GENERAL GEOLOGY

Detailed explanation-1: -Magmas derived from the mantle material beneath the crust have higher levels of iron, magnesium and calcium, but they are still likely to be dominated by oxygen and silicon. All magmas also have varying proportions of dissolved water as well as gases such as carbon dioxide and hydrogen sulphide.

Detailed explanation-2: -Magmas derived from the mantle have higher levels of iron, magnesium, and calcium, but they are still likely to be dominated by oxygen and silicon.

Detailed explanation-3: -Mafic MagmaMafic magma has relatively low silica content, roughly 50%, and higher contents in iron and magnesium. This type of magma has a low gas content and low viscosity, or resistance to flow.

Detailed explanation-4: -Answer and Explanation: The magma that forms at mid-ocean ridges is commonly basalt with mafic mineral composition. This means that it has a high content of iron and magnesium while less than 50 percent of its total composition is silica or silicate minerals.

Detailed explanation-5: -Basaltic magma is high in iron, magnesium, and calcium but low in potassium and sodium. It ranges in temperature from about 1000oC to 1200oC (1832oF to 2192oF). Andesitic magma has moderate amounts of these minerals, with a temperature range from about 800oC to 1000oC (1472oF to 1832oF).