A long-lived silicic magma chamber may form within so-called Deep Crustal Hot Zones when basaltic magmas are repeatedly emplaced into continental crust (Annnen et al., 2006) and foster processes such as magmatic differentiation, assimilation, and magma mingling and mixing (Schmincke, 2004). Differentiation is the magma composition evolution ...

Sep 1, 2012 · A magma chamber is a partially or totally molten body located in the crust and supplied with magma from a deeper source, a reservoir (Fig. 1). While active, a magma chamber acts as a sink for magma from the deeper reservoir, and as a source for magma injections (dykes, sheets, sills) into the surrounding crust and the associated volcano.

Jan 1, 2015 · Oddly enough, although the physical nature of this active magma chamber is known in detail, its chemical composition is not nearly as well known. This is quite the reverse of magma chambers associated with volcanism, where chemical composition is known in excruciating detail, but the shapes, sizes, and cooling rates of the active reservoirs are ...

Mar 8, 2011 · A very clear example of magma-chamber growth through sill intrusions is provided by the Slaufrudalur pluton in Southeast Iceland (Fig. 4, Fig. 5). The pluton is entirely felsic, consisting of a layered granophyre, and has a length of about 8 km, a maximum width of 2 km, and a cross-sectional area of 15 km 2.

Jul 15, 2009 · The magma chamber starts to be sill-like and, if emplacement rates are high enough, it eventually evolves towards a bell shaped chamber (Fig. 3). Because new injected magma is trapped by the high-melt layer, the magma chamber grows from top to bottom so that the highest temperatures are at the bottom of the magma body.

Jun 15, 2014 · Calculated total volume of magma chamber (red circles) for 14 calderas. Red line shows the correlation between the calculated volume of magma chamber and horizontal diameter of caldera. The broken lines show the threshold of magma withdraw to trigger collapse calculated with Eq. (8) (for bubble fraction x = 0.05, 0.10 and 0.20, respectively ...

Jan 1, 2008 · Circular magma chamber located in a layered crustal segment, 20 km thick and 40 km wide, subject to horizontal tensile stress of 5 MPa. Below the chamber, itself with a top at 3 km depth and located in a comparatively soft layer (stiffness 10 GPa), there is a layer with a uniform stiffness of 40 GPa.

Sep 15, 2016 · The evolution from early silicic dacite intrusions to more intermediate andesitic intrusions has been interpreted as evidence for a chemically structured upper crustal magma chamber, with the extraction of silica-rich melts from the upper portions followed by the extraction of the deeper, more mafic units from the hybrid magma chamber (Halter ...

Aug 1, 1986 · Slow dense inputs of magma may mix very little with resident magma of comparable viscosity as they spread across the floor of the chamber. A similar pulse injected with high upward momentum forms a turbulent “fountain”, which is a very efficient mechanism for magma mixing, as is a turbulent plume of less dense magma rising through the host ...

Dec 1, 2013 · A dacitic magma in a 5–9 km deep chamber at 3 wt.% H 2 O experiencing a 600 bar pressure drop quickly doubles the amount of mush at saturation. For rhyolites under similar conditions the increase is much more muted (Figs. 7c, 7d). The saturation front also enters the mobile magma at the top of the chamber in the dacitic case.