Quiz 8: Time and Geology

Relative time refers to the time sequence in which events take place rather than the number of years involved.

Uniformitarianism reflects the belief among geologists that the Earth remains uniform and unchanging through time.

The principle of superposition states that within a sequence of undisturbed sedimentary rocks, the layers get younger going from bottom to top.

The principle of crosscutting relationships states that a disrupted pattern is older than the cause of disruption.

The principle of original horizontality states that beds of sediment are nearly always deposited as nearly horizontal layers.

In an unconformity the contact represents a gap in the geologic record.

Under some circumstances, correlation between two regions can be made by assuming that similar rock types in the two regions formed at the same time.

An index fossil is a fossil from a very short-lived, geographically widespread species known to exist during a specific interval of geologic time.

Earth is between 1 and 2 billion years old.

Geologists use fossils in sedimentary rocks to assign their correct place in geologic history.

The Mesozoic Era precedes (is older than) the Paleozoic Era.

So far, the oldest mineral found on Earth is approximately 4.4 billion years old.

A formation is the process by which sedimentary rocks come into existence.

Isotopes of the same element have different numbers of neutrons.

The proportional amount of atoms that decay with time is only influenced by pressure and temperature.

Half life is the time it takes for a given amount of a radioactive isotope to decay to half its original amount.

Radon is an intermediate product of uranium-238 decay.

Isotopic dates from volcanic ash or lava flows layered between fossiliferous sedimentary rocks have been used to assign numerical ages to the geologic time scale.

Another term for cosmogenic isotope dating is surface exposure dating.

An angular unconformity is an erosion surface that is tilted from the horizontal.

The Earth is approximately _____ years old. A) 4,500 to 4600 B) 450,000 to 460,000 C) 4,500,000 to 4,600,00 D) 4,500,000,000 to 4,600,000,000 E) 4,500,000,000,000 to 4,600,000,000,000

Our ability to assign an age to geological and archaeological materials is based on our ability to measure the relative abundance of radioactive ___ and their stable decay products. A) ions B) protons C) isotopes D) neutrons E) fallout

In geology, _____ usually means determining time equivalency of rock units. A) physical continuity B) unconformity C) lateral continuity D) correlation E) superposition

The ___ of a radioactive material is the time it takes for a given amount of radioactive isotope to be reduced by half. A) atomic life B) atomic mass life C) atomic spin life D) nuclear magnetic life E) half life

The _____ is the principle says that the same processes and natural laws that operated in the past are those we can actually observe or infer from observation as operating at present. A) Uniformitarianism B) Numericalism C) Relativism age D) Actualism E) Absolutism

_____ are subdivisions of eras. A) Ages B) Intervals C) Periods D) Formations E) Eons

When the ____ came to a close, dinosaurs became extinct. A) Holocene Epoch B) Cenozoic Era C) Mesozoic Era D) Precambrian E) Paleozoic Era

Alvarez and others proposed a hypothesis that dinosaur extinction occurred because __. A) they sickened and died because of a cross-species epidemic B) the continents were flooded with seawater and they drowned C) all their eggs were eaten by birds and mammals D) the climate changed as the Ice Age began E) one or more asteroids impacted Earth, resulting in environmental change

The principle of ___ states that an original sedimentary layer extends laterally until it tapers or thins at is edges. A) superposition B) lateral continuity C) cross-cutting relationships D) original horizontality E) actualism

______ denotes the vast amount of time that precedes the Paleozoic Era. A) Mesozoic B) Paleozoic C) Quaternary D) Precambrian E) Cenozoic

Isotopic dating has shown that the Precambrian took up ______% of all geologic time. A) 15 B) 46 C) 87 D) 95 E) 62

The ___ Era began with the appearance of complex life, as indicated by fossils like trilobites. A) Quaternary B) Cenozoic C) Mesozoic D) Paleozoic E) Precambrian

The _______ Era is the Age of Mammals. A) Archean B) Cenozoic C) Mesozoic D) Paleozoic E) Precambrian

The _____ ended with the greatest mass extinction ever to occur on Earth. A) Tertiary Period B) Jurassic Period C) Paleozoic Era D) Precambrian interval E) Cenozoic Era

The ____ is based upon the observation that fossil species succeed one another through layers in a predictable order. A) principle of lateral continuity B) principle of faunal succession C) principle of original horizontality D) principle of unconformities E) principle of radioactivity

