Tectonics and Structure Commons^™

Characterization Of Carbonaceous Fault Rocks, Pioneer Fault Zone, South-Central Idaho, Genna Baldassarre

All Graduate Reports and Creative Projects, Fall 2023 to Present

Differing crystallinities of carbonaceous material are common in fault rocks across a range of geologic settings and spatial scales and may provide constraints on strain rate, the nature of fault slip, fluid-rock interactions, and temperature variations over the earthquake cycle. The Pioneer fault at Little Fall Creek in south-central Idaho provides an excellent opportunity to study nanostructure changes of carbonaceous matter as a function of fault deformation. At this location, the Pioneer Fault exhibits a well-defined principal slip zone (PSZ) composed of multi-layered white siliceous mineralization and black carbon to graphite with a continuously exposed adjacent damage zone that includes …

Digital Appendix Of Masters Thesis "Constraining Deformation Mechanisms Of Damage Zones: A Case Study Of The Shallow San Andreas Fault At Elizabeth Lake, Southern California, James P. Evans, Caroline Studnicky

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We performed macroscopic, optical petrographic, scanning electron microscopy, and geochemical analyses on rock core acquired across the San Andreas Fault at Elizabeth Lake, California, in order to understand the distribution and accommodation of fault-related slip and energy within the shallow damage zone of this continental scale strike-slip fault. We characterized the deformation structures, alteration textures, and elemental variabilities to constrain the properties of the uppermost ~2 km fault-related damage zone at this site. We identified evidence for coseismic slip in the form of pulverized rocks, injection veins, clay-clast aggregates, and pseudotachylyte, and aseismic slip through calcite twins, dilatant vein fills, …

The Dynamic Relationship Between The Bear River, Quaternary Basaltic Center, Normal Faults, And The Resulting Rearrangement Of Rivers In The Northeast Edge Of The Great Basin, Southeast Idaho, Brady Utley

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The objective of this research project in Gem Valley graben, southeast Idaho is to identify the location, age and history of the Quaternary diversion of the Bear River into paleo-Lake Thatcher, and then into the Lake Bonneville basin from the Columbia River basin. Mapping, geochemical analysis, cross-cutting relationships, and five new age determinations, together with prior published research, shed new light on the complex history of interaction between the volcanic rocks, rivers, lakes, and faults in Gem Valley. Research goals were to test the hypothesis that local faulting and volcanism drove the diversion of the Bear River and controlled the …

New Insights Into The Outlet Conditions Of Late Pleistocene Lake Bonneville, Southeastern Idaho, Usa, Susanne U. Janecke, Robert Q. Oaks Jr.

Susanne U. Janecke

Geologic, geomorphic, and geophysical analyses of landforms, sediments, and structures in northern Cache Valley, USA, document a revised history of flooding and recession of Lake Bonneville, the world's premier pluvial lake. Crosscutting relationships suggest that the Riverdale fault produced a surface-rupturing earthquake ∼25 km southeast of Zenda shortly before, during, or after the Bonneville flood, as well as possible younger surface ruptures. Thus fluctuating stresses and pore pressure induced by changing lake levels may have triggered a large earthquake that, in turn, triggered the Bonneville flood. The flood scoured ∼25 km of Cache and Marsh Valleys and activated landslides during …

Tree Rings And Earthquakes, Matthew F. Bekker

Wasatch Dendroclimatology Research

The lithosphere, earth’s rigid outer shell comprising crust and upper mantle rock, is broken into about 14 tectonic plates (Christopherson 2009) that move a few centimeters per year over superheated, pliable rock underneath. Forces within earth’s interior push, pull and twist the plates in different directions, producing three types of plate boundaries: convergent (colliding with one another), divergent (moving away from one another) and transform (sliding past one another). Earthquakes occur when plates become locked together, building strain between and within them that is suddenly released, sending a burst of seismic waves that cause shaking and displacement of the surface. …

Arkosic Rocks From The San Andreas Fault Observatory At Depth (Safod)Borehole, Central California, S. D. Springer, J. P. Evans, J. I. Garver, D. Kirschner, Susanne U. Janecke

Susanne U. Janecke

http://lithosphere.geoscienceworld.org/content/1/4/206 The San Andreas Fault Observatory at Depth (SAFOD) drill hole encountered indurated, high-seismic-velocity arkosic sedimentary rocks west of the active trace of the San Andreas fault in central California. The arkosic rocks are juxtaposed against granitic rocks of the Salinian block to the southwest and against fine-grained Great Valley Group and Jurassic Franciscan rocks to the northeast. We identify three distinct lithologic units using cuttings, core petrography, electrical resistivity image logs, zircon fission-track analyses, and borehole-based geophysical logs. The upper arkose occurs from 1920 to 2530 m measured depth (mmd) in the borehole and is composed of five structural …

