scholarly journals Neocrystallization of clay minerals in the Alhama de Murcia Fault (southeast Spain): implications for fault mechanics

Clay Minerals ◽  
2019 ◽  
Vol 54 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Isabel Abad ◽  
Juan Jiménez-Millán ◽  
Catalina Sánchez-Roa ◽  
Fernando Nieto ◽  
Nicolás Velilla
Keyword(s):  
Clay Minerals ◽  
Fault Plane ◽  
Fault Mechanics ◽  
Fault Rocks ◽  
Rock Interaction ◽  
Frictional Strength ◽  
Ultrafine Grained ◽  
The Stability ◽  
Late Growth ◽  
Southeast Spain

AbstractTwo preferred textures were observed in the Alhama de Murcia Fault rocks: (a) foliated bands (>100 µm thick) rich in well-crystallized dioctahedral micas, quartz, hematite and dolomite; and (b) ultrafine-grained bands (<100 µm thick) made of patches composed of small mica crystals (<15 µm) and dispersed Fe-oxides. In both textures, kaolinite forms intergrowths or patches of randomly oriented crystals filling gaps or opening layers of presumably inherited detrital mica crystals, which is interpreted as an epitaxial growth from fluids. The Na/K ratio of mica crystals in the thin ultrafine-grained bands shows a wider range than the micas from the foliated bands including muscovitic, intermediate Na/K and paragonitic compositions. The absence of the 0.98 nm intermediate peak in the diffractograms indicates that the small micas are submicroscopically paragonite and phengite intergrowths. The d001 values of the K-dioctahedral micas in the <2 µm and whole fractions are clearly different from each other. The d001 values of micas of the <2 µm fraction are larger, indicating a higher K and lower Na content in the small micas. Their composition corresponds to lower temperatures, suggesting their growth during a genetic episode in the fault. The textural relationships indicate a late growth of kaolinite, probably due to the fluid–rock interaction along fault planes and fractures. The neoformed clay minerals might alter the stability of the fault plane. The absence of expandable clay minerals and the relatively high frictional strength of kaolinite under wet conditions might explain the observed velocity-neutral behaviour of this gouge and earthquake propagation towards the surface.

The role of fluid chemistry on permeability and fault strength evolution in granite

2020 ◽  
Author(s):  
Catalina Sanchez ◽  
Giuseppe Saldi ◽  
Tom Mitchell ◽  
Francesco lacoviello ◽  
Philip Meredith ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Fault Plane ◽  
Mineral Dissolution ◽  
New Mineral ◽  
Geothermal Systems ◽  
Rock Interaction ◽  
Frictional Properties ◽  
Mineral Phases ◽  
Reservoir Permeability

&lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;div&gt; &lt;p&gt;Efforts to maintain and enhance reservoir permeability in geothermal systems can contribute to lowering CO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;emissions and sourcing more sustainable energy. The evolution of permeability in geothermal&amp;#160;reservoirs is strongly affected by interactions between the host rock and the fluids flowing through the rock&amp;#8217;s permeable pathways. Mineral dissolution, which results from fluid-rock chemical reactions within the fracture network, can significantly enhance&amp;#160;reservoir permeability, whereas the precipitation of secondary mineral phases, that are also the products of fluid-rock reactions, can significantly reduce the permeability of the system. The interplay between these two important processes dictates the long-term productivity&amp;#160;and lifetime of the reservoir. In the study reported here, we have attempted to simulate the conditions within a geothermal reservoir from initially induced fracturing to the final precipitation or &amp;#8220;clogging&amp;#8221; phase. We have performed, sequentially,&amp;#160;batch,&amp;#160;flow-through&amp;#160;and&amp;#160;circulating&amp;#160;flow&amp;#160;experiments on cores of the Carnmenellis granite, the target unit of geothermal projects in Cornwall (UK), to understand the role of mineral dissolution and precipitation in controlling the permeability of the system. The physico-chemical properties&amp;#160;of the cores are monitored after each reaction-phase using ICP-OES, SEM, hydrostatic permeability measurements, and X-ray Computed Tomography.&lt;/p&gt; &lt;p&gt;Our results show that the evolution of the permeability is strongly dependant on the chemistry of the permeating fluid. We&amp;#160;find that&amp;#160;undersaturated&amp;#160;fluids (pH&lt;sup&gt;&amp;#160;&lt;/sup&gt;10-10.5)&amp;#160;dissolve the most abundant mineral phases in the granite (quartz and feldspars), thus creating micro-cavities along the main fracture traces that lead to enhanced but essentially pressure-independent&amp;#160;permeability.&amp;#160;These results&amp;#160;suggest that the creation of chemical dissolution in the early stages of geothermal operations could generate permeable pathways that are less sensitive to effective stress and will likely remain open at higher pressures. Similarly, maintaining the circulation&amp;#160;of undersaturated and relatively high-pH fluids (pH&lt;sup&gt;&amp;#160;&lt;/sup&gt;10-10.5)&amp;#160;through these granitic reservoirs could prevent the precipitation of clogging mineral phases and preserve reservoir permeability in granite-hosted geothermal systems.&lt;/p&gt; &lt;p&gt;By contrast, we find that&amp;#160;supersaturated&amp;#160;fluids (pH&lt;sup&gt;&amp;#160;&lt;/sup&gt;9-9.5), evolving from extended periods of fluid-rock interaction, promote the precipitation of clay minerals that leads to decreased permeability within the system. In natural systems, such as fault zones, the precipitation of clay minerals on the fault plane can also severely affect the frictional properties of the fault and therefore it's slip mode (seismic or asesismic). Triaxial friction experiments on a direct shear configuration were run on samples extracted from well UD-2, part of the United Downs geothermal drilling campaign. The frictional strength of the drilling cuttings from depths around 2370 (at the intersection with the Porthowan&amp;#8217;s fault plane ) show variations from 0.3 to 0.1, while friction results from unaltered granite show a friction coefficient of 0.6. These results suggest that the frictional properties of the Porthowan fault have been modified, due to the precipitation of new mineral phases.&lt;/p&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt; &lt;/div&gt;

Radiometric Dating of Ochoan (Permian) Evaporites, Wipp Site, Delaware Basin, New Mexico, Usa

1986 ◽  
Vol 84 ◽  
Author(s):  
Douglas G. Brookins ◽  
Steven J. Lambert
Keyword(s):  
New Mexico ◽  
Clay Minerals ◽  
Early Stage ◽  
Local Area ◽  
Radiometric Dating ◽  
Delaware Basin ◽  
Geochemical Study ◽  
Sulfate Salts ◽  
The Stability ◽  
Evaporite Minerals

AbstractWe have attempted radiometric dating of halide-sulfate salts and clay minerals from the Delaware Basin, New Mexico, USA, as part of geochemical study of the stability of the evaporite sequence at the WIPP (Waste Isolation Pilot Plant--a US DOE facility) site. We undertook this dating to determine: (1) primary age of evaporite genesis or time(s) of recrystallization, (2) if previously undated evaporite minerals (leonite, polyhalite, kieserite) give useful data, and (3) if the detrital clay minerals have been radiometrically reset at any time following their incorporation into the evaporite medium. We have shown earlier that polyhalites can indeed be successfully dated by the K-Ar method, and once corrections are applied for admixed halide minerals, dates of 210-230 Ma for the Delaware Basin are obtained. Rb-Sr isochrons from early stage sylvites-polyhalites- anhydrites yield 220 ± 10 Ma, even when some sylvites yield lower K-Ar dates due to l1s of 40Ar*. K-Ar dates on leonites and kieserites are also low due to 40Ar* loss, but their Rb-Sr dates are higher. Detrital clay minerals from the Delaware Basin collectively yield a highly scattered isochron (390 ± 77 Ma), but samples from a local area, such as the WIPP Site, give a much better age of 428 ± 7 Ma. These dates show that the interaction between the clay minerals and the evaporitic brines was insufficient to reset the clay minerals Rb-Sr systematics. In a related study, we note that a dike emplaced into the evaporite at 34 Ma had only very limited effect on the intruded rocks; contact phenomena were all within 2 m of the dike. All of our geochemical (radio-metric and trace element) studies of the WIPP site argue for preservation of the isotopic and chemical integrity of the major minerals for the past 200 Ma.