The relative-dating principle of __ states that fragments included in a host rock are older than the host rock. A) inclusion B) exclusion C) intuition D) supposition E) superposition

The half-life of the carbon 14 isotope is 5730 years. If there were 4 billion atoms of C-14 in a particular organism at the time it died, how many atoms of C-14 would there be in the remains of that organism 11,460 years after it died? A) 1 billion B) 2 billion C) 3 billion D) 4 billion E) 8 billion

The Earth's largest mass extinction coincides with _____ in Siberia. A) a massive meteorite impact B) massive volcanism C) a significant climate change D) flooding of continental areas E) expansion of glaciers

When marine geologists collects a core of undeformed ocean-floor sediment, they know that the youngest layer is on the top of the core and the oldest is at the bottom because of the principle of __. A) supposition B) suspension C) superposition D) inclusion E) cross-cutting relationships

By the principle of __, the surface feature known as the Grand Canyon is ___ than the sedimentary formations that are exposed in the side walls of the Grand Canyon. A) superposition; younger B) inclusion; older C) superposition; older D) cross-cutting relationships; younger E) cross-cutting relationships; older

The truncation of bedding where sedimentary rock layers abut a granite pluton suggests a(n) ______. A) angular unconformity B) intrusive contact C) erosional surface D) fault E) metamorphic aureole

The principle of ______ states that fragments included in a host rock must be _______ than the host rock. A) intrusion; older than B) inclusion; older than C) intrusion; younger than D) inclusion; younger than E) inclusion; the same age as

_______ is the spontaneous nuclear change of isotopes with unstable nuclei. A) Structural geology B) Petrology C) Radioactive decay D) Fission E) Isotopic dating

In radioactive decay a(n) _______ emission is the emission of two neutrons and two protons from a nucleus. A) beta B) gamma C) omega D) alpha E) psi

In the radioactive decay process of __ decay, an electron is emitted from the nucleus of the parent isotope. A) omega B) gamma C) beta D) alpha E) delta

In the radioactive decay process of electron capture a(n) ___ in the nucleus captures an orbiting electron. A) neutrino B) neutron C) alpha particle D) proton E) positron

The proportional amount of atoms that decay with time _____ by the high pressures and temperature of Earth's interior. A) can be slightly accelerated B) can be slightly decelerated C) can be greatly accelerated D) can be greatly decelerated E) is not changed at all

Radiocarbon dating is useful in dating an event that occurred in the past ________ years. A) 4 thousand B) 40 thousand C) 400 thousand D) 4 million E) 40 million

The carbon-14 isotope disintegrates radioactively with a half-life of ______ years. A) 4.5 billion B) 710 million C) 15 billion D) 24,000 E) 5730

Carbon-14 is created in the atmosphere by the nuclear reaction of neutron from the cosmic rays and _______ in the atmosphere. A) hydrogen B) water vapor C) nitrogen D) oxygen E) dust

Uranium-238 ultimately decays to _____ -206. A) lead B) argon C) potassium D) uranium E) carbon

____ dating uses the effect of neutron radiation coming from deep space to date material at Earth's surface. A) Cosmogenic B) Electron spin resonance C) Amino acid racemization D) Fission track E) Potassium-argon

The _____ includes most of geologic time (87%). A) Quaternary Period B) Cenozoic Era C) Mesozoic Era D) Paleozoic Era E) Precambrian

A(n) _______ is an erosional surface that represents a gap in the geologic record. A) basal conglomerate B) unconformity C) boundary layer D) lamination E) marker horizon

A(n) _________ is a contact in which an erosional surface on a pluton or metamorphic rock has been covered by sedimentary (or volcanic) rock. A) disconformity B) basal conglomerate C) nonconformity D) boundary layer E) angular unconformity

In a(n) __________ the erosional contact represents missing rock strata and separates sedimentary beds that are parallel. A) disconformity B) basal conglomerate C) nonconformity D) boundary layer E) angular unconformity

Fossils are common in __. A) all rock types B) plutonic rocks C) sedimentary rocks D) metamorphic rocks E) volcanic rocks

The principle of _____ allows rock layers in different places to be correlated on the basis of their fossils. A) lateral continuity B) faunal succession C) radioactive decay D) original horizontality E) magnetostratigraphy

A(n) _______ fossil is a fossil from a very short-lived, geographically widespread species that existed during a specific interval of geologic time. A) assemblage B) range C) age D) interval E) index