{"id":147434,"date":"2016-06-08T13:16:17","date_gmt":"2016-06-08T12:16:17","guid":{"rendered":"http:\/\/www.madrimasd.org\/blogs\/universo\/?p=147434"},"modified":"2016-06-08T13:16:17","modified_gmt":"2016-06-08T12:16:17","slug":"formacion-de-regolitos-y-suelos-la-importancia-de-las-fracturas-de-las-rocas-y-la-tectonica","status":"publish","type":"post","link":"https:\/\/www.madrimasd.org\/blogs\/universo\/2016\/06\/08\/147434","title":{"rendered":"Formaci\u00f3n de Regolitos y Suelos: La importancia de las fracturas de las rocas y la tect\u00f3nica"},"content":{"rendered":"

\"relieves-graniticos\"\u00a0<\/span><\/p>\n

Relieves Gran\u00edticos. Fuente: Milagros de la Pedriza (Sierra de Guadarrama, Madrid, Espa\u00f1a)<\/span><\/a><\/p>\n

\u00a0<\/span>Ya os hemos ido narrando en varios post, como el <\/span>material litol\u00f3gico<\/strong><\/span> que subyace a un suelo, y al que solemos denominar <\/span>roca madre o material parental, no condicionan por si solas la formaci\u00f3n del\u00a0<\/strong><\/span>Perf\u00edl ed\u00e1fico<\/a>, con independencia de las <\/span>aportaciones de materiales superficiales<\/strong><\/span>, ya sean depositados <\/span>por v\u00eda e\u00f3lica o h\u00eddrica<\/span><\/span><\/strong>. As\u00ed, por ejemplo, una roca gran\u00edtica alberga granos cohesionados por unas determinadas <\/span>sustancias <\/strong>cementantes<\/strong><\/span>. Estas \u00faltimas pueden ofrecer <\/span>resistencias muy dispares a la alteraci\u00f3n biogeoqu\u00edmica<\/strong><\/span>. Si resultan ser f\u00e1cilmente meteorizables, la roca se disgregar\u00e1 f\u00edsicamente con facilidad dando lugar a un espeso regolito, que a la postre resultar\u00e1 m\u00e1s f\u00e1cil de sufrir una transformaci\u00f3n por los agentes biogeoqu\u00edmicos. Si por el contrario el cemento es muy resistente, el espesor del regolito y los suelos suprayacentes ser\u00e1n mucho m\u00e1s delgados. Siguiendo el ejemplo de una sierra gran\u00edtica, no resulta nada extra\u00f1o observar en el paisaje zonas m\u00e1s escarpadas y con suelos m\u00e1s someros que otras, en funci\u00f3n de la composici\u00f3n de las mentadas sustancias cementantes de los granos.<\/span>\u00a0\u00a0<\/span><\/p>\n

Del mismo modo, si el paisaje y los escarpes fisiogr\u00e1ficos (o los taludes generados por el movimientos de rocas ocasionados en la construcci\u00f3n de carreteras u otras infraestructuras) aparecen con claridad,<\/span>\u00a0\u00a0\u00a0<\/span>tampoco resulta nada ins\u00f3lito observar como <\/span>los procesos de alteraci\u00f3n avanzan por la fractura de las rocas dejando enormes bloques intactos entre estas \u00faltimas<\/strong><\/span>.<\/span>\u00a0 <\/span>Empero en muchos materiales litol\u00f3gicos de diversa composici\u00f3n ocurre lo mismo.<\/span>\u00a0 <\/span>Y as\u00ed, <\/span>los espesores de suelos y regolitos ofrecen una gran variabilidad en funci\u00f3n de estos factores, es decir<\/strong><\/span> tipos de cementantes y frecuencia\/tama\u00f1o de las fracturas. En consecuencia, <\/span>en regiones que sufren una intensa actividad tect\u00f3nica<\/strong><\/span>, en los que la fracturaci\u00f3n de las rocas es com\u00fan<\/span><\/strong><\/span>, cabe esperar que la g\u00e9nesis de suelos y regolitos sea m\u00e1s r\u00e1pida e intensa que en<\/strong><\/span> espacios geogr\u00e1ficos estables. Nada nuevo bajo el sol, excepto que muchos edaf\u00f3logos soslayan estas evidencias, f\u00e1cilmente observables sobre el terreno, a la hora de explicar le g\u00e9nesis de los suelos y de los paisajes ed\u00e1ficos. Ya lo mostramos en varios post previos. <\/span>En este entrega, por ejemplo, comentamos la escasa importancia que se le otorga a los suelos someros<\/span><\/a>, como lo son Leptosoles y los Regosoles, y las razones de ello, entra las que ya hablamos de los aludidos cementos. <\/span><\/p>\n

