Simijaca Formation Explained

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).

Etymology

The formation was defined and named in 1991 by Ulloa and Rodríguez after Simijaca, Cundinamarca.[1]

Description

Lithologies

The Simijaca Formation is characterised by a sequence of mudstones, grey and black shales with sandstone and limestone intercalations.[1]

Stratigraphy and depositional environment

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]

Outcrops

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]

See also

Geology of the Eastern Hills

Geology of the Ocetá Páramo

Geology of the Altiplano Cundiboyacense

References

Bibliography

Maps

Notes and References

  1. Montoya & Reyes, 2005, p.21
  2. Acosta & Ulloa, 2001, p.32
  3. Acosta & Ulloa, 2001, p.41
  4. Montoya & Reyes, 2005, p.22
  5. García González et al., 2009, p.209
  6. Villamil, 2012, p.164
  7. Acosta & Ulloa, 2001, p.38
  8. Montoya & Reyes, 2005, p.23
  9. Plancha 190, 2009
  10. Plancha 227, 1998
  11. Plancha 246, 1998