Magma chamber formation by magma intrusion into the Earth's crust

2020 ◽  
Author(s):  
Ivan Utkin ◽  
Oleg Melnik
Keyword(s):  
Magma Chamber ◽  
Flow Rate ◽  
Structural Features ◽  
Numerical Dissipation ◽  
Magma Chambers ◽  
Magma Intrusion ◽  
Magma Flow ◽  
Formation Of Cracks ◽  
Heating Up ◽  
Magma Flow Rate

<p>The main mechanism of transport of magma in the Earth’s crust is the formation of cracks, or dikes, through which the melt moves towards the surface under the action of buoyancy forces and tectonic stresses. Due to the structural features of the crust or external stress fields, dikes often do not reach the surface, but penetrate the localized region in which the rocks melt, leading to the formation of magmatic chambers, whose volume can exceed thousands of cubic kilometers. We present a model of the formation of a magma chamber during the intrusion of dikes at a given flow rate. The model is based on the solution of heat equation and considers the actual melting diagrams of magma and rocks. It Is shown that, in case of magmatic fluxes typical of island arc volcanoes, magma chambers are formed over hundreds of years from the beginning of magma intrusion. The influence of the magma flow rate, the size of the dikes and their orientation on the volume of the formed magma chamber and its shape was investigated. The size of the chamber significantly exceeds the area of dike intrusion due to the displacement of magma and rocks of the crust, their heating up and melting. To calculate displacement of rock and magma in a numerical simulation, a hybrid method based on PIC/FLIP interpolation is developed, making it possible to avoid unphysical mixing due to numerical dissipation, thus preserving the fine details of the formed magma chamber.</p><p>This work was supported by RFBR, project number 18-01-00352</p>

scholarly journals The dynamics of dual-magma-chamber system during volcanic eruptions inferred from physical modeling

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Tomofumi Kozono
Keyword(s):  
Analytical Solution ◽  
Magma Chamber ◽  
Volcanic Eruptions ◽  
Chamber Pressure ◽  
Deformation Pattern ◽  
Chamber System ◽  
Plumbing System ◽  
Magma Chambers ◽  
Magma Flow ◽  
Magma Plumbing System

AbstractA magma plumbing system with dual magma chambers beneath active volcanoes is commonly observed through petrological and geophysical measurements. This paper developed a physical model for the dynamics of a dual-magma-chamber system during volcanic eruptions. The model consists of the plumbing system where two elastically deformable magma chambers are connected in series with non-deformable conduits. Based on this model, we obtained an analytical solution that describes temporal changes in pressures at the two chambers accompanied by the eruption. The analytical solution showed that the feature of the chamber pressure changes is mainly controlled by two non-dimensional numbers $$C'$$ C ′ and $$\Omega '$$ Ω ′ . Here, $$C'$$ C ′ is the ratio of the parameter controlling the magnitude of pressure change in the shallower chamber to that in the deeper chamber, and $$\Omega '$$ Ω ′ is the ratio of conduit’s conductivity (inverse of resistivity to magma flow) between the shallower chamber and the surface to that between the chambers. For smaller $$C'$$ C ′ and $$\Omega '$$ Ω ′ , the shallower chamber’s pressure is kept constant during the decrease in the pressure at the deeper chamber in the initial phase of the eruption. This corresponds to a deformation pattern commonly observed in some eruptions, in which the deflation of the deeper chamber was predominant. The estimation of $$C'$$ C ′ and $$\Omega '$$ Ω ′ based on the parameters related to magma properties and geometries of the chambers and the conduits revealed that the smaller $$C'$$ C ′ and $$\Omega '$$ Ω ′ conditions are satisfied under realistic magmatic and geological parameters. This indicates that the magma dynamics in the dual-chamber system generally cause the dominance of the deeper chamber’s deflation.

The origin of magmatic layering in the High Tatra granite, Central Western Carpathians – implications for the formation of granitoid plutons

2012 ◽  
Vol 102 (2) ◽  
pp. 129-144 ◽  
Author(s):  
Aleksandra Gawęda ◽  
Krzysztof Szopa
Keyword(s):  
Magma Chamber ◽  
Mafic Magma ◽  
Crystal Nucleation ◽  
Tectonic Activity ◽  
Density Currents ◽  
Crystal Mush ◽  
Magma Flow ◽  
Large Numbers ◽  
Crystal Accumulation ◽  
Chamber Floor

