Geological formation in the Colombian Andes
The Venado Formation (
Spanish : Formación Venado , Oir) is a
geological formation of the
Agua Blanca Group , in the
Eastern Ranges of the
Colombian
Andes ,
cropping out along the
Venado River in northern
Huila . The sequence of
pyrite containing dark grey
micaceous
shales interbedded with
siltstones and
sandstones dates to the
Ordovician period;
Middle to Late Floian epoch, and has a maximum thickness of 670 metres (2,200 ft) in the type section.
The unit is one of the few Early Paleozoic
fossiliferous formations of Colombia; many
graptolites of the genus
Phyllograptus have been found in the Venado Formation. The graptolites are mostly found in the silty beds and indicative of a fair weather
environment on a siliciclastic shallow marine platform at the northern edge of
Gondwana . The shallow sea where the Venado Formation was deposited ranged into the deeper cold
Iapetus and
Rheic Oceans , separating the South American continent of the time from
Laurentia ,
Avalonia and
Baltica .
The formation was first described by
Villarroel et al. in 1997 and named after the
Venado River , a left tributary of the
Cabrera River .
[1]
[2]
Type locality of the formation in Huila
The Venado Formation is one of few Ordovician formations outcropping in Colombia. The formation, part of the
Agua Blanca Group ,
[3] crops out on both banks of the Venado River in El Totumo, a
vereda of the
municipality
Baraya in the
department of
Huila .
[4] The thickness of the Venado Formation proper at its
type section is 670 metres (2,200 ft), put in
faulted contact with an overlying 30 metres (98 ft) thin unit and an underlying 50 metres (160 ft) sequence.
[1] The series is
unconformably overlain by the
Jurassic
Saldaña Formation .
[1]
[5] The Venado Formation has been correlated to the contemporaneous
El Hígado Formation of the
Central Ranges in
Tarqui .
[6]
[7]
The Venado Formation comprises laminated dark grey
micaceous
shales , with intercalating
siltstone levels and very fine
sandstone beds.
Calcareous
concretions up to 1 metre (3.3 ft) in diameter are present. The shales frequently contain aggregates of
pyrite . The formation is heavily
folded and in a faulted contact with the
Cretaceous
Caballos Formation ,
[3] at time of definition of the Venado Formation considered part of the
Villeta Group .
[8]
The Venado Formation was deposited in a shallow marine
environment , on a siliciclastic platform with persistent normal wave action with repetitive storm wave activity.
[9]
Anoxic conditions of the shallow sea probably led to the deposition of pyrite. The siltstone layers contain fragmented fossils of graptolites and are probably indicative of a fair weather environment and the coarser sediments resulted from episodic and rhythmic storms.
[10]
During the Ordovician, the present-day area of northwestern South America was located in the southern temperate region. The cold
[11]
Iapetus Ocean to the north of the South American
terrane separated the landmass from
Laurentia , most of present-day North America. The
Rheic Ocean separated South America from the
paleocontinents
Baltica and
Avalonia , that today is part of northeastern North America and northwestern Europe. North of the emerged continent of
Gondwana , a shallow sea existed, bordering the
Guyana and
Brazilian Shields comprising the oldest crustal parts of the current South American continent.
[11] During this time in the Ordovician, Gondwana was experiencing an
orogeny ; the
Famatinian orogeny , when the
Iapetus Plate was
subducting beneath Gondwana.
[12]
Fossiliferous formations of the Early
Paleozoic are rare in Colombia. Apart from the Venado Formation, El Hígado Formation of the Central Ranges also in Huila, has provided fossils dating to the Ordovician, the
Cambrian
Duda Formation of the
Serranía de Macarena in
Meta contains fossils of the
trilobite
Paradoxides ,
[13] and the westernmost Ordovician unit in Colombia,
La Cristalina Formation in the
Central Ranges of eastern
Antioquia that provided four species of
Didymograptus .
[14]
The formation has provided many fossils of
graptolites ; the most frequently occurring genus is
Phyllograptus .
[15] Additionally, Villarroel et al. (1997) reported having found
Lingulella sp. and
Didymograptus cf. D. artus in the formation.
[5]
[9] The latter graptolite genus fossils have been assigned rather to
Acrograptus filiformis by Gutiérrez Marco in 2006.
