quiz 3 earth science lab

Faunal (fossil) succession is useful because:

Organisms appear and disappear in a known, consistent order through geologic time

In a lowland meandering river, the inner bank where deposition dominates is called the:

Point bar

Which radiometric decay pair and half-life combination is correctly matched for geological applications?

Potassium-40 → Argon-40; half-life ~1.3 Ga

Approximately what percentage of Earth’s water is freshwater (non-saline)?

2.5%

A nonconformity is recognized where:

Sedimentary rock lies directly on eroded metamorphic or igneous crystalline rock

In radiometric dating, which factor could produce an incorrect age and thus requires careful evaluation?

Loss or gain of parent or daughter isotopes due to metamorphism or weathering

Which of the following best describes an angular unconformity?

Younger layers overlie older layers that were tilted or folded before erosion, producing angular discordance

According to the Principle of Cross-Cutting Relationships, which of the following is true?

A fault that cuts across several layers is younger than the layers it cuts

Which stage describes when water is confined to the channel and below the floodplain elevation?

Normal Flow Stage

A baked contact between an igneous intrusion and surrounding rock indicates:

The intrusion is younger than the surrounding rock and “cooked” it on emplacement

Which reservoir is described as including permafrost, lakes, rivers, soil water, swamps, and living things?

Surface water

Which reservoir holds about 0.001% of Earth’s water at any one time?

Atmospheric water

Which principle states that undeformed sedimentary layers are originally deposited horizontally?

Principle of Original Horizontality

Which characteristic is NOT typical of a good index fossil?

Long geologic range (persisting for hundreds of millions of years)

What proportion of Earth’s liquid fresh water (reservoir B in the text) is groundwater?

About 99%

Relative dating in geology is primarily used to:

Order geological events as older or younger without assigning exact ages

Which characteristic is most typical of upland river systems?

Steep slopes and straight channels

Which statement best represents the concept of “deep time” in geology?

The recognition that Earth’s history spans billions of years during which slow and large-scale processes operate

Disconformities are often harder to recognize than other unconformities because:

The layers above and below the gap remain roughly parallel, so missing time is not obvious without additional evidence

Which flux is defined as the transfer of water from surface or glacial reservoirs into the groundwater reservoir?

Infiltration

Which process would directly increase salinity of ocean surface water after precipitation falls over the ocean?

Evaporation of freshwater leaving salts behind

The Principle of Inclusions states that:

Included fragments (clasts) in a rock are older than the rock that contains them

Discharge for a stream is defined as:

The volume of water carried by the river per unit time

The modern accepted age of Earth is approximately:

4.54 billion years

Which dating method is MOST appropriate for obtaining a numeric age of a 2.5-billion-year-old granite?

Uranium-lead dating on zircon crystals from the granite

Which ion type listed commonly contributes to a river’s dissolved load as a positive ion?

Sodium (Na+)

Radiometric half-life is best described as:

The time required for half of a parent isotope population to decay to its daughter isotope

The statement “the present is the key to the past” is most closely associated with which concept?

Uniformitarianism (actualism in modern usage)

Which flux term specifically describes the biological transfer of water from plants to the atmosphere?

Transpiration

In a drainage basin, what is the term for the main stream into which all other water of the basin ultimately collects?

Trunk stream

Why is zircon a useful mineral for uranium-lead dating?

Zircon concentrates uranium and typically excludes initial lead from its crystal structure, preserving the radiogenic lead signal

The Principle of Superposition implies that in an undisturbed sedimentary sequence:

The oldest layers are at the bottom and the youngest at the top

Carbon-14 dating is limited in geology because:

Carbon-14’s short half-life (~5730 years) restricts it to dating relatively recent organic materials (up to ~60,000 years)

The smallest sphere (C) representing all freshwater available on Earth’s surface has a diameter closest to:

5 miles

Which feature defines the highest elevations and separates adjacent drainage basins?

Watershed divide

Which reservoir contains the largest percentage of Earth’s water?

Oceans

How long does atmospheric water typically cycle through the atmosphere before returning as precipitation?

8–10 days

An ephemeral stream is best described as:

A stream that only flows during periods of high precipitation or snowmelt

Which of the following is NOT one of the four major fluxes used in this lab?

Condensation

Which type of stream load consists of large-grained sediment transported in contact with the channel bottom?

Bed load