GEOL 102 Midterm cards

The correct relative ages of events 1–6 shown on the figure, from the oldest to the youngest, would be:

1 > 2 > 3 > 4 > 5 > 6

Modern humans, Homo sapiens, first appeared about:

315,000 years ago

The age of the Earth and Mars is about:

4.6 billion years

Studying how ripple marks form in sand in order to interpret ancient sedimentary structures in the past applies:

Actualism

A layer that is cross-cut by a feature is _______ that feature.

older than

His work was the basis for the principle of fossil succession and he is considered as the “Father of English Geology”:

William Smith

Scottish physician, farmer, naturalist—the "father of geology” who wrote “Theory of the Earth” (1795) and was considered as a plutonist:

James Hutton

Author of a 5-volume set Principles of Geology (1835), the first great geology textbook that summarized the principle “the present is the key to the past” and cross-cutting relationships:

Charles Lyell

William T. Kelvin (1824-1907) attempted to calculate the age of the Earth based on the cooling rate. His calculation is about 20-40 million years, much smaller than the radiometrically dated age. The main problems of his calculations may include:

the ignorance of radioactive heat generation and convective heat transfer in the Earth.

An unconformity tells that:

there is missing time at the unconformity

People who tried to estimate the geologic time based on the ocean seawater salinity were:

Edmund Halley and John Joly (1900s)

The person who first developed the principles of Superposition and Original Lateral Continuity is:

Nicolaus Steno

The principle of ‘uniformitarianism’ is often summarized by saying that:

the present is the key to the past

The Mediterranean Sea was hypothesized to have formed by re-opening of a dried basin to the ______________ about 6 million years ago.

Atlantic Ocean

Evidence supporting the hypothesis that the extinction of dinosaurs was caused by meteorite impact include:

Iridium anomaly from a thin clay layer of ~65 million years old

Most of the large iron ores are from the very old (2.4–1.8 billion years old) deposits called the Banded Iron Formation (BIF). The iron in BIFs is mainly composed of:

Oxidized iron [hematite (Fe2O3) and magnetite (Fe3O4)]

Banded Iron Formations (BIFs) were formed in:

ancient oceans

In Red Rock Canyon (Las Vegas), the color of red rocks is caused by:

the presence of iron oxides (e.g., hematite)

In Red Rock Canyon (Las Vegas), the red rocks are ___________ the darker rocks higher in the Mountains.

younger than

When you heat a frying pan, the heat gradually travels from the pan to the metal handle. This process of heat transfer is called:

conduction

The Period beginning about 541 million years ago is:

Cambrian

We are living in the ________ Epoch.

Holocene

K-Ar dating commonly has low precision in rocks that experienced high temperature (e.g., >125ºC) because:

it involves a noble gas that can cause a leakage

Prof. Strauss, an archaeologist from the American Museum of Natural History, wants to date the handwriting in a book stored in a British library. He would most likely choose the ________ method.

14C dating

Dating a stratigraphic unit that contains the earliest animal fossils commonly uses:

U-Pb dating of zircons from ash beds

Among the following, the oldest Eon in the Geological Time Table is:

Archean

The age of the oldest zircon grains from a sandstone in Australia is about:

4.36 billion years

Atomic mass number of an element refers to:

protons + neutrons of the atom

The time span needed for 3/4 of the original parent atoms to decay to daughter products would be:

2 half-lives

Diamond is compositionally identical to graphite, but it is much harder than graphite because:

the chemical bonds in diamond are much stronger than those in graphite

From the ages and cross-cutting relationship in the following diagram, the age of Unit C can be roughly estimated as:

between 180 m. y. and 110 m. y.

If a mineral crystal originally contained 80 atoms of a common, radioactive isotope of uranium, after 3 half-lives, how many atoms of the original isotope would remain in the crystal?

