Granite emplacement by crustal boudinage: example of the Calmayo and El Hongo plutons (Córdoba,Argentina)     

Fernando D'Eramo  José M. Tubía  Lucio Pinotti  Néstor Vegas  Jorge Coniglio  Manuel Demartis  Aitor Aranguren  Miguel Basei 《地学学报》2013,25(5):423-430

This study deals with the structure and emplacement of the Calmayo and El Hongo trondhjemite plutons (Famatinian belt of Córdoba, Argentina). It provides structural data from the granites and the country rocks and a study of the magnetic fabric in the plutons. New U/Pb geochronological data yield intrusion ages of 512.1 ± 3.4 Ma and 500.6 ± 4.5 Ma for the Calmayo and El Hongo plutons respectively. The El Hongo massif and the southern part of the Calmayo trondhjemite preserve magmatic structures, whereas the northern domain of Calmayo shows the imprint of solid‐state deformation. The main foliation in the country rocks outlines a boudin‐like pattern at the map scale and the granites are located along boudin necks, suggesting that the emplacement of these trondhjemite plutons was linked to large‐scale boudinage of the country rocks.  相似文献   

Magma chamber growth models in the upper crust: A review of the hydraulic and inertial constraints     

Eugenio Aragón  Fernando J.D'Eramo  Lucio P.Pinotti  Manuel Demartis  José María Tubía  Roberto F.Weinberg  Jorge E.Coniglio 《地学前缘(英文版)》2019,10(3):1211-1218

Finite volumes of magma moving in confinement, store hydraulic potential energy for the generation,control and transmission of power. The Pascal's principle in a hydraulic jack arrangement is used to model the vertical and lateral growth of sills. The small input piston of the hydraulic jack is equivalent to the feeder dike, the upper large expansible piston equivalent to the magmatic chamber and the inertial force of the magma in the dike is the input force. This arrangement is particularly relevant to the case of sills expanding with blunt tips, for which rapid fracture propagation is inhibited. Hydraulic models concur with experimental data that show that lateral expansion of magma into a sill is promoted when the vertical ascent of magma through a feeder dike reaches the bottom contact with an overlying, flat rigid-layer. At this point, the magma is forced to decelerate, triggering a pressure wave through the conduit caused by the continued ascent of magma further down(fluid-hammer effect). This pressure wave can provide overpressure enough to trigger the initial hydraulic lateral expansion of magma into an incipient sill, and still have enough input inertial force left to continue feeding the hydraulic system. The lateral expansion underneath the strong impeding layer, causes an area increase and thus, further hydraulic amplification of the input inertial force on the sides and roof of the incipient sill, triggering further expansion in a self-reinforcing process. Initially, the lateral pressure increase is larger than that in the roof allowing the sill to expand. However, expansion eventually increases the total integrated force on the roof allowing its uplift into either a laccolith, if the roof preserves continuity, or into a piston bounded by a circular set of fractures. Hydraulic models for shallow magmatic chambers, also suggest that laccolith-like intrusions require the existence of a self-supported chamber roof. In contrast, if the roof of magmatic chambers loses the self-supporting capacity, lopoliths and calderas should be expected for more or less dense magmas, respectively, owing to the growing influence of the density contrast between the host rock and the magma.  相似文献   

Novel insights in hydrological modeling     

Salvatore Grimaldi  Ignacio Rodriguez-Iturbe  Lucio Ubertini 《Advances in water resources》2010

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The Variscan post-collisional volcanism in Late Carboniferous–Permian sequences of Ligurian Alps, Southern Alps and Sardinia (Italy): a synthesis     

L. Cortesogno  G. Cassinis  G. Dallagiovanna  L. Gaggero  G. Oggiano  A. Ronchi  S. Seno  M. Vanossi   《Lithos》1998,45(1-4):305-328

