Chapter 9 Rocks Flashcards
what all rocks are made of
minerals
the outermost layer of the Earth, includes the crust and uppermost part of the mantle
lithosphere
a very hot mixture of molten rock and gases, just below the Earth’s surface, that has come from the mantle
magma
material broken down by weathering and erosion that is moved by wind or water and collects in layers
sediments
elements found uncombined in the Earth’s crust
native elements
substance made up of atoms and molecules arranged in one of seven different shapes.
crystals
appearance of a mineral caused by the way it reflects light. A mineral can appear glassy, waxy, metallic, dull, pearly, silky or brilliant.
lustre
colour of a mineral as a fine powder, found by rubbing it onto an unglazed white ceramic tile
streak
a measure of how difficult it is to scratch the surface of a solid material. The hardness rating of a mineral is determined by comparison with ten standard minerals. Diamond has a hardness rating of 10 and can scratch other minerals with a lower hardness rating.
hardness
eroding or being eroded by wind, water, or other natural agents.
erosion
denoting rocks composed of broken pieces of older rocks.
clastic
interactions of substances as studied in chemistry.
chemical
relating to or derived from living matter.
organic
the remains or impression of a prehistoric plant or animal embedded in rock and preserved in petrified form.
fossils
rocks that form from the cooling of lava or magma as it is thrown through the air from a volcanic eruption
igneous rocks
igneous rock that forms when lava cools above the Earth’s surface
extrusive rocks
a pale rock that forms when frothy lava cools in the air. Pumice often floats on water as it is very light and full of holes that once contained gas.
pumice
a dark, igneous rock formed from gassy lava that cools quickly
scoria
a property of a material or substance that easily scratches another
abrasive
a dark, igneous rock with small crystals formed by fast cooling of hot lava. It sometimes has holes that once contained volcanic gases.
basalt
a black, glassy rock that breaks into pieces with smooth shell-like surfaces
obsidian
igneous rock that forms when magma cools below the Earth’s surface
intrusive rocks
intrusive rock mass that measures more than 100 kilometres across
batholiths
a hard, igneous rock with different-coloured crystals large enough to see. It forms slowly below the Earth’s surface.
granite
flat, open land beside a river where sediments are deposited during floods
floodplains
large bodies of ice that move down slopes and push boulders, rocks and gravel in front of them
glaciers
deposit left by movement of a glacier
moraines
a sedimentary rock with medium-sized grains. The sand grains are cemented together by silica, lime or other salts.
sandstone
a fine-grained, sedimentary rock without layering
mudstone
a fine-grained sedimentary rock formed in layers by the consolidation of clay
shale
a sedimentary rock with a particle size between that of sandstone and mudstone
siltstone
sedimentary rock containing large particles of various sizes cemented together
conglomerate
a sedimentary rock formed from the remains of sea organisms. It consists mainly of calcium carbonate.
limestone
a sedimentary rock formed from dead plants and animals that were buried before rotting completely
coal
a sedimentary deposit formed when a salt lake or seabed dried up. Its main chemical is sodium chloride.
rock salt
the process that changes rocks by extreme pressure or heat (or both)
metamorphism
rock formed from another rock that has been under great heat or pressure (or both)
metamorphic rocks
a fine-grained metamorphic rock formed as a result of moderate heat and pressure on shale
slate
a metamorphic rock formed as a result of great pressure on limestone
marble
a coarse-grained metamorphic rock formed mainly as a result of great pressure on granite
gneiss
rocks mined to obtain a metal or other chemical within them
mineral ores
extraction of natural resources from the Earth
mining
study of the possible effects of a planned project on the environment
environmental impact statement (EIS)
restored to its previous condition
rehabilitated
waste rock removed from below the topsoil. This rock is replaced when the area is restored.
overburden
mining that scours out soil and rocks on the surface of the land
open-cut mining
mining that uses shafts and tunnels to remove rock from deep below the surface
underground mining
any remains, impression, or trace of an animal or plant of a former geological age; evidence of life in the past
fossil
the buckling of rocks. It is caused when rocks are under pressure from both sides.
folding
a scientist who studies fossils
palaeontologists
the age of a rock compared with the age of another rock
relative age
animal that eats other animals
carnivores
animals that eat dead plant and animal material
scavengers
cavity in a rock that shows the shape of the hard parts of an organism; types of fungi found growing on the surface of foods
mould
fossils that provide evidence, such as footprints, that an organism was present when the rock was formed
trace fossils
describes volcanoes that are no longer active. Extinct volcanoes have not erupted for thousands of years and show no sign of future eruption.
extinct
a law that states that energy cannot be made or lost. However, energy can be transformed from one type to another or transferred from one object to another.
Law of Conservation of Energy
the energy made available by the flow of electric charge through a conductor
electrical energy
energy stored due to the height of an object above a base level
gravitational potential energy
potential energy derived from chemical reactions
chemical energy
the potential energy stored in a stretched elastic material
elastic potential energy
the energy stored at the centre of atoms, the tiny particles that make up all substances. Nuclear energy can be released from the radioactive metals uranium or plutonium, and transformed into electrical energy in a nuclear power station.
nuclear energy
the fraction of energy supplied to a device as useful energy. It is usually expressed as a percentage.
efficiency
releasing its own light
luminous
describes objects that emit light when they are hot
incandescent
describes living things that release light energy
bioluminescent
describes light sent in many directions by small particles within a substance
scattered
