PHS 109 - Chpt 4

What is the approximate depth of the calcite compensation depth (CCD) in the ocean?

3 miles (4.5 kilometers)

On average, at what ocean depth does calcite readily dissolve into seawater?

4500 meters (14,764 feet)

On the world ocean pie diagram below, match the percentage to the correct type of sediment.

A: Abyssal clay C: Siliceous ooze B: Calcareous ooze

What did the discovery of tillite in South Africa reveal about southern Africa's past?

An ice sheet covered southern Africa 300 million years ago.

What is calcareous ooze composed of?

At least 30% the remains of calcareous organisms.

This global map shows the distribution of different types of marine sediment (different colors). Match the correct letter to the sediment type listed below.

B: Abyssal clay D: Calcareous ooze C: Neritic continental lithogenous A: Siliceous ooze: diatom E: Siliceous ooze: radiolarian

Why is this drilling process called rotary drilling?

Because the drill bit turns around in a circle.

Why does calcareous material dissolve below the CCD?

Below the CCD, weak acid is formed, which dissolves calcareous material.

This composite photomicrograph image shows various types of calcareous marine microorganisms that are found in sediment. Match the correct letter to the name and correct description of each organism listed below.

C: Coccoliths (individual plates) A: Coccolithophores (multiple) E: Diatom (siliceous) B: Foraminifers D: Coccolithophore (single)

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Choose the one option that does not fit the pattern. Biogenous Calcareous Lithogenous Hydrogenous Cosmogenous

Calcareous

Why might ocean floors be better than continental locations for studying long-term changes in the size of ice sheets?

Continental records are fragmented and discontinuous, missing parts of the climate record.

Generally, what has been the pattern of global temperature change during the past 70 million years?

Earth's average temperature is approximately 15° cooler now than than it was 70 million years ago.

In which setting would calcareous ooze be most likely to form?

On the crest of a seamount under warm surface water.

How does siliceous ooze accumulate on the seafloor if silica-based residues are dissolved slowly at all depths?

Silica tests accumulate faster than seawater can dissolve them.

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Choose the one option that does not fit the pattern. Siliceous ooze Quartz sand Rock fragments Volcanic ash Clay

Siliceous ooze

How does the analysis of forams in ocean sediment cores reveal climate change?

The presence and relative dominance of different species of forams reveal different global climate conditions.

Where do calcareous oozes exist on the seafloor?

Underneath areas where calcareous organisms live, above the CCD.

Why do some organisms thrive in warm surface waters?

Warm water is generally saturated in carbonate.

As a whole, the pH of surface waters of the ocean is slightly __________.

alkaline

Where might one find calcareous oozes on the seafloor?

along the crests of mid-ocean ridges, above the CCD buried beneath siliceous oozes buried beneath abyssal clay

What factor primarily determines the distribution of radiolarian ooze?

areas of upwelling

Sediments derived from the remains of the hard parts of once-living organisms are called __________ sediments.

biogenous

The depth at which calcite dissolves rapidly in the ocean is called the __________.

calcite compensation depth or CCD

Two common types of chemical compounds found in biogenous sediments are __________ and __________.

calcium carbonate; silica

Carbon dioxide (CO2) combines with water (H2O) to form __________.

carbonic acid (H2CO3)

What have oceanographers determined from analyzing sea floor cores?

climate change and past extinctions

Which sediment type dominates in the neritic environment?

coarse lithogenous sediment, such as sand and small rocks

The tests from which of the following organisms will dissolve below the CCD?

coccolithophores foraminifera

Calcite-secreting organisms such as __________ and __________ live in the ocean's sunlit surface waters and form the basis of most marine food webs.

coccolithophores; foraminifers

What sediment type(s) is/are included in the pink category labeled "Other" on the map?

cosmogenous sediments hydrogenous sediments

The two major types of microscopic, planktonic organisms that produce siliceous oozes are __________ and __________.

diatoms; radiolarians

Which of the following factors affect the distribution of biogenic oozes on the seafloor?

dissolution biological productivity water depth seafloor spreading

Forams, which are composed of calcium carbonate, __________ above the CCD and __________ below the CCD.

do not dissolve; dissolve

Diatomaceous earth, which is composed of silica, __________ above the CCD and __________ below the CCD.

does not dissolve; does not dissolve

What conditions exist below the CCD?

high acidity cold temperature high carbon dioxide concentration

Siliceous ooze is particularly abundant on the seafloor at __________ and at __________.

high latitudes; equatorial upwelling zones

The pH scale is a measure of the __________ ion concentration of a solution.

hydrogen

Which of the following organisms thrive in cold surface waters?

siliceous organisms radiolarians diatoms

In the demonstration, what does the apple represent?

the deep sea floor

What factor primarily controls the distribution of calcareous ooze?

water depth

What mechanism(s) is/are responsible for transporting clay to deep ocean basins?

wind slow-moving ocean currents

This composite photomicrograph image shows various types of siliceous marine microorganisms that are found in sediment. Match the correct letter to the name and correct description of each organism listed below.

D: Diatom, top view A: Diatom, showing both halves of its test C: Radiolarian, spherical shape B: Radiolarian, showing long appendages

Consider deposits of oozes and abyssal clay. What are some differences between them?

Deposits of oozes are typically found in areas with high biological activity whereas abyssal clays are widespread throughout the ocean (Trujillo & Thurman, 2020). Deposits of oozes contains biogenous material and lithogenous clays whereas abyssal clay is mostly made up of fine clay-sized particles.

The cross-section below shows an area of the sea floor that is accumulating sediments. Match the type of sediment/feature with the correct letter.

E: Siliceous ooze C: Mid-ocean ridge D: Calcite compensation depth (CCD) A: Abyssal clay B: Calcareous ooze F: Upwelling, cool water

a. What is paleoceanography? b. What variables or conditions from the past can be measured using sediments? c. What technology/methodology is used to examine sediments? Describe one example of a expedition or project that addresses sediment analysis and past ocean state. d. Why is it important to study the past, whether it is related to the oceans or climate?

a. Paleoceanography is "the study of how the ocean, atmosphere and land have have interacted in the past to produce changes in ocean chemistry, circulation, biology, and climate" (Trujillo & Thurman, p. 108) b. Climate change c. One example from the book is rotary drilling which is drilling using a long and hollow pipe. d. It is important to study the past so that we can make positive changes with this information in the future. Climate and our oceans in particular is important to study the past because previously the climate and oceans were in a much better condition than they are today.

What common household item is used in this video to demonstrate rotary drilling?

an apple corer