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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Tectonic Synthesis Of The Olympic Mountains Segment Of The Cascadia Wedge, Using 2-D Thermal And Kinetic Modeling Of Isotopic Ages, Geoffrey E. Batt, Mark T. Brandon, Kenneth A. Farley, Mary K. Roden-Tice
Tectonic Synthesis Of The Olympic Mountains Segment Of The Cascadia Wedge, Using 2-D Thermal And Kinetic Modeling Of Isotopic Ages, Geoffrey E. Batt, Mark T. Brandon, Kenneth A. Farley, Mary K. Roden-Tice
Mary K. Roden-Tice
A fully coupled two-dimensional kinematic and thermal model of a steady state accretionary wedge, constrained by an extensive data set of fission track and (U-Th)/He ages for apatite and zircon, is here used to investigate the development of the Olympic Mountains segment of the Cascadia accretionary wedge. The model has two main free parameters: , the maximum rate of erosion for a generic erosion function operating at the top of the wedge, and α, the distribution of sedimentary accretion into the wedge. The best fit values for and α and their confidence limits are determined through an iterative search of …
Effects Of Sampling Standardization On Estimates Of Phanerozoic Marine Diversification, J. Alroy, C. R. Marshall, R. K. Bambach, K. Bezusko, M. Foote, F. T. Fürsich, Thor A. Hansen, S. M. Holland, L. C. Ivany, D. Jablonski, D. K. Jacobs, D. C. Jones, M. A. Kosnik, S. Lidgard, S. Low, A. I. Miller, P. M. Novack-Gottshall, T. D. Olszewski, M. E. Patzkowsky, D. M. Raup, K. Roy, J. J. Sepkoski Jr., M. G. Sommers, P. J. Wagner, A. Webber
Effects Of Sampling Standardization On Estimates Of Phanerozoic Marine Diversification, J. Alroy, C. R. Marshall, R. K. Bambach, K. Bezusko, M. Foote, F. T. Fürsich, Thor A. Hansen, S. M. Holland, L. C. Ivany, D. Jablonski, D. K. Jacobs, D. C. Jones, M. A. Kosnik, S. Lidgard, S. Low, A. I. Miller, P. M. Novack-Gottshall, T. D. Olszewski, M. E. Patzkowsky, D. M. Raup, K. Roy, J. J. Sepkoski Jr., M. G. Sommers, P. J. Wagner, A. Webber
Thor A. Hansen
Global diversity curves reflect more than just the number of taxa that have existed through time: they also mirror variation in the nature of the fossil record and the way the record is reported. These sampling effects are best quantified by assembling and analyzing large numbers of locality-specific biotic inventories. Here, we introduce a new database of this kind for the Phanerozoic fossil record of marine invertebrates. We apply four substantially distinct analytical methods that estimate taxonomic diversity by quantifying and correcting for variation through time in the number and nature of inventories. Variation introduced by the use of two …
Solute Transport Through Laboratory-Scale Karstic Aquifers, Lee J. Florea, Carol M. Wicks
Solute Transport Through Laboratory-Scale Karstic Aquifers, Lee J. Florea, Carol M. Wicks
Lee J Florea, PhD, P.G.
Laboratory-scale models of branchwork and of network karstic aquifers were constructed to provide data needed for calibration of numerical models. The distribution and connectedness of the conduits and sinkholes were scaled similarly to those found in nature; however, the porosity of models (2 and 3%) and the recharge rate (80 cm/hr) could not be scaled appropriately. Pulses of 1-M NaCl were injected sequentially at ten locations on both models to determine transport parameters using QTRACER. For all experiments, the Reynolds numbers were <150, the Peclet numbers were >6, and the Froude numbers were ~0. The flow regime was laminar and subcritical and advective processes dominated …
In-Cave Dye Tracing And Drainage Basin Divides In The Mammoth Cave Karst Aquifer, Kentucky, Chris Groves, Joe Meiman, Shannon Herstein
In-Cave Dye Tracing And Drainage Basin Divides In The Mammoth Cave Karst Aquifer, Kentucky, Chris Groves, Joe Meiman, Shannon Herstein
Chris Groves
Karst ground-water basin divides are generally depicted as two-dimensional lines on maps, but they are better considered as three-dimensional surfaces within the subsurface. Dye traces are necessary to map out these surfaces and to locate conduits inaccessible to cave surveyors, and are indispensable for understanding the geometry of the complex networks of flow paths through the aquifer. A key reason why the Mammoth Cave System is the world's longest known cave is that its passages extend over several major ground-water basins. The divides between these basins define the drainage system geometry and precise location of them is critical for understanding …
Long Recurrence Records From The Wasatch Fault Zone, Utah, James P. Mccalpin
Long Recurrence Records From The Wasatch Fault Zone, Utah, James P. Mccalpin
James P. McCalpin
The Wasatch fault "megatrench" was excavated in September 1999 across two fault scarps totaling 18 meters high on the Salt Lake City segment of the Wasatch fault zone (WFZ). The purpose of the megatrench was to date a long series of consecutive earthquakes (8-12 events?) on the WFZ and measure the variability of recurrence times between the events.This variability could then be used in calculating the future probability of large earthquakes on the WFZ. The trench was located 1 km north of the mouth of Little Cottonwood Canyon, at an elevation of 1525 m, between the Bonneville highstand (ca. 17.5 …
Paleoseismicity Of Quaternary Faults Near Albuquerque, New Mexico: The Zia Fault, James P. Mccalpin
Paleoseismicity Of Quaternary Faults Near Albuquerque, New Mexico: The Zia Fault, James P. Mccalpin
James P. McCalpin
This study continues USGS-funded efforts to assess the activity and earthquake hazard potential of Quaternary faults in the Albuquerque metropolitan region. Our target in 2000 was the Zia fault, a 37 km-long normal fault that trends N-S in northern Llano de Albuquerque (LdA). The Zia fault is one of three major east-dipping normal faults that define the western margin of the Rio Grande rift in the northern Albuquerque basin, the other faults being the Calabacillas fault (to the west of the Zia fault) and the County Dump fault (to the east of the Zia fault) (Machette et al., 1998). In …
Graptolite Macroevolution: Phylogenetic Analysis And Testing Foundation Hypotheses Of Directional Change, Daniel Goldman
Graptolite Macroevolution: Phylogenetic Analysis And Testing Foundation Hypotheses Of Directional Change, Daniel Goldman
Daniel Goldman
Funding agency: National Science Foundation Amount: $117,107.00 Year: 2001/4 yrs
Geomagnetic Field Behavior Before And After The Kauai Reverse-Normal Polarity Transition, Scott Bogue
Geomagnetic Field Behavior Before And After The Kauai Reverse-Normal Polarity Transition, Scott Bogue
Scott Bogue
New paleomagnetic results from 4 m.y. old lava flows from Kauai, Hawaii, suggest that strong poloidal field is associated with an unusual state of the geodynamo that follows attempts at polarity reversal (successful or not). The new data comprise 50 paleomagnetic sites from superposed lava flows occurring just below and above the Kauai reverse-normal polarity transition. A composite record of 45 distinct field determinations was constructed by combining sites that record similar ancient field and correlating them to previously published results from Kauai. Of the 45 data, 25 include paleointensity estimates derived from double-heating experiments. A comparison of the composite …
Karst Genetic Model For The French Bay Breccia Deposits, San Salvador, Bahamas, Lee J. Florea, John Mylroie, Jim Carew
Karst Genetic Model For The French Bay Breccia Deposits, San Salvador, Bahamas, Lee J. Florea, John Mylroie, Jim Carew
Lee J Florea, PhD, P.G.
No abstract provided.