Earth:Rosablanca Formation

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Rosablanca Formation
Stratigraphic range: Valanginian
~136–133 Ma
↓
TypeGeological formation
UnderliesPaja Fm., Ritoque Fm.
OverliesCumbres Fm., Girón Fm., Los Medios Fm.
Thickness~470 m (1,540 ft)
Lithology
PrimarySandstone
OtherShale
Location
Coordinates [ ⚑ ] : 4°27′07″N 74°03′20″W / 4.45194°N 74.05556°W / 4.45194; -74.05556
RegionAltiplano Cundiboyacense
Eastern Ranges, Andes
CountryColombia
Type section
Named byWheeler
LocationMesa de Los Santos
Year defined1929
Coordinates [ ⚑ ] 4°27′07″N 74°03′20″W / 4.45194°N 74.05556°W / 4.45194; -74.05556
RegionBoyacá, Santander
CountryColombia

The Rosablanca Formation (Spanish: Formación Rosablanca, Kir) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes and the Middle Magdalena Basin. The formation consists of grey limestones, dolomites and shales with at the upper part sandstones. The formation dates to the Early Cretaceous period; Valanginian epoch and has a thickness of 425 metres (1,394 ft) in the valley of the Sogamoso River.

Definition

The formation was first defined by Wheeler in 1929.[1]

Description

Lithologies

The Rosablanca Formation is characterised by a sequence of grey limestones, dolomites and shales with a maximum thickness of 425 metres (1,394 ft) in the Sogamoso River valley.[1]

Stratigraphy and depositional environment

The Rosablanca Formation overlies the Arcabuco Formation and is overlain by the Ritoque Formation. The age has been estimated to be Valanginian. Stratigraphically, the formation is time equivalent with the Macanal Formation.[1]

Fossils

Fossils of the decapod crustacean Diaulax rosablanca have been found in and named after the Rosablanca Formation.[2] In 2019, fossils of brachiopod Sellithyris elizabetha were described from the formation.[3] In 2020 remains of indeterminate pterosaurs were described from the formation, including pterodactyloids and non-Pteranodontian ornithocheiroids.[4] In 2005 the remains of Platychelyid sea turtle Notoemys zapatocaensis were described,[5] and in 2023 the limbs and shell elements of protostegids were described as some of the largest Early Cretaceous turtles.[6] The hybodont shark Strophodus has been reported from the formation.[7]

Outcrops

Rosablanca Formation is located in Santander Department
Rosablanca Formation
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Type locality of the Rosablanca Formation in Santander

The Rosablanca Formation is found, apart from its type locality on the Mesa de Los Santos, Santander, in Boyacá and the Middle Magdalena Basin.

Regional correlations

Template:Stratigraphy of the Llanos Basin

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

Notes and references

Notes

References

  1. ↑ 1.0 1.1 1.2 Galvis & Valencia, 2009, p.17
  2. ↑ Gómez et al., 2015
  3. ↑ Rojas & Sandy, 2019
  4. ↑ Cadena, Edwin-Alberto; Unwin, David M.; Martill, David M. (2020-10-01). "Lower Cretaceous pterosaurs from Colombia" (in en). Cretaceous Research 114. doi:10.1016/j.cretres.2020.104526. ISSN 0195-6671. Bibcode: 2020CrRes.11404526C. http://www.sciencedirect.com/science/article/pii/S0195667120302123. 
  5. ↑ E. A. Cadena Rueda, E. S. Gaffney (2005). "Notoemys zapatocaensis, a New Side-Necked Turtle (Pleurodira: Platychelyidae) from the Early Cretaceous of Colombia". American Museum Novitates (3470): 1–19. doi:10.1206/0003-0082(2005)470<0001:NZANST>2.0.CO;2. https://bioone.org/journals/american-museum-novitates/volume-2005/issue-3470/0003-0082_2005_470_0001_NZANST_2.0.CO_2/Notoemys-zapatocaensis-a-New-Side-Necked-Turtle-Pleurodira--Platychelyidae/10.1206/0003-0082(2005)470%3C0001:NZANST%3E2.0.CO;2.full. 
  6. ↑ Cadena, Edwin-Alberto; Combita-Romero, Diego A (2023-07-12). "The onset of large size in Cretaceous marine turtles (Protostegidae) evidenced by new fossil remains from the Valanginian of Colombia" (in en). Zoological Journal of the Linnean Society. doi:10.1093/zoolinnean/zlad053. ISSN 0024-4082. https://academic.oup.com/zoolinnean/advance-article/doi/10.1093/zoolinnean/zlad053/7223393. 
  7. ↑ Carrillo-Briceño, Jorge D.; Cadena, Edwin-Alberto (2022-06-02). "A new hybodontiform shark (Strophodus Agassiz 1838) from the Lower Cretaceous (Valanginian-Hauterivian) of Colombia" (in en). PeerJ 10. doi:10.7717/peerj.13496. ISSN 2167-8359. PMID 35673391. 

Bibliography

Maps

Template:Colombian emeralds



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