Tectonics and Structure Commons^™

The Global Stratotype Section And Point (Gssp) For The Base Of The Katian Stage Of The Upper Ordovician Series At Black Knob Ridge, Southeastern Oklahoma, Usa, Daniel Goldman, Stephen A. Leslie, Jaak Nõlvak, Seth Young, Stig M. Bergström, Warren D. Huff

Department of Earth, Environment and Sustainability Faculty Publications

The International Subcomission on Ordovician Stratigraphy (ISOS) of the International Commission on Stratigraphy (ICS) recently defined the base of the global Upper Ordovician Series to be at the first appearance datum (FAD) of the graptolite species Nemagraptus gracilis in the Fågelsång GSSP in southern Sweden. This designation recognized the tremendous utility for global correlation of the first appearance of a cosmopolitan taxon that occurs within a consistent succession of other first appearance datums (e.g., Finney and Bergström, 1986; Bergström et al., 2000). Current efforts by the ISOS have focused on subdividing the Upper Ordovician into three stages and choosing appropriate …

Seismicity In The Vicinity Of Yucca Mountain, Nevada, For The Period October 1, 2002 To September 30, 2003, Ken Smith, David Vin Seggern, John G. Anderson, Richard Quittmeyer, Amy J. Smiecinski

Publications (YM)

Earthquake activity in the Yucca Mountain from October 1, 2002 through September 30, 2003 (FY03) is assessed and compared with previous activity in the region. FY03 is the first reporting year since the 1992 M 5.6 Little Skull Mountain earthquake with no earthquakes greater than M 3.0 within 65 km of Yucca Mountain. In addition, FY03 includes the fewest number of earthquakes greater than M 2.0 in any reporting year since the LSM event. With 3075 earthquakes in the catalog, FY03 represents the second largest number of earthquakes (second to FY02) since FY96 when digital seismic network operations began. The …

Seismicity In The Vicinity Of Yucca Mountain, Nevada, For The Period October 1, 2003, To September 30, 2004, David Von Seggern, Ken Smith, John G. Anderson, Amy J. Smiecinski

Publications (YM)

This report describes the seismicity and earthquake monitoring activities within the Yucca Mountain region during fiscal year 2004 (FY2004 - October 1, 2003, through September 30, 2004) based on operation of the Southern Great Basin Digital Seismic Network (SGBDSN). Network practices and earthquake monitoring conducted at the Nevada Seismological Laboratory (NSL) under DOE directives for prior fiscal years are covered in similar yearly reports (see references). Real-time systems, including regional data telemetry and data management at NSL, provide for the automatic determination of earthquake locations and magnitudes and notification of important earthquakes in the region to UNR staff and DOE …

Condensed And Expanded Sections In The Lower Mesaverde Clastic Wedge, Campanian Of Wyoming: Evidence For Tectonic Rectification Of Sea Level, Matthew W. Botzler

OES Theses and Dissertations

The stratigraphy of the Cretaceous Western Interior basin indicates that sea level oscillated during the late Cretaceous. The oscillations were polyharmonic, with periods ranging from millions of years to hundred thousands and ten thousands of years. However, there is disagreement over the extent to which sea level change was global in nature and the extent to which it was driven by local uplift or subsidence (tectonism). In orogenic regions where subsidence, sediment supply, and eustatic variation are all affecting sea level, comparisons of high and low frequency cycles can help to sort out forcing mechanisms. Low frequency eustatic sea level …

Episodic Tremor And Slip In The Pacific Northwest, Kenneth C. Creager, Timothy I. Melbourne

Geological Sciences Faculty Scholarship

Every 14 months the Pacific Northwest experiences slow slip on a fault that is the equivalent of about a magnitude 6.5 earthquake. While a typical earthquake of this magnitude happens in less than 10 seconds, the duration of these slip events is two to several weeks. The most recent event occurred from January 14 through February 1, 2007.

Evidence For Prehistoric Coseismic Folding Along The Tsaotun Segment Of The Chelungpu Fault Near Nan-Tou, Taiwan, Ashley R. Streig, Charles M. Rubin, Wen-Shan Chen, Long-Shen Lee, Stephen C. Thompson, Chris Madden, Shih-Ting Lu

All Faculty Scholarship for the College of the Sciences

Taiwan's 1999 M_w 7.6 earthquake generated over 85 km surface rupture along the Chelungpu thrust fault. Paleoseismic studies at the Shi‐Jia site near Nantou city, reveal folding as the predominant form of deformation. Stratigraphic relations across the 1999 fold scarp show the style and degree of deformation caused by the penultimate event is similar to observed 1999 deformation. A boring transect across the fold scarp provides additional evidence of an earlier earthquake. Investigations at the Shi‐Jia site revealed three prehistoric events; accelerator mass spectrometry (AMS) radiocarbon ages indicate that the penultimate earthquake occurred between 1160 and 1440 A.D. Paleoseismic …

Extreme Ground Motion Studies, James N. Brune, John G. Anderson

Publications (YM)

Subtasks: 1. Constraints on Yucca Mountain extreme ground motion based on precariously balanced rocks, unstable precipitous cliffs, and un-fractured sandstone along the San Andreas fault. 2. Prepare summary report on large recorded ground motions.