[16]
Stratigraphy of the
Llanos Basin and surrounding provinces
Ma
Age
Paleomap
Regional events
Catatumbo
Cordillera
proximal
Llanos
distal
Llanos
Putumayo
VSM
Environments
Maximum thickness
Petroleum geology
Notes
0.01
Holocene
Holocene volcanism
Seismic activity
alluvium
Overburden
1
Pleistocene
Pleistocene volcanism
Andean orogeny 3
Glaciations
Guayabo
Soatá
Sabana
Necesidad
Guayabo
Gigante
Alluvial to
fluvial (Guayabo)
550 m (1,800 ft) (Guayabo)
[17]
[18]
[19]
[20]
2.6
Pliocene
Pliocene volcanism
Andean orogeny 3
GABI
Subachoque
5.3
Messinian
Andean orogeny 3
Foreland
Marichuela
Caimán
Honda
[19]
[21]
13.5
Langhian
Regional flooding
León
hiatus
Caja
León
Lacustrine (León)
400 m (1,300 ft) (León)
Seal
[20]
[22]
16.2
Burdigalian
Miocene inundations
Andean orogeny 2
C1
Carbonera C1
Ospina
Proximal fluvio-deltaic (C1)
850 m (2,790 ft) (Carbonera)
Reservoir
[21]
[20]
17.3
C2
Carbonera C2
Distal lacustrine-deltaic (C2)
Seal
19
C3
Carbonera C3
Proximal fluvio-deltaic (C3)
Reservoir
21
Early Miocene
Pebas wetlands
C4
Carbonera C4
Barzalosa
Distal fluvio-deltaic (C4)
Seal
23
Late Oligocene
Andean orogeny 1
Foredeep
C5
Carbonera C5
Orito
Proximal fluvio-deltaic (C5)
Reservoir
[18]
[21]
25
C6
Carbonera C6
Distal fluvio-lacustrine (C6)
Seal
28
Early Oligocene
C7
C7
Pepino
Gualanday
Proximal deltaic-marine (C7)
Reservoir
[18]
[21]
[23]
32
Oligo-Eocene
C8
Usme
C8
onlap
Marine-deltaic (C8)
Seal
Source
[23]
35
Late Eocene
Mirador
Mirador
Coastal (Mirador)
240 m (790 ft) (Mirador)
Reservoir
[20]
[24]
40
Middle Eocene
Regadera
hiatus
45
50
Early Eocene
Socha
Los Cuervos
Deltaic (Los Cuervos)
260 m (850 ft) (Los Cuervos)
Seal
Source
[20]
[24]
55
Late Paleocene
PETM
2000 ppm CO2
Los Cuervos
Bogotá
Gualanday
60
Early Paleocene
SALMA
Barco
Guaduas
Barco
Rumiyaco
Fluvial (Barco)
225 m (738 ft) (Barco)
Reservoir
[17]
[18]
[21]
[20]
[25]
65
Maastrichtian
KT extinction
Catatumbo
Guadalupe
Monserrate
Deltaic-fluvial (Guadalupe)
750 m (2,460 ft) (Guadalupe)
Reservoir
[17]
[20]
72
Campanian
End of rifting
Colón-Mito Juan
[20]
[26]
83
Santonian
Villeta /
Güagüaquí
86
Coniacian
89
Turonian
Cenomanian-Turonian anoxic event
La Luna
Chipaque
Gachetá
hiatus
Restricted marine (all)
500 m (1,600 ft) (Gachetá)
Source
[17]
[20]
[27]
93
Cenomanian
Rift 2
100
Albian
Une
Une
Caballos
Deltaic (Une)
500 m (1,600 ft) (Une)
Reservoir
[21]
[27]
113
Aptian
Capacho
Fómeque
Motema
Yaví
Open marine (Fómeque)
800 m (2,600 ft) (Fómeque)
Source (Fóm)
[18]
[20]
[28]
125
Barremian
High biodiversity
Aguardiente
Paja
Shallow to open marine (Paja)
940 m (3,080 ft) (Paja)
Reservoir
[17]
129
Hauterivian
Rift 1
Tibú- Mercedes
Las Juntas
hiatus
Deltaic (Las Juntas)
910 m (2,990 ft) (Las Juntas)
Reservoir (LJun)
[17]
133
Valanginian
Río Negro
Cáqueza
Macanal
Rosablanca
Restricted marine (Macanal)
2,935 m (9,629 ft) (Macanal)
Source (Mac)
[18]
[29]
140
Berriasian
