1-50

An ice cap covers less than 50,000 km², while an ice sheet covers more than 50,000 km².

Which of the following correctly distinguishes an ice cap from an ice sheet based primarily on its areal extent?

Earth is currently in an interglacial period.

Which statement best describes Earth's current climatic state?

17,000–21,000 years ago

Approximately when did the Last Glacial Maximum (LGM) occur?

It is a general term for instruments used to measure humidity.

Which statement correctly describes a hygrometer?

Anemometer

Which instrument is used to measure wind speed?

Barometer

Which instrument is used to measure atmospheric pressure?

It is non-rotational and coaxial.

Which statement correctly describes pure shear?

A. It is rotational and non-coaxial.
B. It is non-rotational and coaxial.
C. It is rotational and coaxial.
D.

The steepest angle at which loose material remains stable without sliding.

What is the angle of repose?

June 15, 1991

When did Mt. Pinatubo in the Philippines erupt violently?

It decreased global average temperatures by about 0.5°C for 1–2 years.

What was a significant global climatic effect of the June 15, 1991 eruption of Mt. Pinatubo?

By using the distances from at least three seismographs and finding where their distance circles intersect

How is the epicenter of an earthquake determined using triangulation?

A very small, shallow channel formed by surface runoff

What is a rill?

A larger and deeper channel that develops as rill erosion continues

What is a gully?

Creek

Which of the following is best described as a small stream that generally flows year-round?

River

Which of the following is best described as the largest channel with continuous flow and significant discharge?

Einkanter

Which type of ventifact is characterized by having one dominant facet?

Zweikanter

Which type of ventifact is characterized by having two facets?

Dreikanter

Which type of ventifact is characterized by having three facets?

Vierkanter

Which type of ventifact is characterized by having four facets?

Fünfkanter

Which type of ventifact is characterized by having five facets?

A rock or stone shaped and polished by wind-driven sand

What is a ventifact?

Rock units defined and classified based on their lithologic characteristics and geologic relationships, rather than their stratigraphic position

What are lithodemic units?

Rock units defined based on their lithologic characteristics, such as rock type and composition

What are lithostratigraphic units?

The chemical alteration of a rock by hydrothermal fluids, transporting ions and introducing elements not originally present

Which of the following best characterizes metasomatism in metamorphic processes?

The planar alignment of platy or elongate minerals under directed stress, producing a layered texture independent of compositional banding

In metamorphic petrology, foliation is best distinguished from other processes by which of the following?

The growth of new mineral grains of the same composition, typically larger and more stable, without changing overall chemistry

Which of the following best defines recrystallization in metamorphic processes?

The permanent strain of rocks under high temperature and pressure, where they bend and flow without fracturing

Which of the following best describes ductile deformation in rocks?

σ1 > σ2 > σ3, three distinct principal stresses with no equality among them

Which of the following stress conditions correctly represents the triaxial stress regime in structural geology?

σ1 = σ2 > σ3, two equal maximum principal stresses greater than the minimum principal stress

Which of the following stress conditions correctly represents the axial stress regime in structural geology?

σ1 > 0; σ2 = σ3 = 0, stress acting only along one axis while the other two are absent

Which of the following stress conditions correctly represents the uniaxial compressive stress regime in structural geology?

Darker, cooler areas formed by intense magnetic activity that inhibits convection

Which statement most accurately explains the nature of sunspots on the solar photosphere?

Brief, energetic eruptions of electromagnetic radiation and plasma emanating from the photosphere, extending into the corona

Which statement most accurately describes solar flares in relation to the Sun’s structure?

The apparent deflection of winds and currents due to Earth’s rotation, to the right in the Northern Hemisphere and to the left in the Southern Hemisphere

Which of the following best explains the Coriolis effect as it applies to atmospheric circulation?

A rapid diversification of animal phyla around 538–485 million years ago, introducing hard skeletons and complex body plans

The Cambrian Explosion is significant in Earth’s history because it represents:

Indonesia

Which country currently has the largest number of active volcanoes?

Ordinate: intrinsic brightness (absolute magnitude or luminosity); Abscissa: surface temperature, spectral type, or color index

In an H–R diagram, which of the following correctly identifies the parameters plotted on its axes?

Diagonal band from upper left to lower right, the main sequence

Where do most stars, including the Sun, lie on the H–R diagram?

Upper right

Which region of the H–R diagram contains stars that are luminous but relatively cool?

Lower left, hot but faint

Where are white dwarfs located on the H–R diagram?

Moves upward and to the right, becoming a giant

When a star exhausts hydrogen in its core, how does its position change on the H–R diagram?

O–B–A–F–G–K–M

Which of the following correctly represents the spectral sequence used on the horizontal axis of the Hertzsprung–Russell diagram, arranged from hottest to coolest stars?

Top = luminous stars; Bottom = dim stars; Left = hot stars; Right = cool stars

In the Hertzsprung–Russell diagram, which of the following correctly describes the distribution of stars?

Ejnar Hertzsprung and Henry Norris Russell

The Hertzsprung–Russell diagram is named after two astronomers who independently developed it in the early 20th century. Who are they?

A diagram that shows the relationship between a star’s intrinsic brightness and its surface temperature

What is the Hertzsprung–Russell (H–R) diagram?

