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MJ's Journey: History of Our Rockies

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S: The History of Our Rockies by ACS 6th Grade, 2015-16

BC: During the summer of 2015, we found a sea shell fossil (pictured above) in a canyon in northwest Colorado. We were shocked - how did it get there? So, we set off on a 5-month long learning expedition to answer that question. We conducted field work in the mountains, worked with a paleontologist at the Denver Museum of Nature and Science, and read and wrote a lot about the geologic history of our state. This book is the product of all our learning - we hope you enjoy it! Thanks for reading our book, and taking this journey with us through the geologic history of Colorado! | Annunciation Catholic School | AnnunciationK8.org | 3536 Lafayette St., Denver, CO 80218

FC: MJ's Journey: The History of Our Rockies | by Annunciation's 2015-16 6th Grade Class Denver, CO

1: Introduction Hello, my name is MJ (for Makuei Junior), and in this book I will be talking to you about the history of Colorado over the past 400 million years. To begin, I would like to tell you that I am a seashell with a very interesting past; I have experienced a lot of things, like watching the dinosaurs come into existence and feeling the intense impact of the asteroid that wiped them out. I was there when ‘North America’ didn't exist, and when the Rocky Mountains started forming. When the supercontinent Pangaea was forming and deconstructing, I was there. I started in a sea millions of years ago and then managed to get all the way to a modern day science classroom. I'm going to try to do my best to teach you about plate tectonics and how they affect the earth’s topography. Scientists have this theory that the earth’s outer surface consists of 12 rigid plates that hold together the continents and countries we live in. Anyway, I have tried to snapshot every major event in my life with scientific explanations, and have put together a little scrapbook of my experiences. I hope you enjoy it and learn something about our Rockies! | By: Nayla and Xavier

2: Widespread Shallow Seas Paleozoic Era Mississippian Period ~350 million years ago | How did it look? Let's go way back to 400-300 million years ago, when I was born! I wish you humans were able to see the magnificent things I saw back then. It seemed to me like the whole earth was covered in salt water. There were a lot of sea creatures, like nautiloids, trilobites, sea scorpions, and so much more! My favorite friend was this rare futuristic creature called the nautilus. It had a spiral shaped shell and was like a half snail and half octopus. Oh! Let me tell you about the coral. Man, these living things are interesting! The first time I saw it, I thought It was a sea plant because my friend, a dunkleosteus, knows a fish that lives in a coral reef, but I found out that they are living and can feed themselves. I rarely saw land from my point of view, and in my opinion the continents didn't look as pretty and green as they do today. The earth looked fairly lifeless because there was no life on land yet--only in water. If Colorado, Seattle, and New York existed then, most of them would be under water. I think even our tallest buildings today would be halfway under water. The duration of the continents coming together was long enough. I couldn't wait to see what would happen next! | How did this happen? All around me there were rustling waves, and the sea floor kept cracking because the supercontinent called Pangaea was forming. The sound down here was amazing! The North American plate smashed into other plates and became a part of Pangaea, and this process caused over half of the earth to be covered in water. | nautilus | By: Aradely and D'mitri

4: Rise of the Ancestral Rockies Paleozoic Era Pennsylvanian Period ~300 million years ago | How did it look? So around 300 million years ago, I was just hanging out in the water, when something started to push me up slowly. Some people think our current Rockies are the only ones that ever existed, but this was the time period that saw the rise of the ancestral Rockies! It was cold during this process - so cold that it was an ice age period. I hid in a little spot where no rocks would hit me, and I was lonely. The other animals were confused too. | How did this happen? Now let's explore the time when the South American and North American plates smashed together. If they were oceanic plates, one oceanic plate would go under the other, but since they weren't, they just collided. Neither went under, and the pressure formed land to rise, creating the ancestral Rockies across Colorado, Utah, Texas, Oklahoma, and Wyoming. This whole process lifted our region out of the sea and into a continental mountain range. The rocks that became the mountains were already made before they were raised. The cores of the mountain ranges were in most places formed by pieces of the continental crust that had existed over one billion years ago. I was scared with all that tectonic activity going on! | By: Gonzalo and Kyntessa