scholarly journals Shear Strength of Compacted Clays as Affected by Mineral Content and Wet-Dry Cycles

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Frederick Nai Charkley ◽  
Kunyong Zhang ◽  
Guoxiong Mei
Keyword(s):  
Shear Strength ◽  
Clay Minerals ◽  
Mineral Content ◽  
Strength Properties ◽  
High Plasticity ◽  
Wetting And Drying ◽  
Frictional Strength ◽  
Precautionary Measures ◽  
Weather Changes ◽  
Clay Slopes

The behaviors of high-plasticity clays depend largely on the clay mineral content. Recently, it has been observed that sudden slope failures of most clay slopes occur in regions pronounced with repeated rainfall and sunny climate. The reason for this is still unclear. Examining the effect of clay minerals and drastic weather changes on shear strength will be useful in predicting the performance of structures built in such soils and to take precautionary measures to improve the properties before failure. Therefore, a series of quick direct shearing tests were conducted on 11 artificial clay mixtures. The cohesion and frictional strength properties were determined and linked to the proportion of clay minerals and the number of wetting and drying cycles. The results show a significant reduction in shear strength after exposure to wetting and drying. Generally, montmorillonite-dominated mixtures were less susceptible to the changes in cohesion strength than kaolin-dominated mixtures, and the reduction in frictional strength was relatively insignificant.

Study on the Mechanism of Water-Rock Interaction of the Black Rock Strata

2011 ◽  
Vol 243-249 ◽  
pp. 3319-3324
Author(s):  
Xin Liao ◽  
Xi Yong Wu ◽  
Jiang Tao Duan
Keyword(s):  
Immersion Test ◽  
Ecological Environment ◽  
Acidic Water ◽  
Engineering Project ◽  
Rock Interaction ◽  
Geological Characteristics ◽  
The Stability ◽  
Short Time ◽  
Rock Strata ◽  
Water Rock Interaction

Black rock strata with special engineering geological characteristics are distributed widely in different geological periods and areas. The scattered sulfide minerals in the rock strata are changed in a short time under the action of the oxygen-rich surface water and oxygen-rich groundwater. And the acidic water with strong erosiveness is formed. Then water--rock interaction between other minerals and the acidic water subsequently occurs with a series of chemical reactions. It can affect the stability of the black rocks themselves and other non-black rocks nearby directly, and cause engineering and environmental geological problems. Through the combination of engineering project and immersion test indoor, the mechanism of water-rock interaction of the black rock strata is researched. Engineering preventions and measures in the black strata region are proposed to avoid the damage to project and the ecological environment around.

scholarly journals Mitigation of Torsional Vibrations in Drilling Systems using Adaptive Nonlinear Control System

2020 ◽  
Vol 9 (4) ◽  
pp. 3317-3321
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
String Model ◽  
Stick Slip ◽  
Rock Interaction ◽  
Performance Specifications ◽  
Level Model ◽  
Multi Level ◽  
The Stability ◽  
Level Training

The reason for this work is to plan a robust yield feedback control way to deal with dispense with torque stick-slip vibrations in boring frameworks. Current industry controllers generally neglect to dispose of stick-slip vibrations, particularly when different torque flex modes assume a job in maniacal assault. In terms of build controller production, a real trainingstring system performs a multi-level model work such as torque mechanics. The proposed controller design is artfully distorted at optimizing the stability with respect to the uncertainty of the nonlinear bit-rock interaction. Based on heroes and intentions. Besides, a closed loop strength examination of the nonlinear preparing string model is displayed. This controller structure system offers a few points of interest contrasted with existing controllers. To begin with, just surface estimations are utilized, barring the requirement for entire estimations underneath it. Second, multi-level training-string dynamics are effectively handled in ways to access state-training controllers. Third, stability is explicitly provided with respect to bit-rock contact uncertainty and closed-loop performance specifications include controller design. The results of the study report confirm that stick-slip vibrations are actually eliminated in realistic drilling scenarios using a controller designed to achieve this state-ofcontrol control.