La noticia que os ofrecemos hoy, y que parte de un estudio previo de campo, avala lo anteriormente mentado, constatando que haciendo uso de <\/span>dos t\u00e9cnicas geof\u00edsicas<\/strong><\/span> habituales, <\/span>resulta factible predecir el espesor de suelos y regolitos, de toda la denominada <\/span><\/span><\/strong>zona cr\u00edtica terrestre<\/span><\/a>. Los autores del estudio que abajo os exponemos elaboraron sobre estas premisas un modelo num\u00e9rico, test\u00e1ndolo en varios espacios geogr\u00e1ficos sometidos a diferentes fuerzas tect\u00f3nicas. Seg\u00fan ellos, el modelo demostr\u00f3 atesorar un buen poder predictivo. Se trata de un resultado que avala conocimientos previos sobre el terreno, empero que <\/span>tiene el valor y utilidad \u201cen potencia\u201d para afinar m\u00e1s en estos temas de gran inter\u00e9s para la edafolog\u00eda, zona cr\u00edtica terrestre, hidrolog\u00eda y en definitiva constituirse en otra herramienta con vistas a comprender mejor la estructura y din\u00e1mica de los sistemas superficiales terrestres<\/strong><\/span> y su relaci\u00f3n con los ecosistemas que albergan. <\/span>Os dejo pues con la nota de prensa. Eso si, somos de la opini\u00f3n de que tal informaci\u00f3n debiera incluirse en la <\/span>futura generaci\u00f3n de mapas edafol\u00f3gicos<\/span><\/a>, que en nada tiene que ver con la basura de deconstruccionista que <\/span>\u00a0<\/span>intentan vender aquellos que sin saber lo que es un suelo defienden las cartograf\u00edas digitales de variables ed\u00e1ficas, bajo la pomposa denominaci\u00f3n de <\/span>digital soil mapping<\/span><\/a>.\u00a0<\/span>\u00a0<\/span>\u00a0<\/span><\/p>\n

Juan Jos\u00e9 Ib\u00e1\u00f1ez<\/span>\u00a0<\/span> <\/span><\/strong><\/p>\n

<\/span><\/p>\n

New research uses surface features to predict weathering of <\/span>rocks beneath<\/span><\/a><\/p>\n

University of Hawai\u02bbi at M\u0101noa<\/span><\/strong><\/p>\n

Contact: <\/span>Stephen Martel, (808) 956-7797 <\/a>
\n Professor, Department of Geology and Geophysics, School of Ocean and Earth Science and Technology
\n<\/span>Marcie Grabowski, (808) 956-3151<\/a>
\n Outreach Coordinator, School of Ocean and Earth Science and Technology<\/span><\/p>\n

Posted: Nov 6, 2015<\/span><\/p>\n

Just below Earth\u2019s surface, beneath the roots and soil, is a hard, dense layer of bedrock that is the foundation for all life on land. Cracks and fissures within the bedrock provide pathways for air and water, which chemically react to break up rock, ultimately creating soil \u2014 an essential ingredient for all terrestrial organisms<\/span><\/strong>. <\/span>This weathering of bedrock is fundamental to life on Earth.<\/span><\/strong><\/p>\n

Accurate predictions of where <\/span>open fractures are beneath the surface are valuable<\/span><\/strong> for additional reasons. <\/span>Fractures in the bedrock affect where drinking water will flow; the paths that magma takes as it moves to the surface in volcanic eruptions; the strength of rock masses on slopes; and how severe shaking will be during earthquakes.<\/span><\/strong>\u00a0<\/span><\/p>\n

Now scientists at UH\u00a0M\u0101noa, Massachusetts Institute of Technology (MIT), University of Wyoming\u00a0and elsewhere have found <\/span>a way to predict the extent of bedrock weathering, given a location\u2019s topography \u2013 the shape and features on the surface<\/span><\/strong>. The results are published in the journal <\/span>Science<\/span><\/em>.<\/span><\/p>\n

The group sought <\/span>to estimate the depth to which bedrock is broken up, or fractured, using a mathematical model. This fractured rock forms the base of a layer scientists have dubbed <\/span>Earth\u2019s \u201ccritical zone<\/strong>,\u201d where the interaction of rock, air\u00a0and water allows life to thrive. Steve Martel, professor of Geology and Geophysics at UH M\u0101noa’s\u00a0School of Ocean and Earth Science and Technology (SOEST), and the team developed <\/span>a stress model that estimated the thickness of this critical zone, given the forces generated by topography, gravity\u00a0and plate tectonics<\/strong>.\u00a0<\/span><\/p>\n

