principle that Earth's processes occurring today are similar to those that occurred in the past
The view that most of earth's geological features are the result of large-scale catastrophes such as floods, volcanic eruptions, etc.
determining whether an object or event is older or younger than other objects or events
a principle that states that younger rocks lie above older rocks if the layers have not been disturbed
A theoretical picture in which layers of rock from around the world are meshed together into a single, unbroken record of earth's past.
breaks in Earth's crust where rocks have slipped past each other
molten rock from the earth's interior that squeezes into existing rock and cools
the bending of rock layers due to stress
occurs when internal forces in the Earth slant rock layers without folding them
A gap or break in the rock layer due to some disturbance.
the stoppage of deposition when a supply of sediment is cut off
condition in which the earth's surface is worn away by the action of water and wind
exists where part of a sequence of parallel rock layers are missing.
exists where sedimentary rock layers lie on top of an eroded surface of nonlayer igneous or metamorphic rock
rock layers are tilted, and younger sediment layers are deposited horizontally on top of the eroded and tilted layers
any method of measuring the age of an event or object in years. the actual age for a rock or mineral
atoms of the same element that have different numbers of neutrons
the process in which a radioactive isotope tends to break down into a stable isotope of the same element or another element.
Determining the absolute age of a sample based on the ratio of parent material to daughter material
time it takes for half the atoms of an isotope to decay
The naturally preserved evidence of life
Process in which pore spaces in a fossil are filled in with mineral substances.
a process in which an organism's tissues are completely replaced by minerals
preserved feces, or dung, from animals
any naturally preserved evidence of animal activity, includes the footprints, tracks, trails, and burrows made by living things.
a cavity in the ground or rock where a plant or animal was burried
an object created when sediment fills a mold and becomes a rock
A Fossil that is associated with a particular span of geologic time.
Geological time scale
A time scale established by geologists that reflects a consistent sequence of historical periods, grouped into four eras: Precambrian, Paleozoic, Mesozoic, and Cenozoic.
largest division of geologic time
divides the 4 eons
unit of time into which eras are subdivided
smallest and 4th largest divisions of geologic time
the thin and solid outermost layer of the Earth above the mantle
the layer of the earth between the crust and the core
extends from the bottom of the mantle to the center of the Earth
the solid, outer layer of the earth that consists of the crust and the rigid upper part of the mantle
The Soft layer of the mantle on which pieces of the lithosphere move
The strong, lower part of the mantle between the asthenosphere and the outer core
the liquid layer of the Earth's core that lies beneath the Mantle and surrounds the inner Core
the solid, dense center of our planet that extends from the bottom of the outer core to the center of the Earth
pieces of the lithosphere that move around on top of the asthenosphere
the theory that continents can drift apart from one another and have done so in the past
Sea- floor spreading
is the process by which new oceanic lithosphere is created as older materials are pulled away
when Earth's magnetic poles change places
the theory that the Earth's lithosphere is divided into tectonic plates that move around on top of the asthenosphere
the process by which an oceanic plate slides down the lithosphere-asthenosphere boundary
hot material from deep within the earth rises while cooler material near the surface sinks
a process in which the edge of the oceanic plate sinks and pulls the rest of the tectonic plate with it
A tectonic plate boundary where two plates collide, come together, or crash into each other.
a plate boundary where two plates move away from each other
the boundary between two tectonic plates that are sliding past each other horizontally
The region where oceanic plates sink down into the asthenosphere.
the amount of force per unit area that is put on a given material
when rock changes its shape due to stress
the type of stress that occurs when an object is squeezed, as when 2 tectonic plates collide
stress that occurs when forces act to stretch an object
the bending of rock layers due to stress in the Earth's crust
Upward folds of rock layers, forms when horizontal stress acts on rock
downward, troughlike folds od rock layers, also forms when horizontal stress acts on rocks
rock layers are folded so that both ends of the fold are horizontal
the surface along which rock break and slide past each other
the fault block that is below a fault
the fault block that is above a fault
a block of the Earth's crust on 1 side of a fault
a type of fault where the hanging wall slides downward; caused by tension in the crust
A fault in which the hanging wall moves up relative to the foot wall
opposing forces cause rock to break and move horizontally