from the Utah Geological Survey

The Cenozoic (66 mya – Recent) is very dynamic time in Earth history, involving many rapid and dramatic fluctuations in global climate, culminating in the late Neogene icehouse with it’s associated alternating glacial and interglacial cycles. Within this interval, we see turnover in global flora and fauna, changes in thermohaline circulation patterns (which in turn affect atmospheric patterns), fluctuations in global weathering patterns, and much more. This page is setup to explore some of these feedbacks and key connections.

You’ll begin by learning the fundamental planetary-scale processes and forces that directly (and indirectly) influence climate throughout Earth history. From here, you’ll explore feedbacks, both positive and negative, that govern cyclic patterns in glacial-interglacial intervals. Lastly, you’ll explore how these patterns affect the abundance, diversity, and distribution of life on the Earth’s surface. Once you have completed all of this, you will then create an infographic as your final assignment.

So, let’s begin! Below is a video that described and explains Milankovitch Cycles, which are an important planetary-scale process that forces changes in the amount of insolation (i.e.,solar energy received at the Earth’s surface) through time. Let’s see how they work – watch the video, and answer the questions as they appear onscreen.

For more information on Milankovitch Cycles, checkout this PowerPoint posted by California State University at Northridge.

Now that you’ve got an idea about extraterrestrial forcings, but what terrestrial forcings impact dynamic changes in this icehouse state? One of the more important processes that has influenced Earth’s climate throughout the Cenozoic is ocean circulation. Ocean circulation is one of the principal teleconnections linking planetary spheres across dynamic intervals in Earth history.

from NASA

The video above is a beautiful model reconstruction for how our present day ocean circulations track. Note the partitioning of the different depths of water. What could cause these? What about the areas where the arrows representing water appear to sink or rise? To explore these questions, read the following paper.

Now that you have gone through the above materials, you should begin to start piecing together how each of these systems interconnect. Think about how global temperatures are governed by insolation, which is in turn governed by Milankovitch Cycles. Think back to what you have previously learned about how the ocean and the atmosphere exchange gases (such as carbon dioxide), and now add your newly learned knowledge about thermohaline circulation. All of these are coming together to influence climate throughout the Cenozoic. Below is another paper to read. It outlines how the geosphere is interacting with the biosphere and hydrosphere to affect the atmosphere. To understand it, you will need to understand carbon fluxes into the deep ocean as well as upwelling centers.

Clear as mud, right? Although there is still much to learn, you should now have the necessary pieces to paint a picture (or in our case, draw a model) that outlines the mechanisms behind the Cenozoic Glaciation cycles. Create an inforgraphic, or a strip of cartoon models, that outlines how these each of these spheres come together in these glacial and interglacial times. Submit your work to the Submission Page.

References
http://geology.utah.gov/map-pub/survey-notes/glad-you-asked/ice-ages-what-are-they-and-what-causes-the m
https://pmm.nasa.gov/education/videos/thermohaline-circulation-great-ocean-conveyor-belt
http://cdiac.ornl.gov/oceans/glodap/glodap_pdfs/Thermohaline.web.pdf
Jaccard, Samuel L., et al. “Covariation of deep Southern Ocean oxygenation and atmospheric CO2 through the last ice age.” Nature 530.7589 (2016): 207-210.

External sources accessed on Nov. 2016