10

A mafic magma gradually rises to the shallow crust and cools down. During the shallowing and cooling process, which of the following minerals would likely form at the last stage?

muscovite and quartz

Among the following rocks, which one has the highest metamorphic grade?

schist

The two most abundant silicate minerals of Earth's crust are:

quartz and feldspar

A laminated or layered structure in metamorphic rocks produced by the parallel alignment of platy mineral grains is called:

foliation

In a cooling magma, ultra-mafic and mafic minerals such as olivine and pyroxene crystallized first at high temperature, followed by intermediate and sialic minerals such as amphibole, biotite, muscovite, and then Quartz. In the following, which mineral would be most vulnerable to weathering when they are exposed in Earth's surface environments?

Olivine

Which of the following elements is the most abundant in the Earth's crust?

Oxygen

Rocks formed by the very slow cooling of magmas beneath Earth's surface would have:

large mineral crystals

Marble is a metamorphic rock derived from:

carbonate rocks (limestone and dolostone)

Which of the following sediments is typical of the deep oceans?

Siltstone and mudsstone (or shale)

Which of the following is a transitional (from continental to marine) environment of deposition?

Delta

Which of the following minerals is abundant in modern coral reefs and carbonate platforms but is unstable and rarely found in ancient carbonate rocks?

Aragonite

______ refers to the grain size range of a siliciclastic sedimentary rock.

Sorting

A matrix-supported and poorly sorted conglomerate with large angular boulders was most likely deposited from:

a glacial moraine environment

The rock record distinguished by its lithology, texture, and sedimentary structures that can tell you about the ancient depositional environment is called a:

Facies

Carbonate sediments are most common in:

warm and clear shallow oceans

Turbidites are most likely to be found in this depositional environment:

submarine fans in continental slope and basin

Ancient current directions (paleocurrents) of moving water can be determined by direct study of:

cross bedding and asymmetric ripple marks

In modern marine environments, corals typically inhabit warm, tropical to subtropical oceans within 30° latitude. During a trip to Mongolia, Dr. Lingeton discovered Cretaceous-aged coral fossils from marine environments at paleolatitudes of 45–60°. This finding suggests that during the Cretaceous Period, when dinosaurs thrived on Earth’s surface, the climate was _______ today’s.

warmer than

The formal stratigraphic (rock) unit lower in rank than a Formation is a:

Member

When you read a geological map, which of the following information can tell you that the sedimentary rocks are folded?

the dips of sedimentary rocks

A sandstone that consists of 90% quartz has _______ compositional maturity than a sandstone that is composed of 90% rock fragments.

higher

Siltstone layers with mud cracks and current ripples on the surface were most likely deposited from:

tidal flat environment

Sea-level fall or regression would result in which of the following depositional sequences?

coarsening-upward sequence

The rock equivalent of a Period is a (an):

System

In Walther’s facies law, only geographically adjacent depositional environments can overlap their depositional facies together vertically. The following diagram shows the modern depositional environments. If the sea-level rises 100 m, the vertical facies stacking at location 1 would be, from the bottom to the top:

Facies 1→Facies 2→Facies 3→Facies 4

The stratigraphic correlation method using carbon isotope (δ13C) profiles of stratigraphic units is called:

chemostratigraphy

In modern depositional environments, from the coast (beach, for examples) to outer shelf to slope depositional environments (e.g., the New Jersey shelf), sediments change from coarse- to medium-grained sandstone to fine-grained sandstone and to siltstone and shale (fining towards the deeper ocean). If the polar ice sheets melt and a major seawater transgression happens in the next 104 -105 years, the sedimentary record of this process would be a:

fining-upward sequence

Lithostratigraphic units (e.g., Groups, Formations, Members) composed of similar lithologies imply they were formed during the same time periods.

False

An index fossil should satisfy all of the following except:

Pyritization

Animals first appeared in the fossil record about __________ years ago in the ____________ Period.

600 million; Ediacaran

Which of the following types of fossils would be most useful in telling if two continents were connected together?