The model showed that if a landscape is undergoing little tectonic compression, the fractured zone should parallel the overlying topography<\/span><\/strong>, like layers of lasagna. <\/span>If, however, a region is under high tectonic compression, the fractured zone will resemble a mirror image of the landscape \u2014 thicker beneath ridges, and thinner under valleys<\/span><\/strong>.<\/span><\/p>\n

To test the model\u2019s predictions<\/span><\/strong>, the researchers went to three sites in the U.S.\u00a0with varying tectonic forces \u2013 Colorado, South Carolina\u00a0and Maryland. In each location, <\/span>they took extensive seismic and electrical conductivity measurements to gauge the extent of fracturing in the underlying bedrock. Seismic waves move faster through solid rock, and slower through rock containing many fractures filled<\/span><\/strong>with air, water\u00a0or weathered material such as clay. The scientists also drilled boreholes to obtain photos of the bedrock at depth. The photographic data provided further confirmation<\/span><\/strong> that the seismic and conductivity measurements did indeed <\/span>reveal fractured zones that matched well with their model\u2019s predictions<\/span><\/strong>.<\/span><\/p>\n

Said Martel, \u201c<\/span>I knew from work done for a paper I published in 2011 that the stress models could predict fracture patterns in parts of Yosemite National Park.\u00a0However, everyone on the team, including me, was surprised to see how well the stress modeling results matched the geophysical results in these diverse geologic environments<\/span><\/strong>.\u00bb<\/span><\/p>\n

As an extension of this work, Martel and a group of <\/span>several SOEST scientists anticipate using the stress models to better understand geothermal energy<\/span><\/strong> resources in Hawaii. \u00a0<\/span>Geothermal energy is obtained from hot water that flows through open rock fractures underground<\/span><\/strong>. The model will help predict where open fractures are most likely to be, and where\u00a0open fractures are unlikely to be \u2013 thereby enhancing predictions of geothermal energy resource locations.<\/span><\/p>\n

Fuente (Source): <\/strong><\/span>Portions of this release sourced from an <\/span>MIT news story<\/a> (used with permission); <\/span>Watch \u201c<\/span>Bedrock weathering based on topography<\/a>\u201d for an explanation of the recent findings. Credit: Melanie Gonick\/MIT. <\/span>For more information, visit: <\/span>https:\/\/www.soest.hawaii.edu\/S<\/a>. Use of this site implies consent with our <\/span>Usage Policy<\/a> .\u00a0<\/span> The University of Hawai\u02bbi is an <\/span>equal opportunity\/affirmative action institution<\/a>.\u00a0<\/span>copyright \u00a92011 University of Hawaii <\/span><\/p>\n

Otro post previo relacionados con el tema<\/strong><\/span><\/p>\n

Los Tipos de Suelos Condicionan las Repercusiones de los Se\u00edsmos o Terremotos<\/span><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

\u00a0 Relieves Gran\u00edticos. Fuente: Milagros de la Pedriza (Sierra de Guadarrama, Madrid, Espa\u00f1a) \u00a0Ya os hemos ido narrando en varios post, como el material litol\u00f3gico que subyace a un suelo, y al que solemos denominar roca madre o material parental, no condicionan por si solas la formaci\u00f3n del\u00a0Perf\u00edl ed\u00e1fico, con independencia de las aportaciones de materiales superficiales, ya sean depositados por v\u00eda e\u00f3lica o h\u00eddrica. As\u00ed, por ejemplo, una roca gran\u00edtica alberga granos cohesionados por unas determinadas sustancias cementantes. Estas \u00faltimas pueden ofrecer resistencias muy dispares a la alteraci\u00f3n biogeoqu\u00edmica. Si resultan ser f\u00e1cilmente meteorizables, la roca se disgregar\u00e1 f\u00edsicamente\u2026<\/p>\n","protected":false},"author":26,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[603,590,588,604,617,611],"tags":[47763,9747,47350,35680,18053,47093,47762,46676,28055,27804],"blocksy_meta":{"styles_descriptor":{"styles":{"desktop":"","tablet":"","mobile":""},"google_fonts":[],"version":4}},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/147434"}],"collection":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/users\/26"}],"replies":[{"embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/comments?post=147434"}],"version-history":[{"count":8,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/147434\/revisions"}],"predecessor-version":[{"id":148237,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/posts\/147434\/revisions\/148237"}],"wp:attachment":[{"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/media?parent=147434"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/categories?post=147434"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.madrimasd.org\/blogs\/universo\/wp-json\/wp\/v2\/tags?post=147434"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}