Girón Formation
The Girón Formation (Spanish: Formación Girón, Jg) is an extensive geological formation stretching across 325 kilometres (202 mi) from the north in Teorama, Norte de Santander, across the Mesa de Los Santos and Chicamocha Canyon towards west of Nobsa, Boyacá in the northern part of the Altiplano Cundiboyacense in the south. The formation extends across the northern and central part of the Eastern Ranges of the Colombian Andes.
| Girón Formation | |
|---|---|
| Stratigraphic range: Late Jurassic ~ | |
| Type | Geological formation |
| Underlies | Rosablanca, Río Negro, Tambor & Tibú-Mercedes Formations |
| Overlies | Bucaramanga Gneiss, Arboleda Granite, Diamante, Floresta, Bocas & Jordán Formations |
| Thickness | Up to 3,346 m (10,978 ft) |
| Lithology | |
| Primary | Sandstone, siltstone, conglomerate |
| Other | Shale, claystone, rhyolite, tuff |
| Location | |
| Location | Mesa de Los Santos & Altiplano Cundiboyacense Eastern Ranges, Andes |
| Coordinates | 6°46′17″N 73°02′30″W |
| Region | Santander, Norte de Santander, Boyacá |
| Country | Colombia |
| Extent | 325 km (202 mi) |
| Type section | |
| Named for | Girón |
| Named by | Hettner (1892) Langenheim |
| Location | Lebrija River |
| Year defined | 1954 |
| Coordinates | 7°11′39″N 74°09′13″W |
| Region | Santander |
| Country | Colombia |
| Thickness at type section | 3,346 m (10,978 ft) |
Paleogeography of Northern South America 150 Ma, by Ron Blakey | |
The formation forms the basement in the Middle Magdalena Valley and is forming the Serranía de Los Cobardes. The Girón Formation consists of thickly bedded red sandstones, shales, siltstones and conglomerates deposited in a terrestrial alluvial and fluvial to fluvio-lacustrine environment in an extensional basin setting. The formation dates to the Late Jurassic period and has a maximum thickness of 3,346 metres (10,978 ft) at its type locality in the valley of the Lebrija River.