Benthic animal fossils

In the Linnaean binomial name system, a species is named as Tyrannosaurus rex. The first word of this name refers to the:

genus

Shelly animals could be preserved as shell fossils, or as internal/external molds and casts when the shells were dissolved during burial. In the figure (below), F1 and F2 are ammonite fossils preserved in shales of Mesozoic units in UK. Which one is a mold and which one is a cast?

F1 is a cast and F2 is a mold

A sedimentary bed with abundant burrows or intensive bioturbation implies:

oxic bottom-water conditions

Animal fossils are unlikely to be found in ____________ strata.

Precambrian

_______ is a group of organisms having structural, functional, and developmental similarities, and are able to interbreed and produce fertile offspring.

Species

Filling in many small pores in a fossil by silica, calcite, phosphorite, pyrite, etc., is called:

permineralization

The oldest strata in which bird fossils were found are of ___________ age.

Jurassic

The stratigraphic interval in which the ranges of two (or more) taxa overlap is called a (an):

concurrent range zone

The Phanerozoic began about _____ million years ago.

541

In ______________, new biologic structures appear because of "need" or "inner want".

Lamarck's Theory

The oldest vascular land plants were found from strata of ____________ age.

Silurian

Vertebrate forelimbs serve different functions (flippers for swimming, legs for running, hands for grabbing, etc.), but they all have similar bone construction. This similarity of structures in superficially dissimilar organisms is termed as:

homology

Fossil evidence, such as the changes of lower foreleg in horses through time, supports which of the following:

Natural selection: “the survival of the fittest”

In the marine ecosystem, modern or ancient, plants make their food directly from processing solar energy. Among the following organisms, which one makes its food directly from solar energy?

Phytoplankton

In deep-marine environments below the Carbonate Compensation Depth (CCD), which of the following deposits may be found?

Siliceous ooze (diatoms and radiolarians)

In the fossil record, paleontologists found that sudden changes of species occurred following or after long periods of little evolutionary progress. This evolutionary mode is called:

punctuated equilibrium

During the Archean (4.0–2.5 billion years ago, or Ga) and Paleoproterozoic (2.5–1.6 Ga), and potentially on ancient Mars, organisms living in the oceans were mostly:

prokaryotes

Before the Plate Tectonics theory, mountains and sedimentary basins were interpreted as formed by:

cooling and contraction of the crust

The earth’s outer core is inferred to be liquid. This information is obtained by analyzing the:

shadow zones of P- and S-waves

The plastic layer within the Earth’s upper mantle is called the:

asthenosphere

Strike and dip of strata are:

perpendicular to each other

The continental crust is __________ the oceanic crust.

thicker and less dense than

The Moho discontinuity marks the boundary between:

the crust and the mantle

Thermo-remnant magnetism is found in:

igneous rocks

Evidence for continental drifts includes the following except for:

the volcanic rocks exposed in eastern African rift

Magnetic stripes on the sea floor are evidence of:

seafloor spreading

Alfred Wegener envisioned the concept of a supercontinent of the past called:

Pangaea

Select the transform fault margin below:

Western US along San Andreas fault

Earthquakes can be recorded by seismographs as seismograms. In a seismogram that recorded an earthquake, P-wave, S-wave (P- and S-waves are called body waves), and surface waves (Love and Rayleigh waves) arrive at slightly different times. The right order of P-wave, S-wave, and surface wave arrival in a seismogram would be:

P-wave first, followed by S-wave and then surface wave

The inference of a metallic inner core of the Earth is based on the following except for:

the isostasy of the continental and oceanic crust

Re-melting of subducted crust happens at:

trenches in convergent margins

Which of the following contains older rocks in the center and younger rocks on the flanks?

Anticline

The Himalaya mountains represent the result of:

continental - continental collision

The eastern African Rift and Red Sea represent examples of:

continental rifting

The "ring of fires" refers to:

the volcanos and hot spots surrounding the Pacific Plate

In continents, regions with exposure of crystalline basement of Precambrian age (> 2.5 billion years) that are stable and undeformed during the past 500 Ma are named as:

continental shields

Regional metamorphism is commonly seen in:

convergent plate boundary like the Himalaya mountains