ABSTRACTThe High Tatra granite intrusion is an example of a Variscan syn-tectonic, tongue-shaped intrusion. In some portions of the intrusion, structures occur which appear to be of sedimentary origin. These include structures similar to graded bedding, cross-bedding, troughs and flame structures, K-feldspar-rich cumulates and magmatic breccias. Formation of these structures might be related to changing magma properties, including crystal fraction, development of a crystal mush and a decrease in magma viscosity, stimulated by influx of mafic magma and high volatile content. The suggested processes in operation are: gravity-controlled separation, magma flow segregation, deposition on the magma-chamber floor, filter pressing and density currents stimulated by tectonic activity.%The formation of the sedimentary structures was also aided by the presence of large numbers of xenoliths that acted as a heat sink and influenced the thermal field in the intrusion, stimulating rapid cooling and crystal nucleation. Sinking xenoliths deformed the layering and, to some extent, protected the unconsolidated crystal mush from erosion by magma flowing past.%Areas with well-developed sedimentary magmatic structures can be viewed as having involved magma rich in crystals locally forming closely-packed networks from which residual melt was extracted by filter pressing, and preserved in leucocratic pods and dykes. Interleaved, non-layered granite may be interpreted to have formed from the magma with initially low crystal fractions.%It is suggested that the intrusion was formed from numerous magma injections representing different stages in the mixing and mingling of felsic and mafic sources. It solidified by gravitation-driven crystal accumulation and flow sorting on the magma chamber floor and on the surfaces of large numbers of xenoliths. Shear stress acting during intrusion might have influenced the formation of magmatic structures.

The geochemistry of mafic and ultramafic from the Archaean greenstone belts of Sierra Leone

1983 ◽  
Vol 47 (344) ◽  
pp. 267-280 ◽  
Author(s):  
H. R. Rollinson
Keyword(s):  
Sierra Leone ◽  
Magma Chamber ◽  
Source Region ◽  
Double Diffusion ◽  
Ultramafic Rocks ◽  
Magma Chambers ◽  
Basaltic Rocks ◽  
Ocean Ridges ◽  
Different Depths ◽  
Greenstone Belts

AbstractThe Archaean (c. 2800 Ma) ultramafic rocks in eastern Sierra Leone cut basalt lavas and are mostly olivine-rich cumulates either iron-rich (Fo85–86) and derived from a basaltic or picritic parent, or more magnesian (Fo92–93) derived from an ultramafic melt with c. 18–25 wt. % MgO. In central Sierra Leone the ultramafic rocks are lavas predating tholeiitic basalts.The basalts show a wide variation in Zr/Y, suggesting that garnet was present in the source region of some of these rocks but not others. This implies that melting took place at different depths in the mantle. The REE evidence for basaltic rocks in the upper part of the Nimini belt succession suggests that they were derived from a mantle source region which had already suffered melt extraction. Ti/Zr ratios in the basaltic rocks are also variable and individual belts define different trends on a Ti vs. Zr plot implying that the basaltic rocks evolved in geographically distinct magma chambers. It is likely that the basaltic rocks evolved from a parental liquid with Ti/Zr = 90 via shallow level crystal fractionation. The source region for these rocks therefore had a lower than chondritic Ti/Zr.There are two possible models for the basaltic and ultramafic magmas in the Sierra Leone greenstone belts. First that the ultramafic and basaltic liquids were derived from mantle diapirs of differing size, but originating in the same region of the mantle. Ultramafic liquids were produced in small diapirs, which store large melt fractions, and basaltic liquids in larger diapirs which segregate larger melt fractions. A second model is based upon the double diffusion process suggested for magma chambers at mid-ocean ridges and involves a transient magma chamber from which basalts, derived from parental ultramafic liquids, are erupted, with ultramafic liquids rising directly to the surface when the magma chamber is frozen. The available data does not discriminate between these two models.

scholarly journals Magma chamber decompression during explosive caldera-forming eruption of Aira caldera

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Nobuo Geshi ◽  
Tadashi Yamasaki ◽  
Isoji Miyagi ◽  
Chris E. Conway
Keyword(s):  
Pressure Drop ◽  
Water Content ◽  
Magma Chamber ◽  
Quartz Glass ◽  
Roof Rock ◽  
Theoretical Models ◽  
Caldera Collapse ◽  
Magma Chambers ◽  
Pyroclastic Deposits ◽  
Fundamental Condition

AbstractDecompression of a magma chamber is a fundamental condition of caldera collapse. Although theoretical models have predicted the decompression of magma chambers before caldera collapse, few previous studies have demonstrated the amount of magma chamber decompression. Here, we determine water content in quartz glass embayments and inclusions from pyroclastic deposits of a caldera-forming eruption at Aira volcano approximately 30,000 years ago and apply this data to calculate decompression inside the magma chamber. We identify a pressure drop from 140–260 MPa to 20–90 MPa during the extraction of around 50 km3 of magma prior to the caldera collapse. The magma extraction may have caused down-sag subsidence at the caldera center before the onset of catastrophic caldera collapse. We propose that this deformation resulted in the fracturing and collapse of the roof rock into the magma chamber, leading to the eruption of massive ignimbrite.

