Valle Alto Formation
| Valle Alto Formation Stratigraphic range: Late Jurassic ~150–145 Ma |
|
|---|---|
| Type | Geological formation |
| Unit of | Quebradagrande Complex |
| Lithology | |
| Primary | Shale, sandstone |
| Other | Conglomerate |
| Location | |
| Coordinates | 5°22′08″N 75°22′03″W / 5.36889°N 75.36750°WCoordinates: 5°22′08″N 75°22′03″W / 5.36889°N 75.36750°W |
| Region |
Caldas Department Central Ranges Andes |
| Country |
 Colombia
|
| Type section | |
| Named for | Hacienda Valle Alto |
| Named by | González et al. |
| Location | San Félix |
| Year defined | 1977 |
| Coordinates | 5°22′08″N 75°22′03″W / 5.36889°N 75.36750°W |
| Approximate paleocoordinates | 3°06′N 72°24′W / 3.1°N 72.4°W |
| Region | Caldas |
| Country |
Colombia
|
 Paleogeography of Northern South America 150 Ma, by Ron Blakey |
|
The Valle Alto Formation (Spanish: Formación Valle Alto, Jva) is a geological formation of the Central Ranges of the Colombian Andes. The formation is composed of shales, sandstones and conglomerates and dates to the Late Jurassic period. Ammonites and fossil flora have been found in the Valle Alto Formation.
The formation was described and named in 1977 by González et al. after Hacienda Valle Alto, San Félix, Caldas.
The Valle Alto Formation is composed of shales, sandstones and conglomerates.
The Valle Alto Formation, part of the Quebradagrande Complex, is not defined as a proper formation, rather as a collection of rocks of different facies origin segmented by tectonic forces of the Central Ranges.
The Valle Alto Formation has been deposited as the result of marine incursions from the proto-Caribbean into Colombia, preceding the larger-scale transgression of the Cretaceous.
Fossils of Piazopteris branneri,Cladophlebis sp., Classopollis sp., Ctenozamites sp., Desmiophyllum sp., Gleichenites sp., Nilssoniopteris sp., Otozamites sp., Pachypteris sp., Ptilophyllum sp., Rhabdoderas sp., Sagenopteris sp., Sandlingites sp., Sphenopteris sp., Substeuroceras sp., Trigonia sp., and Zamites sp. have been found in the Valle Alto Formation.
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