Week 9, Day 4: Paleoclimates of New Mexico

Participants hold up a shark tooth that they found on a PEEC geology outing to Shark’s Tooth Ridge. (Photo by Denise Matthews)

During week nine of Take It Outside, we are learning about our climate!

New Mexico hasn’t always been home to the dry desert and mountainous landscapes that we know today. Did you know that our state was once under water? In our past, ocean creatures and dinosaurs occupied our home!

We can study paleoclimates, the climates that were prevalent in our geological past, to better understand the climates we live in today.

Upcoming Event:

Join PEEC’s Ashleigh Lusher today for our Critter Chronicles live-stream! Ashleigh will introduce Hazel, the Chihuahuan Spotted Whiptail Lizard, via YouTube livestream at 11 AM. She will take questions about Hazel and our critters via the live chat.

This program will last for about 15 minutes, and will also be available to watch on our YouTube channel after the live event. Tune in here.

Blog Post:

PEEC Educator and geologist Siobhan Niklasson explores the paleoclimates of New Mexico in today’s blog post. Learn about the creatures that once roamed — or swam around — the place we now call home.


A fossil-bearing specimen found on a PEEC geology trip to Rio Puerco. (Photo by David Schiferl)

Make a fossil today! This fun, hands-on craft can be made with cold coffee, coffee grounds, flour, and salt. Use toy dinosaurs, shells, or other small objects to make your imprint. You can also try out leaves, sticks, rocks, and other natural materials that you might find in your yard and want to preserve!

If you have a sandbox or sandy area in your yard, you can take the fossils outside once they’ve hardened and have your own paleontological dig! You can also make a small hole in the top of your fossil and hang it up in your house or use it as an ornament.

Find instructions here. The coffee adds a nice color and grittiness to the fossils, but isn’t necessary for this craft. If you don’t have coffee drinkers in your house, here are some coffee-free instructions.

Outdoor Challenge (Beginner):

Go outside and try to imagine our marine past! Read today’s blog post, then pretend you are a creature living in the Western Interior Seaway: maybe a fish, or a shark, or a long-necked plesiosaur. Maybe you are the mighty mosasaur! What do you need to survive? What do you eat? Who might eat you?

Outdoor Challenge (Advanced):

Look for examples of the carbon cycle in action. There are reservoirs where carbon is stored, and processes that move it around. Find out more about processes in the carbon cycle here.

Go outside and look for evidence of the carbon cycle in action. For instance, plants combine carbon dioxide from the atmosphere with water to make sugars and new cells. When animals breathe, each breath moves carbon dioxide from the animal’s cells into the atmosphere. Our volcanic rocks are evidence that materials were moved from rocks out to the atmosphere, and burned forests moved carbon from trees to the atmosphere.

Think of human impacts. How do our activities, fossil fuel use, agriculture, and industry, move carbon?

Other Resources:

Share Your Experience:

Tell us what you learn about our climate this week! We’d love to see your photos, too. Please send them to takeitoutside@peecnature.org or share them on Facebook or Instagram with the hashtag #peectakeitoutside.

Join us tomorrow to learn about the future of our climate!

Who Roamed Our Home?

Plesiosaurs once lived in the waters that covered our state. Fossils have been found at Chaco Culture National Historical Park, which is about a 3 hour drive from Los Alamos. (NPS Illustration)

By Siobhan Niklasson

We’re familiar with the climate of New Mexico as it is now, but the climate of this part of the world hasn’t always been the same!

The primary variable controlling climate on Earth is the amount of carbon dioxide in the atmosphere. When there’s more carbon dioxide, the atmosphere can trap more of the sun’s heat, and when there’s less carbon dioxide, more of the sun’s heat is reflected back into space. It’s like using different blankets at night: some are warmer than others.

The total amount of carbon on Earth is pretty much constant, but it’s not all in the atmosphere. Carbon can also be stored in rocks, in the ocean, or in living things. So the balance of carbon between the atmosphere and other reservoirs is what determines the warmth of our atmospheric blanket. You can think of it this way: sometimes you might have a lot of blankets on your bed, and sometimes they might be folded up and stored in the closet.

During the Cretaceous period (145 – 66 million years ago), the global climate on Earth was warmer than it is now. The supercontinent Pangea had started to break up, and the volcanic activity that accompanied this breakup moved lots of carbon from the rocks into the atmosphere. Because of the warm temperatures, the sea level was higher than it is now, and the divided land masses allowed warm ocean currents to carry heat all around the globe.

Map showing North America as it was during the late Cretaceous period. The tan is land and the blue is water. Look at the state outlines. Would your home be on the land or in the water? (Image by US Geological Survey)

In fact, during this period, a shallow sea stretched north to south across all of what is now North America. The western part of New Mexico was a low-lying coastline with huge rivers and dense jungle vegetation. The central and eastern parts of New Mexico were under water.

Imagine being right here in New Mexico during the late Cretaceous period: you’d be swimming in a warm, shallow sea, with oysters clustering on surfaces. Ammonites, spiral-shelled creatures related to octopuses, would be swimming by. A variety of bony fish and sharks shared the waters. Reptiles, including sea turtles, plesiosaurs, flying pterosaurs, and the giant apex predators, mosasaurs, swam and hunted here too. We can see examples of each of these animals in Cretaceous-age fossil finds from New Mexico.

The Cretaceous period marked the last time that New Mexico was underwater. During the Tertiary period following it (66 – 2.6 million years ago), the Rocky Mountains were uplifted, and the climate on the globe cooled significantly, as excess carbon was stored in fossil fuels and limestone rocks, and ocean currents changed to create distinct climate zones from the poles to the tropics. So our underwater past is now apparent only in the fossil record.

Currently, human activity is moving carbon from geologic storage into the atmosphere again, primarily through the excavation and burning of fossil fuels. Carbon dioxide levels are rising in the atmosphere, and we’re seeing a rapid increase in temperature. We know from our geologic history that different climates favor different assemblages of organisms, so it remains to be seen how our natural and human communities will change in response to today’s changing climate.