| Simijaca Formation | |
| Period: | Turonian |
| Age: | Cenomanian-Turonian ~ |
| Type: | Geological formation |
| Prilithology: | Mudstone |
| Otherlithology: | Shale, sandstone, limestone |
| Unitof: | Villeta Group |
| Underlies: | La Frontera Formation |
| Overlies: | Chiquinquirá Sst., Churuvita Fm., Hiló Fm., Pacho Fm. |
| Thickness: | up to 693-1NaN-1 |
| Map: | Blakey 090Ma - COL.jpg |
| Coordinates: | 5.4875°N -73.8486°W |
| Region: | Altiplano Cundiboyacense Eastern Ranges, Andes |
| Namedfor: | Simijaca |
| Namedby: | Ulloa & Rodríguez |
| Year Ts: | 1991 |
| Location Ts: | South of Simijaca |
| Coordinates Ts: | 5.4875°N -73.8486°W |
| Region Ts: | Cundinamarca, Boyacá |
| Thickness Ts: | 432m (1,417feet) |
The Simijaca Formation (Spanish; Castilian: Formación Simijaca, K2S, Kss) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The predominantly mudstone formation dates to the Late Cretaceous period; Turonian and Cenomanian epochs, and has a maximum thickness of 693m (2,274feet).
The formation was defined and named in 1991 by Ulloa and Rodríguez after Simijaca, Cundinamarca.[1]
The Simijaca Formation is characterised by a sequence of mudstones, grey and black shales with sandstone and limestone intercalations.[1]
The Simijaca Formation conformably overlies the Chiquinquirá Sandstone, and the Hiló and Pacho Formations, and is overlain by the La Frontera Formation.[2] The age has been estimated to be Turonian,[1] or Cenomanian.[3] Stratigraphically, the formation is time equivalent with the Chipaque Formation.[4] The formation has been deposited in an open marine platform setting.[5] The deposition is represented by a maximum flooding surface.[6]
The Simijaca Formation is apart from its type locality in the Quebrada Don Lope,[7] found at surface in the north of the Bogotá savanna, in the Tabio anticlinal, along the road Ubaté-Carmen de Carupa,[8] at the western and eastern flanks of the Aponsentos-Chiquinquirá Synclinal,[9] near Tena, south of Anolaima and Cachipay,[10] and between Anapoima and Granada.[11]
Geology of the Eastern Hills
Geology of the Ocetá Páramo
Geology of the Altiplano Cundiboyacense