The Grand Canyon is located in the state of Arizona and forms the major feature of the Grand Canyon National Park. It is one of the largest canyons in the world, an astonishing two hundred seventy-seven miles long and more than a mile deep. The climate in the canyon varies from top to bottom, meaning there are different plants and animals as well.
The warmest part of the canyon is the Inner Gorge which is at the very bottom. Water is brought into the Inner Gorge by creeks, giving life to many different species. These creeks run into the Colorado River which runs the entire length of the canyon. This river has eroded through the various layers of rocks for over five million years.
The Colorado River is currently eroding into the very bottom rocks of the canyon, the Vishnu Basement Formation which is at least 1.64 Billion years old.
Walking up out of the canyon, means passing younger and younger rocks. From the basement layer, a hiker will first encounter the rocks of the Grand Canyon Supergroup (1.2 billion years old), the the Bright Angel Shale containing trilobite fossils when the area was covered by a sea.
The Redwall Limestone comes next, overlain by the Hermit formation which formed 280 million years ago when giant dragonflies filled the sky and fish, amphibians and reptiles had evolved. the sea had treated but rivers were an important part of the landscape.
Above the Hermit Formation is the Cocinino Sandstone, formed 275 million years ago when the area was filled with sand dunes. The Cocinino Sandstone is overlain by the Toroweap Formation then capped by the Kaibab Formation which was deposited when the ocean once again covered this area 270 million years ago. Bryozoans, sponges and corals were a part of this diverse ecosystem, along with trilobites, nautiloids and sharks.
As the hiker and his daughter climb through these different rock formations, the present-day ecosystem of the canyon also changes, offering a wide range of climates and habitats to experience.
Discussion
Grand Canyon by Jason Chin is a beautifully illustrated book that offers readers information about the geology, climate and wildlife of the Grand Canyon. This is done through the story of a young girl and her father as they walk the South Kaibab Trail up to the South Rim of the canyon.
To help readers become oriented, Chin offers two cross-sections at the beginning of the book: the ecological communities in Grand Canyon which highlights the boreal forest for example, and the Rock Layers in Grand Canyon which identifies the different rock formations and their ages. As the hikers make their way along the trail they also journey through geologic time from the oldest formation to younger and younger rocks. Chin explains what the Grand Canyon area was like during this time by highlighting fossils or geologic features they see in the rocks. For example in the Grand Canyon Supergroup he writes that hikers "may find ripple marks preserved in the stone. Clues like these tell us what this place was like when the rock formed. They are like windows...." A cutout showing the ripple entices the reader to turn the page and view an illustration of what that vast sea with ripples on the tidal flat might have looked like 1.2 billion years ago!
Following each geological period are colourful picture panels showing the ecological community the hikers experience as they climb past the rocks in the canyon. For example, as the hikers encounter the Redwall Limestone formed 340 million years ago from a vast sea, they see the California condor, an endangered vulture that nests in the caves of this rock formation. Chin also includes native species found in each of the ecological communities as well as how some geologic processes such as erosion, occur.
Grand Canyon is rich in detail and facts, all presented in a wonderfully engaging way. There is a beautiful two-page panorama view of the Grand Canyon and at the back of the book there are numerous notes on the Grand Canyon. These include Human History of the canyon, Grand Canyon Ecology, Grand Canyon Geology which informs on sedimentary rocks and fossils, How Canyons Are Formed, The Colorado River, Grand Mystery which presents a short geologic history of the canyon area. A Note From The Author also explains his interest in geology and rocks, and how the illustrations for the book were designed based on his research. The illustrations were rendered with pen and ink, watercolour and gouache. There is a beautiful generalized cross-section of the Grand Canyon at the back of the book. Chin has also included a list of selected sources in the back matter.
Anyone who has marveled at the Grand Canyon and wishes to know more, will enjoy Jason Chin's masterpiece picture book Grand Canyon.
Book Details:
Grand Canyon by Jason Chin
New York: Roaring Brook Press 2017
Grand Canyon by Jason Chin
New York: Roaring Brook Press 2017
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