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introduction |
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Geologic History of the Front Range |
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The uplifting forces that drained the Cretaceous Seaway and formed the Front Range were compressional forces, which resulted from thrust faults in the shallow subduction zone below. The Fountain formation resulted from the uplifting mountain building forces, along with the Lyons Formation. The Fountain Formation was first developed as a series of shedding fans that were deposited sub horizontally, as rivers deposited sands and gravels that would eventually form the conglomerate composition of the Fountain Formation. The Lyons formation, was also composed of similar materials. The formation first evolved in this period as sand dunes with sandstone deposits. |
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| The important formations of this period were created from ocean deposition. The ocean moved further west to form the western interior cretaceous seaway, depositing clay, silt, and marine sediments that formed shales and limestone in the process. |
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| As the ocean regressed, its sediments still remained deposited on top of the Lykins Formation, forming the Morrison, Dakota and Pierre Shale formations. The sediments created many layers of mudstone and limestone once the continent began to shift westward and the cretaceous seaway regressed. |
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| In the Cenozoic period, the modern day Rocky Mountains were created. The uplifting forces created a tilting effect that moved the sedimentary rocks of the Fountain Formation, and eventually made the Flatirons. |
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| Now that we have a brief background of how the Flatirons have developed as we see them today, it is time to experience the different formations first hand. The virtual field trip map will give us a broad spatial reference to the area we will be examining. | |
page created 2006.3.20 page created 2006.4.2- last revised 2006.4.12 AJR - contact me at andrew.ratchford@colorado.edu
