Subachoque Formation
| Subachoque Formation Stratigraphic range: ~2.5–1 Ma |
|
|---|---|
| Type | Geological formation |
| Underlies | Sabana Formation |
| Overlies |
Tilatá Formation Guadalupe Gp. Guaduas Fm., Cacho Fm., Bogotá Fm., Regadera Fm. |
| Thickness | up to 150 metres (490 ft) |
| Lithology | |
| Primary | Shale, lignite |
| Other | Sandstone |
| Location | |
| Coordinates | 4°57′17.3″N 74°13′07.5″W / 4.954806°N 74.218750°WCoordinates: 4°57′17.3″N 74°13′07.5″W / 4.954806°N 74.218750°W |
| Region |
Bogotá savanna, Altiplano Cundiboyacense Eastern Ranges, Andes |
| Country |
 Colombia
|
| Type section | |
| Named for | Subachoque |
| Named by | Helmens & Hammen |
| Location | Subachoque Synclinal |
| Year defined | 1995 |
| Coordinates | 4°57′17.3″N 74°13′07.5″W / 4.954806°N 74.218750°W |
| Region | Cundinamarca |
| Country |
Colombia
|
 Paleogeography of the Pleistocene by Ron Blakey |
|
The Subachoque Formation (Spanish: Formación Subachoque, Q1su) is a geological formation of the Bogotá savanna, Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists mainly of sandy shales and lignite with sandstone beds. The Subachoque Formation dates to the Quaternary period; epoch (from approximately 2.5 to 1 Ma), and has a maximum thickness of 150 metres (490 ft). It is the lowermost formation of the lacustrine and fluvio-glacial sediments of Lake Humboldt.
The formation was first defined and named by Helmens and Van der Hammen in 1995 after Subachoque, Cundinamarca.
The Subachoque Formation consists mainly of sandy shales, some organic, with lignite and sandstone beds.
The Subachoque Formation is the lowermost of the lagunal and alluvial sequence of the Bogotá savanna. In parts, it conformably overlies the Tilatá Formation and other parts unconformably the Cretaceous Guadalupe Group and the Paleogene Guaduas, Cacho, Bogotá, and Regadera Formations. The Subachoque Formation is overlain by other Quaternary deposits of Lake Humboldt. The age has been estimated to be based on fission track analysis, with reported ages between 2.5 and 1 Ma. The depositional environment has been interpreted as lacustrine and fluvio-glacial with alluvial fans.
...
Wikipedia