Girón
145
Tithonian
Break-up of Pangea
Jordán
Arcabuco
Buenavista
Saldaña
Alluvial ,
fluvial (Buenavista)
110 m (360 ft) (Buenavista)
"Jurassic"
[21]
[30]
150
Early-Mid Jurassic
Passive margin 2
La Quinta
Noreán
hiatus
Coastal
tuff (La Quinta)
100 m (330 ft) (La Quinta)
[31]
201
Late Triassic
Mucuchachi
Payandé
[21]
235
Early Triassic
Pangea
hiatus
"Paleozoic"
250
Permian
300
Late Carboniferous
Famatinian orogeny
Cerro Neiva ()
[32]
340
Early Carboniferous
Fossil fish
Romer's gap
Cuche (355-385)
Farallones ()
Deltaic ,
estuarine (Cuche)
900 m (3,000 ft) (Cuche)
360
Late Devonian
Passive margin 1
Río Cachirí (360-419)
Ambicá ()
Alluvial -
fluvial -
reef (Farallones)
2,400 m (7,900 ft) (Farallones)
[29]
[33]
[34]
[35]
[36]
390
Early Devonian
High biodiversity
Floresta (387-400)
Shallow marine (Floresta)
600 m (2,000 ft) (Floresta)
410
Late Silurian
Silurian mystery
425
Early Silurian
hiatus
440
Late Ordovician
Rich fauna in Bolivia
San Pedro (450-490)
Duda ()
470
Early Ordovician
First fossils
Busbanzá (>470±22 )
Guape ()
Río Nevado ()
[37]
[38]
[39]
488
Late Cambrian
Regional intrusions
Chicamocha (490-515)
Quetame ()
Ariarí ()
SJ del Guaviare (490-590)
San Isidro ()
[40]
[41]
515
Early Cambrian
Cambrian explosion
[39]
[42]
542
Ediacaran
Break-up of Rodinia
pre-Quetame
post-Parguaza
El Barro ()
Yellow: allochthonous basement (
Chibcha Terrane ) Green: autochthonous basement (
Río Negro-Juruena Province )
Basement
[43]
[44]
600
Neoproterozoic
Cariri Velhos orogeny
Bucaramanga (600-1400)
pre-Guaviare
[40]
800
Snowball Earth
[45]
1000
Mesoproterozoic
Sunsás orogeny
Ariarí (1000)
La Urraca (1030-1100)
[46]
[47]
[48]
[49]
1300
Rondônia-Juruá orogeny
pre-Ariarí
Parguaza (1300-1400)
Garzón (1180-1550)
[50]
1400
pre-Bucaramanga
[51]
1600
Paleoproterozoic
Maimachi (1500-1700)
pre-Garzón
[52]
1800
Tapajós orogeny
Mitú (1800)
[50]
[52]
1950
Transamazonic orogeny
pre-Mitú
[50]
2200
Columbia
2530
Archean
Carajas-Imataca orogeny
[50]
3100
Kenorland
Sources
Legend
group
important formation
fossiliferous formation
minor formation
(age in Ma)
proximal Llanos (Medina)
[note 1]
distal Llanos (Saltarin 1A well)
[note 2]
^ based on Duarte et al. (2019)
[53] , García González et al. (2009),
[54] and geological report of Villavicencio
[55]
^ based on Duarte et al. (2019)
[53] and the hydrocarbon potential evaluation performed by the
UIS and
ANH in 2009
[56]
^
a
b
c Villarroel et al., 1997, p.42
^ Moreno Sánchez, 2008, p.10
^
a
b Plancha 303, 2002
^ Moreno Sánchez, 2008, p.11
^
a
b Moreno Sánchez, 2008, p.13
^ Moreno Sánchez, 2008, p.9
^ Borrero et al., 2007, p.44
^ Villarroel et al., 1997, p.43
^
a
b Villarroel et al., 1997, p.46
^ Villarroel et al., 1997, p.47
^
a
b Moreno Sánchez, 2008, p.14
^ Chernicoff et al., 2010, p.679
^ Toro Toro et al., 2014, p.16
^ González, 2001, p.49
^ Moreno Sánchez, 2008, p.12
^ Moreno Sánchez, 2008, p.16
