title: Pacho Formation
text: # Pacho Formation
  
  The Pacho Formation (Spanish: Limolitas de Pacho, Kslp) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consisting of alternating siltstones and shales with siderite concretions dates to the Middle Cretaceous period; Late Albian to Cenomanian epochs and has an approximate thickness of 1,050 metres (3,440 ft).
  
  ## Etymology
  
  The formation was defined and named in 1982 by Ulloa after Pacho, Cundinamarca.
  
  ## Description
  
  ### Lithologies
  
  The Pacho Formation has an approximate thickness of 1,050 metres (3,440 ft), and is characterised by a sequence of alternating siltstones and shales with siderite concretions.
  
  ### Stratigraphy and depositional environment
  
  The Pacho Formation, pertaining to the Villeta Group, partly overlies and is partly lateral equivalent with the Hiló Formation and is partly overlain by and partly time equivalent with the Simijaca Formation. The age has been estimated to be Late Albian to Cenomanian. Stratigraphically, the formation is time equivalent with the Une Formation. The formation has been deposited in an outer marine platform environment.
  
  ## Outcrops
  
  The Pacho Formation is found around its type locality near Pacho.
  
  ## Regional correlations
  
  Cretaceous stratigraphy of the central Colombian Eastern Ranges :
  
  | Age | VMM | Guaduas-Vélez | Guaduas-Vélez | W Emerald Belt | W Emerald Belt | Villeta anticlinal | Villeta anticlinal | Chiquinquirá- Arcabuco | Tunja- Duitama | Altiplano Cundiboyacense | Altiplano Cundiboyacense | El Cocuy |
  | - | - | - | - | - | - | - | - | - | - | - | - | - |
  | Maastrichtian | Umir | Córdoba | Córdoba | Seca | Seca | eroded | eroded | Guaduas | Guaduas | Guaduas | Guaduas | Colón-Mito Juan |
  | Maastrichtian | Umir | Córdoba | Córdoba | Umir | Umir | eroded | eroded | Guadalupe | Guadalupe | Guadalupe | Guadalupe | | | | Colón-Mito Juan |
  | Campanian | Umir | Córdoba | Córdoba | Córdoba | Córdoba | | eroded | eroded | Guadalupe | Guadalupe | Guadalupe | Guadalupe | Colón-Mito Juan |
  | Colón-Mito Juan ||
  | Santonian | La Luna | Cimarrona - La Tabla | Cimarrona - La Tabla | Oliní | Oliní | eroded | eroded | Guadalupe | Guadalupe | Guadalupe | Guadalupe | La Luna |
  | Coniacian | La Luna | Oliní | Oliní | Oliní | Oliní | Villeta | Conejo | Conejo | Chipaque | Chipaque | Chipaque | | | La Luna |
  | Coniacian | La Luna | Güagüaquí | Loma Gorda | undefined | undefined | Villeta | La Frontera | La Frontera | | Chipaque | Chipaque | Chipaque | La Luna |
  | Turonian | La Luna | Güagüaquí | Hondita | La Frontera | Otanche | Villeta | La Frontera | La Frontera | Chipaque | Chipaque | Chipaque | La Luna |
  | Cenomanian | Simití | hiatus | hiatus | La Corona | Otanche | Villeta | Simijaca | Simijaca | Chipaque | Chipaque | Chipaque | Capacho |
  | Cenomanian | Simití | hiatus | hiatus | Pacho Fm. | Otanche | Villeta | Hiló - Pacho | Churuvita | Une | Une | Une | Aguardiente |
  | Albian | Simití | hiatus | hiatus | Hiló | Otanche | Villeta | Hiló - Pacho | Chiquinquirá | Tibasosa | Une | Une | | Aguardiente |
  | Albian | Tablazo | hiatus | hiatus | Tablazo | Tablazo | Villeta | Capotes - La Palma - Simití | Simití | Tibasosa | Une | Une | Tibú-Mercedes |
  | Aptian | Tablazo | hiatus | hiatus | Capotes | Capotes | Villeta | Socotá - El Peñón | Paja | Tibasosa | Fómeque | Fómeque | | Tibú-Mercedes |
  | Aptian | Paja | hiatus | hiatus | Paja | El Peñón | Villeta | Trincheras | Paja | Tibasosa | Fómeque | Fómeque | Río Negro |
  | Río Negro ||
  | Barremian | Paja | hiatus | hiatus | Paja | El Peñón | La Naveta | La Naveta | Paja | Tibasosa | Fómeque | Fómeque | Río Negro |
  | Hauterivian | Paja | hiatus | hiatus | Paja | Muzo | La Naveta | La Naveta | Paja | Tibasosa | Cáqueza | Las Juntas | Río Negro |
  | Hauterivian | Rosablanca | hiatus | hiatus | Paja | Muzo | La Naveta | La Naveta | Ritoque | Tibasosa | Cáqueza | Las Juntas | Río Negro |
  | Valanginian | Rosablanca | hiatus | hiatus | Ritoque | Furatena | Útica - Murca | Útica - Murca | Rosablanca | hiatus | Cáqueza | Macanal | Río Negro |
  | Valanginian | Rosablanca | hiatus | hiatus | Rosablanca | Furatena | Útica - Murca | Útica - Murca | Rosablanca | hiatus | Cáqueza | Macanal | Río Negro |
  | Berriasian | Cumbre | hiatus | hiatus | Cumbre | Cumbre | Útica - Murca | Útica - Murca | Los Medios | hiatus | Cáqueza | Guavio | Río Negro |
  | Berriasian | Tambor | hiatus | hiatus | Arcabuco | Arcabuco | Útica - Murca | Útica - Murca | Cumbre | hiatus | Cáqueza | Guavio | Río Negro |
  | Sources ||||||||||||||
  