Crack propagation by differential insolation on desert surface clasts

Moores, John E.; Pelletier, Jon D.; Smith, Peter H.

doi:10.1016/j.geomorph.2008.05.012

Cited by 56 publications

(46 citation statements)

References 42 publications

(61 reference statements)

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“…The importance of moisture (e.g., Hall and Hall, 1996;Nicholson, 2001), salts (e.g., Amit et al, 1993), and exposure to diurnal insolation (e.g., Blackwelder, 1933;Hall, 1999;Moores et al, 2008) in fracturing rock has been debated extensively. Although individual mechanisms of physical weathering have been addressed through field studies (e.g., McFadden et al, 2005;Eppes et al, 2010), numerical modeling (e.g., Tanigawa and Takeuti, 1983;Moores et al, 2008), and experimentation (e.g., McKay et al, 2009;Molaro and McKay, 2010), no study has collected the data Published by Copernicus Publications on behalf of the European Geosciences Union.…”

Section: Introductionmentioning

confidence: 99%

Automated field detection of rock fracturing, microclimate, and diurnal rock temperature and strain fields

Warren

Eppes

Swami

et al. 2013

Geosci. Instrum. Method. Data Syst.

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Abstract. The rates and processes that lead to non-tectonic rock fracture on Earth's surface are widely debated but poorly understood. Few, if any, studies have made the direct observations of rock fracturing under natural conditions that are necessary to directly address this problem. An instrumentation design that enables concurrent high spatial and temporal monitoring resolution of (1) diurnal environmental conditions of a natural boulder and its surroundings in addition to (2) the fracturing of that boulder under natural full-sun exposure is described herein. The surface of a fluvially transported granite boulder was instrumented with (1) six acoustic emission (AE) sensors that record micro-crack associated, elastic wave-generated activity within the three-dimensional space of the boulder, (2) eight rectangular rosette foil strain gages to measure surface strain, (3) eight thermocouples to measure surface temperature, and (4) one surface moisture sensor. Additionally, a soil moisture probe and a full weather station that measures ambient temperature, relative humidity, wind speed, wind direction, barometric pressure, insolation, and precipitation were installed adjacent to the test boulder. AE activity was continuously monitored by one logger while all other variables were acquired by a separate logger every 60 s. The protocols associated with the instrumentation, data acquisition, and analysis are discussed in detail. During the first four months, the deployed boulder experienced almost 12 000 AE events, the majority of which occur in the afternoon when temperatures are decreasing. This paper presents preliminary data that illustrates data validity and typical patterns and behaviors observed. This system offers the potential to (1) obtain an unprecedented record of the natural conditions under which rocks fracture and (2) decipher the mechanical processes that lead to rock fracture at a variety of temporal scales under a range of natural conditions.

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Section: Introductionmentioning

confidence: 99%

Automated field detection of rock fracturing, microclimate, and diurnal rock temperature and strain fields

Warren

Eppes

Swami

et al. 2013

Geosci. Instrum. Method. Data Syst.

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“…In these areas the gap between the cracking plates and the wall measures up to 5 cm, and the two are attached at the bottom only, forming what are known locally as "mushrooms". The intense development of these polygons and the depth of the groove along their edges may be explained by the fact that rainwater and runoff are retained longer in areas with a shallower slope, further to the model proposed by Moores et al (2008), in which hydration-and thermal weathering-mediated crack growth depends on the local water content around the rims of the cracks. b) Cracking on intrusive dikes that fill fractures in the granite (Type B, Fig.…”

Section: Polygonal Cracking In La Pedrizamentioning

confidence: 61%

“…In heterogeneous rock such as granite, the quartz and feldspar crystals have different thermal expansion coefficients and consequently react differently to weathering. Moores et al (2008) proposed a model in which hydrationand thermal weathering-mediated crack growth depends on the local water content around the rims of the cracks. Cracks exposed to less solar radiation retain more moisture than those receiving more radiation and are altered more quickly.…”

Section: Polygonal Cracking: Origin and Descriptionmentioning

confidence: 99%

Polygonal cracking in granite and considerations for a morphological classification (La Pedriza de Manzanares, Spain)

