Subachoque Formation

For other uses, see Subachoque (disambiguation).

The Subachoque Formation (Spanish: Formación Subachoque, Q_1su) is a geological formation of the Bogotá savanna, Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists mainly of sandy shales and lignite with sandstone beds. The Subachoque Formation dates to the Quaternary period; Early to Middle Pleistocene epoch (from approximately 2.5 to 1 Ma), and has a maximum thickness of 150 metres (490 ft). It is the lowermost formation of the lacustrine and fluvio-glacial sediments of Lake Humboldt.

Subachoque Formation
Stratigraphic range: Early to Mid Pleistocene ~2.5–1 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Underlies	Sabana Formation
Overlies	Tilatá Formation Guadalupe Gp. Guaduas Fm., Cacho Fm., Bogotá Fm., Regadera Fm.
Thickness	up to 150 metres (490 ft)
Lithology
Primary	Shale, lignite
Other	Sandstone
Location
Coordinates	4°57′17.3″N 74°13′07.5″W
Region	Bogotá savanna, Altiplano Cundiboyacense Eastern Ranges, Andes
Country	Colombia
Type section
Named for	Subachoque
Named by	Helmens & Hammen
Location	Subachoque Synclinal
Year defined	1995
Coordinates	4°57′17.3″N 74°13′07.5″W
Region	Cundinamarca
Country	Colombia
Paleogeography of the Pleistocene by Ron Blakey

Etymology

The formation was first defined and named by Helmens and Van der Hammen in 1995 after Subachoque, Cundinamarca.^[1]

Description

Lithologies

The Subachoque Formation consists mainly of sandy shales, some organic, with lignite and sandstone beds.^[1]

Stratigraphy and depositional environment

The Subachoque Formation is the lowermost of the lagunal and alluvial sequence of the Bogotá savanna. In parts, it conformably overlies the Tilatá Formation and other parts unconformably the Cretaceous Guadalupe Group and the Paleogene Guaduas, Cacho, Bogotá, and Regadera Formations. The Subachoque Formation is overlain by other Quaternary deposits of Lake Humboldt. The age has been estimated to be Early to Middle Pleistocene based on fission track analysis, with reported ages between 2.5 and 1 Ma.^[2] The depositional environment has been interpreted as lacustrine and fluvio-glacial with alluvial fans.^[1]

Outcrops

Type locality of the Subachoque Formation on the northwestern Bogotá savanna

The Subachoque Formation is found at its type locality in the western flank of the synclinal of Subachoque and in the western flank of the synclinal of Guasca.^[1] The deposition of the Subachoque Formation postdates the main reverse movement of the Bogotá Fault.^[3]

