocene, ... -
Magnetic Stratigraphy of the Upper Miocene Montesano Formation, Olympic Peninsula of Washington: Implications for Miocene Molluscan Biostratigraphy
(1999-01-01)The Montesano Formation in the Wishkah River near Aberdeen, WA, was the original basis for the late Miocene "Wishkahan" and "Graysian" molluscan stages of Addicott (1976). Yet the precise age of these formations has long ... -
Paleocene Silverado Formation, Orange County, California
(1999-01-01)The late Paleocene Silverado Formation of the Santa Ana Mountains in Southern California is one of the few Paleocene sedimentary units in the West Coast. Up to 1700 feet thick, it records a marine transgression from ... -
Magneto Stratigraphy of the Coaledo Formation, Coos Bay, Oregon.
(1999-01-01)The Coaledo Formation, exposed in Coos Bay on the southern coast of Oregon, consists of 6000 feet of deltaic sediments, which filled the forearc basin in the Oregon Coast Ranges. This unit has yielded middle Eocene molluscs ... -
Geomorphology of Mugu Lagoon 1857 to Present, Ventura County, California
(1999-01-01)Mugu Lagoon is a large and relatively undisturbed estuary located at the mouth of Calleguas Creek on the Ventura County coast. Estuaries are rare in California as a result of high shoreline relief, arid climate, and human ... -
Petrology, Mineralogy and Petrography of a Type II-III Carbonaceous Chondrite.
(2000-01-01)Meteorite thin section EET-92-070, 3 is a cross section of a Carbonaceous Chondrite, a rock consisting of, among other bodies, several igneous droplets called chondrules that likely formed in the accretionary disk of our ... -
Preliminary Paleomagnetic Results from Early Tertiary Plutons of the British Columbia Coast Ranges, Mt. Waddington Area.
(2001-01-01)New paleomagnetic results from two early Tertiary granodioritic-to-tonalitic plutons suggest that NE-side-up tilting is not ubiquitous in the Coast Ranges of British Columbia. The study area, located ~350km NNW of Vancouver, ... -
Evidence from the Sheep Creek Range [Nevada] of a Very Rapid Field Change during a Geomagnetic Polarity Reversal
(2002-01-01)Detailed thermal demagnetizations of samples from a 15 million year old lava flow from the Sheep Creek Range in Nevada show that the ancient geomagnetic field direction changed by over 80? during the time it took the flow ... -
Magnetic Stratigraphy of the Miocene Round Mountain Silt and Olcese Sand, Bakersfield, California
(2003-01-01)The Round Mountain Silt and the underlying Olcese Sand, northeast of Bakersfield, California, are famous for their large collection of marine vertebrates from the Sharktooth Hill Bonebed and fossil mollusks from both units. ... -
Paleomagnetism of the Miocene Tung Gur Formation, Mongolia, with a review of the Extinct Mustelid Sthenictis
(2003-01-01)I plan to reorganize the extinct genus of Sthenictis , re-evaluating as many known specimens are possible in order to rectify any problems within the genus. In addition I will describe a new species of Sthenictis from ... -
Geothermal Research in Iceland: Implications and Applications to the United States
(2003-01-01)I will be traveling to Reykjavik, Iceland for 5 weeks to learn about their new geothermal technology so that I may apply it to the southwestern United States. I will spend two weeks with the United Nations Geothermal ... -
Rapid Variation of Field Strength during a Geomagnetic Polarity Reversal
(2003-01-01)New paleomagnetic results show that the ancient magnetic field intensity changed from 4.5 to 8 uT during the cooling of a 5 meter thick lava flow erupted during a geomagnetic reversal 16.2 million years ago. The lava flow ... -
Paleomagnetism Tectonic Rotation of the MIOCENE OBISPO Formation, Western Santa Barbara County, CA.
(2004-01-01)This is a paleomagnetic study on the Obispo Formation in the coastal region between Santa Barbara and San Luis Obispo. In this area lies the Santa Maria basin, which contains many faults, including the Santa Ynez fault, ... -
Effects of Plate Boundary Variations on Elevation, Coast Mountains, British Columbia
(2004-01-01)New Geographic Information Systems (GIS) analysis reveals that the width and height of the elevated topography of the Coast Mountains in British Columbia is largely controlled by the type of adjacent plate boundary. This ... -
Rapid Variation of the Geomagnetic Field in Reversal: Evidence from the Sheep Creek Range, North-Central Nevada
(2004-01-01)A paleomagnetic study of middle-Miocene basalts from the Sheep Creek Range of north-central Nevada was conducted to investigate prior evidence of extremely rapid change in geomagnetic field direction during a polarity ... -
Is Australia the United States' "Deputy Sheriff?"
(2005-01-01)A lot can be said about Australia: loyal, trusted ally, confidante, and friend. In the post-9/11 world, the long-standing relationship between the U.S and Australia continues to draw closer based upon: the threat of ...