Middle of the main sequence, as a G2V star with luminosity ~1

Where is the Sun located on the Hertzsprung–Russell diagram?

External forces driven by solar energy and gravity that wear down, transport, and deposit Earth’s materials

Which of the following best describes exogenic processes in geology?

Internal forces powered by Earth’s heat that build and reshape landforms through volcanism, tectonics, and earthquakes

Which of the following best describes endogenic processes in geology?

The formation of broad, nearly flat erosional surfaces by slope retreat and coalescence of pediments in arid regions

What is pediplanation in geomorphology?

The internal process of crustal deformation, including folding, faulting, uplift, and subsidence, driven by Earth’s internal forces

Which of the following best describes diastrophism in geology?

The low‑temperature and pressure processes (compaction, cementation, recrystallization) that convert sediments into sedimentary rock

Which of the following best describes diagenesis in sedimentary geology?

Third‑largest, eliminating ~85% of marine species

How does the Ordovician–Silurian extinction event rank among the “Big Five” mass extinctions?

They are inarticulate brachiopods with organophosphatic shells, first appearing in the Cambrian Period and still extant today

Which of the following statements correctly describes the brachiopod order Lingulida?

A large-scale sand-dune complex composed of superimposed smaller dunes

Which of the following is the best description of a draa (dra) in desert geomorphology?

Small volcanic hills or cones, especially in the Chaîne des Puys of central France

What are puys in geomorphology?

Nuclides that existed before the formation of the Earth and Solar System and have survived to the present

Which of the following best describes primordial nuclides?

Hydrogen, helium, and trace amounts of lithium

Which of the following elements were primarily produced during Big Bang nucleosynthesis (Big Bang Primordial Elements) in the early universe?

Elements with atomic numbers 1–82, except technetium (43) and promethium (61)

Which of the following correctly describes the stable primordial elements?

They are radioactive elements with half-lives long enough to have survived since the formation of the Solar System.

Which of the following best characterizes radioactive primordial elements?

Sediments → Pillow lavas → Sheeted dykes → Gabbro → Layered gabbro → Layered peridotite → Peridotite

Which of the following correctly presents the generalized ophiolite sequence from top to bottom?

The measurable deformation experienced by a rock body as a result of stress

Which of the following best defines strain in structural geology?

Stress that acts parallel to the plane of deformation

Which of the following best describes shear stress?

The ability of a rock to resist deformation or failure

In structural geology, which of the following best defines the strength of a rock?

Ca-Al-rich inclusions (CAIs) in the Allende meteorite

Which of the following is most closely associated with determining the age of the Solar System at approximately 4.567 Ga?

Zircon crystals from lunar samples collected during the Apollo 17 mission

Which of the following was used to help determine the age of the Moon at approximately 4.53 Ga?

Acasta Gneiss

Which of the following is recognized as one of the oldest known rocks on Earth, with an age of approximately 4.03 Ga?

Plutonic rocks cool slowly underground and are generally coarse-grained, while volcanic rocks cool rapidly at or near the surface and are generally fine-grained.

Which of the following correctly compares plutonic and volcanic igneous rocks?

Granite, gabbro, diorite; basalt, obsidian, pumice, rhyolite

Which of the following correctly lists common plutonic and volcanic igneous rocks, respectively?

Large, parallel, pillar-like or fluted linear structures formed during strong tectonic deformation

In structural geology, which of the following best describes mullions?

Columnar jointing

Which geological structure forms when cooling and contracting lava or magma fractures into regular polygonal columns, commonly producing six-sided prisms?

Laetoli footprints

Which of the following is a famous example of a trace fossil that records bipedal locomotion of early hominins approximately 3.6 million years ago?

Chlorophyta

Which group of algae contains chlorophyll a and b, typically stores food as starch, and includes organisms such as Ulva and Chlorella?

Rhodophyta

Which group of algae is predominantly marine, contains characteristic red pigments, and includes species used to produce carrageenan and nori?

Phaeophyta

Which group of algae includes large, complex marine seaweeds such as giant kelp and is characterized by cell walls containing algin?

Bacillariophyceae

Which group of microscopic, primarily unicellular algae is characterized by intricately patterned cell walls composed of silica and is an important component of marine and freshwater phytoplankton?

Dinoflagellates

Which group of primarily unicellular organisms possesses flagella for movement and includes species responsible for harmful algal blooms commonly called red tides?

Euglenoids

Which group consists mainly of unicellular freshwater flagellates, some of which possess chloroplasts and photosynthesize while others obtain nutrients from their environment?

670–2,900 km; 55%

Which combination of depth range and approximate percentage of Earth’s volume correctly describes the lower mantle?

Bridgmanite and ferropericlase

Which two mineral phases together constitute roughly 80% of Earth’s lower mantle?

Evolution of cyanobacteria → oxygenic photosynthesis → saturation of oxygen sinks → atmospheric O₂ accumulation → decline of many anaerobic organisms

Which sequence best explains the development and major consequences of the Great Oxidation Event (GOE)?

Immediate appearance and diversification of dinosaurs

Which of the following was NOT a major consequence associated with the Great Oxidation Event?