scholarly journals Spatiotemporal history of fluid-fault interaction in the Hurricane fault zone, western USA

2020 ◽  
Author(s):  
Jace M. Koger ◽  
Dennis L. Newell
Keyword(s):  
Damage Zone ◽  
Carbon Sources ◽  
Normal Fault ◽  
Fault Interaction ◽  
Calcite Vein ◽  
Regional Flow ◽  
Fault Strength ◽  
Primary Fluid ◽  
History Of ◽  
Fault Damage Zone

Abstract. The Hurricane Fault is a ~250-km-long, west-dipping normal fault located along the transition between the Colorado Plateau and Basin and Range tectonic provinces in the western U.S. Extensive evidence of fluid-fault interaction, including calcite mineralization and veining, occur in the footwall damage zone. Calcite vein carbon (δ13CVPDB) and oxygen (δ18OVPDB) stable isotope ratios range from −4.5 to 3.8 ‰ and −22.1 to −1.1 ‰, respectively. Fluid inclusion microthermometry constrain paleofluid temperatures and salinities from 45–160 °C and 1.4–11.0 wt % as NaCl, respectively. These data identify mixing between two primary fluid sources including infiltrating meteoric groundwater (70 ± 10 °C, ~1.5 wt % NaCl, δ18OSMOW ~−10 ‰) and sedimentary brine (100 ± 25 °C, ~11 wt % NaCl, δ18OSMOW ~5 ‰). Interpreted carbon sources include crustal- or magmatic-derived CO2, carbonate bedrock, and hydrocarbons. U-Th dates from 5 calcite vein samples indicates punctuated fluid-flow and fracture healing at 539 ± 10.8, 287.9 ± 5.8, 86.2 ± 1.7, and 86.0 ± 0.2 ka in the upper 300 m of the crust. Collectively, the data imply that the Hurricane Fault imparts a strong influence on regional flow of crustal fluids, and that the formation of veins in the shallow parts of the fault damage zone has important implications for the evolution of fault strength and permeability.

scholarly journals Spatiotemporal history of fault–fluid interaction in the Hurricane fault, western USA

Solid Earth ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 1969-1985
Author(s):  
Jace M. Koger ◽  
Dennis L. Newell
Keyword(s):  
Damage Zone ◽  
Carbon Sources ◽  
Normal Fault ◽  
Western Usa ◽  
Calcite Vein ◽  
Regional Flow ◽  
Fault Strength ◽  
History Of ◽  
Fault Damage Zone ◽  
Fluid Interaction

Abstract. The Hurricane fault is a ∼250 km long, west-dipping, segmented normal fault zone located along the transition between the Colorado Plateau and the Basin and Range tectonic provinces in the western USA. Extensive evidence of fault–fluid interaction includes calcite mineralization and veining. Calcite vein carbon (δ13CVPDB) and oxygen (δ18OVPDB) stable isotope ratios range from −4.5 ‰ to 3.8 ‰ and from −22.1 ‰ to −1.1 ‰, respectively. Fluid inclusion microthermometry constrains paleofluid temperatures and salinities from 45 to 160 ∘C and from 1.4 wt % to 11.0 wt % as NaCl, respectively. These data suggest mixing between two primary fluid sources, including infiltrating meteoric water (70±10 ∘C, ∼1.5 wt % NaCl, δ18OVSMOW ∼-10 ‰) and sedimentary brine (100±25 ∘C, ∼11 wt % NaCl, δ18OVSMOW ∼ 5 ‰). Interpreted carbon sources include crustal- or magmatic-derived CO2, carbonate bedrock, and hydrocarbons. Uranium–thorium (U–Th) dates from five calcite vein samples indicate punctuated fluid flow and fracture healing at 539±10.8 (1σ), 287.9±5.8, 86.2±1.7, and 86.0±0.2 ka in the upper 500 m of the crust. Collectively, data predominantly from the footwall damage zone imply that the Hurricane fault imparts a strong influence on the regional flow of crustal fluids and that the formation of veins in the shallow parts of the fault damage zone has important implications for the evolution of fault strength and permeability.

scholarly journals Episodic fluid flow in an active fault

Geology ◽  
2019 ◽  
Vol 47 (10) ◽  
pp. 938-942 ◽  
Author(s):  
Sarah Louis ◽  
Elco Luijendijk ◽  
István Dunkl ◽  
Mark Person
Keyword(s):  
Fluid Flow ◽  
Numerical Models ◽  
Damage Zone ◽  
Normal Fault ◽  
Geothermal Gradient ◽  
Hydrothermal Activity ◽  
The Past ◽  
Discharge Rates ◽  
Fault Damage Zone ◽  
Wide Zone