^
a
b
c
d
e
f García González et al., 2009, p.27
^
a
b
c
d
e
f García González et al., 2009, p.50
^
a
b García González et al., 2009, p.85
^
a
b
c
d
e
f
g
h
i
j Barrero et al., 2007, p.60
^
a
b
c
d
e
f
g
h Barrero et al., 2007, p.58
^ Plancha 111, 2001, p.29
^
a
b Plancha 177, 2015, p.39
^
a
b Plancha 111, 2001, p.26
^ Plancha 111, 2001, p.24
^ Plancha 111, 2001, p.23
^
a
b Pulido & Gómez, 2001, p.32
^ Pulido & Gómez, 2001, p.30
^
a
b Pulido & Gómez, 2001, pp.21-26
^ Pulido & Gómez, 2001, p.28
^ Correa Martínez et al., 2019, p.49
^ Plancha 303, 2002, p.27
^ Terraza et al., 2008, p.22
^ Plancha 229, 2015, pp.46-55
^ Plancha 303, 2002, p.26
^ Moreno Sánchez et al., 2009, p.53
^ Mantilla Figueroa et al., 2015, p.43
^ Manosalva Sánchez et al., 2017, p.84
^
a
b Plancha 303, 2002, p.24
^
a
b Mantilla Figueroa et al., 2015, p.42
^ Arango Mejía et al., 2012, p.25
^ Plancha 350, 2011, p.49
^ Pulido & Gómez, 2001, pp.17-21
^ Plancha 111, 2001, p.13
^ Plancha 303, 2002, p.23
^ Plancha 348, 2015, p.38
^ Planchas 367-414, 2003, p.35
^ Toro Toro et al., 2014, p.22
^ Plancha 303, 2002, p.21
^
a
b
c
d Bonilla et al., 2016, p.19
^ Gómez Tapias et al., 2015, p.209
^
a
b Bonilla et al., 2016, p.22
^
a
b Duarte et al., 2019
^ García González et al., 2009
^ Pulido & Gómez, 2001
^ García González et al., 2009, p.60
Borrero, C.; Sarmiento, G.N.; Gómez González, C.; Gutiérrez Marco, J.C. (2007),
"Los Conodontos de la Formación El Hígado y su contribución al conocimiento del metamorfismo y la paleogeografía del Ordovícico en la Cordillera Central Colombiana" ,
Boletín de Geología , 29 : 39–46, retrieved 2019-03-07
Chernicoff, Carlos J.; Zappettini, Eduardo O.; Santos, João O.S.; Allchurch, Shelley; McNaughton, Neal J. (2010),
"The southern segment of the Famatinian magmatic arc, La Pampa Province, Argentina" ,
Gondwana Research , 17 (4): 662–675,
Bibcode :
2010GondR..17..662C ,
doi :
10.1016/j.gr.2009.10.008 , retrieved 2019-03-07
González, Humberto (2001), Mapa Geológico del Departamento de Antioquia - 1:400,000 - Memoria explicativa ,
INGEOMINAS , pp. 1–120
Moreno Sánchez, Mario; Jesus Gómez Cruz, Arley de; Castillo González, Hardany (2008),
"Graptolitos del Ordovícico y geología de los afloramientos del Río Venado (norte del Departamento del Huila)" (PDF) ,
Boletín de Geología , 30 : 9–19, retrieved 2019-03-07
Toro Toro, Luz Mary; Moreno Sánchez, Mario; Gómez Cruz, Arley (2014),
"Metagabro del Ariarí, plutonismo MORB, Cordillera Oriental de Colombia" (PDF) ,
Boletín de Geología , 36 : _, retrieved 2019-03-07
Villarroel A., C. ; Macia S., C.;
Brieva B, J. (1997),
"Formación Venado, nueva unidad litoestratigráfica del Ordovícico colombiano" ,
Geología Colombiana , 22 : 41–49, retrieved 2019-03-07
Acosta, Jorge; Caro, Pablo; Fuquen, Jaime; Osorno, José (2002), Plancha 303 - Colombia - 1:100,000 ,
INGEOMINAS , p. 1