Intro to Geosciences - Unit 8

placer:

Deposit of heavy ores in stream or beach sediments.

gangue:

Material found around ore which is less valuable and needs to be removed in order to obtain ore.

Which of the following best defines an ore?

Metal-bearing minerals that can be extracted for profit.

Mississippi Valley-type:

Metallic mineral deposit of mainly lead and zinc from groundwater movements within sedimentary rocks.

The best type of coal in terms of purity is:

anthracite

Tar sands, or oil sands:

are sandstones that contain petroleum products that are highly viscous (like tar), and thus, can not be drilled and pumped out of the ground, unlike conventional oil.

Waste rock left over after a mine has removed the ore is known as:

tailings

All items we use can come from only three sources:

they can be farmed, hunted or fished, or they can be mined.

An energy resource becomes uneconomic once the:

total cost of extracting it exceeds the revenue which is obtained from the sale of extracted material.

Which geologic setting below were most of the world's coal reserves deposited?

tropical to subtropical fluvial and shallow marine systems where swamps could occur.

Refining is done one of three ways:

1. items can either be mechanically separated and processed based on the unique physical properties of the ore mineral, like recovering placer gold based on its high density; 2. items can also be heated to chemically separate desired components, like refining crude oil into gasoline; or 3. items can be smelted, in which controlled chemical reactions unbind metals from the minerals they are contained in, such as when copper is taken out of chalcopyrite (CuFeS2).

evaporite:

A chemical sedimentary rock that forms as water evaporates. Evaporite minerals like halite are used in our food as common table salt. Gypsum is a common nonmetallic mineral used as a building material, being the main component of dry wall. It is also used as a fertilizer. Other evaporites include sylvite (potassium chloride) and bischofite (magnesium chloride), both of which are used in agriculture, medicine, food processing and other applications.

trap:

A geologic circumstance (such as a fold, fault, change in lithology, etc.) which allows petroleum resources to collect. A combination of a subsurface geologic structure and an impervious layer that helps block the movement of oil and gas and concentrates it for later human extraction.

bauxite:

A highly weathered soil deposit that consists of aluminum ores.

concentrator:

A mechanical process which takes ore and separates it from gangue material.

mineral:

A natural substance that is typically solid, has a crystalline structure, and is typically formed by inorganic processes. Minerals are the building blocks of most rocks.

fusion:

A process inside stars where smaller atoms combine and form larger atoms.

fracking (hydraulic fracturing):

A process of injecting pressurized fluids into the ground to aid in hydrocarbon migration.

smelting:

A process which chemically separates desired element(s) from ore minerals.

nonrenewable:

A resource that is not able to be replaced on human time scales.

renewable:

A resource which is replaced on human time scales.

pegmatite:

A rock (or texture within a rock) with unusually-large crystals, minerals with rare trace element concentrations, and/or unusual minerals, typically forming in veins as the last dredges of magma crystallize.

source rock:

A rock that contains material which can be turned into petroleum resources. Organic-rich muds form good source rocks.

banded iron formation:

A sedimentary rock that formed long ago as free oxygen changed the solubility of iron, causing layers of iron rich and iron-poor sediments to form in thin layers, or bands.

Which of the following problems is associated with the burning of coal?

All of the above. (acid rain, carbon dioxide emissions, ash with toxic metal impurities)

"Fossil fuels" refers to:

All of the above. (coal, oil, natural gas.)

formation:

An extensive, distinct, and mapped set of geologic layers.

kimberlite:

An ultramafic rock from deep volcanic vents that can contain diamonds.

skarn:

Carbonate rock that reacts with hot magmatic fluids, creating concentrated ore deposits, which include copper, iron, zinc, and gold.

sediment-hosted copper:

Diagenetic copper deposit within sedimentary rocks.

geothermal:

Energy derived from the heat in the interior of the earth. The heat of the Earth, known as geothermal, can be viable anywhere if drilling goes deep enough. In practice it is more useful where heat flow is great, such as volcanic zones or regions with thinner crust. Renewable Energy.

fossil fuel:

Energy resources (typically hydrocarbons) derived from ancient chemical energy preserved in the geologic record. Includes coal, oil, and natural gas.

Biofuel is harnessed from the potential energy of water.

False

coal:

Former swamp-derived (plant) material that is part of the rock record.

natural gas:

Gaseous fossil fuel derived from petroleum, mostly made of methane.

Metallic minerals are most commonly associated with ____________ rocks.

Intrusive igneous

porphyry:

Large metallic mineral deposit that forms near magma bodies like plutons. Commonly contains copper, lead, zinc, molybdenum, and gold.

sediment-hosted disseminated gold:

Low grade, broad deposits of microscopic gold found in sedimentary rocks with diagenetic alteration. deposits consist of low concentrations of microscopic gold as inclusions and disseminated atoms in pyrite crystals. These deposits are also called Carlin-type deposits because the disseminated deposit near Carlin, Nevada is where the new technology was first applied and because the first definitive scientific studies were conducted there.

volcanogenic massive sulfide:

Metallic mineral deposit which forms near mid-ocean ridges.

nonmetallic:

Minerals that have a luster that is not similar to metal, and typically do not contain valuable metals like copper, lead, zinc, tin, etc.

metallic:

Minerals with a luster similar to metal and contain metals, including valuable elements like lead, zinc, copper, tin, etc.

supergene enrichment:

Oxidation that occurs in sulfide deposits which can concentrate valuable elements like copper.

redox (short for reduction/oxidation):

Reactions that are related to the availability of oxygen. Many minerals or ions change their solubility based on redox conditions.

