Layers Of The Grand Canyon
Layers of the Grand Canyon
During the earliest periods of the Grand Canyon formation where we have Tapeats sand stone, bright angel shale and muav limestone it would appear that there was a relatively shallow, warm sea. This is indicated by the presence of Trilobite fossils found in this layer which thrived in that environment. Trilobites were early animals that had exoskeletons that are usually the only part of them that is preserved in the fossil record. They were marine bottom feeders who thrived in warm nutrient rich waters. The Redwall and Temple Butte limestone that compromises the next layer of rock and the marine fossils there indicate that the sea had deepened and given rise to a more advanced form of sea life to include brachiopods, clams, coral, and fish. This gives way to the Supai group which is mainly sandstone with some shale layers present. The presence of reptile and plant fossils indicates a drier climate at the time, however towards the Western regions of the canyon there is more limestone which indicates a more marine environment in that area. Next comes Hermit shale whose fern and conifer fossils as well as reptile and amphibian fossils indicate a coastal plain with many streams. Then comes the Coconino sandstone which is mostly quarts sand with vertebrate animal fossils indicating a dry desert environment in the area. Finally we come to the youngest layer of the Grand Canyon, the Kalibab limestone which has many marine fossils which indicate that the area was again under a shallow sea with clear water and a sandy bottom. The multiple layers of the Grand Canyon give us a good indicator of what the environment and weather was like many years ago and give us a glimpse into the rich history of the area.
References
Layers in Time: Geology of Grand Canyon. (n.d.). Retrieved February 8, 2015, from http://www.nps.gov/grca/forteachers/upload/GeoArticle-11-1-11-2.pdf
Ribokas, B. (2000, January 1). Grand Canyon Rock Layers.
During the earliest periods of the Grand Canyon formation where we have Tapeats sand stone, bright angel shale and muav limestone it would appear that there was a relatively shallow, warm sea. This is indicated by the presence of Trilobite fossils found in this layer which thrived in that environment. Trilobites were early animals that had exoskeletons that are usually the only part of them that is preserved in the fossil record. They were marine bottom feeders who thrived in warm nutrient rich waters. The Redwall and Temple Butte limestone that compromises the next layer of rock and the marine fossils there indicate that the sea had deepened and given rise to a more advanced form of sea life to include brachiopods, clams, coral, and fish. This gives way to the Supai group which is mainly sandstone with some shale layers present. The presence of reptile and plant fossils indicates a drier climate at the time, however towards the Western regions of the canyon there is more limestone which indicates a more marine environment in that area. Next comes Hermit shale whose fern and conifer fossils as well as reptile and amphibian fossils indicate a coastal plain with many streams. Then comes the Coconino sandstone which is mostly quarts sand with vertebrate animal fossils indicating a dry desert environment in the area. Finally we come to the youngest layer of the Grand Canyon, the Kalibab limestone which has many marine fossils which indicate that the area was again under a shallow sea with clear water and a sandy bottom. The multiple layers of the Grand Canyon give us a good indicator of what the environment and weather was like many years ago and give us a glimpse into the rich history of the area.
References
Layers in Time: Geology of Grand Canyon. (n.d.). Retrieved February 8, 2015, from http://www.nps.gov/grca/forteachers/upload/GeoArticle-11-1-11-2.pdf
Ribokas, B. (2000, January 1). Grand Canyon Rock Layers.