Modeling of magmatic channel formation in thin lithosphere areas

2020 ◽  
Author(s):  
Yuri Perepechko ◽  
Konstantin Sorokin ◽  
Georgiy Vasilyev
Keyword(s):  
Mathematical Model ◽  
Porous Medium ◽  
Porous Media ◽  
Saturated Porous Medium ◽  
High Stress ◽  
Marked Change ◽  
Porous Matrix ◽  
Small Scale ◽  
Magma Intrusion ◽  
Magma Flow

<p>The aim of the research is to construct a mathematical model of the formation of a fracture system in magma intrusion in the permeable zones of the lithosphere and on this basis to study the formation of magmatic channels in the lithosphere and crust. The lithosphere substrate is modeled by a saturated porous medium in which the processes of small-scale destruction in the mantle magma intrusion lead to the formation of faults and, consequently, to a magmatic channel. Destruction and occurrence of micro-fracture fields can be associated with both magma flow and external seismic effect leading to the rock breaking. The process of small-scale destruction is described within the framework of the dynamics of the elastoplastic fracture-porous medium and causes variations in the rheological properties of the lithosphere substrate. A feature of this process is the destruction substrate in the compression zone represented by a narrow area with a sharply changing concentration of micro-fractures. The micro-fracture accumulation provides the conversion of the broken area into a macro-fissure. The elastoplastic porous matrix in the destruction zone contains both broken and intact substrate, the relative content of which is determined by relaxation of deformations, the speed of which depends on stress and yield stress point according to the power law. The obtained mathematical model provides investigation of currents in fractured-porous media and their effect on the small-scale destruction. Based on the TVD-Runge Kutta method numerical simulation of the compressible fluid infiltration into the fracture-porous permeable channel has shown that stresses in the compression domain can reach stress limits of breaking and result in fracture formation. Change in relaxation time does not result in a marked change in stress fields. The concentration of maximum stresses is observed in the channel center leading to an increase in its fracture porosity. The computational results show the appearance of high stress values in the compression domain in the process of a liquid phase injection, for instance, magma, into a low-permeable fracture-porous layer. The introduction of the destruction criterion will help to associate the occurrence of such regions to the local breaking of the porous matrix. Thus, the proposed micro-fracture generation mechanism can be used to describe the formation of fracture or channels in micro-fracture porous media. Work is done on state assignment of IGM SB RAS with partial support from the Russian Foundation for Basic Research, grants No. 16-29-15131, 19-05-00788.</p>

Thermal evolution of silicic magma chambers after basalt replenishments

2000 ◽  
Vol 91 (1-2) ◽  
pp. 47-60 ◽  
Author(s):  
Takehiro Koyaguchi ◽  
Katsuya Kaneko
Keyword(s):  
Magma Chamber ◽  
Thermal Evolution ◽  
Bulk Composition ◽  
Thermal Fluctuations ◽  
Silicic Magma ◽  
Magma Chambers ◽  
Solid States ◽  
Liquid Part ◽  
Two Stages

In order to understand the governing factors of petrological features of erupted magmas of island-arc or continental volcanoes, thermal fluctuations of subvolcanic silicic magma chambers caused by intermittent basalt replenishments are investigated from the theoretical viewpoint. When basaltic magmas are repeatedly emplaced into continental crust, a long-lived silicic magma chamber may form. A silicic magma chamber within surrounding crust is composed of crystal-melt mixtures with variable melt fractions. We define the region which behaves as a liquid in a mechanical sense (‘liquid part’) and the region which is in the critical state between liquid and solid states (‘mush’) collectively as a magma chamber in this study. Such a magma chamber is surrounded by partially molten solid with lower melt fractions. Erupted magmas are considered to be derived from the liquid part. The size of a silicic magma chamber is determined by the long-term balance between heat supply from basalt and heat loss by conduction, while the temperature and the volume of the liquid part fluctuate in response to individual basalt inputs. Thermal evolution of a silicic magma chamber after each basalt input is divided into two stages. In the first stage, the liquid part rapidly propagates within the magma chamber by melting the silicic mush, and its temperature rises above and decays back to the effective fusion temperature of the crystal-melt mixture on a short timescale. In some cases the liquid part no longer exists. In the second stage, the liquid part ceases to propagate and cools slowly by heat conduction on a much longer timescale. The petrological features of the liquid part, such as the amount of unmelted preexisting crystals, depend on the intensity of individual pulses of the basalt heat source and the degree of fractionation during the first stage, as well as the bulk composition of the silicic magma.

