Unveiling the Secrets of Epithermal Gold Deposits
This video explores the discovery process and characteristics of epithermal gold deposits, emphasizing the importance of observations over theoretical models. It highlights the significance of recognizing alteration and exploring feeder zones.
00:00:51 This video discusses the discovery process and characteristics of epithermal gold deposits, highlighting the importance of observations over theoretical models. It explores the formation of acidic condensates and their role in altering rock compositions. Examples of well-studied deposits in the Philippines are examined.
📺 Exploration for epithermal gold deposits is the focus of the video.
🌍 The speaker emphasizes the importance of observing rocks and not forcing them into theoretical models.
🔬 The video discusses the formation of epithermal deposits through condensation of acidic vapors near the surface.
00:19:02 This video discusses the discovery process for epithermal gold deposits and highlights the significance of recognizing barren alteration and exploring feeder zones. Examples of successful discoveries are also provided.
🌋 Epithermal gold deposits form along an unconformity between volcanic basement and overlying rocks.
⛰️ Residual quartz and quartz adit form cliffs due to erosion.
🔍 Mapping and identifying feeder zones is crucial for successful identification of high-grade deposits.
00:37:16 The video discusses the discovery of epithermal gold deposits in various regions. It highlights the importance of drilling deep and looking for feeder zones. Several examples of successful discoveries are presented.
🔑 Drilling deep and looking for feeder zones is important for gold deposit discovery.
💎 Major gold companies initially overlooked southern Peru as a gold district due to its reputation as a silver district, but a Peruvian national company discovered large gold deposits there.
⛰️ The discovery of gold deposits in various regions, including Chile and northern Peru, led to the importance of exploring steam-heated alteration caps and other potential mineralization in those areas.
00:55:29 This video discusses the importance of good geology in exploration for epithermal gold deposits. It emphasizes the need to rely on observations rather than theoretical models from other countries and highlights the role of lateral thinking in developing targets for deep drilling.
🔑 There are no magic bullets in exploration, it's about applying good geology by good geologists.
🌍 Local knowledge and observations are crucial, while theoretical models from other countries should be used only as a guide.
🔬 Lateral thinking and deep drilling are important for developing and testing exploration targets.
01:13:39 This video explores the concept of epithermal gold deposits, comparing different perspectives and discussing the formation process. It also touches on the role of lateral thinking in geology and the use of geophysical techniques to identify potential drilling sites.
🔑 The terminology used to describe different types of gold deposits can vary, causing confusion and debates among experts.
⏰ Epithermal and porphyry systems have similar time scales for deformation, with metal deposition occurring over short periods of time but overall district formation spanning hundreds of thousands to millions of years.
🧠 Lateral thinking is important in the field of geology, as it allows geologists to make connections between different deposits and explore new possibilities based on their experiences and observations.
🔍 Geophysical techniques, like magnetics and resistivity analysis, can be used to identify potential drill targets for epithermal deposits, but the presence of a little cap may affect the usefulness of these techniques.
🌎 The size and grade of epithermal deposits do not necessarily indicate the presence or size of underlying porphyry systems, and there is a wide variety of possibilities in terms of deposit formation and preservation.
🔬 Geochemical anomalies can be useful indicators of an epithermal environment, but it is important to consider local variations and thresholds of anomalies in order to determine their significance.
💧 Boiling processes, which play a role in the formation of low and intermediate sulfidation epithermal deposits, may not be as significant in high sulfidation deposits.
01:31:54 Exploration for Epithermal Gold Deposits: Discovery vs. Dogma by Jeffrey W. Hedenquist. The video discusses the deposition mechanisms of gold in epithermal deposits and the importance of dilution and boiling. It also touches on the relationship between gold and arsenic, mapping in dense vegetation areas, and the significance of calderas in gold deposits.
Gold is deposited in liz' caps by neutral pH solutions, often accompanied by laminated colloidal silica.
Dilution and boiling play a role in the deposition of high-grade gold.
Vegetation can make geological mapping challenging in dense environments.
01:50:05 Exploration for Epithermal Gold Deposits: Discovery vs. Dogma by Jeffrey W. Hedenquist. The video discusses the use of the term 'caldera' and the importance of mapping structures and basement structures in geology. It also explores the different environments that can generate acid fluids and emphasizes the need to understand acid alteration and its relationship to gold anomalies. The speaker talks about the geometry of ore bodies and the significance of feeder zones in finding high-grade mineralization. The video concludes by addressing the presence of multiple mineralized bands and their association with earthquakes in epithermal deposits.
🔍 Exploration for epithermal gold deposits involves mapping caldera or circular structures and understanding their origin and significance.
🗺️ Basement structures and north-south or north-southwest arches play a crucial role in controlling the focus of deep intrusive systems.
🌋 The origin of acid fluids in epithermal deposits can be traced back to magmatic hydrothermal and volcanic vapors condensing environments.
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