Regional correlations

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 Neiva		Alluvial to fluvial (Guayabo)	550 m (1,800 ft) (Guayabo)		[4][5][6][7]
2.6	Pliocene		Pliocene volcanism Andean orogeny 3 GABI		Subachoque
5.3	Messinian		Andean orogeny 3 Foreland		Marichuela			Caimán	Honda				[6][8]
13.5	Langhian		Regional flooding	León	hiatus	Caja	León			Lacustrine (León)	400 m (1,300 ft) (León)	Seal	[7][9]
16.2	Burdigalian		Miocene inundations Andean orogeny 2	C1		Carbonera C1		Ospina		Proximal fluvio-deltaic (C1)	850 m (2,790 ft) (Carbonera)	Reservoir	[8][7]
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	[5][8]
25				C6		Carbonera C6				Distal fluvio-lacustrine (C6)		Seal
28	Early Oligocene			C7		C7		Pepino	Gualanday	Proximal deltaic-marine (C7)		Reservoir	[5][8][10]
32	Oligo-Eocene			C8	Usme	C8	onlap			Marine-deltaic (C8)		Seal Source	[10]
35	Late Eocene			Mirador		Mirador				Coastal (Mirador)	240 m (790 ft) (Mirador)	Reservoir	[7][11]
40	Middle Eocene				Regadera				hiatus
45
50	Early Eocene			Socha		Los Cuervos				Deltaic (Los Cuervos)	260 m (850 ft) (Los Cuervos)	Seal Source	[7][11]
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	[4][5][8][7][12]
65	Maastrichtian		KT extinction	Catatumbo	Guadalupe				Monserrate	Deltaic-fluvial (Guadalupe)	750 m (2,460 ft) (Guadalupe)	Reservoir	[4][7]
72	Campanian		End of rifting	Colón-Mito Juan									[7][13]
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	[4][7][14]
93	Cenomanian		Rift 2
100	Albian				Une	Une		Caballos		Deltaic (Une)	500 m (1,600 ft) (Une)	Reservoir	[8][14]
113	Aptian			Capacho	Fómeque			Motema	Yaví	Open marine (Fómeque)	800 m (2,600 ft) (Fómeque)	Source (Fóm)	[5][7][15]
125	Barremian		High biodiversity	Aguardiente	Paja					Shallow to open marine (Paja)	940 m (3,080 ft) (Paja)	Reservoir	[4]
129	Hauterivian		Rift 1	Tibú- Mercedes	Las Juntas	hiatus				Deltaic (Las Juntas)	910 m (2,990 ft) (Las Juntas)	Reservoir (LJun)	[4]
133	Valanginian			Río Negro	Cáqueza Macanal Rosablanca					Restricted marine (Macanal)	2,935 m (9,629 ft) (Macanal)	Source (Mac)	[5][16]
140	Berriasian			Girón
145	Tithonian		Break-up of Pangea	Jordán	Arcabuco	Buenavista Batá		Saldaña		Alluvial, fluvial (Buenavista)	110 m (360 ft) (Buenavista)	"Jurassic"	[8][17]
150	Early-Mid Jurassic		Passive margin 2	La Quinta	Montebel Noreán	hiatus				Coastal tuff (La Quinta)	100 m (330 ft) (La Quinta)		[18]
201	Late Triassic			Mucuchachi				Payandé					[8]
235	Early Triassic		Pangea		hiatus							"Paleozoic"
250	Permian
300	Late Carboniferous		Famatinian orogeny						Cerro Neiva ()				[19]
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)		[16][20][21][22][23]
390	Early Devonian		High biodiversity	Floresta (387-400) El Tíbet						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) Chuscales Otengá	Guape ()		Río Nevado ()	Hígado () Agua Blanca Venado (470-475)				[24][25][26]
488	Late Cambrian		Regional intrusions	Chicamocha (490-515)	Quetame ()	Ariarí ()		SJ del Guaviare (490-590)	San Isidro ()				[27][28]
515	Early Cambrian		Cambrian explosion										[26][29]
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	[30][31]
600	Neoproterozoic		Cariri Velhos orogeny	Bucaramanga (600-1400)				pre-Guaviare					[27]
800			Snowball Earth										[32]
1000	Mesoproterozoic		Sunsás orogeny			Ariarí (1000)			La Urraca (1030-1100)				[33][34][35][36]
1300			Rondônia-Juruá orogeny			pre-Ariarí	Parguaza (1300-1400)		Garzón (1180-1550)				[37]
1400				pre-Bucaramanga									[38]
1600	Paleoproterozoic						Maimachi (1500-1700)		pre-Garzón				[39]
1800			Tapajós orogeny				Mitú (1800)						[37][39]
1950			Transamazonic orogeny				pre-Mitú						[37]
2200			Columbia
2530	Archean		Carajas-Imataca orogeny										[37]
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]}

See also

• Colombia portal
• Geology portal

Geology of the Eastern Hills

Geology of the Ocetá Páramo

Geology of the Altiplano Cundiboyacense

Notes

1. based on Duarte et al. (2019)^[40], García González et al. (2009),^[41] and geological report of Villavicencio^[42]
2. based on Duarte et al. (2019)^[40] and the hydrocarbon potential evaluation performed by the UIS and ANH in 2009^[43]