High Instantaneous Efficiency and High Flow Rate Slotted-Plate Solar Collectors

2013 ◽  
Vol 860-863 ◽  
pp. 88-92
Author(s):  
Zhen Xing Zhang ◽  
Yong Min He ◽  
Xiao Dong Li ◽  
Jin Yuan Zhou ◽  
Xiao Zhi Liu ◽  
...  
Keyword(s):  
Flow Rate ◽  
Working Environment ◽  
Solar Collectors ◽  
Flow Rates ◽  
Key Factor ◽  
The Common ◽  
Slotted Plate ◽  
Heating Up ◽  
Near Future ◽  
Working Efficiency

With the highlight of less regards to insulation measures and the key factor of the flow rates, slotted-plate solar collectors possess rather lower thickness and lighter mass, higher heat production, and better matching with various buildings compared with the common plate solar collectors. Results show that a much higher instantaneous efficiency could be obtained by increasing the flow rates suitably in a low-temperature working environment. The average efficiency could reach up to 51% with the maximum instantaneous efficiency of 61%. Based on the analysis of the relation between instantaneous efficiency and flow rates or the relation between instantaneous efficiency and the temperature difference of the inlet and the outlet water, a experiential formula for the optimal flow rate is proposed to improve the heating-up rates and working efficiency. The performances investigation of slotted-plate solar collectors would pave a way for their widespread and positive applications in the near future.

scholarly journals Просветляющие покрытия на основе ZnO, полученные методом электронно-лучевого испарения

2021 ◽  
Vol 55 (12) ◽  
pp. 1248
Author(s):  
Л.К. Марков ◽  
А.С. Павлюченко ◽  
И.П. Смирнова
Keyword(s):  
Light Propagation ◽  
Heating Temperature ◽  
Structural Features ◽  
Antireflection Coatings ◽  
Material Density ◽  
Substrate Heating ◽  
Wide Range ◽  
Aluminum Doped Zinc Oxide ◽  
Heating Up ◽  
Main Material

In this work, research was carried out to analyze the possibility to fabricate nanostructured antireflection coatings based on ZnO. The dependence of structural features of the film on the substrate heating temperature during deposition of an aluminum-doped zinc oxide (AZO) has been studied. It is shown that it is impossible to obtain the required structural properties of the film by changing one parameter, the substrate temperature during deposition of the material, in the range of 20 – 600 °C. For this purpose, an approach has been suggested, which consists in preliminary deposition of a nanometer-thick Sn layer with subsequent substrate heating up to the temperature of deposition of the main material layer. The optimization of coating deposition conditions led to the fabrication of a medium consisting of many whiskers with transverse dimensions of tens of nanometers and a length of hundreds of nanometers, which are oriented mainly perpendicular to the substrate. It is shown that the gradient nature of a change in the material density, and, hence, in the effective refractive index in the direction perpendicular to the substrate plane, provides antireflection properties of the coating over a wide range of wavelengths as well as in different directions of light propagation.

scholarly journals MAGMA INTRUSION IN 'PROTO-CALDERA CALDERA' SYSTEMS: EXAMPLE FROM THE NISYROS VOLCANO

2018 ◽  
Vol 40 (1) ◽  
pp. 512 ◽  
Author(s):  
D. Zouzias ◽  
K. St. Seymour
Keyword(s):  
Remote Sensing ◽  
Magma Ascent ◽  
Magma Chambers ◽  
Magma Intrusion ◽  
Ongoing Research ◽  
Aegean Arc ◽  
Remote Sensing Techniques ◽  
Tectonic Features ◽  
Remote Sensing Methods ◽  
Tectonic Line

The interdependence of volcanism and tectonism has been focused upon in the last decade as a result of previously accumulated evidence, as well as, due to the application of remote sensing techniques in both these fields. Volcanoes depend on tectonic features such as faults for their positioning and operation and on petrotectonic environment for the chemistry of their magmas. Faults provide the plumbing system for magma ascent and therefore volcano localisation and distribution in space greatly depends on the tectonic pattern of an area. On the other hand, volcanoes locally imprint their volcanotectonic features such as radial and ring faults which result from cycles of magma replenishment (inflation) and evacuation (deflation) of magmatic reservoirs (magma chambers). Under this light, the area in the easternmost extremity of the Aegean Arc is being reconsidered. Our main preliminary findings of ongoing research in the area, using field and remote sensing methods indicate localization of volcanic activity on Kos and on the Datca Peninsula of Asian Minor since Miocene due to the northbounding faults of the Datca Graben. Localisation of volcanic vents and calderas in the Kos-Nisyros area follows intersection of a major tectonic line of northnorthwesterly trending faults the 'Kos-Nisyros-Tilos Line' with N50°E, N30°E and N20°W trending faults. On the well-preserved volcano ofNisyros the architecture of the volcanic edifice has significantly been affected by 'trap-door' volcanotectonics of a major volcanic infrastructure in the area namely the Kos-Caldera

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