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Early Paleogene Climate

By: Caleb Schindel, Isabella Frey, Alexia Stephens, and Charles Cummings

Learning Objectives

By the end of this presentation we hope you are able to:

OVERVIEW

- Understand the Early Paleogene Period climate.

- Explain how we are able to understand historical climate.

- Tie the past to the present

What is the Paleogene?

TIMELINE

Date Range: 66 million years ago was the end of the Cretaceous and the beginning of the new period "The Palegoene." This era lasted up until 23 million years ago.

The Paleogene can be subdivided into three Epochs: Paleocene (Early Paleogene 66-56 Mya), Eocene (Middle Paleogene 56-34 Mya), and the Oligocene (Late Paleogene 34-23 Mya).

Encyclopaedia Britannica Editors. (2023). Geologic Time [Photograph]. Encyclopaedia Britannica. https://www.britannica.com/science/Paleogene-Period

Paleogene

Fun Facts

- The Paleogene Period was known for the rise of the mammals!

- It is known for the first appearance of whales in Earth's history.

- The continents started to look like how they are today.

Fun Facts!

Atmospheric Conditions of the Paleogene

The overall conditions of the Paleogene started out cool and dry after the dinosaur extinction event with a short warming period. In general during the Paleogene there was an overall cooling and drying trend.

Climate Overview

This picture represents a cooling period during the Paleogene with a drier climate and the first known grass and herbs appearing.

Sekscinska, A. (2005). The Paleogene Period [Photograph]. SOU. https://www.secretsofuniverse.in/history-of-life-17-paleogene-period/

How do we know?

Representative Data

https://commons.wikimedia.org/wiki/File:Calcita_y_aragonito.001_-_MSNBrussel.JPG

- Things like ice, rocks, and sea shells are made out of the materials

that are available in the environment

- The composition of a natural object tells us about what kinds of

materials were around at the time it was formed

Representative Data

https://www.flickr.com/photos/oregonstateuniversity/45690255762

https://www.flickr.com/photos/wessexarchaeology/5470163353

https://www.flickr.com/photos/virginiaseagrant/7362874456

https://commons.wikimedia.org/wiki/File:Dennstaedtia_americana_%28fossil_fern%29_%28Fort_Union_Formation,_Paleocene;_Yellowstone_County,_Montana,_USA%29.jpg

Sediment Cores

We might find...

Sediment Cores

https://commons.wikimedia.org/wiki/File:PS1920-1_0-750_sediment-core_hg.jpg

Fossils

Fossils

- the type of organism tells us about what the climate was like

- the presence of most life implies there is running water, sunlight, and some kind of nutrients available

Dennstaedtia body fossils

(Wing and Currano 2013)

Shell Fragments

Calcium Carbonate - CaCO3

- made by marine animals when they produce shells, exoskeletons, other hard parts

- seen in sponges, squids, snails, clams, coral, and more

- the type of oxygen (heavy or light) can be tracked, and indicates the conditions of the ocean at the time the shell was made

Shell Fragments

when it's hot, heavy carbon is also evaporated, so carbon in ocean is relatively light

when it's cold, light carbon evaporates more easily, so carbon in ocean is relatively heavy

aragonite pen (Decapoda)

https://www.flickr.com/photos/jsjgeology/49763509518

Recall... aragonite instead of calcite indicates a cool ocean!

https://pixabay.com/illustrations/nature-beach-sea-ocean-travel-sky-5320012/

Fine grains

  • may be carried on the wind

Large Boulders

  • more likely transported by ice
  • dropstones drop out of glacial ice as it moves

Sediment Types

Sediment Types

https://forestrybloq.com/texture-and-structure-of-sedimentary-rocks/

https://en.wikipedia.org/wiki/Dropstone

Organic Materials

  • indicate presence of life

(ie. coal)

https://www.dreamstime.com/photos-images/coal-hunter-valley.html

Most of our data for the Paleogene is from sediment cores... how do we know this?

