chapter 9 rocks Flashcards
what are all rocks made out of
minerals
what is the outer layer of the earth called
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
sidements
elements found uncombined in the Earth’s crust
native elements
geometrically-shaped substance made up of atoms and molecules arranged in one of seven different shapes. The elements that make up a crystal and the conditions present during the crystal’s growth determine the arrangement of atoms and molecules and the shape of the crystals.
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
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 formed from sediments deposited by water, wind or ice. The sediments are cemented together in layers, under pressure.
sedimentary rocks
the wearing away and removal of soil and rock by natural elements, such as wind, waves, rivers and ice, and by human activity
erosion
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 fine-grained sedimentary rock formed in layers by the consolidation of clay
shale
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 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
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
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
basalta
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)
estored to its previous condition
rehabilitated
the time beginning about two million years ago during which early humans made implements of stone
Stone Age
a mixture of a metal with a non-metal or another metal
alloy
a fine-grained sedimentary rock which leaves a very sharp edge when broken
flint
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
palaeontologist
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
