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Geology Dictionary
Geological Terms Beginning With "N"
For Terms Beginning With Other Letters Please Click Below
Nannofossils:
A generic term used in reference to very small fossils that
are at the limit of resolution by a light microscope. They are therefore
studied with electron microscopes and are frequently fossil discoasters
and coccoliths.
Nappe:
A large slab of earth's surface that has been moved in a horizontal
or near horizontal direction over a plane of separation. This motion
can be produced by faulting or sliding. The term is generally used
for very large slabs which are many square kilometers or miles in
surface area.
Native Metal:
A natural deposit of a metallic element such as gold, silver,
copper or iron in a pure form.
Natural Bridge:
An arch-shaped rock formation produced by weathering and/or
erosion.
Natural Gas:
Naturally occurring hydrocarbons that exist in subsurface
rock units in the gaseous state. Methane is the most abundant but
ethane, propane and others also occur.
Natural Levee:
A mound of sediment that parallels a stream channel forming
a levee-like deposit. When flood waters leave the normal stream
channel and enter the flood plain there is a reduction of velocity
that causes suspended sediments to fall to the bottom, producing
this deposit.
Natural Reservoir Pressure:
The pressure within an oil or gas reservoir that forces oil or gas up the well bore when the reservoir is penetrated by drilling.
Neap tide:
A daily tidal range of minimal amplitude that occurs when the moon and sun are positioned at 90 degrees to one another. In this moon-earth-sun configuration, the gravitational attraction of the moon and sun compete for Earth's water. Occurs at the first and third quarters of the moon. See spring tide for contrast.
Nebula:
A cloud of interstellar dust that is faintly visible from Earth.
Neutron:
A subatomic particle, contained in the nucleus of an atom. It has no electrical charge and a mass similar to that of a proton.
Nodule:
A mineral mass that has a different composition or is more
weathering resistant than its surrounding rock. These are normally
rounded in shape. Examples include: chert masses in a limestone
rock unit, pyrite masses in a coal seam, or carbonate masses in
a shale. In most cases these "nodules" have formed within
the rock unit or its former sediment mass. The term is also applied
to rounded masses of manganese minerals that occur on some parts
of the ocean floor.
Non-Operating Interest:
A mineral lease interest that does not involve the rights and responsibilities of exploration, development, or production. A royalty interest is a non-operating interest.
Non-Point Source Pollution:
Pollution that does not originate at a single location. In
an urban area runoff water can be polluted as it flows to a stream
by gasoline, antifreeze, road salt or other contaminants. In rural
areas runoff can be contaminated by insecticides, manure, or fertilizer.
This contamination can be significant but can not be traced back
to a specific source.
Non-Producing:
A term that refers to a property, a well or a mine from which commercial amounts of a mineral resource have not yet been produced.
Normal Fault:
A fault with vertical movement and an inclined fault plane. The block above the fault has moved down relative to the block below the fault.
Nuclear Electric Power (Nuclear Power):
The generation of electricity using the heat released from a nuclear fuel.
Nuclear Fuel:
Fissionable materials that are rich enough to sustain a fission chain reaction.
Nuclear Reactor:
A facility where a nuclear fission chain reaction can be initiated, controlled, and sustained.
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