Dating to the Paleogene

Absolute Dating

  • trying to find a precise age for a single material
  • just like fruit or leaves, the material in rocks and fossils decays over time
  • based on how much these rocks have

decayed, we can estimate how long ago they formed

Relative Dating

  • comparing materials to see which is older relative to the others
  • older materials tend to be buried under newer materials
  • sediment is in layers with relatively young

layers on top

  • we can also consider

how old rocks are

relative to the fossils

we find within them

https://study.com/academy/lesson/law-of-superposition-definition-lesson-quiz.html

https://www.istockphoto.com/photo/apples-gm1151389908-312031376

Atmosphere

ATMOSPHERE

- Critical to temperature regulation on Earth!

- Changes observed in the Paleogene helps us understand the mechanisms of how this regulation occurs!

Cretaceous - Paleogene Boundary was Explosive!

Volcanic reactions from India released very large amounts of both CO2 and SO2.

This is seen in sediment cores through layers of volcanic ash [3].

Volcanism:

SO2, CO2,

and You

While atmospheric CO2 absorbs reflected radiation off the Earth's surface, SO2 reflects incoming solar radiation from space. ---> While CO2 keeps Earth warm by retaining heat, SO2 cools it down by reflecting heat away.

However... SO2 doesn't stay in the atmosphere for very long, so overall, the cooling from SO2 isn't able to fully counteract the warming from CO2.

The result was gobal warming - with an average temperature rise of 3˚C!

https://clipground.com/animated-volcano-clipart.html

But how did the Earth's temperature cool down after all this volcano-related warming?

Removal of CO2?

Silicate weathering: the breakdown of silicate rocks

The chemical reaction of silicate weathering consumes CO2 molecules from the atmosphere, and locks carbon atoms into long-term storage.

Where did all this CO2 go?

However, silicate weathering rates must have been much higher than they are today to reduce CO2 levels enough to result in the cooling trends we see in the representative data!

What factors resulting from the eruptions could have accelerated silicate weathering rates enough to lower global temperatures?

Silicate Weathering

Silicate Weathering Intensity (SWI) can be increased by:

- Amount of surface area physically exposed for chemical weathering to occur

- Vegitation growth - Precipitation - Ice Wedging - Wind Abrasion

Which is controlled by:

- Physical Weathering (Increasing surface area of pre exposed silicates)

- Mountain Growth Rates

Silicate Weathering

- Mountain building exposes new silicate rocks to be weathered

- Vegatation Growth (Root Pry)

- Precipition (Rain, Snow fall)

- Ice Wedging (Melting and Freezing of Water)

- Wind Abrasion (Wind strength)

Temperature

Temperature

Temperature

Temperature

What do all drivers of physical weathering have in common?

All driven by temperature!

Could the sudden increase in temperaure as a result of the volcanic eruptions increase silicate weathering rates, triggering global cooling?

Volcanic Eruptions

Yes!

This cycle led to a 5˚C decrease in the global average annual temperature! [2]

What does this tell us?

Volcanic Eruptions

http://www.atmosedu.com/Geol390/figures/figure%2005-21.jpg

A Dynamic Water World

OCEANS

- Importance

- Sea Surface Temperature (SST)

- Major Events

<a href="https://www.flaticon.com/free-icons/ocean" title="ocean icons">Ocean icons created by Freepik - Flaticon</a>

How the Ocean Influences Climate

Why

- Heat Absorption and transport

- Carbon sink

Heat Absorption & Transport

Heat

Heat from the tropics is absorbed by the ocean and transported around the world.

This kept the poles snow free in the winter. [4]

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016PA002997

During the Paleogene, the oceans were critical in absorbing carbon from the atmosphere.

This regulates temperature and climate across the globe [6].

CO2

SST: What & Why?

SST

- How the oceans circulate

- More heat means more dynamic weather

<a href="https://www.flaticon.com/free-icons/ocean" title="ocean icons">Ocean icons created by surang - Flaticon</a>

Low Implications

- Changes in weather patterns

- Less ocean circulation

High Implications

- Increased storm intensity

- Loss of ecosystems

Big Changes!

- Todays SST is 20˚C

- Paleogene low: 17.0˚ C

- Paleogene high: 24.8˚C [5]

Big

Changes!

<a href="https://www.flaticon.com/free-icons/coral" title="coral icons">Coral icons created by Icongeek26 - Flaticon</a>

<a href="https://www.flaticon.com/free-icons/storm" title="storm icons">Storm icons created by Freepik - Flaticon</a>

Brand New World!

