Documenting Past Climate
Time required to complete this unit:
Earth Science Content:
Key Terms: paleoclimate, glacial cycles, Milankovich Cycles, sediment, sedimentology, paleomagnetism, paleontology, proxy data, dropstone, tectonics, microfossil, diatoms, foraminifera, iceberg, isotope, sediment drilling and coring, drillship. scientific ocean drilling
Earth's climate has changed, sometimes dramatically, in the past. If you had lived on the island of Manhattan about 20,000 years ago, you would have found yourself living during an ice age on top of a 4-kilometer thick slab of ice. Does it matter? Is it important to understand Earth's climate history? Can knowledge about past climate help us understand how Earth's Earth's climate may change in the future? Indeed, the paleoclimatic record allows us to examine the causes of past climate change. Looking into Earth's climate history can help scientists determine how much of the 20th and 21st century warming can be explained by natural causes, such as solar variability, and how much may be explained by human influences.
To find out how Earth's climate has changed in the past and how this knowledge sheds light on how Earth's climate may change in the future, students join the International Ocean Discovery Program (IODP) Expeditiion 341 to study sediment cores collected from drill sites in the Gulf of Alaska. As members of an international group of scientists on the drillship Joides Resolution, students investigate how regional climate changed from about 7 million years ago to the present. Like the real scientists, they work collaboratively with classmates to examine data from an 80-meter section of Core U1417B to answer a set of questions questions related to past climate.
This unit is based largely on the EarthLabs Climate Detectives module, which uses a challenge-based pedagogical approach to drive student learning. Students work through a series of labs designed to organize the curriculum so that key science concepts and science practices are established. In the final lab, students conduct activities and use this knowledge to solve the challenge.
Developed by Jeff Lockwood (TERC) and Allison Mote (Austin Independent School District). Tested by Texas teachers.
Students will be able to (do)
- Design a coring apparatus and to recover a "core" sample.
- Carry out core-to-core stratigraphic correlation
- Analyze patterns, sediments and features found in sediment cores as a way to establish periods of glacial advance and glacial retreat.
- Use and interpret data, including proxy data.
- Relate the occurrence of different types of diatoms (plants) and their abundance in the core reveal to the timing of the cycles of the advance and retreat of glaciation.
- Relate microfossil and paleomagenetic data found in cores to estimate geologic time.
- Estimate the timeline represented by this section of core.
- Work collaboratively as members of a team
- Compare results of environmental change recorded in the IODP core from the Gulf of Alaska with the global record of glaciations during the same time span based on oxygen isotopes measured in microfossils?
Students will know
- How environmental conditions in in the Gulf of Alaska changed during the time span (5 million years) in which sediments in the core were deposited.
- The advance and retreat of glaciers affect rates of deposition.
- What climate cycles are and what causes them.
- What proxy data is and how it is used to reveal past climate history
- That the chronology for the timeline of a sediment core is based on a combination of the paleomagnetic stratigraphy and relative geologic ages of microfossils found in the sediment core.
- How do scientists work together to accomplish an expedition's science mission.
- About scientific and engineering careers/training required for the JOIDES Resolution to accomplish its science and mission goals.
The activities we have selected are congruent with the Next Generation Science Standards (NGSS), and are arranged to build upon one another. Therefore, to follow the storyline we recommend that teachers complete the activities in the order provided. To open an activity in a new tab or window, right click the activity link and select the preferred option.
In this module of six lessons from the EarthLabs series, learners assume the role of participants on the International Ocean Discovery Program's drillship, the JOIDES Resolution. Using data collected from Expedition 341, students will explore how climatic changes are recorded in the rock record, learn about careers associated with the IODP, and gain an appreciation for the ocean drilling process, and data collection methods.
Instructional Strategies: Inquiry
Resource Type: Laboratory investigation, experiment or demonstration
Time Required: 750 minutes
The linked titles are directed to the teacher pages. Lab activities that are contained within this module are as follows:
Students learn about the R/V JOIDES Resolution, meet the scientists and support crew members, and discover where their voyage will take them and why the drill sites were chosen.
Time Required: 150 minutes
Students use the engineering design process to build a working model of a coring apparatus and attempt to recover a core sample from a layered-clay model of the ocean floor.
Time Requires: 60 minutes
In Part A of this activity, students investigate how massive ice sheets can alter the landscape and deposit their sediments in the ocean. In Part B, students examine the phenomena that trigger the onset of ice building and subsequent periods of ice melting—Milankovich Cycles.
Time Required: 100 minutes
In the first part of this activity, students learn how particle size affects the rate of sediment deposition, and how sediment layers form. In Part B, students use a model to explore how sediments are deposited in ocean basins by icebergs.
Time required: 100 minutes
In Part A of this activity, students investigate the scope of geologic time by creating a timeline that marks major geologic and biological events over the 4.6 billion year history of planet Earth. In Part B, they make another timeline that encompasses the 23 million year span of time that the IODP expedition will focus on in terms of sedimentation and climate change.
Time required: 100 minutes
In this culminating activity, students put their observational skills to work to analyze core features to uncover clues about what Earth's climate was in the past. In Part A, they use an online glossary to investigate the nature of different core features and what the presence of these features means in terms of climate and climate change. In Part B, they use "The Core Lab" visualization to examine sedimentary features of core U1417B. In Part C, students gather evidence to support their predictions about what changes in climate have occurred in the southern Alaska region.Then in Part D they continue to assemble evidence by examining microfossils found at different points in the sediment column, again using the "The Core Lab" visualization. Finally, in Part E, they assemble their data and evidence to draw some conclusions about climate changes in the S. Alaska region during the time the sediments were deposited.Time required: 240 minutes
Studies that examine how geologists think and learn about the Earth point to the value of field experiences in helping students develop practices that constitute geologic reasoning. We encourage teachers to take students into the field as much as possible. To this end, we include ideas for virtual and actual field trips. The former recognizes the limitations of the K-12 classroom setting. Field learning provides a chance to encourage the ability to see features that are important to professional practice. Indeed, many geoscientists report that fieldwork was a key factor influencing their choice of geoscience as a career.
Teachers must develop their own individual plan for how they will teach the unit. The learning activities and educational resources in this unit are intended to complement other instructional activities led by the teacher. Many of the selected learning experiences provide links to excellent background preparatory materials, additional hands-on resources, teaching tips, and cross-curricular connections.
Teachers will need to create their own multimedia presentations, deliver lectures and assign ancillary work to their students in order to set the stage for effective use of the learning activities contained herein. Therefore, it is imperative to allocate time to review the activities and background material prior to using the learning experiences in this unit and to probe students for their prior knowledge before starting an activity.
In addition, although some activities may incorporate assessments, teachers may need to create their own assessments to ensure that are appropriate for the students they teach.
Asterisks (*) indicate teacher resource and background information recommendations for activity support.
Next Generation Science Standards
We anticipate that students should be able to achieve the NGSS Performance Expectation(s) listed after completing the activities in this unit. However, we have not carried out educational research to verify this.
The recommended additional resources may be used to extend or augment the storyline.
JOIDES Resolution is the home page for the R/V JOIDES Resolution. When it is at sea, expedition updates are posted here.
This article by Ben Anderson, in the Alaska Dispatch News, talks about the mixing of the glacial river sediments and the ocean waters. It also points out about misconceptions and misinformation that is found on the Internet.
Dropstones - Wilton Formation - Sydney Basin is a YouTube video that shows what glacial dropstones look like in-situ. The narrator also explains about how dropstones are carried out and deposited.