scholarly journals A contribution to the study of the stability of clay minerals from the soil solution composition at different pF values

Clay Minerals ◽  
1979 ◽  
Vol 14 (1) ◽  
pp. 29-37 ◽  
Author(s):  
M. L. Fernandez-Marcos ◽  
F. Macías ◽  
F. Guitián-Ojea
Keyword(s):  
Pore Size ◽  
Clay Minerals ◽  
Soil Solution ◽  
Parent Material ◽  
Solution Composition ◽  
Weathering Processes ◽  
Stability Diagrams ◽  
Silica Concentration ◽  
The Stability ◽  
Insight Into

AbstractThe composition of the soil solution of various horizons of Galician soils was studied to gain insight into the direction of the processes of weathering and neoformation by means of stability diagrams of the clay minerals. The soil solution was extracted by compression at various pF values.The most significant results are as follows. In all the cases studied the mineral in equilibrium with the soil solution is a 1:1 philosilicate. As the pF at which the soil solution is extracted increases, corresponding to smaller pore size, pH increases and silica concentration falls. The stable mineral does not vary significantly between different horizons of the same profile. Each parent material gives rise to a different zonation in the stability diagrams. The predictions of the stability diagrams are in general agreement with the mineralogical data of the clays of the horizons in question.Finally, weathering processes in Galicia are briefly commented on.

Improving the Co-seismic Slip Distributions of Synthetic Catalogs With Real Observations

2020 ◽  
Author(s):  
Hafize Başak Bayraktar ◽  
Antonio Scala ◽  
Gaetano Festa ◽  
Stefano Lorito
Keyword(s):  
Subduction Zones ◽  
Fault Plane ◽  
Active Regions ◽  
Fault Mechanics ◽  
Rupture Velocity ◽  
Seismic Slip ◽  
Tsunami Earthquakes ◽  
Seismic Cycles ◽  
Model Features ◽  
Shallow Part

&lt;p&gt;Subduction zones are the most seismically active regions on the globe and about 90% of historical events, including the largest ones with the magnitude M&gt;9, occurred along these regions (Hayes et al., 2018). Most of these events were followed by devastating tsunamis with, in some cases, perhaps unexpected wave height distributions. Observation of events in the megathrust environment reveals that some earthquakes are characterized by slip concentration on the very shallow part of the subduction zone. This shallow slip phenomenon was repeatedly observed in the last two decades for both ordinary megathrust events (e.g. 2010 Maule and 2011 Tohoku) and tsunami earthquakes (2006 Java and 2010 Mentawai). Shallow ruptures feature depleted short&amp;#8211;period energy release and very slow rupture velocity possibly due to the presence of (hydrated) sediments (Lay et al., 2011; Lay 2014; Polet and Kanamori, 2000). Associated long rupture durations have been explained with fault mechanics-related rigidity and stress drop variation with depth (Bilek and Lay, 1999) or, more recently, with lower rigidity of surrounding materials (Sallares and Ranero, 2019).&lt;/p&gt;&lt;p&gt;The characteristics of co-seismic slip distribution have an important impact on tsunami hazard. There are numerous methods that have been proposed to generate stochastic slip distributions, also including shallow slip amplification (Le Veque et al., 2016; Sepulveda et al., 2017; Scala et al., 2019). However, these models need to be calibrated against slip models estimated for real events.&lt;/p&gt;&lt;p&gt;Here, we investigate similarities and differences between the synthetic slip distributions provided by Scala et al. (2019) and a suite of 144 slip models of real events that occurred in different subduction zones (Ye et al.,2016). In particular, Scala et al. (2019) model features shallow slip amplification in single events, whose relative probabilities are balanced to restore cumulative slip homogeneity on the fault plane over multiple seismic cycles. This study also aims to improve and/or calibrate this model to account for the behavior observed from real events.&lt;/p&gt;

