Marichuela Formation Explained

Marichuela Formation
Period:Miocene
Age:Late Miocene-Early Pliocene
~
Type:Geological formation
Prilithology:Conglomerate
Underlies:Tilatá Formation
Overlies:Guadalupe Group
Thickness:up to 40m (130feet)
Coordinates:4.3612°N -74.1306°W
Region:Bogotá savanna, Altiplano Cundiboyacense
Eastern Ranges, Andes
Namedfor:Marichuela neighbourhood
Namedby:Helmens & Hammen
Year Ts:1995
Location Ts:Usme, Bogotá
Coordinates Ts:4.3612°N -74.1306°W
Region Ts:Cundinamarca

The Marichuela Formation (Spanish; Castilian: Formación Marichuela, N1m) is a geological formation of the Bogotá savanna, Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists of coarse to very coarse conglomerates. The Marichuela Formation dates to the Neogene period; Late Miocene to Early Pliocene epochs, and has a maximum thickness of 40m (130feet).

Etymology

The formation was defined by Helmens and Van der Hammen in 1995 and named after the Marichuela neighbourhood of Usme.[1] Part of the Marichuela Formation had been included in the Conos de Tunjuelo, defined by Julivert in 1961.[2]

Description

Lithologies

The Marichuela Formation consists of coarse to very coarse conglomerates.[1]

Stratigraphy and depositional environment

The Marichuela Formation unconformably overlies the Cretaceous rocks of the Guadalupe Group. The age has been estimated to be Late Miocene to Early Pliocene.[3] The depositional environment has been interpreted as alluvial fans, caused by earthquakes or heavy rains.[4]

Outcrops

The Marichuela Formation is apart from its type locality in the Usme Synclinal, the valley of the Tunjuelo River, found in the synclinals of Neusa, Sisga and La Calera.[1]

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.65
  2. Suna Hisca, s.a., p.45
  3. Montoya & Reyes, 2005, p.67
  4. Montoya & Reyes, 2005, p.66