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Articles 1 - 7 of 7
Full-Text Articles in Tectonics and Structure
Glacier Slip And Seismicity Induced By Surface Melt, Peter L. Moore, J. Paul Winberry, Neal R. Iverson, Knut A. Christianson, Sridhar Anandakrishnan, Miriam Jackson, Mark E. Mathison, Denis Cohen
Glacier Slip And Seismicity Induced By Surface Melt, Peter L. Moore, J. Paul Winberry, Neal R. Iverson, Knut A. Christianson, Sridhar Anandakrishnan, Miriam Jackson, Mark E. Mathison, Denis Cohen
All Faculty Scholarship for the College of the Sciences
Many of the key processes governing fast glacier flow involve interaction between a glacier and its basal hydrological system, which is hidden from direct observation. Passive seismic monitoring has shown promise as a tool for remotely monitoring basal processes, but lack of glacier-bed access prevents clear understanding of the relationships between subglacial processes and corresponding seismic emissions. Here we describe direct measurements of basal hydrology, sliding, and broadband seismicity made in a unique subglacial facility in Norway during the onset of two summer melt seasons. In the most pronounced of these episodes, rapid delivery of surface meltwater to the bed …
An Apparent Angular Unconformity In Western Connecticut, Stanley Schleifer, Nazrul I. Khandaker, Adisa Charles, Hernando Martinez, Shirley Jackson, Chiemeka Ihebom
An Apparent Angular Unconformity In Western Connecticut, Stanley Schleifer, Nazrul I. Khandaker, Adisa Charles, Hernando Martinez, Shirley Jackson, Chiemeka Ihebom
Publications and Research
The recent extension, to the north, of the U. S. Route 7 ‘superhighway’ in the town of Brookfield, Connecticut has involved the excavation of crystalline bedrock of lower Paleozoic to upper Proterozoic age in the area. The road cuts produced by this excavation have exposed some interesting features of structure and lithology. An outcrop, observed by the authors off the east side of route 7, at grid coordinates 41.482444 N, 73.415307 W is of particular interest. It appears, to the casual observer to be an angular unconformity. Maps and publications regarding this area of Western Connecticut support the likelihood of …
Incision History Of Glenwood Canyon, Colorado, Usa, From The Uranium-Series Analyses Of Water-Table Speleothems, Victor J. Polyak, Harvey R. Duchene, Donald G. Davis, Arthur N. Palmer, Margaret V. Palmer, Yemane Asmerom
Incision History Of Glenwood Canyon, Colorado, Usa, From The Uranium-Series Analyses Of Water-Table Speleothems, Victor J. Polyak, Harvey R. Duchene, Donald G. Davis, Arthur N. Palmer, Margaret V. Palmer, Yemane Asmerom
International Journal of Speleology
Uranium-series analyses of water-table-type speleothems from Glenwood Cavern and “cavelets” near the town of Glenwood Springs, Colorado, USA, yield incision rates of the Colorado River in Glenwood Canyon for the last ~1.4 My. The incision rates, calculated from dating cave mammillary and cave folia calcite situated 65 and 90 m above the Colorado River, are 174 ± 30 m/My for the last 0.46 My and 144 ± 30 m/My for the last 0.62 My, respectively. These are consistent with incision rates determined from nearby volcanic deposits. In contrast, δ234U model ages (1.39 ± 0.25 My; 1.36 ± 0.25 …
A Study Of Knickpoint Formation: Geomorphic Analysis Of San Simeon Creek, Keith Moffatt
A Study Of Knickpoint Formation: Geomorphic Analysis Of San Simeon Creek, Keith Moffatt
Natural Resources Management and Environmental Sciences
The highest point of orogeny in the Santa Lucia range occurs 50-60km from the nearest active faulting. This orogeny is believed to have occurred hear due to relatively weak Franciscan Mélange versus the granitic material at the fault boundary. This paper studies the development of a knickpoint in San Simeon creek to identify the role of relatively recent (graded time) tectonic activity in orogeny of the Santa Lucia range.
The 2003 earth quake is evidence of recent base level change with the occurrence of orogeny supporting the theory of continuous orogeny in recent and graded time scale. Although the knickpoint …
Alluvial Sediment Or Playas: What Is The Dominant Source Of Sand And Silt In Desert Soil Vesicular A Horizons, Southwest Usa, Mark R. Sweeney, Eric V. Mcdonald, Christohper E. Markley
Alluvial Sediment Or Playas: What Is The Dominant Source Of Sand And Silt In Desert Soil Vesicular A Horizons, Southwest Usa, Mark R. Sweeney, Eric V. Mcdonald, Christohper E. Markley
All Faculty Scholarship for the College of the Sciences
Vesicular A (Av) soil horizons form beneath desert pavements from the accretion of aeolian sediment (dust) commonly thought to be derived primarily from desiccating pluvial lakes and playas, with contributions from ephemeral washes and alluvial fans. Particle size distributions of Av horizons are typically bimodal with primary modes of very fine silt and fine sand, suggesting that the horizon matrix is derived from multiple sources. Here we conduct detailed chemical and physical analysis of both Av horizon soil samples and potential sources of aeolian sediment to better constrain the relative contributions of dust associated with the development of Av horizons. …
Nucleation And Seismic Tremor Associated With The Glacial Earthquakes Of Whillans Ice Stream, Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Douglas A. Wiens, Richard B. Alley
Nucleation And Seismic Tremor Associated With The Glacial Earthquakes Of Whillans Ice Stream, Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Douglas A. Wiens, Richard B. Alley
All Faculty Scholarship for the College of the Sciences
The ability to monitor transient motion along faults is critical to improving our ability to understand many natural phenomena such as landslides and earthquakes. Here, we usedata from a GPS and seismometer network that were deployed to monitor the regularly repeating glacial earthquakes of Whillans Ice Stream, West Antarctica to show that a unique pattern of precursory slip precedes complete rupture along the bed of the ice stream. Additionally, we show that rupture can be independently tracked by increased levels of microseismic activity, including harmonic tremor, that are coincident with the onset of slip at any location, thus providing a …
Pliocene Sinistral Slip Across The Adobe Hills, Eastern California-Western Nevada: Kinematics Of Fault Slip Transfer Across The Mina Deflection, Sarah Nagorsen-Rinke, Jeffrey Lee, Andrew Calvert
Pliocene Sinistral Slip Across The Adobe Hills, Eastern California-Western Nevada: Kinematics Of Fault Slip Transfer Across The Mina Deflection, Sarah Nagorsen-Rinke, Jeffrey Lee, Andrew Calvert
All Faculty Scholarship for the College of the Sciences
The Adobe Hills region (California and Nevada, USA) is a faulted volcanic field located within the western Mina deflection, a right-stepping zone of faults that connects the northern Eastern California shear zone (ECSZ) to the south with the Walker Lane belt (WLB) to the north. New detailed geologic mapping, structural studies, and 40Ar/39Ar geochronology in the Adobe Hills allow us to calculate fault slip rates and test predictions for the kinematics of fault slip transfer into the Mina deflection. The Adobe Hills are dominated by Pliocene tuffaceous sandstone, basaltic lavas that yield 40Ar/39Ar ages …