5: Plant and Animal Life: There were two trees that we don't have today. One of the trees was the seed fern tree, which was eaten by herbivorous dinosaurs, including one huge dinosaur called lizard feet. The other tree that there was the early conifer, also called the walchia piniformis, and this was my favorite tree. There were also giant millipedes that could be 6 or 7 inches long, and immense cockroaches that were 5 to 10 times bigger than the normal size of cockroaches today. When I saw those, I got scared that they were going to eat me! I also saw the fin-backed lizard called the dimetrodon. These reptiles were the coolest-looking out of all the animals I saw. | fin-backed lizard

6: Erosion of the Ancestral Rockies Paleozoic Era Permian Period ~250 million years ago | How did it look? Almost as soon as they were up, the ancestral Rockies started falling apart and continued to erode for more than 50 million years. The mountains were turning into pieces of sediment like sand, rocks, and dust. The southern ice cap melted off permanently, and this water helped erode the mountains. Whenever it rained or snowed, the water got in the cracks, froze, expanded, and put pressure on the rocks. | End of an era... Eventually, the mountains crumbled and fall apart, and these sights were how the Permian period ended for me. By the beginning of the Mesozoic era, the ancestral Rockies were almost gone into the earth. The immensity of the ancestral Rockies started to turn into the debut of the dunes and deserts. | Geology fact! When these Rockies eroded away, we call what they left behind sediment rock. Sediment rocks are just the remains of other weathered away rocks. | Plants and animals: The animals that lived during that time were fin-backed reptiles, amphibians, and large dragonflies. The trees were still very primitive. | By: Jaden and Camila

8: Dunes and Deserts Mesozoic Era Triassic Period ~200 million years ago | How did it look? Moving on to 200-250 million years ago! The erosion of the ancestral Rockies provided sediment rock to build dunes and deserts, and we can see the evidence for this period in the Grand Canyon. Different periods have different layers in the Grand Canyon: the bottom layer is the oldest, and the top layer is the newest. Many layers from the Triassic period show evidence of a lot of dry sand, or fossilized dunes and deserts. | Climate, plants, and animals: In physical geography, the definition of a dune is a hill made of mud or sand. Dunes and deserts occur around the middle of the hottest places, and they come in many different shapes and sizes. In the Triassic period, the climate was much drier than it had been at the time of the first forests and coal swamps. Conifers, cycads, ferns, and giant horse tails adapted to these conditions. Dinosaurs became the dominant life forms. The coelophysis was one of the earliest dinosaurs in North America, existing about 225 millions years ago. These small dinosaurs with hollow bones and slender bodies were built for speed. They were meat-eating hunters with many, small sharp teeth and claws that could grasp prey. One of the long necked dinosaurs was the diplodocus longus sauropod. Sauropods were called plant eaters and the largest land animals that ever lived. They thrived worldwide throughout the Jurassic time period and into the Cretaceous time period too. | By: RaeAnn and Breanna

10: Western Interior Seaway Mesozoic Era Cretaceous and Jurassic Periods ~150 million years ago | How did it look? At this time, we had a lot of water, dinosaurs, palm trees, sand, mud, and shells. There was an immense sea that separated the left and the right sides of our continent that we now call the Western Interior Seaway, or the Cretaceous Seaway. There were a lot of palm trees that dinosaurs ate. Some of the dinosaurs there were back then were called tyrannosaurus rex, duckbill, albertosaurus, corythosaurus, anatosaurus, parasaurolophus, carnotaurus, monoclonius, pteranodon, kronosaurus, and more. The topography at this time was very dynamic. My senses were always kept busy. I was scared that I would get smashed by the tall dinosaurs everywhere. The water from the Western Interior Seaway was really salty and nasty. I could hear the dinosaurs ROAR, but I got used to it. I could smell the plants that were all around me and the dampness from the water made me feel sick. The seaweed in the ocean felt really slimy and gooey but it was somewhat soft. | How did this happen? Pangaea was close to gone at this point, and the world was separating into two big land masses: Laurasia and Gondwana. Laurasia was North America, Europe, and Asia. Africa, India, South America, Australia, Antarctica, and Madagascar made up Gondwana. The Farallon tectonic plate was flat, and it subducted under the immense North American plate, gripping it and pulling it down. This downward pull made room for the seaway to pass through the continent. Water from the Arctic Ocean and the Gulf of Mexico flooded through, making the Western Interior Seaway. The current states that are Colorado, Utah, Kansas, Wyoming, Montana, New Mexico, and Texas were completely under salt water. | By: Xavier and Kimberly