In the considered wide sector of the West-Mediterranean southern Europe, the collisional phase of the Variscan orogeny during Late Carboniferous and Permian times was followed by magmatic intrusive and effusive activity and sedimentation into intracontinental, alluvial to lacustrine basins originated by wrench- to normal-fault systems. The first volcanic cycle (generally Late Carboniferous-Early Permian in age) is represented by early calc-alkaline andesites and rhyolites, in variable amounts, and by following large volume of rhyolites, and by dacites. Both andesites and rhyolites show K-normal and high-K calc-alkaline character. The origin of the liquids of the first cycle is ascribed to partial melting processes at the mantle–crust interface telescoped within a thickened crust. The melting is considered as the consequence of thermal re-equilibration following isostatic disequilibrium and the subsequent collapse of the orogenic belt; the ascent of liquids occurred in a (trans-)tensional regime. The second magmatic cycle is represented by alkaline magmatism, and exhibits typical anorogenic features consistent with a rifting regime. This event was no more related with the collapse of the Variscan belt, but rather to the post-Variscan global re-organization of plates that evolved during Late Triassic times to the neo-Tethyan rifting. In both cycles, important differences in timing, areal distribution and outpoured volumes arise.  相似文献   

Geochemical trends in the alkali basaltic suite of the Assab range (Ethiopia)     

Lucia Civetta  Maria De Fino  Luigi La Volpe  Lucio Lirer 《Chemical Geology》1974,13(3):149-162

Two groups of rocks are distinguished in the Assab volcanic range (Afar) on the basis of their petrology. The first one is a typical alkaline suite with high Li, Ba, Rb, Sr, Th and U concentrations. A second subalkaline group may be related to a parental basalt characterized by low trace-element concentrations and intermediate in character between alkali and tholeiitic basalt.U and Th concentrations of the analyzed Assab basalts, as well the reported values for the alkali and transitional basalts of the East African Rift and the Afar depression, are higher than values reported for similar basalts from oceanic and continental environments.  相似文献   

The role of infiltration processes in steep slope stability of pyroclastic granular soils: laboratory and numerical investigation   总被引：1，自引：0，他引：1  

Emilia Damiano  Lucio Olivares 《Natural Hazards》2010,52(2):329-350

Rainfall-induced landslides on steep slopes are a common feature in much of Italy’s mountain areas covered by shallow-pyroclastic deposits. Generally, these deposits are unsaturated and have a slope angle higher than 40°–50°; hence their stability is due to the positive effect of matric suction on soil shear strength. During rainfall, rainwater infiltration causes a decrease in suction, which in turn causes changes in soil mechanical and hydraulic properties, leading towards an instability process. However, the response of pyroclastic soil slopes to rainwater infiltration is not fully understood. The aim of this study is to link slope instability to the infiltration process on the basis of advanced geotechnical characterization, in situ monitoring and numerical analysis calibrated through a back-analysis of well-instrumented flume tests.  相似文献   

Gravitational instability in binary protoplanetary discs: new constraints on giant planet formation     

Lucio Mayer  James Wadsley  Thomas Quinn  Joachim Stadel 《Monthly notices of the Royal Astronomical Society》2005,363(2):641-648

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COMPASS: an instrument for measuring the polarization of the CMB on intermediate angular scales     

Philip C. Farese  Giorgio Dall&#x;Oglio  Josh Gundersen  Brian Keating  Slade Klawikowski  Lloyd Knox  Alan Levy  Chris O&#x;Dell  Alan Peel  Lucio Piccirillo  John Ruhl  Peter Timbie 《New Astronomy Reviews》2003,47(11-12):1033

COMPASS is an on-axis 2.6-m telescope coupled to a correlation polarimeter. The entire instrument was built specifically for CMB polarization studies. Careful attention was given to receiver and optics design, stability of the pointing platform, avoidance of systematic offsets, and development of data analysis techniques. Here we describe the experiment, its strengths and weaknesses, and the various things we have learned that may benefit future efforts to measure the polarization of the CMB.  相似文献   

Fundamental differences between SPH and grid methods   总被引：1，自引：0，他引：1  

Oscar Agertz  Ben Moore  Joachim Stadel  Doug Potter  Francesco Miniati  Justin Read  Lucio Mayer  Artur Gawryszczak  rey Kravtsov  Åke Nordlund  Frazer Pearce  Vicent Quilis  Douglas Rudd  Volker Springel  James Stone  Elizabeth Tasker  Romain Teyssier  James Wadsley  Rolf Walder 《Monthly notices of the Royal Astronomical Society》2007,380(3):963-978

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Simultaneous ram pressure and tidal stripping; how dwarf spheroidals lost their gas     

Lucio Mayer  Chiara Mastropietro  James Wadsley  Joachim Stadel  Ben Moore 《Monthly notices of the Royal Astronomical Society》2006,369(3):1021-1038

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