verified answers
Uniformitarianism - correct answer ✔✔the same geological processes acting today were the
same processes in the past
Catastrophism - correct answer ✔✔theory that states that natural disasters such as floods and
volcanic eruptions shaped Earth's landforms and caused extinction of some species
relative time - correct answer ✔✔The determination of the sequence in which events occurred,
relative to each other
Principle of superposition - correct answer ✔✔in undisturbed strata of sediment or rock, the
bottom layer is oldest, the top layer is youngest
Principle of original horizontality - correct answer ✔✔sediments are deposited in horizontal
layers; tilting & deformation happen later
Principle of lateral continuity - correct answer ✔✔layers initially extend in all directions; later
events (e.g., erosion, faulting) can separate layers
Principle of cross-cutting - correct answer ✔✔intrusions, erosion, or faults are younger than the
rock they cut through
Principle of faunal succession - correct answer ✔✔some fossil species occur in unique time
intervals; age of rock may be determined from those fossils
, absolute time - correct answer ✔✔actual time elapsed (usually in millions of years, for geologic
time)
radiometric dating - correct answer ✔✔the process of measuring the absolute age of geologic
material by measuring the concentrations of radioactive isotopes and their decay products
geologic time scale - correct answer ✔✔scale used by paleontologists to represent evolutionary
time; eon, era, period, epoch
Precambrian Era - correct answer ✔✔Earth's first era that began 4.6 billion years ago that
includes creation of the Sun, Earth, the atmosphere, oceans and life
Phanerozoic Eon - correct answer ✔✔The most recent eon, an interval of time from 540 mya to
the present.
Composition of Earth's crust - correct answer ✔✔oxygen, silicon, aluminum, iron
rock - correct answer ✔✔an assemblage of minerals bound together
mineral - correct answer ✔✔naturally occurring, inorganic substances with specific chemical
formula, physical properties, and crystalline structure
mineralology - correct answer ✔✔study of the composition, properties, & classification of
minerals
luster - correct answer ✔✔the way a mineral reflects light from its surface; metallic & non-
metallic luster