Granite is a felsic rock Viscosity is the resistance to flow (opposite of fluidity). Theoretical studies predict an increase over 3 orders of magnitude for MgSiO3 and CaSiO3 melts on the 4000 K isotherm over the mantle P range [Karki and Strixrude, 2010; Verma and Karki, 2012], and the initial drop with P has been predicted only on the 3000 K isotherm but neither at lower or higher T. Once the packing limit of silicate melts has been reached [Wang et al., 2014], there are no difference in atom‐void structure among these fully depolymerized silicate melts, and as a result, viscosity of these melts converges into a constant value. However, only one data point was clearly at a higher viscosity but had been collected at 5.33 GPa and 1990 K, i.e., quite close to the solidus (∼1925 K–1975 K depending on basalt composition [Tsuruta and Takahashi, 1998; Yasuda et al., 1994]). Mafic materials can also be described as ferromagnesian. The viscosity of lava is an important control on the explosiveness of a volcanic eruption. This is because the mafic minerals melt at much higher temperatures than potassium and sodium, the felsic minerals. The type of magma in the chamber determines the type of volcanic eruption. MgSiO, Journal of Advances We now need a comprehensive viscosity data set in the Ca‐Mg‐Fe‐Si‐O system. However, because of its high gas content, when felsic magma does erupt, the eruption is the most violent. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007‐2013) under grant agreements 312284 and 259649 (European Research Council starting grant to C.S.). Coriolis forces are often considered negligible in the magma ocean dynamics [Solomatov, 2007]. First quantitative in situ X‐ray radiographic measurements on diopside [Reid et al., 2003] melts were interpreted as an initial increase of viscosity with P followed by a decrease. Lassen Peak currently has geothermal activity and could erupt explosively again. Basalt, with low-viscosity magma, provides an easy escape of the gases to the surface. The explosive eruption often results in … Mafic Magma This type of magma has low silica content but higher contents of magnesium and iron. However, spheres falling from a sphere trap show linear distance‐time path while spheres located in peridotite powder show nonuniform velocity, indicating that the terminal velocity was not reached with the possibility that such data points overestimated viscosity as pointed out by Liebske et al. In the case of magmas or lavas, the hotter the lava, the easier it flows, and the less silica that is present, the lower the viscosity (see right side of the diagram in Figure 9.7).  measured the viscosity of molten peridotite up to 13 GPa using a sphere trap on top of the sample to prevent the sphere from falling within the large T interval between solidus and liquidus, while another sphere was embedded within the peridotitic sample. Viscosity is a liquid’s resistance to flow. Amagma's viscosity is largely controlled by its temperature, composition,and gas content (see downloadable programs at the bottom of thispage). a. slower, higher. and Chemical Oceanography, Physical Electron microprobe analyses were carried out at the CAMPARIS center at UPMC (Table 1) using a SX5 Cameca electron microprobe. Magma pushes toward the surface through fissures and reaches the surface through volcanic vents. Most felsic magma will stay deeper in the crust and will cool to form igneous intrusive rocks such as granite and granodiorite. Whereas, felsic rocks have high viscosity. Journal of Geomagnetism and Aeronomy, Nonlinear Physics, Solar An steady stream of volcanic water and mud down the slopes of a volcano. High‐pressure experiments were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. • Mafic rocks are rich in iron and magnesium, whereas Felsic rocks are rich in silica and aluminum. It also has a low content of gas and viscosity.