Evolution Of A Late Cenozoic Supradetachment Basin Above A Flat-On-Flat Detachment With A Folded Lateral Ramp, Se Idaho, A. N. Steely, Susanne U. Janecke, S. P. Long, S. C. Carney, R. Q. Oaks Jr., V. E. Langenheim, P. K. Link

Susanne U. Janecke

Uplift and exposure of the Bannock detachment system and the synextensionalbasin fi ll deposits of the Salt Lake Formation provide a unique exposure of the threedimensionalgeometries of a low-angle normal fault system and the stratal architectureof the overlying supradetachment basin. Within this system, structural andstratigraphic analyses, outcrop patterns, tephra geochronology, and geological crosssections document several important relationships: (1) the Bannock detachment systemdeveloped above the Sevier-age Cache-Pocatello culmination and resembles theSevier Desert detachment in its geometry, structural setting, and kinematic evolution;(2) the Bannock detachment system initiated and slipped at low angles; (3) fl aton-fl at, ramp-fl at, and lateral ramp geometries, …

Late Miocene-Pliocene Detachment Faulting And Pliocene-Pleistocene Basin-And-Range Extension Inferred From Dismemberedrift Basins Of The Salt Lake Formation, Susanne U. Janecke, S. M. Carney, M. E. Perkins, J. C. Evans, P. K. Link, R. Q. Oaks Jr., B. P. Nash

Susanne U. Janecke

No abstract provided.

Extensional Folds Associated With Paleogene Detachment Faults In Se Part Of The Salmon Basin, Susanne U. Janecke, J. C. Blankenau

Susanne U. Janecke

No abstract provided.

Stratigraphy And Tectonics Of Tertiary Strata Of Southern Cache Valley, R. Q. Oaks Jr., K. A. Smith, Susanne U. Janecke, M. E. Perkins, W. P. Nash

Susanne U. Janecke

No abstract provided.

Geometry,Mechanisms, And Significance Of Extensional Folds From Examples In The Rockymountain Basin And Range Province, Susanne U. Janecke, C. J. Vandenburg, J. J. Blankenau

Susanne U. Janecke

No abstract provided.

Central Utah Regional Seismotectonic Study, U.S. Deparment Of The Interior, Bureau Of Reclamation

Elusive Documents

This report presents the results of a Bureau of Reclamation seismotectonic

evaluation for dams in the Wasatch Mountains in north-central Utah. The

major objectives of this study were to identify potential earthquake sources

in the region and to estimate MCEs (maximum credible earthquakes) for these

sources. The conclusions presented in this report are based on geologic

mapping, trenching, study of aerial photography, mapping and correlation of

Quaternary deposits, soil profile descriptions and sampling, and analysis of

historic seismicity. The Regional Study area includes an area on the eastern

margin of the Basin and Range province that extends east from the …

Chemical Trends In The Ice Springs Basalt, Black Rock Desert, Utah, W. C. Lynch, W. P. Nash

All U.S. Government Documents (Utah Regional Depository)

The Holocene Ice Springs volcanic field of west-central Utah consists of 0.53 km3 of tholeitic basalts erupted as a sequence of nested cinder cones and associated lava flows. Whole rock x-ray fluorescence and atomic absorption analysis of ninety-six samples of known relative age document statistically significant inter- and intra- eruption chemical variations. Elemental trends include increases in Ti, Fe, Ca, P, and Sr and decreases in Si, K, Rb, Ni, Cr, and Zr with decreasing age. Microprobe analyses of microphenocrysts of olivine, plagioclase, and Fe-Ti oxides and of groundmass olivine, plagioclase, and clinopyroxene indicate limited chemical variation between mineral assemblages …

Study Of Earthquake Recurrence Intervals On The Wasatch Fault, Utah: Little Cottonwood Canyon Site, F. H. Swan, Iii, Kathryn L. Hanson, David P. Schwartz, Peter L. Knuepfer, U.S. Geological Survey

All U.S. Government Documents (Utah Regional Depository)

Detailed geologic mapping, topographic profiling, and trenching are being conducted at selected sites along the Wasatch fault zone to measure the cumulative fault displacements in Quaternary strata of various ages and to obtain data regarding the amount of displacement per surface faulting event and the number and recurrence of faulting events that produced the cumulative displacement. These data are used to estimate the frequency of occurrence and magnitude of earthquakes associated with surface faulting along individual segments of the Wasatch fault zone. Investigations have been completed at three sites, the Kaysville, Hobble Creek, and Little Cottonwood Canyon sites. The results …