12: Laramide Orogeny Mesozoic Era Cretaceous Period ~80 million years ago | How did it look? Let’s now jump to 80 million years ago, when the current Rocky Mountains were formed! When they were first created they were rising little by little, but they are very tall now. Watching the mountains was so serene. This time period was called the Laramide Orogeny. You’re probably wondering what that means, so let me explain. Laramide Orogeny was the birth of the Colorado plateau that went vertically across the United States. | How did this happen? Oh yeah I can’t forget! I am going to tell you how the plate tectonics helped form the present-day Rockies! How did this happen, you ask? Let me explain. The Farallon plate was subducting beneath the North American plate. This happened slowly over many years. The edge of the Farallon plate extended all the way to modern day Utah at the time. It was going along the west coast. However, the Farallon plate didn’t go deep into the mantle. Instead, it subducted because it wasn’t as dense as normal oceanic crust. While it slid and pushed under the North American plate, the Rockies rose away from the plate boundary. The movement felt like an earthquake for me, and possibly everywhere on the continent! It was so upsetting seeing the ancestral Rockies wither away in the Permian period, but now I had awesome new Rocky Mountains! | By: Perla

14: Asteroid Impact Cenozoic Era K/T Boundary 66 million years ago | What happened? Let me tell you about the scariest and most thrilling event in my whole life that happened 66 million years ago. Imagine this. A t-rex was stomping its way across the land hunting for juicy, bloody meat. Trees were everywhere he looked, as well as volcanoes that were erupting, and other dinosaurs were looking for prey. It was a normal day. | But then, suddenly, something happened: we all looked up to see a load of shooting rocks, followed by flames and burning trees. A huge asteroid had hit Earth. I saw this t-rex run for his life. Some dinosaurs ran for shelter trying to overcome this problem, but the only animals that had a chance to survive where the small creatures like rodents. This t-rex’s life was sadly coming to an end. A rock that splashed into the water almost crushed me into bits! I was lucky to survive, because this asteroid impact wiped out 85% of all animals and their habitats, and totally devastated the dinosaurs. The destruction of this asteroid, which was the size of Mt. Everest and came at our planet at 20 times the speed of a rifle bullet, spread world wide. The impact had the power of 10,000,000 nuclear bombs. It caused massive volcano eruptions and huge earthquakes. When the fires finally went out, there were lots of dinosaurs’ bones on the floor as if there had been a war. Some of the bones went in the water until they hit the bottom. After that, the creatures that had survived had the whole world to themselves. It was a sad ending, but it paved the way for the Mammal Age. | By: Yadhira and Martir

