Economic Geology and Energy Flashcards
7 cards from real ASBOG practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Economic Geology and Energy flashcards as text
Sedimentary exhalative (SEDEX) deposits form when:
Answer: Metal-rich hydrothermal brines vent onto the seafloor and precipitate sulfides within sediments
SEDEX deposits form when hydrothermal brines exhale onto the seafloor and precipitate stratiform Pb-Zn-Ag sulfides within marine sediments.
Which factor MOST directly controls the economic viability of a phosphate rock deposit?
Answer: P2O5 content and proximity to agricultural markets
The P2O5 grade of the ore and transportation costs to fertilizer markets are the primary economic factors for phosphate mining.
In the context of oil sands (tar sands), the hydrocarbon extracted is called bitumen, which differs from conventional crude oil primarily because it:
Answer: Is too viscous to flow without heating or dilution
Bitumen has very high viscosity (API gravity <10°) and cannot flow under reservoir conditions without thermal treatment or dilution with lighter hydrocarbons.
The 'critical zone' of a Bushveld Complex-type layered mafic intrusion is significant because it hosts:
Answer: Platinum group element (PGE)-bearing reefs such as the Merensky Reef
The Critical Zone of the Bushveld Complex contains the Merensky Reef and UG2 Reef, which are the world's dominant sources of platinum group elements.
Carbon capture and storage (CCS) for CO2 sequestration is BEST suited to which geologic setting?
Answer: Deep saline aquifers or depleted oil and gas reservoirs with impermeable caprock
Deep saline aquifers and depleted hydrocarbon reservoirs are preferred CCS targets because they have proven trapping capacity and seal integrity.
A skarn deposit forms when:
Answer: Magmatic fluids react metasomatically with carbonate country rock adjacent to an intrusion
Skarns form by metasomatic replacement of carbonate rocks (limestone, dolomite) by calc-silicate minerals and associated ore minerals introduced by magmatic fluids.
Which renewable energy resource directly utilizes the thermal gradient within the Earth's crust rather than solar or gravitational energy?
Answer: Geothermal energy
Geothermal energy taps the Earth's internal heat from radioactive decay and residual heat of formation, independent of solar or tidal forcing.