“Rocks are records of events that took place at the time they formed. They are books. They have a different vocabulary, a different alphabet, but you learn how to read them.”
|Let's go kids! We're going on an adventure, back in time!|
The rocks of Dreamy Draw were largely formed during the Precambrian Era, a huge length of time stemming from the beginning of Earth's formation approximately 4.5 billion years ago and ending approximately 600 million years ago. The oceans and atmosphere were formed during this time, as well as Earth's magnetic field, the tectonic plates, and the land masses.The bulk of Earth's geologic time is contained within the Precambrian Era. Long before the first dinosaurs roamed the Earth and the first fish were swimming in the oceans, even before the first trilobites appeared, North America was just beginning to take shape. After many hundreds of millions of years, when the rocks of Dreamy Draw were forming, the only life forms on Earth consisted of bacteria, algea, and primitive microscopic rooted organisms (something like a very primitive sea cucumber). During this time, Arizona was located near Antarctica and Antarctica was near the equator!
|A map of the continental organization approximately 650 million years ago.|
Image Credit: Tucson Citizen
I followed the studies of two geologists, Dr. Stephen Reynolds and Julia Johnson, as they surveyed the land and identified the formations, mineral veins, and rocks that make up the Phoenix mountain chain. I was fascinated as I read about how Dreamy Draw specifically contains many rocks from both oceanic and continental origins. That would mean that Dreamy Draw was at one time, a place that was transitioning from an oceanic zone to a continental zone!
|Arizona geography during the late Proterozoic Era|
Image Credit: The Arizona Experience Paleogeograhy Timeline
Some of the oceanic rocks included Greenstone (greenish metamorphic rock, formed by pressure and warm liquids, usually in oceanic areas), Ferruginous Quartz (a quartz with red, brown, or yellow veins which are deposited by iron rich water), and Meta-Mudstone (mud stone that has undergone a metamorphosis, changing the original properties of the rock).
Some of the continental rocks included Gray and Tan Phyllite (metamorphic rocks with reflective mica, usually found at the eroded base of ancient mountain collisions), Schist (a metamorphic rock that usually originated in mudstone/shale and has undergone intense heat and pressure), and Orthoquartzite (one of the purest forms of quartz, yet mixed with sandstone, thus it is a sedimentary rock).
|The girls' rock collection, gathered from Dreamy Draw. |
Pictured are: Greenstone, Gray Phyllite, Coal, Quartz,
Ferruginous Quartz, Schist, and Meta-Mudstone
|I printed out an evolutionary timeline to give a scale of how much time we're talking about.|
I also printed out sample pictures of the rocks we would be looking for.
The girls were thrilled to go on a geology adventure! As we drove there, I explained the story of Arizona's transformation. The drama of pushing, pulling, exploding, collapsing, and washing over was exciting for the kids and they were really looking forward to seeing the remains of that epic saga. As soon as I brought the car to a stop in the parking lot, they jumped out and began looking for a place to "go mining". They ran up to a huge chunk of schist and immediately began speculating as to how it was formed.
|"Look! It's Mudstone! Wait, it's Schist!"|
They saw a white dust covering large areas of rock and tried to picture the volcano that may have deposited it. They collected samples of found coal and wondered about the plants that may have contributed to its formation. I didn't yet have the answers to all of their questions but I was more than happy to encourage them as they excitedly ran about calling out to each other to check out each new find.
|Where did all of this white dust come from? Volcanoes? Erosion? BBQ's?|
|Checking their samples against their checklists|
|Kat and Amelie, reading Arizona's history in the rocks.|
|The girls loved mining with their hammers, this is definitely something we'll do again.|
The best part of all for them, however, was something they added on to our lesson themselves! As they were hiking and looking for rocks, they decided to rest near a large quartz vein. Dazzled by the brilliance of the white crystals, they decided to start a trail side collection. They grabbed tiny pieces by the handful and worked together to carefully move the heavier pieces. Before long, they had amassed quite a collection!
They built a large mouse sculpture out of the rocks, and left it on the side of the trail to greet passing hikers. Many who passed by were delighted by the sight of these two girls excitedly talking about quartz while building their sculpture. Kat and Amelie came here to learn about the story of the Earth and its many transformations. They ended up leaving behind a piece of their own story for others to find and be delighted by!
|This mouse has been left as a hello from the girls to Dreamy Draw's hikers!|
This lesson in geology was one of my favorite lessons of the year so far! During my research, I was able to contact the Phoenix Parks and Recreation Department, where I was pointed in the direction of the North Mountain Visitor's Center. I also contacted the Arizona Geological Survey, who provided me with a fantastic resource of maps pertaining to Arizona's geology. Kat and I will definitely be utilizing these resources to not only learn more about the history of Arizona, but to also learn more about our desert parks and the rangers who attend to them.
In the coming months, Kat and I will be visiting the Phoenix mountains of North Mountain, South Mountain, and Papago Park. Considering the beautiful geology Arizona has to offer, we'll also take our lessons to Sedona, Tucson, and we'll eventually culminate our adventures with a trip to The Grand Canyon! I am excited to see where our curiosity takes us, as well as the kinds of stories we'll get to read in the rocks when we get there.
For now though, it was wonderful to be able to include my niece in our studies. Not only did we all learn a lot about our local parks, but we had a lot of fun along the way. She is just as much of an enthusiastic learner as the rest of us, and I hope I get more chances to include her in our wonderful learning adventures!
|These two girls can conquer mountains and take on the world!|