16: Tropical Rockies, Regional Uplift, and Volcanoes Cenozoic Era Tertiary Period ~20 million years ago | How did the plate tectonics look? On the surface, Colorado was warm and tropical at this time, and small mammals were spreading all over the place! But also during this time, volcanoes erupted, changing the landscape. But while all this commotion was happening, underneath the lithosphere there were a few tectonic plates named the Farallon plate, the Pacific plate and the North American plate who were having complications. The Pacific plate was shoving the Farallon plate towards the North American plate. This is called a convergent boundary; when two plates are pushing against each other. The Farallon plate continued pushing against the North American plate for a few million years. In this time, the Farallon plate slowly started melting away into the mantle. Anyway, as a result of the Farallon plate getting shoved towards the North American plate, the west region of the States (Utah, Colorado, New Mexico etc.) was being lifted up and the crust was getting ruffled, creating mountains. All of this tumult really shook the Earth and while I couldn't really feel the plates moving, I could definitely see that the lava that was coming out of the earth meant that things were changing underneath. While all of this was happening, I might have been lifted up along with the mountains when the crust started to change. The movement underneath caused a drastic change in the terrain above the mantle, and I'm not just referring to the Rocky mountains being created. As I mentioned before, volcanoes were erupting. Why were volcanoes erupting though? As a result of the Farallon plate subducting, the plate hit quite a few slabs of rock under the lithosphere that were millions of years old. When the rocks were disturbed, they made cracks in the crust, allowing magma to go through. One thing to know is that the odors on earth while all of this was happening were not pleasant. The air often had ash in it, or smelled like a dirty river. The thing that scared me the most while all of this was happening was that the lava seemed to be advancing and never stopping, destroying everything in its path. Man, did my heart beat fast when I had a near miss with the lava. Anyway, today, the Farallon plate no longer exists. It's remains are now called ‘the Cocos plate’ and ‘the Juan de Fuca plate’. Though there aren't any active volcanoes in Colorado today, there is volcanic activity along some of the plate boundaries. Today in Colorado, the volcanoes’ only remains are layers of igneous rock in the Rocky Mountains. | By: Nayla and Domanic

18: Recent and Present Topography Cenozoic Era Quaternary Period 1.8 million years ago to today | How does it look today? Today in Colorado, many things have changed from millions and thousands of years ago. There are more people, and we have a city full of buildings and skyscrapers. We also still have the great Rockies. So what changed between about a million years ago and today? Say, if we went back about 1.8 million years ago, we would see things such as glaciers that helped cause larger animal extinctions like sabertooth tigers and mammoths. You would also see animals that aren't here in the present day in Colorado like mastodons, mammoths, who lived in the snowy mountains, stegosauruses, and apatosauruses. You humans will never know how amiable they could be. Also, you would see seasonal changes causing parts of the land to become very arid, and the land might have been flatter than now. When the current Rocky Mountains started to erode away about 55-80 million years ago, they created AWESOME landforms like hogbacks and the Red Rocks. The cool colors and layers are so beautiful. The Rockies and the other Colorado landforms are attracting people to come visit Colorado. After a long duration of ups and downs, I am very happy to be here in a peaceful and beautiful time today. | Current tectonics The 12 Tectonic plates in the world today are the North American, South American, Juan de Fuca, Pacific, Scotia, Antarctica, African, Arabian, Eurasian, Philippine, Indo-Australian, Nazca, Cocos, and Caribbean plates. The Pacific plate is rubbing against the North American plate, which creates earthquakes on the west coast of the US today. | By: Mothaing and Vincent

21: Meet the Authors! | 6th Grade Authors: Breanna Archuleta, Jaden Barrientos, Domanic Dean-Castillo, Camila Diaz-Martinez, Kelsy Espino, Aradely Flores, Perla Garcia, Martir Guardado, Nayla Hernandez, Kimberly Jurado, Yadhira Lomeli, Mothiang Mabil, Makueigalam Majok, Vincent Martinez, RaeAnn Melendez, Gonzalo Perez, Kyntessa Roybal, Dmitri Vargas, Xavier Wake. Teachers: Crystal Lee (Language Arts), Carmel Russo (Art), Robbie Bernardin (Science)

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  • Title: MJ's Journey: History of Our Rockies
  • A sea shell fossil's first-person account of the last 400 million years of Colorado geologic history. This book takes you on an epic journey exploring the changing geology, geography, paleontology, and plate tectonic activity that have given rise to the present-day Colorado & Rocky Mountains that we know and love.
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