Marichuela Formation

Marichuela Formation
Stratigraphic range: Late Miocene-Early Pliocene
~8.2–5 Ma
↓
Type Geological formation
Underlies Tilatá Formation
Overlies Guadalupe Group
Thickness up to 40 metres (130 ft)
Lithology
Primary Conglomerate
Location
Coordinates 4°21′40.3″N 74°07′50″W / 4.361194°N 74.13056°W / 4.361194; -74.13056Coordinates: 4°21′40.3″N 74°07′50″W / 4.361194°N 74.13056°W / 4.361194; -74.13056
Region Bogotá savanna, Altiplano Cundiboyacense
Eastern Ranges, Andes
Country  Colombia
Type section
Named for Marichuela neighbourhood
Named by Helmens & Hammen
Location Usme, Bogotá
Year defined 1995
Coordinates 4°21′40.3″N 74°07′50″W / 4.361194°N 74.13056°W / 4.361194; -74.13056
Region Cundinamarca
Country  Colombia

The Marichuela Formation (Spanish: 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 40 metres (130 ft).

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

Type locality of the Marichuela Formation to the southeast of the Bogotá savanna

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

  1. 1 2 3 Montoya & Reyes, 2005, p.65
  2. ↑ Suna Hisca, s.a., p.45
  3. ↑ Montoya & Reyes, 2005, p.67
  4. ↑ Montoya & Reyes, 2005, p.66

Bibliography

  • Montoya Arenas, Diana María, and Germán Alfonso Reyes Torres. 2005. Geología de la Sabana de Bogotá, 1–104. INGEOMINAS.
  • N., N. s.a. Parque Ecológico Distrital de Montaña Entrenubes – Tomo I – Componente Biofísico – Geología, 36–51. Corporación Suna Hisca.

Maps

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