As iron-rich silicates are normally dark in color, mafic rocks are dark-colored. Intermediate magmas produce diorite (the plutonic equivalent of andesite) . Unlock to view answer. Davidson, et al., 1991]. Q 21 Q 21. The former has more felsic lavas that clump more easily, creating explosive eruptions. It is formed during the eruption of felsic lavas, which are distinguished by having high concentrations of the chemical element silica. Pillow lavas are also mafic lavas. • Mafic rocks are denser and heavier than Felsic rocks. In turn, felsic magma is associated with the volatile stratovolcano characterized by Plinian eruptions (mushroom cloud) followed by a deadly pyroclastic flow of hot ash, gas, and lava. higher silica content. Mafic or basaltic lavas have a silica content of 52% to 45%. lower density. Increased (Na 2 O, K 2 O, Ta, a.s.o.) "Mafic" is a term that describes igneous rocks or silicate material characterized by a rich content of iron and magnesium while felsic rocks are igneous rocks that are rich in light elements such as oxygen, aluminum, silicon, potassium, and sodium. Summary: 1.Mafic lava is more viscous than felsic lava. The latter have more mafic lavas that flow more readily, creating spectacular geysers of lava and accompanying rivers. The word derives from a composite of the chemical symbols for Magnesium (Ma) and Iron (Fe). Mafic enclaves have significantly higher U/Th ratios than their dacitic host lavas, precluding simple models that relate the mafic and felsic magmas by fractionation or aging alone. compared to felsic lavas, mafic lavas have a . The term “felsic” refers to the high content of quartz laden feldspar minerals in the lava. Pillow lavas are associated with ________ eruptions. The vast majority of lava out there falls into one of three types: mafic, intermediate, and felsic. In turn, felsic magma is associated with the volatile stratovolcano characterized by Plinian eruptions (mushroom cloud) followed by a deadly pyroclastic flow of hot ash, gas, and lava. The term “felsic” refers to the high content of quartz laden feldspar minerals in the lava. Archean greenstone belts contain low grade metamorphic volcanic sequences with localised examples of preserved original volcanic textures and relict m… The lava flow has a medium viscosity as well, and once cooled, the resulting rock is known as Andesite. A mixture of air, hot ash, and pumice lapilli that rushes down the side of a volcano in a scalding avalanche is termed a(n) _____. Geologists traditionally divide the compositions of the igneous rocks into four major groups or … The felsic end is lighter due to the preponderance of the more lightly hued silica. a. higher silica content c. lower viscosity b. lighter color d. lower density. Felsic magma generally forms in ________. still have a magma source but show no signs of impending eruption. Mafic has low levels of silica. Slowly cooling felsic magmas produce granite (the plutonic equivalent of rhyolite). As a result, eruptions of volcanoes made of mafic lavas are less explosively violent than felsic … Slowly cooling felsic magmas produce granite (the plutonic equivalent of rhyolite). Intermediate lavas will form blocky lavas, which are higher viscosity lavas that break off into angular blocks. Compared to felsic lavas, mafic lavas have a _____. 3.Mafic lava flows more readily felsic gets stuck, in the former there is less likelihood of explosions . b. through the freezing or crystallization of a melt. Lava contained within the Earth’s crust is known as magma; rock that has been liquefied due to the intense pressure and heat within the mantle. Water and other volatiles can more easily and gradually escape from mafic lava, so eruptions of volcanoes made of mafic lavas are less explosively violent than felsic lava eruptions. The textural term for a basaltic lava flow that has a smooth, ropy appearance is ________. They're also called basaltic, andesitic, and rhyolitic lavas, respectively. Which of the following volcanic products can decrease global temperatures? There are two types of felsic lava: rhyolite and dacite. The ash released by explosive volcanic eruptions can also produce ________. Felsic magmas are normally between 650 and 800 degrees Celsius, whereas mafic magmas are between 1,000 and 1,200 degrees. The average time between eruptions is called a(n) ________. Felsic lavas have the highest silica and lowest magnesium concentration (rich in feldspar, and generally lighter in color than mafic lavas). Compared to felsic lavas, mafic lavas have a ________. Quartz has a relatively low melting temperature, so magma with a higher silica content can form at much cooler temperatures relative to magma that contains denser elements such as iron or magnesium.