What geological factors contribute to the gold mineralization at Van Gogh?

Question

Accepted Answer

Geological Factors Contributing to Gold Mineralization at Van Gogh

The Van Gogh discovery exhibits gold mineralization within a significant geological structure, characterized by a ~30-meter-wide mylonite zone. This zone hosts mineralized intervals featuring intensely silicified country rock and quartz. Within these gold-rich sections, sulphides, primarily pyrite, can constitute up to 15% of the rock. Notably, the highest-grade gold occurrences are frequently associated with brecciation, a process involving the fragmentation and recementation of rock. Furthermore, the entire mineralized interval and extending into the surrounding country rock displays moderate to strong alteration, identified as sericite-chlorite-ankerite.
Mylonite Zone and Silicification

Gold mineralization at Van Gogh is structurally controlled, occurring within a ~30-meter-wide mylonite zone. Mylonite zones are typically formed under intense shear stress deep within the Earth's crust, resulting in highly deformed and recrystallized rock. Within this zone, the presence of strongly silicified country rock and quartz veins signifies a significant influx of silica-rich fluids. Silicification is a common geological process in gold deposits, where silica replaces existing minerals, often acting as a host for or a pathway for gold-bearing fluids.
Sulphide Content and Brecciation

The gold-rich intervals at Van Gogh are further distinguished by their sulphide content, with pyrite locally making up as much as 15% of the rock. Pyrite, an iron sulphide mineral, can sometimes be associated with gold deposition. The highest concentrations of gold are often found in areas where brecciation has occurred. Brecciation involves the fracturing of rock followed by the introduction of mineralizing fluids that cement the fragments, creating a complex network that can effectively trap and concentrate gold.
Alteration Patterns

Geological examination of the Van Gogh site reveals moderate to strong sericite-chlorite-ankerite alteration. This type of alteration is indicative of hydrothermal fluid activity, where pre-existing minerals in the rock are chemically altered by hot, mineral-rich water. Sericite, chlorite, and ankerite are common alteration minerals found in many epithermal and mesothermal gold systems. The presence of this alteration throughout the mineralized interval and extending into the surrounding rock suggests a pervasive fluid system was responsible for both altering the host rocks and depositing the gold.

Reading history

Hide →

This history is cleared when the page is closed.

What geological factors contribute to the gold mineralization at Van Gogh?

Loading

Was this article helpful?

Helpful

Not helpful

Report an issue

1

0

0

Share with friends