Geodetic Monitoring Of The Yucca Mountain Region Using Continuous Gps Measurements, Geoff Blewitt, Jonathan Price, Nevada Geodetic Laboratory, Nevada Bureau Of Mines & Geology

Publications (YM)

What Task 3 is About:

Monitor current crustal deformation at YM
– In the broader tectonic context of the NA-Pacific plate boundary
– In the regional context of the East California Shear Zone (ECSZ)
– In the geological context of specific fault activity
– Vertical motion associated with geophysical fluids

Using geodetic methods
– GPS – mature, proven
track the 3-D point-positions of 47 stations with < 1 mm precision
– InSAR – new, experimental
regional map of displacement along the line-of-sight (accuracy??)
proven capability: (1) co-seismic deformation; (2) local instabilities

Longbase Laser Strainmeter Measurements At Yucca Mountain, James N. Brune

Publications (YM)

Why Operate a Strainmeter?

To monitor strain over a broader bandwidth and with much higher sensitivity than GPS (or other instruments):
– Measure strain from seismic, earth-tide, temperature and air pressure inputs--gives local rock properties, and changes in them.
– Independently constrains GPS results.

To directly measure in the Yucca Mountain Block:
– Sensitive to potential very local tectonic events, (including any triggered slip), or volcanic events.

To establish a baseline for future strain changes:
– E.g., events developing from loading and heating of the repository

Outcrop Analog For Lower Paleozoic Hydrothermal Dolomite Reservoirs, Mohawk Valley, Ny, Brian E. Slater

Geology Theses and Dissertations

Geochemical analysis and field relations of linear dolomite bodies occurring in outcrop in the Mohawk Valley of New York suggest that they have undergone significant fault-related hydrothermal alteration. The dolomite occurs in the Lower Ordovician Tribes Hill Formation, which is regionally an early Ordovician shaley limestone with patchy dolomitization. The outcrop has an en echelon fault, fracture, and fold pattern. A 3D ground penetrating radar survey of the quarry floor has helped to map out faults, fractures, anticlines, synclines and the extent of dolomitization. Most of the dolomitization occurs in fault-bounded synclines or “sags” flanked by anticlines. The dolomite structures …

Late Cretaceous To Paleocene Metamorphism And Magmatism In The Funeral Mountains Metamorphic Core Complex, Death Valley, California, Chris G. Mattinson, Joseph P. Colgan, James R. Metcalf, Elizabeth L. Miller, Joseph L. Wooden

All Faculty Scholarship for the College of the Sciences

Amphibolite-facies Proterozoic metasedimentary rocks below the low-angle Cenozoic Boundary Canyon Detachment record deep crustal processes related to Mesozoic crustal thickening and subsequent extension. A 91.5 ± 1.4 Ma Th-Pb SHRIMP-RG (sensitive high-resolution ion microprobe–reverse geometry) monazite age from garnet-kyanite-staurolite schist constrains the age of prograde metamorphism in the lower plate. Between the Boundary Canyon Detachment and the structurally deeper, subparallel Monarch Spring fault, prograde metamorphic fabrics are overprinted by a pervasive greenschist-facies retrogression, high-strain subhorizontal mylonitic foliation, and a prominent WNW-ESE stretching lineation parallel to corrugations on the Boundary Canyon Detachment. Granitic pegmatite dikes are deformed, rotated into parallelism, and …

Seismic Constraints On Slow Slip Events Within The Cascadia Subduction Zone, Ana Cristina Aguiar

All Master's Theses

Reanalysis of geodetic GPS time series from the Cascadia subduction zone have revealed at least 30 resolvable slow slip events along the megathrust, ranging from northern California to southern British Columbia, since 1997. Many of the smaller and more recent events are barely resolvable with GPS, but stand out clearly as tremor sequences. Since tremor bursts lasting less than 10-seconds are often visible across multiple stations, they offer the highest resolution for studying moment release through time. To test the hypothesis that tremor and transient deformation are two manifestations of the same faulting process, and to quantify the relative contribution …

Late Holocene Uplift Of The Chihshang Segment Of The Longitudinal Valley Fault At Fuli, Eastern Taiwan, Brian Thomas Gray

All Master's Theses

Uplifted Holocene strath terraces of the Bieh River drainage, eastern Taiwan, were analyzed in order to determine millennial-scale uplift and horizontal shortening rates of the Longitudinal Valley fault. Detrital charcoal fragments collected from three terraces within the Bieh River drainage yield ages between 1395 and 555 cal. yr B.P, suggesting an average uplift rate of 11.3 ± 3.6 mm yr^-1 for the last 1400 cal. yr B.P. The average horizontal shortening rate of 19.7 ± 9.5 mm yr^-1 was within error of present-day conventional geodetic measurements, but near the lower limit of the geodetic measurements. This suggests that …

Geostatistical And Stochastic Study Of Radionuclide Transport In The Unsaturated Zone At Yucca Mountain, Feng Pan, Ming Ye, Jianting Zhu

Publications (YM)

Motivation: Why Study of Unsaturated Zone? The unsaturated zone (UZ), where the proposed repository would be located, acts as a critical natural barrier by delaying the arrival of radionuclides at the saturated zone and by reducing radionuclide concentrations in groundwater through dispersion and dilution Quantitative prediction of radionuclide transport in the unsaturated zone becomes critical for performance assessment and design of the proposed repository of the Yucca Mountain Project