Oliní Group

Oliní Group
Stratigraphic range: Coniacian-Campanian
~87–75 Ma
Type Geological group
Sub-units See text
Underlies Córdoba Fm., La Tabla Fm.
Overlies Güagüaquí Group
 Loma Gorda Formation
Thickness up to 287 m (942 ft)
Lithology
Primary Radiolarite, siltstone, chert, mudstone
Other Sandstone, limestone, conglomerate
Location
Coordinates 3°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
Region VMM, VSM
and Central, Eastern Ranges, Andes
Country  Colombia
Extent ~700 km (430 mi)
Type section
Named for Quebrada Oliní
Named by Peters
Location Chaparral, Tolima
Year defined 1954
Coordinates 3°44′12.6″N 75°27′55.5″W / 3.736833°N 75.465417°W / 3.736833; -75.465417
Approximate paleocoordinates 1°30′N 54°30′W / 1.5°N 54.5°W / 1.5; -54.5
Region Cundinamarca, Boyacá, Huila, Santander, Tolima
Country  Colombia

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, VSM 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 De Porta 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

  • Native name - Spanish: Nivel de Lutitas (Ksl, Ksom)[5]
  • Definition - De Porta (1965)
  • Age - Santonian
  • Thickness - 100 metres (330 ft)
  • Lithologies - siltstones, calcareous and siliceous mica-bearing mudstones intercalated by thick banks of fine sandstones and sporadic shaly limestones
  • Fossil content - Bulimina compreza, Dentalina lorneiana, Haplophragmoides excavata, Anomalina redmondi,[5] Dicarinella asymetrica, D. concavata, Rosita fornicata[6]
  • Depositional environment - platform[7]

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 - Wheelerella, Sporobulimina, Siphogenerinoides,[5] Globirinelloides praeriehillensis, Rugoglobigerina sp., Globotruncana aff. insignis?, G. ?ventricosa[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 Güagüaquí Group and is overlain by the Cimarrona Formation in the VMM, the Córdoba Formation in the Guaduas Syncline and the La Tabla Formation 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 La Luna Formation and Guadalupe Group.[14] The Oliní Group was deposited in a relative high sea level environment in an outer platform 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

Type locality of the Oliní Group in Tolima
Northern- and southernmost outcrops of the Oliní Group
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 El Minero Fault,[17] around Caparrapí,[18] in the footwall of the El Cámbulo Fault 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 Alto del Trigo Fault,[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 Salcedo Fault to the west of Apulo,[22] on both sides of the Cucuana River near Ortega,[23] in both the hangingwall and footwall of the El Páramo Fault east and south of Carmen de Apicalá and in the hangingwall of the Prado Fault,[24] the hangingwall of the Quinini Fault west and south of Icononzo,[25] the footwall of the La Pava Fault east and southeast of Chaparral,[26] in the footwall and hangingwall of the Altamizal Fault east of Dolores, east and west of the Prado Reservoir near Prado,[27] in the footwall and hangingwall of the Chusma Fault, west of Aipe,[28] east of Alpujarra,[29] in the footwall of the Baché Fault in Palermo,[30] offset by the Picarní and San Andrés Faults,[31] north of Yaguará,[32] east of La Plata, Huila,[33] and the southernmost exposure is found in Naranjal, where the group is emplaced by the Altamira Fault.[34]

Regional correlations

Cretaceous stratigraphy of the central Colombian Eastern Ranges
AgePaleomapVMMGuaduas-VélezW Emerald BeltVilleta anticlinalChiquinquirá-
Arcabuco		Tunja-
Duitama		Altiplano CundiboyacenseEl Cocuy
MaastrichtianUmir Fm.Córdoba Fm.Seca Fm.erodedGuadalupe Gp.Colón-Mito Juan Fm.
Umir Fm.
CampanianCórdoba Fm.
Oliní Gp.
SantonianLa Luna Fm.Cimarrona Fm. - La Tabla Fm.La Luna Fm.
ConiacianOliní Gp.Conejo Fm.Chipaque Fm.
Güagüaquí Gp
Loma Gorda Fm.undefinedLa Frontera Fm.
TuronianHondita Fm.La Frontera Fm.Otanche Fm.
CenomanianSimití Fm.hiatusLa Corona Gb.Simijaca Fm.Capacho Fm.
Pacho Fm.Hiló Fm. - Pacho Fm.Churuvita Fm.Une Fm.Aguardiente Fm.
AlbianHiló Fm.Chiquinquirá Sst.Tibasosa Fm.Une Fm.
Tablazo Fm.Tablazo Fm.Capotes Fm. - La Palma Fm. - Simití Fm.Simití Fm.Tibú-Mercedes Fm.
AptianCapotes Fm.Socotá Fm. - El Peñón Fm.Paja Fm.Fómeque Fm.
Paja Fm.Paja Fm.El Peñón Fm.Trincheras Fm.Río Negro Fm.
La Naveta Fm.
Barremian
HauterivianMuzo Fm.
Cáqueza Gp
Las Juntas Fm.
Rosablanca Fm.Ritoque Fm.
ValanginianRitoque Fm.Furatena Fm.Útica Fm. - Murca Fm.Rosablanca Fm.Girón Fm.Macanal Fm.
Rosablanca Fm.
BerriasianCumbre Fm.Cumbre Fm.Los Medios Fm.Guavio Fm.
Tambor Fm.Arcabuco Fm.Cumbre Fm.
Sources

See also

Geology of the Eastern Hills
Geology of the Ocetá Páramo
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. 1 2 3 4 5 Acosta & Ulloa, 2002, p.25
  6. 1 2 3 Acosta & Ulloa, 2001b, p.51
  7. 1 2 Acosta & Ulloa, 2001b, p.52
  8. 1 2 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

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