Geology & Mineral Exploration Flashcards
7 cards from real CMA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Geology & Mineral Exploration flashcards as text
In mineral exploration drilling, what is the advantage of HQ-size diamond core over NQ-size core?
Answer: HQ produces a larger diameter core (63.5 mm) providing more sample for assay and geological logging
Larger HQ core provides better sample representivity for assaying, better structural data, and reduced sampling error compared to the smaller NQ core.
What geological process forms placer gold deposits?
Answer: Mechanical weathering and fluvial transport concentrate dense gold particles in stream sediments
Placer deposits form when weathering liberates gold from primary lode sources and streams concentrate it by density in gravel bars and bends.
The term 'epithermal deposit' refers to a mineral deposit formed at:
Answer: Shallow crustal depths (less than 1.5 km) at low temperatures (150–300°C) from hydrothermal fluids
Epithermal deposits form in the upper crust from low-temperature hydrothermal fluids and are major sources of gold and silver in volcanic terranes.
Which remote sensing technique is most useful for mapping iron oxide alteration zones associated with mineral deposits from satellite imagery?
Answer: Shortwave infrared (SWIR) and visible near-infrared (VNIR) multispectral analysis
SWIR and VNIR bands detect iron oxide and hydroxyl mineral absorption features that indicate hydrothermal alteration zones favorable for mineralization.
What is a 'manto' deposit in the context of mineral exploration in carbonate rocks?
Answer: A stratabound replacement deposit where hydrothermal fluids replace carbonate host rock along bedding planes
Manto deposits are laterally extensive, bedding-parallel replacements of carbonate rock by sulfide minerals, commonly hosting silver, lead, and zinc.
In airborne electromagnetic (AEM) surveys, what subsurface property is primarily being measured?
Answer: Electrical conductivity of rocks and overburden
AEM systems induce eddy currents in conductive materials (massive sulfides, graphite, saline groundwater) and measure the resulting secondary electromagnetic field.
What is the significance of the 'red bed copper' deposit type for mineral exploration in sedimentary basins?
Answer: Copper minerals precipitate where reduced fluids encounter oxidized red-colored sandstones and conglomerates
Red bed copper deposits form at redox interfaces in sedimentary basins where copper-bearing brines encounter organic-rich or reduced rock units.