Oliní Group

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Oliní Group
Stratigraphic range: Coniacian-Campanian
~87–75 Ma
TypeGeological group
Sub-unitsSee text
Underlies,
Overlies
 Loma Gorda Formation
Thicknessup to 287 m (942 ft)
Lithology
PrimaryRadiolarite, siltstone, chert, mudstone
OtherSandstone, limestone, conglomerate
Location
Coordinates3°44′12.6″N 75°27′55.5″W / 3.736833°N 75.465417°W / 3.736833; -75.465417Coordinates: 3°44′12.6″N 75°27′55.5″W / 3.736833°N 75.465417°W / 3.736833; -75.465417
RegionVMM,
and Central, Eastern Ranges, Andes
Country Colombia
Extent~700 km (430 mi)
Type section
Named forQuebrada Oliní
Named byPeters
LocationChaparral, Tolima
Year defined1954
Coordinates3°44′12.6″N 75°27′55.5″W / 3.736833°N 75.465417°W / 3.736833; -75.465417
Approximate paleocoordinates1°30′N 54°30′W / 1.5°N 54.5°W / 1.5; -54.5
RegionCundinamarca, Boyacá, Huila, Santander, Tolima
Country Colombia
Blakey 090Ma - COL.jpg
Paleogeography of Northern South America
90 Ma, by Ron Blakey

The Oliní Group (Spanish: Grupo Oliní, K3k5o, K2ol, Kso) is a fossiliferous geological group of the VMM, and the eastern flanks of the Central and western flanks of the Eastern Ranges of the Colombian Andes. The regional group stretches from north to south across approximately 700 kilometres (430 mi) and dates to the Late Cretaceous period; Coniacian, Santonian and Campanian epochs, and has a maximum thickness of 287 metres (942 ft). Fossils of Eonatator coellensis have been found in the unit, near Coello, Tolima.

Etymology[]

The group was named in 1954 by Peters, and redefined by in 1965.[1] The group was named after Quebrada Oliní in Chaparral, Tolima.[2]

Subdivisions[]

The Oliní Group is a geological group usually described as a whole due to the problematic lateral continuity,[3] although in other cases the individual formations forming the group are used. Earlier names used were Lower Chert member, Upper Sandstone Member and Upper Chert member.[4] According to Acosta and Ulloa (2002), the group is subdivided into, from bottom to top:

Lower Lydite Formation[]

Claystone Level[]

Upper Lydite Formation[]

  • Native name - Spanish: Formación Lidita Superior (Ksls)[8]
  • Definition - De Porta (1965)
  • Age - Campanian
  • Thickness - 100 to 114 metres (328 to 374 ft)[9]
  • Lithologies - calcareous siltstones, chert, radiolarites and micritic limestones with thin beds of conglomerates
  • Fossil content - , , ,[5] , , , [6]
  • Depositional environment - outer platform[7]

Paleontology[]

Restoration of Eonatator coellensis

Fossils of the mosasaur Eonatator coellensis were found near Coello, Tolima in the Oliní Group.[10][11]

Stratigraphy and depositional environment[]

The Oliní Group conformably[12] overlies the Loma Gorda Formation of the and is overlain by the in the VMM, the in the Guaduas Syncline and the near Tocaima and in Huila and Tolima.[8] The age has been estimated on the basis of ammonites to be ranging from Coniacian to Campanian. Stratigraphically, the lower part of the formation is time equivalent with the upper part of the Chipaque Formation and the Conejo Formation,[13] while the upper portion correlates with the and Guadalupe Group.[14] The Oliní Group was deposited in a relative high sea level environment in an setting,[15] following a sequence boundary, forming the base of the unit. The radiolarites of the Upper Lydite Formation represent a maximum flooding surface.[16]

Outcrops[]

Oliní Group is located in Tolima Department
Oliní Group
Type locality of the Oliní Group in Tolima
Oliní Group is located in Colombia
Oliní Group
Oliní Group
Oliní Group
Lightgreen pog.svg Northern- and southernmost outcrops of the Oliní Group
Green pog.svg Type locality