Hydration Layers on Clay Mineral Surfaces in Aqueous Solutions: a Review/Warstwy Uwodnione Na Powierzchni Minerałów Ilastych W Roztworach Wodnych: Przegląd

2014 ◽  
Vol 59 (2) ◽  
pp. 489-500 ◽  
Author(s):  
Fanfei Min ◽  
Chenliang Peng ◽  
Shaoxian Song
Keyword(s):  
Aqueous Solutions ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Structural Model ◽  
Mineral Surfaces ◽  
Solution Ph ◽  
Hydration Layer ◽  
Hydration Force ◽  
The Stability ◽  
Hydration Layers

Abstract Hydration layer on clay mineral surfaces is originated from the adsorption of polar water molecules and hydrated cations on the surfaces through unsaturated ionic bonds, hydrogen bonds and van der Waals bonds. It has attracted great attentions because of their important influences on the dispersive stability of the particles in aqueous solutions. This review highlighted the molecular structure of clay minerals, the origin of hydration layers on clay mineral surfaces, the hydration layer structural model, hydration force and the main parameters of affecting the hydration layers on clay minerals (crystal structure, cationic type and strength, and solution pH). Also, the research methods for hydration layers were briefly described, especially the determination of hydration layer thickness by the Einstein viscosity method and AFM method. In addition, the applications of the stability of fine clay mineral particles in aqueous suspensions were summarized.

Hydrogen effect on the stability of structural and phase state and mechanical properties of the ultrafine-grained alloy (Ti-Al-V-Mo system)

2020 ◽  
Author(s):  
O. V. Zabudchenko ◽  
G. P. Grabovetskaya ◽  
I. P. Mishin ◽  
E. N. Stepanova ◽  
A. O. Khovanova
Keyword(s):  
Mechanical Properties ◽  
Phase State ◽  
Hydrogen Effect ◽  
Ultrafine Grained ◽  
The Stability

scholarly journals Hybrid Pigments from Bixin Dye and Inorganic Matrices

2021 ◽  
Vol 6 (1) ◽  
pp. 21
Author(s):  
André F. do A. Oliveira ◽  
Pollyana Trigueiro ◽  
Dihêgo H. L. Damacena ◽  
Luzia M. C. Honorio ◽  
Josy A. Osajima ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Chemical Properties ◽  
High Specific Surface Area ◽  
Exchange Capacity ◽  
Practical Applications ◽  
Modified Clay ◽  
Pharmaceutical Industries ◽  
The Stability ◽  
The One ◽  
Main Components

Annatto dye is a natural organic dye belonging to carotenoids, whose main components are bixin and norbixin. Due to its low stability, it is convenient to protect the dye molecules with other materials. The use of clay minerals is an alternative, which are phyllosilicates with attractive physico-chemical properties, such as high specific surface area, cation exchange capacity, mechanical/chemical stability and non-toxicity. The main purpose of this work was to develop hybrid materials, using annatto dye and clay mineral modified with different inorganic cations, and then, to evaluate the stability of the new pigments. The process of preparing the modified clay minerals involved mixing a synthetic montmorillonite in solutions containing the precursor salts of the metal cations. Subsequently, the dye was dissolved in a solution containing water and alcohol, followed by filtration and mixed with the modified clay, giving rise to the hybrid pigments. Through the characterizations, it was noted that a variety of colors were obtained, and the sample containing aluminum was the one that most adsorbed the dye and showed a significant increase in stability at high temperatures. This hybrid material was better to dye than its pure form. Therefore, the bixin/montmorillonite pigments are promising for replacing artificial colors in practical applications such as in the cosmetics, food or pharmaceutical industries.

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