The Guaduas Formation (, K2P1G, K2E1G, KPgg, KTg, TKg, Ktg) is a geological formation of the Middle Magdalena Basin and the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The predominantly shale with coalbed formation dates to the Late Cretaceous and Paleogene periods; Maastrichtian-Paleocene epochs, and has a maximum thickness of . Fossils of Coussapoa camargoi, Ficus andrewsi, Berhamniphyllum sp. and Archaeopaliurus boyacensis have been found in coalbeds in Zipaquirá and Tasco, Boyacá.
Etymology The formation was first described by Hettner in 1894 and named in 1931 by Hubach after Guaduas, Cundinamarca, former northern territory of the Panche.Montoya & Reyes, 2005, p.51
Description Lithologies The Guaduas Formation consists mainly of shales with intercalated sandstone beds. The formation contains coalbeds that are widely explored in the area. Fossil remains of Coussapoa camargoi, Ficus andrewsi, Berhamniphyllum sp. and Archaeopaliurus boyacensis have been found in coalbeds in Zipaquirá and Tasco, Boyacá.Coussapoa camargoi, Ficus andrewsi at fossilworks.orgBerhamniphyllum sp. & Archaeopaliurus boyacensis at fossilworks.org
Stratigraphy and depositional environment The Guaduas Formation unconformablyVillamil, 2012, p.208 overlies the Arenisca Labor-Tierna Formation of the Guadalupe Group and is overlain by the Cacho Formation. The age has been estimated to be Upper Maastrichtian-Lower Paleocene, spanning the K-T boundary.Montoya & Reyes, 2005, p.54 The Guaduas Formation is thicker in Cundinamarca than in Boyacá. This has been explained by a decrease in subsidence and a higher amount of erosion in the northern area of original deposition.Mariño & Amaya, 2016, p.B9 The lateral thickness variations are thought to be the result of the movement of the Soapaga Fault.Amaya et al., 2010 The formation has been deposited in a coastal plain setting.
Outcrops
The Guaduas Formation is apart from its type locality, found in the Eastern Hills of Bogotá, the Ocetá Páramo and many other locations in the Eastern Ranges, such as Granada,Plancha 246, 1998 the Dintel Synclinal north of Facatativá,Plancha 227, 1998 the Suesca Synclinal,Plancha 190, 2009 east of Junín,Plancha 191, 1998 and surrounding Lake Tota.Plancha 192, 1998 The northeast-southwest Canocas Fault crosscuts the Guaduas Formation near San Cayetano.Planchas 171 & 191 The synclinals of the Río Frío, Neusa, Zipaquirá, Checua-Lenguazaque, Sesquilé, Sisga, Subachoque, Teusacá and Usme and Soacha are composed of the Guaduas Formation.Montoya & Reyes, 2005, p.52 The Suba Hills are entirely composed of the Guaduas Formation.Geological Map Bogotá, 1997 The formation also has outcrops in the Sumapaz Páramo. Geología y geomorfología - Salida de Campo: Región Llanos Orientales
Regional correlations
Gallery
See also
Geology of the Eastern Hills Geology of the Ocetá Páramo Geology of the Altiplano Cundiboyacense
Notes and references Notes
References
Bibliography
Maps
External links