E&E 151 S Introductory Geology: Chapter 22.3 (Metallic Resources) Definitive Study

Metallic Resources

Essential materials, alongside fossil fuels, upon which modern industrial society heavily relies.

Ore

A naturally occurring material containing metals in sufficient concentrations that it can be profitably mined.

Potential Ore Body

A localized rock deposit where the metal concentration is significantly higher than its average crustal abundance.

Profitability Requirement

The economic principle defining an ore, stating that a mineral deposit is not an ore if extraction costs exceed market value (e.g., gold dissolved in seawater is not an ore, whereas hematite with 70% iron content is profitably mined).

Economic Geology

The field of geology dedicated to understanding the origins of ore deposits to locate and develop new mineral reserves efficiently.

Magmatic Crystal Settling

An igneous ore formation process where early-crystallizing minerals settle by gravity to the bottom of a cooling magma body or sill.

Bushveld Complex

A major geological intrusion in South Africa containing massive layered deposits of chromite formed by magmatic crystal settling.

Stillwater Complex

A major geological intrusion in Montana containing large deposits of chromite formed by magmatic crystal settling.

Hydrothermal Fluids

Hot water and magmatic solutions injected into country rock during plutonic cooling, representing the primary source of non-ferrous metallic ore deposits.

Hydrothermal Ore Origin

The process where metals residually concentrate in water-rich magma and migrate into country rock to precipitate metallic sulfides.

Hydrothermal Fluid Sources

The two sources of ore-forming fluids, arising either directly from magmatic water or from groundwater heated by plutons.

Convective Hydrothermal Circulation

A thermal circulation system driven by magma heat that circulates groundwater through country rock to deposit metals.

Chemical Precipitation (Sedimentary)

A surface ore formation process in shallow water basins that serves as the most common origin for layered iron and manganese ores.

Supergene Enrichment

A weathering process where downward-moving groundwater leaches copper and sulfur near the surface and redeposits copper below the water table.

Supergene Enrichment Chemistry

The chemical reaction where copper-bearing groundwater moves below the water table and reacts with chalcopyrite to precipitate richer chalcocite.

Supergene Enrichment Result

The economic enhancement that converts an unprofitable 0.3% copper deposit into a profitable 1.0% copper ore.

Placer Deposits

Ore bodies formed when stream currents or wave action mechanically concentrate heavy, durable sediment grains.

Bauxite Formation

The concentration of aluminum ore caused by intense chemical weathering in warm, humid tropical climates.

Smelter Scrubbing

Modern pollution control technology that removes 99% of toxic sulfuric acid smoke emissions during ore processing.

Aluminum

A light metal used in soft drink cans, aircraft, and electrical cables.

Bauxite

The principal ore mineral source for aluminum, formed by tropical weathering.

Chromium

A metal used as an essential alloy in stainless steel and automobile coatings.

Chromite

The principal ore mineral for chromium, formed by magmatic crystal settling.

Copper

A conductive metal used extensively in electrical wiring, equipment, and brass manufacturing.

Native Copper

Pure, uncombined metallic copper occurring naturally in rock deposits.

Chalcopyrite

A primary copper sulfide mineral found in disseminated and hydrothermal ore bodies.

Chalcocite

A rich copper sulfide mineral precipitated below the water table during supergene enrichment.

Gold

A noble metal used in coinage, jewelry, dentistry, and electronics.

Native Gold

Pure gold metal found in hydrothermal veins and placer sediment deposits.

Iron

A primary structural metal serving as the essential ingredient in steel.

Hematite

An iron oxide ore mineral containing up to 70% iron content.

Magnetite

An iron oxide mineral mined commercially as a primary source of iron.

Lead

A dense metal extracted primarily for manufacturing industrial batteries.

Galena

The principal sulfide ore mineral source for lead.

Manganese

A metal utilized as an alloy ingredient to enhance the strength and properties of steel.

Pyrolusite

The principal oxide ore mineral source for manganese.

Mercury

A liquid metal used in thermometers, silent electrical switches, and specialized batteries.

Cinnabar

The principal bright red sulfide ore mineral source for mercury.

Nickel

A metal used extensively as an alloy in steel production.

Pentlandite

The primary nickel sulfide ore mineral.

Silver

A precious metal extracted for coinage, tableware, jewelry, and photographic film.

Argentite

A primary silver sulfide ore mineral.

Native Silver

Pure silver metal occurring directly in host rock.

Tin

A metal used in solders, bronze alloys, and anticorrosion plating.

Cassiterite

The primary tin oxide mineral concentrated in hydrothermal veins and placer deposits.

Zinc

A metal heavily utilized for galvanizing steel and producing brass.

Sphalerite

The principal zinc sulfide ore mineral.

Platinum (Native Platinum)

A heavy, durable noble metal concentrated mechanically in placer deposits.

Titanium

A strong metal extracted from heavy oxide mineral grains concentrated in placer deposits.