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Volcanic and igneous plumbing systems
Volcanic and igneous plumbing systems (VIPS) consist of interconnected magma channels and chambers through which magma flows and is stored within Earth's crust. Volcanic plumbing systems can be found in all active tectonic settings, such as mid-oceanic ridges, subduction zones, and mantle plumes, when magmas generated in continental lithosphere, oceanic lithosphere, and in the sub-lithospheric mantle are transported. Magma is first generated by partial melting, followed by segregation and extraction from the source rock to separate the melt from the solid. As magma propagates upwards, a self-organised network of magma channels develops, transporting the melt from lower crust to upper regions. Channelled ascent mechanisms include the formation of dykes and ductile fractures that transport the melt in conduits. For bulk transportation, diapirs carry a large volume of melt and ascent through the crust. When magma stops ascending, or when magma supply stops, magma emplacement occurs. Different mechanisms of emplacement result in different structures, including plutons, sills, laccoliths and lopoliths.
Partial melting is the first step for generating magma and magma is the basis of VIPS. After magma is generated, it will travel across the crust and lead to the formation of magma conduits and chambers. In continental crust, partial melting occurs when a portion of the solid rock melts into felsic magma. Rocks in the lower crust and the upper mantle are subject to partial melting. The rate of partial melting and the resultant silicate melt composition depend on temperature, pressure, flux addition (water, volatiles) and the source rock composition. In oceanic crust, decompression melting of mantle materials forms basaltic magma. When the mantle materials rise, the pressure greatly decreases which significantly lowers the melting point of the rock.
After magma is generated, magma will migrate out of its source region by the process of magma segregation and extraction. These processes define the resulting composition of the magma. Depending on the efficiency of the segregation and extraction, there will be different structures of the volcanic and igneous plumbing systems.
Melt segregation is the process of melt separating from its source rock. After the silica-rich melt is generated by partial melting, melt segregation is achieved by the gravitational compaction of the source rock. It causes the squeezing of the melt through the pores and the melts are produced at grain boundaries. When the melt droplets continue to build up and the proportion of melt continues to increase, they tend to gather together as melt pools. The interconnectivity of the melt determines whether and when melt may be extracted. When the melt percentage in the source rock approaches the first percolation threshold at 7%, the melt starts to migrate. At this point, 80% of the grain boundaries are melted and the rock becomes very weak. As melting advances and the melt continues to accumulate, it reaches the second percolation threshold at a melt percentage of 26% to 30%. The matrix of the source rock will start to break down and the melt will start to be extracted.
After the melt segregates from the solid, melt extraction takes place. The rate of magma extraction depends on the spatial distribution and interconnectivity of the magma channel network developed out of its source rock. There are two end members of melt extraction: melt can be extracted in pulses if the development of magma channels are rapid and the network is highly interconnected, or melt can be constantly drained from the source if the magma channels are developed in a continuous and steady manner.
Also, magma extraction controls the chemical composition of the melt, the amount of magma transported by dykes, and consequently, the volume flux of magma into plutons. These will eventually control the overall structure of the VIPS such as the formation of dykes and plutons.
For instance, if the magma channels are not well connected, the source may not be drained successfully, and dykes may freeze before propagating far enough to feed plutons. If the source rock could not initiate dyke ascent with sufficient melt, the source rock may remain undrained, favouring diapiric ascent of the source rock.
When there is sufficient melt accumulation, the magma in the source will migrate from the source to the shallower level of the crust through magma conduits to feed and form different magma reservoirs and structures in VIPS. The buoyancy of magma is the main driving force of all types of transportation mechanism.
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Volcanic and igneous plumbing systems AI simulator
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Volcanic and igneous plumbing systems
Volcanic and igneous plumbing systems (VIPS) consist of interconnected magma channels and chambers through which magma flows and is stored within Earth's crust. Volcanic plumbing systems can be found in all active tectonic settings, such as mid-oceanic ridges, subduction zones, and mantle plumes, when magmas generated in continental lithosphere, oceanic lithosphere, and in the sub-lithospheric mantle are transported. Magma is first generated by partial melting, followed by segregation and extraction from the source rock to separate the melt from the solid. As magma propagates upwards, a self-organised network of magma channels develops, transporting the melt from lower crust to upper regions. Channelled ascent mechanisms include the formation of dykes and ductile fractures that transport the melt in conduits. For bulk transportation, diapirs carry a large volume of melt and ascent through the crust. When magma stops ascending, or when magma supply stops, magma emplacement occurs. Different mechanisms of emplacement result in different structures, including plutons, sills, laccoliths and lopoliths.
Partial melting is the first step for generating magma and magma is the basis of VIPS. After magma is generated, it will travel across the crust and lead to the formation of magma conduits and chambers. In continental crust, partial melting occurs when a portion of the solid rock melts into felsic magma. Rocks in the lower crust and the upper mantle are subject to partial melting. The rate of partial melting and the resultant silicate melt composition depend on temperature, pressure, flux addition (water, volatiles) and the source rock composition. In oceanic crust, decompression melting of mantle materials forms basaltic magma. When the mantle materials rise, the pressure greatly decreases which significantly lowers the melting point of the rock.
After magma is generated, magma will migrate out of its source region by the process of magma segregation and extraction. These processes define the resulting composition of the magma. Depending on the efficiency of the segregation and extraction, there will be different structures of the volcanic and igneous plumbing systems.
Melt segregation is the process of melt separating from its source rock. After the silica-rich melt is generated by partial melting, melt segregation is achieved by the gravitational compaction of the source rock. It causes the squeezing of the melt through the pores and the melts are produced at grain boundaries. When the melt droplets continue to build up and the proportion of melt continues to increase, they tend to gather together as melt pools. The interconnectivity of the melt determines whether and when melt may be extracted. When the melt percentage in the source rock approaches the first percolation threshold at 7%, the melt starts to migrate. At this point, 80% of the grain boundaries are melted and the rock becomes very weak. As melting advances and the melt continues to accumulate, it reaches the second percolation threshold at a melt percentage of 26% to 30%. The matrix of the source rock will start to break down and the melt will start to be extracted.
After the melt segregates from the solid, melt extraction takes place. The rate of magma extraction depends on the spatial distribution and interconnectivity of the magma channel network developed out of its source rock. There are two end members of melt extraction: melt can be extracted in pulses if the development of magma channels are rapid and the network is highly interconnected, or melt can be constantly drained from the source if the magma channels are developed in a continuous and steady manner.
Also, magma extraction controls the chemical composition of the melt, the amount of magma transported by dykes, and consequently, the volume flux of magma into plutons. These will eventually control the overall structure of the VIPS such as the formation of dykes and plutons.
For instance, if the magma channels are not well connected, the source may not be drained successfully, and dykes may freeze before propagating far enough to feed plutons. If the source rock could not initiate dyke ascent with sufficient melt, the source rock may remain undrained, favouring diapiric ascent of the source rock.
When there is sufficient melt accumulation, the magma in the source will migrate from the source to the shallower level of the crust through magma conduits to feed and form different magma reservoirs and structures in VIPS. The buoyancy of magma is the main driving force of all types of transportation mechanism.