A new campaign was undertaken by Justinian's nephew Germanus Justinus, but he died in 551 CE, succeeded by the general Narses. In 553 CE, Narses defeated Totila and Italy was once again Roman. Justinian's reign lasted almost 40 years, but it was not always popular.
Volcanism is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics and volcanic gases erupt through a break in the surface called a vent.ome of this magma may cool extremely rapidly and will form volcanic glass (rocks without crystals) such as obsidian. Magma that remains trapped below ground in thin intrusions cools slower than magma exposed to the surface and produces rocks with medium-sized crystals.
Image on the right courtesy of http://www.csmate.colostate.edu). Carbonation is the process of rock minerals reacting with carbonic acid. Carbonic acid is formed when water combines with carbon dioxide. Carbonic acid dissolves or breaks down minerals in the rock.hemical weathering is the weakening and subsequent disintegration of rock by chemical reactions. These reactions include oxidation, hydrolysis, and carbonation. These processes either form or destroy minerals, thus altering the nature of the rockâs mineral composition.