| 词条 | Fountain Formation |
| 释义 |
| name = Fountain Formation | image = Roxborough.jpg | caption = Red rocks typical of The Fountain Formation seen at Roxborough State Park near Littleton, Colorado | type = sedimentary | age = Late Pennsylvanian | period = Pennsylvanian | prilithology = sandstone, conglomerate | otherlithology = limestone, shale | namedfor = Fountain Creek | namedby = C. W. Cross, 1894 | region = Denver Basin | country = | coordinates = | unitof = | subunits = | underlies = Lyons Formation | overlies = Gleneyrie Formation | thickness = {{convert|0-4500|ft|||}}[1] | extent = Colorado, Wyoming | area = | map = | map_caption = }} The Fountain Formation is a Pennsylvanian bedrock unit consisting primarily of conglomerate, sandstone, or arkose, in the states of Colorado and Wyoming in the United States, along the east side of the Front Range of the Rocky Mountains, and along the west edge of the Denver Basin. Origin of nameThe Fountain Formation was named by geologist W. C. Cross in 1894 for exposures along Fountain Creek in El Paso County, Colorado.[2] StratigraphyThe Fountain unconformably overlies Precambrian granite and gneiss. Outcrops of the formation typically dip steeply to the east. Depositional environmentThe formation was formed by the erosion of the Ancestral Rocky Mountains, and deposition by fluvial processes as alluvial fans. The characteristic predominant red color and the composition of the Fountain reflect that of the granites and gneisses from which it was eroded. Notable outcrops
FossilsMarine invertebrates have been discovered in a limestone and shale member of the Fountain Formation, cropping out on a low hogback in Perry Park. Invertebrates include bryozoans, brachiopods, crinoids, echinoids, and gastropods.[3] Plant fossils have been discovered in Garden Park north of Cañon City, including Lepidophloios laricinus, Sigillaria, Syringodendron sp., Lepidophyloides sp., Lepidostrobus sp., Lepidostrobophyllum sp., Calamites, Neuropterus sp., Cyclopteris sp., and Stigmaria ficoides.[4] AgeRocks of the Fountain Formation are considered to be of Late Pennsylvanian age, and are between 290 and 340 million years old. References1. ^Frederickson, E.A., De Lay, M., and Saylor, W.W., 1956, Ralston formation of Canon City embayment, Colorado: American Association of Petroleum Geologists Bulletin, v. 40, no. 9, p. 2120-2148. 2. ^Cross, C.W., 1894, Description of the Pikes Peak sheet [Colorado]: U.S. Geological Survey Geologic Atlas of the United States, Pikes Peak folio, no. 7, 5 p. 3. ^Ellis, C.H., 1966, Paleontologic age of the Fountain Formation south of Denver, Colorado: The Mountain Geologist, v. 3, no. 4, p. 155-160. 4. ^Jennings, J.R., 1980, Fossil plants from the Fountain Formation (Pennsylvanian) of Colorado: Journal of Paleontology, v. 54, no. 1, p. 149-158. External links
11 : Fountain Formation|Geologic formations of Colorado|Fountain, Colorado|Landforms of El Paso County, Colorado|Sandstone formations of the United States|Conglomerate formations|Carboniferous Colorado|Pennsylvanian Series|Pennsylvanian North America|Fluvial deposits|Carboniferous southern paleotropical deposits |
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