Abstract We present a reconstruction of episodic fluid flow over the past ∼250 k.y. along the Malpais normal fault, which hosts the Beowawe hydrothermal system (Nevada, USA), using a novel combination of the apatite (U-Th)/He (AHe) thermochronometer and a model of the thermal effects of fluid flow. Samples show partial resetting of the AHe thermochronometer in a 40-m-wide zone around the fault. Numerical models using current fluid temperatures and discharge rates indicate that fluid flow events lasting 2 k.y. or more lead to fully reset samples. Episodic fluid pulses lasting 1 k.y. result in partially reset samples, with 30–40 individual fluid pulses required to match the data. Episodic fluid flow is also supported by an overturned geothermal gradient in a borehole that crosses the fault, and by breaks in stable isotope trends in hydrothermal sinter deposits that coincide with two independently dated earthquakes in the past 20 k.y. This suggests a system where fluid flow is triggered by repeated seismic activity, and that seals itself over ∼1 k.y. due to the formation of clays and silicates in the fault damage zone. Hydrothermal activity is younger than the 6–10 Ma age of the fault, which means that deep (∼5 km) fluid flow was initiated only after a large part of the 230 m of fault offset had taken place.

scholarly journals Nonlinear fault damage zone scaling revealed through analog modeling

Geology ◽  
2021 ◽  
Author(s):  
Sylvain Mayolle ◽  
Roger Soliva ◽  
Stéphane Dominguez ◽  
Christopher Wibberley ◽  
Yannick Caniven
Keyword(s):  
Failure Modes ◽  
Damage Zone ◽  
Normal Fault ◽  
Fault Segment ◽  
Mechanical Unit ◽  
Analog Modeling ◽  
Fault Damage Zone ◽  
Fault Growth ◽  
Fault Displacement ◽  
Zone Growth

Fault damage zones strongly influence fluid flow and seismogenic behavior of faults and are thought to scale linearly with fault displacement until reaching a threshold thickness. Using analog modeling with different frictional layer thicknesses, we investigate damage zone dynamic evolution during normal fault growth. We show that experimental damage zone growth with displacement is not linear but progressively tends toward a threshold thickness, being larger in the thicker models. This threshold thickness increases significantly at fault segment relay zones. As the thickness threshold is approached, the failure mode progressively transitions from dilational shear to isochoric shear. This process affects the whole layer thickness and develops as a consequence of fault segment linkage as inferred in nature when the fault matures. These findings suggest that fault damage zone widths are limited both by different scales of mechanical unit thickness and the evolution of failure modes, ultimately controlled in nature by lithology and deformation conditions.

Microfractures within the fault damage zone record the history of fault activity

2013 ◽  
Vol 40 (10) ◽  
pp. 2023-2027 ◽  
Author(s):  
Kazuo Mizoguchi ◽  
Keiichi Ueta
Keyword(s):  
Damage Zone ◽  
Fault Activity ◽  
History Of ◽  
Fault Damage Zone

Integrated estimates of the thickness of the fault damage zone in granitic terrain based on penetrative mesocracks and XRD analyses of quartz

2012 ◽  
Vol 35 ◽  
pp. 64-77 ◽  
Author(s):  
Hideo Takagi ◽  
Kazuhiro Takahashi ◽  
Koji Shimada ◽  
Kosuke Tsutsui ◽  
Reiko Miura ◽  
...  
Keyword(s):  
Damage Zone ◽  
Granitic Terrain ◽  
Fault Damage Zone

scholarly journals QUANTITATIVE ANALYSIS OF DEFORMATION ALONG THE FAULT DAMAGE ZONE OF THE KLIMATIA THRUST (NW GREECE, IONIAN ZONE)

2001 ◽  
Vol 34 (4) ◽  
pp. 1643
Author(s):  
A. Kostakioti ◽  
P. Xypolias ◽  
S. Kokkalas ◽  
T. Doutsos
Keyword(s):  
Hanging Wall ◽  
Damage Zone ◽  
Deformation Pattern ◽  
Fracture System ◽  
Fracture Density ◽  
Fracture Orientation ◽  
Transport Direction ◽  
Structural Fracture ◽  
Fault Damage Zone ◽  
Northwestern Greece