- Drake Passage

- Antarctic Ice

Events

https://agupubs.onlinelibrary.wiley.com/cms/asset/56a9fe1a-88cf-4256-8d5d-20ff30658f05/palo20904-fig-0001-m.jpg

Drake's

Location of Drake's Passage

50 MA

The opening isolated Antarctica.

This kept cold water from moving away from the South pole.

Allowed glaciers and sea ice to form! [7]

Impacts

https://i.pinimg.com/originals/d8/5d/2c/d85d2c0793459c085f5a1259740309e5.jpg

So what should we take away from this?

CONCLUSION

  • Earth has been around for a really long time
  • We can understand Earth's climate throughout time by looking at representative data
  • One type of data is sediment cores, which tells us about the Earth's conditions at the time the sediment formed and was deposited
  • We know how old the sediment is through relative and absolute dating techniques
  • For the Paleogene, representative data indicates:
  • an overall trend of climate cooling, and drying
  • silicate weathering played a major role in temperature regulation
  • continental movement created new passages for ocean currents
  • ocean currents affect how heat and carbon moved around the globe

https://news.harvard.edu/gazette/story/2019/11/mammalian-vertebral-columns-may-reflect-pace-of-evolution/

understanding previous conditions helps us predict current and future climate trends

Earth's historical climate tells us about what environments were necessary for life (and humans) to evolve in the ways it did

So what?

But why should we care?

https://slideplayer.com/slide/5224334/

seeing how previous climate events impacted Earth's systems can indicate how human behaviour might be influencing modern climate

the mechanism's of Earth's climate system have implications on how climate system's of other planets might work

https://hub.jhu.edu/2022/11/17/interactive-universe-map/

References

REFERENCES

Milligan, J. N., Flynn, A. G., Kowalczyk, J. B., Barclay, R. S., Gang, J., Royer, D. L., & Peppe, D. J. (2022). Moderate to Elevated Atmospheric CO2 During the Early Paleocene Recorded by Platanites Leaves of the San Juan Basin, New Mexico. Advancing Earth and Space Science, 37(4). https://doi.org/10.1029/2021PA004408

Sekscinska, A. (2005). The Paleogene Period [Photograph]. SOU. https://www.secretsofuniverse.in/history-of-life-17-paleogene-period/

Wing SL, Currano ED. 2013. Plant response to a global greenhouse event 56 million years ago. American Journal of Botany. 100(7):1234–1254. doi:https://doi.org/10.3732/ajb.1200554.

[2] V.S. Volkova; Paleogene and Neogene stratigraphy and paleotemperature trend of West Siberia (from palynologic data). Russ. Geol. Geophys. 2011;; 52 (7): 709–716. doi: https://doi.org/10.1016/j.rgg.2011.06.003

[3] Tobin, Bitz, C. M., & Archer, D. (2017). Modeling climatic effects of carbon dioxide emissions from Deccan Traps volcanic eruptions around the Cretaceous–Paleogene boundary. Palaeogeography, Palaeoclimatology, Palaeoecology, 478, 139–148. https://doi.org/10.1016/j.palaeo.2016.05.028

[4] Weber, T., & Thomas, M. (2017). Influence of ocean tides on the general ocean circulation in the early Eocene. Paleoceanography and Paleoclimatology, 32(6), 553-570. https://doi.org/10.1002/2016PA002997

[5] Tripati, A. K., Delaney, M. L., Zachos, J. C., Anderson, L. D., Kelly, D. C., and Elderfield, H. (2003), Tropical sea-surface temperature reconstruction for the early Paleogene using Mg/Ca ratios of planktonic foraminifera, Paleoceanography, 18, 1101, doi:10.1029/2003PA000937, 4

[6] Haynes, L. L., & Hönisch, B. (2020). The seawater carbon inventory at the Paleocene–Eocene Thermal Maximum. PNAS, 117(39), 24088-24095. https://doi.org/10.1073/pnas.2003197117

[7] Toumoulin, A., Donnadieu, Y., Ladant, J.-B., Batenburg, S. J., Poblete, F., Dupont-Nivet, G. (2020). Quantifying the effect of the Drake Passage opening on the Eocene Ocean. Paleoceanography and Paleoclimatology, 35, e2020PA003889. https://doi.org/10.1029/2020PA003889

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