TA3101 Genesa Bahan Galian - Materi 05a Endapan Magmatik Cair

Summary

In this video, Andi Hakim introduces the topic of magmatic deposits, specifically focusing on the formation of magmatic sulfide ores. He explains the processes behind the formation of these deposits, including the importance of immiscibility in magma, which leads to the separation of sulfide minerals from silicate minerals. Various key metals such as copper, nickel, platinum, and iron are discussed, along with their associations with ultramafic rocks. The lecture explores the unique characteristics and environments of magmatic sulfide deposits, providing examples from different global locations. The video concludes with an overview of the textural features and mineral distribution of these deposits.

Takeaways

• 😀 The lesson introduces the topic of magmatic deposits, focusing on the formation and characteristics of magma-derived deposits.
• 😀 Magmatic deposits, also known as 'magma deposits', are formed directly from magma through aggregation and crystallization processes.
• 😀 These deposits have a direct relationship with magma and the channels through which magma flows, often forming in deep parts of the Earth or at the surface.
• 😀 Two important processes in the formation of these deposits are 'graffiti serviks' and 'immiscibility', where different magma solutions do not mix.
• 😀 Key metals found in magmatic deposits include copper, titanium, nickel, platinum, and other platinum group elements.
• 😀 Magmatic sulfide deposits are closely related to ultramafic rocks like olivine and pyroxene, which are rich in sulfides and form through immiscibility processes.
• 😀 Sulfide solutions act as collectors for valuable metals, such as copper, gold, and platinum group elements, as they separate from the magma.
• 😀 When sulfide and silicate solutions separate, they form layered structures in the deposits, with sulfides generally found in the lower layers.
• 😀 Example deposits of magmatic sulfides include still water deposits in America and nickel-copper deposits in Indonesia and Russia.
• 😀 Magmatic sulfide deposits are typically formed in ultramafic or mafic rocks and can be found in diverse geological environments like convergent margins and continental rifts.
• 😀 The deposits exhibit unique textures, such as the 'stringy texture', which is commonly found in nickel-rich sulfide deposits.

Q & A

What is the primary topic of this class session?

The primary topic of this class is the discussion about 'magmatic deposits,' specifically focusing on the processes and mechanisms of their formation, with an emphasis on sulfide deposits.

What is the relationship between magma and the formation of magmatic deposits?

Magmatic deposits form directly from magma through processes like crystallization or aggregation. These deposits often originate from early-stage crystallization in magma, which can either remain in deep bodies or be transported to the surface.

What are the two important processes involved in the formation of magmatic deposits?

The two important processes are 'graffiti serviks' and 'immiscibility.' Graffiti serviks involves the segregation of minerals, while immiscibility refers to the inability of certain magmatic solutions to mix, which leads to the separation of sulfide and silicate liquids.

Why is the study of magmatic sulfide deposits important?

Magmatic sulfide deposits are important because they contain valuable metals like copper, nickel, platinum group elements, and others. These metals are essential for various industrial applications and are often concentrated in sulfide-rich magmatic systems.

What role do sulfides play in the formation of these deposits?

Sulfides serve as collectors or concentrators of valuable metals within magma. When magma cools, sulfides can trap metals like copper, nickel, and platinum, leading to the formation of economic mineral deposits.

What is the significance of olivine in magmatic processes?

Olivine is a primary mineral that forms early in the cooling of ultrabasic magma. It can carry along other valuable metals, including copper, and is crucial for the formation of magmatic sulfide deposits.

How does the process of immiscibility work in magma?

Immiscibility occurs when two liquid solutions, such as sulfide and silicate liquids in magma, do not mix. Instead, they separate into distinct phases, with sulfide-rich phases collecting valuable metals like copper and platinum.

What is the 'net texture' in magmatic sulfide deposits?

The 'net texture' refers to the characteristic pattern that forms when sulfide minerals separate from silicate minerals in magma. This texture appears like a network or mesh, signifying the separation of the two phases.

What are some common locations where magmatic sulfide deposits are found?

Magmatic sulfide deposits are often found in regions with ultramafic or mafic rocks, such as parts of Russia, Finland, Sweden, and Australia. They are also present in certain areas of the United States and Africa.

What are the environmental conditions that lead to the formation of magmatic sulfide deposits?

These deposits typically form in environments with high-temperature magmatic systems, particularly in areas of tectonic activity such as convergent plate boundaries, ophiolite complexes, and areas with rifting or volcanic activity.