The type locality of the Oliní Group is Quebrada Oliní in Chaparral, Tolima. The group is furthermore found over a large stretch in the eastern Central and western Eastern Ranges of Colombia, bordering the Magdalena River on both sides. The group crops out to the northwest of Vélez in the hanging wall of the ,[17] around Caparrapí,[18] in the footwall of the between Útica and Guaduas and in the Bituima Synclinal,[19] where it is cross-cut by the Vianí Fault and occurs in the hanging wall of the ,[20] in the heavily faulted banks of the Magdalena River surrounding Guataquí and northwest of Coello and in the Eastern Ranges cross-cut by the Sumapaz River northeast of Ricaurte,[21] in the hangingwall of the to the west of Apulo,[22] on both sides of the near Ortega,[23] in both the hangingwall and footwall of the east and south of Carmen de Apicalá and in the hangingwall of the ,[24] the hangingwall of the west and south of Icononzo,[25] the footwall of the east and southeast of Chaparral,[26] in the footwall and hangingwall of the east of Dolores, east and west of the near Prado,[27] in the footwall and hangingwall of the , west of Aipe,[28] east of Alpujarra,[29] in the footwall of the in Palermo,[30] offset by the and ,[31] north of Yaguará,[32] east of La Plata, Huila,[33] and the southernmost exposure is found in , where the group is emplaced by the .[34]

Regional correlations[]

Cretaceous stratigraphy of the central Colombian Eastern Ranges hide
Age Paleomap VMM Guaduas-Vélez W Emerald Belt Villeta anticlinal Chiquinquirá-
Arcabuco		 Tunja-
Duitama		 Altiplano Cundiboyacense El Cocuy
Maastrichtian Blakey 065Ma - COL.jpg eroded Guaduas
Guadalupe
Campanian
Oliní
Santonian -
Coniacian Oliní Conejo Chipaque
Loma Gorda undefined La Frontera
Turonian Blakey 090Ma - COL.jpg Hondita La Frontera
Cenomanian hiatus Simijaca
Pacho Fm. Hiló - Pacho Une
Albian Blakey 105Ma - COL.jpg Hiló Une
Capotes - -
Aptian Capotes Socotá - El Peñón Paja Fómeque
Paja Paja El Peñón Trincheras
La Naveta
Barremian Blakey 120Ma - COL.jpg
Hauterivian
Las Juntas
Rosablanca Ritoque
Valanginian Ritoque - Murca Rosablanca hiatus Macanal
Rosablanca
Berriasian Blakey 150Ma - COL.jpg Guavio
Arcabuco
Sources


See also[]

Featured article candidate Geology of the Eastern Hills
B-Class article Geology of the Ocetá Páramo
C-Class article Geology of the Altiplano Cundiboyacense

References[]

  1. ^ Acosta & Ulloa, 2002, p.24
  2. ^ Quebrada Oliní, Chaparral
  3. ^ Guerrero et al., 2000, p.58
  4. ^ Reyes et al., 2006, p.65
  5. ^ Jump up to: a b c d e Acosta & Ulloa, 2002, p.25
  6. ^ Jump up to: a b c Acosta & Ulloa, 2001b, p.51
  7. ^ Jump up to: a b Acosta & Ulloa, 2001b, p.52
  8. ^ Jump up to: a b Acosta & Ulloa, 2002, p.27
  9. ^ Reyes et al., 2006, p.66
  10. ^ Eonatator coellensis at Fossilworks.org
  11. ^ Páramo Fonseca, 2013
  12. ^ Acosta & Ulloa, 2001a, p.60
  13. ^ Montoya & Reyes, 2005, p.34
  14. ^ Acosta & Ulloa, 2002, p.22
  15. ^ Acosta & Ulloa, 2001a, p.62
  16. ^ Villamil, 2012, p.205
  17. ^ Plancha 170, 2009
  18. ^ Plancha 189, 2005
  19. ^ Plancha 208, 1998
  20. ^ Plancha 227, 1998
  21. ^ Plancha 245, 1999
  22. ^ Plancha 246, 1998
  23. ^ Plancha 263, 2009
  24. ^ Plancha 264, 2002
  25. ^ Plancha 265, 2009
  26. ^ Plancha 282, 1993
  27. ^ Plancha 283, 1995
  28. ^ Plancha 302, 1993
  29. ^ Plancha 303, 2002
  30. ^ Plancha 323, 1998
  31. ^ Plancha 344, 1999
  32. ^ Plancha 345, 1999
  33. ^ Plancha 366, 1998
  34. ^ Plancha 389, 2003

Bibliography[]

Maps[]

External links[]

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