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Porphyry copper deposits are among the most significant sources of copper globally, accounting for over 60% of the world’s copper production . 1. Geological Overview a) Geological Background Porphyry copper deposits are typically associated with magmatic arcs related to subduction zones, where an oceanic plate subducts beneath a continental or another oceanic plate. This tectonic […]Table of Contents Toggle 1. Geological Overviewa) Geological Background
Introduction Ore-bearing hydrothermal fluids are one of the most important agents in the formation of mineral deposits. These fluids, which originate from various geological processes, have the ability to dissolve, transport, and deposit metals in economic concentrations. The study of hydrothermal fluids is crucial for understanding ore genesis and guiding mineral exploration. This article provides […]Table of Contents Toggle Introduction1. Sources of Hydrothermal Fluids
Gold has been one of the most sought-after minerals for centuries due to its value and rarity. Prospectors, geologists, and even hobbyists often search for gold-bearing rocks in the field. But how do you identify rocks that contain gold? This guide will provide an in-depth look at the geological features, rock types, and mineral indicators […]Table of Contents Toggle 1. Understanding the Geological Settings of Gold
Introduction Alteration in geology refers to mineralogical, textural, and chemical changes in rocks due to interactions with fluids, temperature variations, and pressure changes. This process occurs in diverse geological settings, including hydrothermal systems, weathering environments, and metamorphic terrains. Understanding alteration is essential in mineral exploration, petrology, geotechnical engineering, and environmental studies. This article explores the […]Table of Contents Toggle IntroductionTypes and Processes of Alteration
Introduction The Induced Polarization (IP) method is one of the most effective geophysical techniques used in the exploration of sulfide ore deposits. This method is particularly useful for identifying disseminated sulfide minerals, which are commonly associated with copper (Cu), gold (Au), silver (Ag), zinc (Zn), and lead (Pb) deposits. This article provides a detailed overview […]Table of Contents Toggle Introduction1. Understanding the Induced Polarization ...
Introduction Gold exploration is a complex process that requires a combination of geological knowledge, geochemistry, and geophysical techniques. One of the most effective methods for locating gold deposits is the identification of pathfinder elements and minerals. Pathfinder elements and minerals are geochemical indicators that suggest the presence of gold nearby, even if the gold itself […]Table of Contents Toggle IntroductionWhat Are Pathfinders for Gold Deposits?
Introduction Structural control is one of the most significant factors influencing the formation and distribution of hydrothermal gold deposits. Structural geology determines the pathways for mineralizing fluids, the locations of ore deposition, and the overall geometry of gold-bearing zones. Understanding these structural controls is essential for exploration geologists seeking new gold deposits and for mining […]Table of Contents Toggle IntroductionStructural Controls in Hydrothermal Gold Deposits
Introduction to Geology Geology, derived from the Greek words geo (Earth) and logos (study), is the scientific discipline dedicated to understanding the Earth’s composition, structure, processes, and history. It seeks to answer fundamental questions: How did mountains form? Why do volcanoes erupt? What clues do rocks hold about ancient life? From the atomic structure of […]Table of Contents Toggle Introduction to Geology
Engineering geological tests are critical for assessing the physical, mechanical, and chemical properties of rocks and soils to ensure safe and cost-effective design of infrastructure (e.g., dams, tunnels, foundations). These tests help determine material strength, stability, permeability, and susceptibility to hazards like landslides or subsidence. Below are key tests categorized by their application: 1. Field […]Table of Contents Toggle 1. Field Tests (In-Situ)2. Laboratory Tests
Sand Dune Landform: Formation, Types, and Significance Sand dunes are dynamic landforms created by the interaction of wind, sand, and vegetation. These striking natural features are common in deserts, coastal regions, and even in some semi-arid and arid zones. This article explores every aspect of sand dunes, including their formation, types, ecological significance, and role […]Table of Contents Toggle Sand Dune Landform: Formation, Types, and Significance
Magmatic Sulfides and Cumulates Mafic and ultramafic magmas, like all common magmas, contain the major elements oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium. But they typically also contain other elements including sulfur, nickel, and less common metals such as platinumRead more
Magmatic Sulfides and Cumulates
Mafic and ultramafic magmas, like all common magmas, contain the major elements oxygen, silicon, aluminum, iron, calcium, sodium, potassium, and magnesium.
But they typically also contain other elements including sulfur, nickel, and less common metals such as platinum, palladium, and chromium.
As these magmas cool and crystallize, the first minerals to form are plagioclase, pyroxene, and olivine – all made of major elements.
Consequently, the concentrations of sulfur and other minor elements increase in remaining melt.
Eventually, sulfur concentration becomes great enough so that sulfide minerals begin to crystallize.
The sulfide minerals, typically containing iron and nickel, may also contain relatively high concentrations of platinum, palladium, and other minor metals.
Sulfides have greater densities than silicate minerals and the mafic or ultramafic melts.
So, the denser sulfide minerals will, over time, begin to sink. Eventually, after more cooling and crystallization, significant deposits of sulfide minerals may accumulate on the bottom of a magma chamber.
The deposits, which may form centimeters-, or meters-thick layer called a cumulate, are often entirely, or nearly entirely, composed of sulfide minerals.
This process produces magmatic sulfide deposits, which are the most important sources of platinum, palladium, chromium, and several other metals.
Cumulate sulfide minerals include pentlandite (Fe,Ni)9S8, chalcopyrite (CuFeS2), pyrrhotite (Fe1-xS), and pyrite (FeS2)
Cumulate sulfide deposits account for almost 60% of the world’s nickel production and more than 95% of platinum and palladium production.
These deposits are associated with mafic and ultramafic magmas but not, generally, with felsic magmas, because felsic magmas are so viscous that they cool and crystallize before dense minerals can settle.
Sulfides are not the only kind of mineral that can become concentrated in a cumulate deposit.
Oxides – including magnetite (Fe3O4), ilmenite (FeTiO3), and chromite (FeCr2O4) – may settle and collect at the bottom of a magma chamber, too.
These chromite cumulates produce not only significant amounts of chrome, but also very large amounts of platinum, palladium, and related elements.
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