García–Rodríguez

Heras

Buergo

et al. 2016

Journal of Iberian Geology

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The area known as Pedriza de Manzanares forms part of the Upper Manzanares River Basin and of the recently (June 2013) listed Sierra de Guardarrama National Park, located in the Spanish province of Madrid. The region is home to Late Palaeozoic granites characteristic of the Spanish Central Systam, which were intruded during the Variscan Orogeny and uplifted to their present position during the Alpine Orogeny.Previous studies of polygonal cracking in granite suggest several possible control mechanisms. Some authors contend that weathering patterns are governed by internal geodynamic factors, such as the final stages of magmatic consolidation or differential movements in fault planes as a result of their structural position. Others claim that climate-related external factors, specifically insolation rates and thermal differences, can explain the predominance of a given orientation in such patterns.The present paper is a study of the effect of case hardening on polygonal cracking, and the role of variables such as temperature and rock surface hardness in granite weathering. It also aims to establish a general systematic classification for polygonal cracking, focusing particularly on the cracking associated with the sub-vertical planes of fracture at Pedriza de Manzanares. The morphometric parameters associated with cracks and fractures, including strike and dip, are analysed, along with the height of occurrence and shape of polygonal cracks.Keywords: Polygonal cracking, case hardening, granite weathering, Sierra de Guardarrama National Park La Pedriza de Manzanares forma parte de la cuenca alta del río Manzanares en la provincia de Madrid, y desde junio de 2013 forma parte del Parque Nacional de la Sierra de Guadarrama. La zona está formada por granitos característicos del Sistema Central Español que intruyeron a finales del Paleozoico durante la orogenia Varisca y sufrieron un levantamiento hasta su posición actual durante la orogenia Alpina.Trabajos previos sobre agrietamientos poligonales en granitos sugieren diversos posibles mecanismos de control. Algunos autores mantienen que los patrones de meteorización están controlados por factores geodinámicos internos relacionados con estados tardíos de consolidación magmática, o por movimientos diferenciales de planos de fractura, como consecuencia de su posición estructural. Otros autores apuntan que los factores externos tales como el clima, específicamente por diferencias térmicas debido a la insolación, pueden explicar la abunadancia de estas formas de acuerdo con un patrón de la orientación del afloramiento.En este trabajo se estudia la influencia de los endurecimientos superficiales en la evolución de los agrietamientos poligonales, y se analizan variables como la temperatura y la dureza de la superficie rocosa en el proceso de meteorización del granito. Además, el trabajo trata de presentar una clasificación general de los agietamientos poligonales, incidiendo en los agrietamientos asociados a planos de fractura subverticales identificados en La Pedriza ...

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“…En estas zonas las placas de los agrietamientos llegan a quedar separadas de la pared hasta unos cinco centímetros, y permanecen unidas a la pared sólo por la parte inferior, formando lo que localmente se conoce como "setas". El fuerte desarrollo de estos agrietamientos y la gran incisión que presentan sus bordes puede explicarse por un mayor tiempo de permanencia del agua sobre las grietas al tratarse de zonas con menos pendiente que permiten retener el agua de lluvia y escorrentía directa por más tiempo Moores et al (2008).…”

Section: La Pedrizaunclassified

“…En rocas heterogéneas como el granito, los diferentes cristales que componen la roca, como por ejemplo el cuarzo y el feldespato, tienen diferentes coeficientes de dilatación térmica y por tanto diferente respuesta ante la meteorización por efecto de la temperatura. Moores et al (2008) proponen un modelo en el que el crecimiento por hidratación y por efecto térmico sobre las grietas depende del contenido local de agua en los bordes de los extremos de las grietas. Las grietas sometidas a una menor insolación retienen más humedad que las que tienen mayor insolación, alterándose más rápido.…”

Section: Introductionunclassified

Caracterización de agrietamientos poligonales sobre granito en la Pedriza de Manzanares y en Cenicientos, Madrid (Sistema Central)

Buergo

González

Carrillo³

et al. 2014

M+A. Revista Electrónica De Medioambiente

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Caracterización de agrietamientos poligonales sobre granito en la Pedriza de Manzanares y en Cenicientos, Madrid (Sistema Central) GARCÍA RODRÍGUEZ, M.; GÓMEZ HERAS, M; ALVAREZ DE BUERGO, M.; FORT GONZÁLEZ, R.; CENTENO CARRILLO, J.D.M+A. RESUMENEl Sistema Central español recorre el interior de la Península Ibérica en dirección Este -Oeste y está constituido principalmente por granitoides y gneises. Los granitoides incluyen distintos tipos de granito, con variaciones mineralógicas y texturales. Estos granitos muestran un complejo sistema de fracturas producidas durante las orogenias Varsica y Alpina que han dado como resultado paisajes con paredes de alturas que pueden superar el centenar de metros, alternando con bolos sueltos (La Pedriza de Manzanares, Madrid), así como paisajes en los que únicamente se encuentran bolos aislados (Cenicientos, Madrid). Este trabajo de carácter descriptivo, tiene por objeto reconocer y caracterizar los agrietamientos poligonales que aparecen en los granitos de ambas zonas con características geomorfológicas diferentes, con el fin de intentar establecer las relaciones genéticas existentes entre ellos.

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Crack propagation by differential insolation on desert surface clasts

Cited by 56 publications

References 42 publications

Automated field detection of rock fracturing, microclimate, and diurnal rock temperature and strain fields

Automated field detection of rock fracturing, microclimate, and diurnal rock temperature and strain fields

Polygonal cracking in granite and considerations for a morphological classification (La Pedriza de Manzanares, Spain)

Caracterización de agrietamientos poligonales sobre granito en la Pedriza de Manzanares y en Cenicientos, Madrid (Sistema Central)

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