View source for Earth:Pacho Formation

{{Infobox rockunit
| name           = Pacho Formation
| period         = Cenomanian
| age            = [[Earth:Albian|Late Albian]]-[[Earth:Cenomanian|Cenomanian]]<br />~{{fossil range|102|97}}
| image          = 
| imagesize      = 
| caption        = 
| type           = [[Earth:Geological formation|Geological formation]]
| prilithology   = [[Earth:Siltstone|Siltstone]]
| otherlithology = [[Chemistry:Shale|Shale]]
| unitof         = [[Earth:Villeta Group|Villeta Group]]
| subunits       = 
| underlies      = [[Earth:Simijaca Formation|Simijaca Formation]]
| overlies       = [[Earth:Hiló Formation|Hiló Formation]]
| thickness      = ~{{convert|1050|m|ft|abbr=on}}
| area           = 
| map            = Blakey 105Ma - COL.jpg
| map_caption    = Paleogeography of Northern South America<br />105 Ma, {{small|by Ron Blakey}}
| location       =
| coordinates    = {{coord|4|27|07|N|74|03|20|W|display=inline,title}} 
| region         = Altiplano Cundiboyacense<br />Eastern Ranges, [[Place:Andes|Andes]]
| country        = {{COL}}
| extent         = <!--{{convert||mi|km}}-->
| namedfor       = Pacho
| namedby        = Ulloa
| year_ts        = 1982
| location_ts    = Pacho
| coordinates_ts = {{coord|4|27|07|N|74|03|20|W|display=inline}}
| paleocoordinates_ts = 
| region_ts      = Cundinamarca
| country_ts     = {{COL}}
| thickness_ts   = 
}}
The '''Pacho Formation''' ({{lang-es|Limolitas de Pacho}}, Kslp) is a geological formation of the Altiplano Cundiboyacense, Eastern Ranges of the Colombian [[Place:Andes|Andes]]. The formation consisting of alternating siltstones and shales with [[Chemistry:Siderite|siderite]] concretions dates to the [[Earth:Cretaceous|Middle Cretaceous]] period; [[Earth:Albian|Late Albian]] to [[Earth:Cenomanian|Cenomanian]] epochs and has an approximate thickness of {{convert|1050|m|ft}}.

== Etymology ==
The formation was defined and named in 1982 by Ulloa after Pacho, Cundinamarca.<ref name=Acosta2002_p45/>

== Description ==
=== Lithologies ===
The Pacho Formation has an approximate thickness of {{convert|1050|m|ft}}, and is characterised by a sequence of alternating [[Earth:Siltstone|siltstone]]s and [[Chemistry:Shale|shale]]s with [[Chemistry:Siderite|siderite]] concretions.<ref name=Acosta2002_p45>Acosta & Ulloa, 2002, p.45</ref>

=== Stratigraphy and depositional environment ===
The Pacho Formation, pertaining to the [[Earth:Villeta Group|Villeta Group]], partly overlies and is partly lateral equivalent with the [[Earth:Hiló Formation|Hiló Formation]] and is partly overlain by and partly time equivalent with the [[Earth:Simijaca Formation|Simijaca Formation]]. The age has been estimated to be [[Earth:Albian|Late Albian]] to [[Earth:Cenomanian|Cenomanian]]. Stratigraphically, the formation is time equivalent with the [[Earth:Une Formation|Une Formation]]. The formation has been deposited in an outer marine platform [[Earth:Depositional environment|environment]].<ref name=Acosta2002_p45/>

== Outcrops ==
{{Location map | Bogotá savanna
| width   = 250
| lat_deg = 5.253664
| lon_deg = -74.341091
| label   = 
| float = left
| position = right
| mark = Green pog.svg
| marksize = 12
| caption = Type locality of the Pacho Formation to the northwest of the Bogotá savanna
}}
The Pacho Formation is found around its [[Earth:Type locality (geology)|type locality]] near Pacho.<ref name=Acosta2002_p45/>

{{clear left}}

== Regional correlations ==

== See also ==
:{{icon|FAC}} Geology of the Eastern Hills
:{{icon|B}} Geology of the Ocetá Páramo
:{{icon|C}} Geology of the Altiplano Cundiboyacense

{{clear}}

== References ==
{{reflist|30em}}

=== Bibliography ===
* {{cite LSA |last=Acosta Garay |first=Jorge E. |last2=Ulloa Melo |first2=Carlos E. |year=2002 |title=Mapa Geológico del Departamento de Cundinamarca - 1:250,000 - Memoria explicativa |url=http://nebula.wsimg.com/ca3411dab87400d504f8461f0256772a?AccessKeyId=75F883B260454DDA3D4B&disposition=0&alloworigin=1 |publisher=INGEOMINAS |pages=1–108 |accessdate=2017-04-26}}
* {{cite LSA |last=Villamil |first=Tomas |year=2012 |title=Chronology Relative Sea Level History and a New Sequence Stratigraphic Model for Basinal Cretaceous Facies of Colombia |publisher=[[Organization:Society for Sedimentary Geology|Society for Sedimentary Geology]] (SEPM) |pages=161–216}}

==== Maps ====
* {{cite LSA |last=Ulloa |first=Carlos |last2=Acosta |first2=Jorge |year=1998 |title=Plancha 208 - Villeta - 1:100,000 |url=https://drive.google.com/open?id=0BwFQPMJEi17QMjhLeWJ0aU1Za1U |publisher=INGEOMINAS |pages=1 |accessdate=2017-06-06}}
* {{cite LSA |last=Ulloa |first=Carlos E |last2=Rodríguez |first2=Erasmo |last3=Acosta |first3=Jorge E. |year=1998 |title=Plancha 227 - La Mesa - 1:100,000 |url=https://drive.google.com/open?id=0BwFQPMJEi17QR0k3cWk2aTlwbEk |publisher=INGEOMINAS |pages=1 |accessdate=2017-06-06}}

== External links ==
* {{cite LSA |last=Gómez |first=J. |last2=Montes |first2=N.E. |last3=Nivia |first3=Á. |last4=Diederix |first4=H. |year=2015 |title=Plancha 5-09 del Atlas Geológico de Colombia 2015 – escala 1:500,000 |url=https://www.researchgate.net/publication/309533589_Plancha_5-09_del_Atlas_Geologico_de_Colombia_2015 |publisher=Servicio Geológico Colombiano |pages=1 |accessdate=2017-03-16}}

[[Category:Albian Stage]]
[[Category:Cenomanian Stage]]
[[Category:Shale formations]]

{{Sourceattribution|Pacho Formation}}