In this study, we present structural, fracture orientation and fracture density (FD) data in order toquantify the deformation pattern of a damage zone that form around the slip plane of a large scalethrust fault which is located on the Ionian zone (External Hellenides) in northwestern Greece. Structuralanalysis showed at least two major deformation stages as indicated by the presence of refolding,backthrusting and break-back faulting. The fracture orientation analysis revealed three mainfracture systems, a dominant conjugate fracture system which is perpendicular to the transport direction(NW-to NNW trending sets), a conjugate fracture system trending parallel to the transport direction(ENE-trending conjugate sets) and a third diagonal conjugate fracture system (WNW andNNE trending sets). Resulting fracture density-distance diagrams display a decrease of total fracturedensity away from the studied fault, which is largely heterogeneous and irregular on both footwalland hanging wall. The conjugate fracture system trending perpendicular to the transport directionhas the dominant contribution to the accumulation of total fracture density. Based on theseresults we suggest that the observed heterogeneous and irregular distribution of fracture densityfashioned during the second deformation stage and is attributed to the formation of backthrusts andbreak-back thrust faults.

scholarly journals New constraints on the exhumation history of the western Tauern Window (European Alps) from thermochronology, thermokinematic modeling, and topographic analysis

2021 ◽  
Author(s):  
Reinhard Wolff ◽  
Ralf Hetzel ◽  
István Dunkl ◽  
Aneta A. Anczkiewicz
Keyword(s):  
Hanging Wall ◽  
Thermal Relaxation ◽  
Slip Rate ◽  
Normal Fault ◽  
European Alps ◽  
Valley Bottom ◽  
Topographic Analysis ◽  
Tauern Window ◽  
History Of ◽  
Exhumation History

AbstractThe Brenner normal fault bounds the Tauern Window to the west and accommodated a significant portion of the orogen-parallel extension in the Eastern Alps. Here, we use zircon (U–Th)/He, apatite fission track, and apatite (U–Th)/He dating, thermokinematic modeling, and a topographic analysis to constrain the exhumation history of the western Tauern Window in the footwall of the Brenner fault. ZHe ages from an E–W profile (parallel to the slip direction of the fault) decrease westwards from ~ 11 to ~ 8 Ma and suggest a fault-slip rate of 3.9 ± 0.9 km/Myr, whereas AFT and AHe ages show no spatial trends. ZHe and AFT ages from an elevation profile indicate apparent exhumation rates of 1.1 ± 0.7 and 1.0 ± 1.3 km/Myr, respectively, whereas the AHe ages are again spatially invariant. Most of the thermochronological ages are well predicted by a thermokinematic model with a normal fault that slips at a rate of 4.2 km/Myr between ~ 19 and ~ 9 Ma and produces 35 ± 10 km of extension. The modeling reveals that the spatially invariant AHe ages are caused by heat advection due to faulting and posttectonic thermal relaxation. The enigmatic increase of K–Ar phengite and biotite ages towards the Brenner fault is caused by heat conduction from the hot footwall to the cooler hanging wall. Topographic profiles across an N–S valley in the fault footwall indicate 1000 ± 300 m of erosion after faulting ceased, which agrees with the results of our thermokinematic model. Valley incision explains why the Brenner fault is located on the western valley shoulder and not at the valley bottom. We conclude that the ability of thermokinematic models to quantify heat transfer by rock advection and conduction is crucial for interpreting cooling ages from extensional fault systems.

Use of products of straw decomposition by N2-fixing (C2H2-reducing) populations of bacteria in three soils from wheat-growing areas

1986 ◽  
Vol 37 (1) ◽  
pp. 1 ◽  
Author(s):  
MM Roper ◽  
DM Halsall
Keyword(s):  
Nitrogenase Activity ◽  
New South ◽  
Carbon Sources ◽  
Clay Content ◽  
Free Living ◽  
Straw Decomposition ◽  
South Wales ◽  
History Of ◽  
Straw Incorporation ◽  
The Difference

The potential for N2 fixation by free-living bacteria using straw as a source of energy was evaluated in three soils (one from Gunnedah and two from Cowra) representative of the wheat belt in New South Wales. All three soils had a history of straw incorporation. The abilities of the respective microbial populations to use a range of carbon sources, including potential products of decomposition of straw, was determined and compared with the size and composition of each population. Neutral to alkaline (pH 7.4) soil of high (51%) clay content from Gunnedah produced higher rates of nitrogenase activity with straw than more acid (pH 5.6) lower (17%) clay containing soil from Cowra (site B). Gunnedah soil also contained a larger population of N2-fixing bacteria which used a broader range of energy sources than soil from either Cowra site B or Cowra site W (pH 5.8, clay content 34%). There was little difference in the composition of the N2-fixing populations in each of the soils except that Azotobacter spp. were absent from the acid Cowra soils. It was concluded that the difference in behaviour of the respective N2-fixing populations was primarily due to the physical characteristics of the soil affecting the numbers and activities of diazotrophic microorganisms. In addition some soil environments failed to support specific organisms.

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