Refining:

Removing trace elements from desired elements.

reservoir:

Rocks which allow petroleum resources to collect or move.

The definition of ore is dependent on ______________

Size

If a mineral deposit is located deep within the Earth, ____________ mining methods are used to mine the deposit.

Subsurface

Solid resources are extracted by two principal methods, of which there are many variants:

Surface mining is the practice of removing material from the outermost part of the Earth. Open pit mining is used to target shallow, broadly disseminated resources. Strip mining and mountaintop mining are surface mining techniques also used for resources that cover large areas, especially layered resources like coal. Underground mining is often used for higher-grade, more localized, or very concentrated resources.

The general sequence of a swamp turning into the various stages of coal are:

Swamp => Peat => Lignite => Sub-bituminous => Bituminous => Anthracite => Graphite.

sequence stratigraphy:

The study of changes in the rock record caused by changing sea level over time.

period:

The third largest span of time recognized by geologists; smaller than a era, larger than a epoch. We are currently in the Quaternary period. Rocks of a specific period are called systems.

Which of the following best describes the sustainability of most mineral resources?

They are nonrenewable because they are formed at slower rates than we use them.

acid rock drainage:

Toxic waters rich in heavy metals and often of low pH that come from unregulated mining districts.

What is the name for the general feature is responsible for collecting and concentrating petroleum?

Trap

Nonmetals extracted from metals during smelting are termed slag.

True

Underground-mining may be selected over surface-mining when the ore is concentrated and deep.

True

ore:

Valuable material in the Earth, typically used for metallic mineral resources.

The development of a trap could be a result of many different geologic situations. Common examples include:

an anticline or domal structure, an impermeable salt dome, or a fault bounded stratigraphic block (porous rock next to non-porous rock). The different traps have one thing in common: they pool the fluid fossil fuels into a configuration in which extraction is more likely to be profitable.

Fossils fuels:

are extractable sources of stored energy created by ancient ecosystems. The natural resources that typically fall under this category are coal, oil (petroleum), and natural gas. This energy was originally formed via photosynthesis by living organisms such as plants, phytoplankton, algae, and cyanobacteria.

Layered intrusions (typically ultramafic to mafic):

can be host to deposits that contain copper, nickel, platinum-palladium-rhodium, and chromium. The Stillwater Complex in Montana is an example of an economic layered mafic intrusion.

Oil that is taken directly from the ground without being treated is called:

crude oil.

Most of the world's energy supply comes from:

fossil fuels.

Conventional oil and gas reserves are those:

in which oil and gas can be pumped relatively easily

Oil shale (or tight oil):

is a fine-grained sedimentary rock that has a significant quantity of petroleum or natural gas.

Phosphorus:

is an essential element that occurs in the mineral apatite, which is found in trace amounts in common igneous rocks. Phosphorite rock, which is formed in sedimentary environments in the ocean, contains abundant apatite and is mined to make fertilizer. Phosphorous is a major component of bone and a key component of DNA.

Wind energy:

is maybe the oldest form of renewable energy, used in sailing ships and windmills. Renewable Energy.

Solar energy:

is the energy that comes from fusion within the Sun, which radiates electromagnetic energy. Renewable Energy.

Which sequence correctly shows an increase in coal ranks from lowest to highest?

lignite, bituminous, anthracite

Mineral resources, while principally nonrenewable, are generally placed in two main categories:

metallic (containing metals) or nonmetallic (containing other useful materials). Most mining is focused on metallic minerals.

Which of the following lists contains only fossil fuels?

natural gas, coal, oil

The ingredients for fertilizers are mined:

nitrogen from the atmosphere using the Haber process, potassium from the hydrosphere (lakes or oceans) by evaporation, and phosphorus from the lithosphere (minerals like apatite from phosphorite rock, found in Florida, North Carolina, Idaho, Utah, and around the world).

Many nonrenewable resources are chiefly a result of:

planetary, tectonic, or long-term biologic processes, and include items such as gold, lead, copper, diamonds, marble, sand, natural gas, oil, and coal.

Several types of porphyry deposits exist:

porphyry copper, porphyry molybdenum, and porphyry tin.

Hydroelectric dams:

provide energy by allowing water to fall through the dam activating turbines that produce the energy. Ocean tides can also be a reliable source of energy. Renewable Energy.

Resources generally come in two major categories:

renewable, which can be reused over and over, or replicate over the course of a short (less than a human life span) time, and nonrenewable, which cannot.

Oil and gas source rocks are always:

sedimentary.

The industrial process that separates metals from ore material is known as:

smelting

A rock that has the potential to generate oil or gas if subjected to elevated temperature and pressure is known as:

source rock