Soatá Formation

The Soatá Formation (Spanish: Formación Soatá) is a geological formation of the northern Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists mainly of shales with conglomerates and dates to the Quaternary period; Late Pleistocene epoch. The heavily eroded formation has a maximum measured thickness of 30.8 metres (101 ft). It contains the lacustrine and fluvio-glacial sediments of elongated paleolake Soatá, that existed on the Altiplano in the valley of the Chicamocha River.

Soatá Formation
Stratigraphic range: Late Pleistocene ~0.0475–0.0388 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Underlies	Holocene sediments of the Chicamocha River
Overlies	Capacho Formation
Area	~130 km2 (50 sq mi)
Thickness	up to 30.8 m (101 ft)
Lithology
Primary	Shale
Other	Conglomerate, siltstone
Location
Coordinates	6°18′00″N 72°39′46″W
Region	Altiplano Cundiboyacense Eastern Ranges, Andes
Country	Colombia
Extent	~30 km × 7 km (18.6 mi × 4.3 mi)
Type section
Named for	Soatá
Named by	Villarroel et al.
Location	Portugalete, Soatá
Year defined	2001
Coordinates	6°18′00″N 72°39′46″W
Approximate paleocoordinates	6.3°N 72.5°W / 6.3; -72.5
Region	Boyacá
Country	Colombia
Thickness at type section	30.8 m (101 ft)
Paleogeography of the Pleistocene

The Chicamocha River, seen here farther downstream at the Chicamocha Canyon, heavily eroded the former Pleistocene terraces of the Soatá Formation

Fossils of the gomphothere Haplomastodon waringi, the capibara Neochoerus sp. and the deer species Odocoileus cf. salinae have been found in the Soatá Formation.

Knowledge about the formation has been provided by Colombian geologists Carlos Villarroel, Jorge Brieva and others.

Etymology

The formation was first proposed and named after Soatá by Villarroel et al. in 2001. The type locality is defined near Portugalete, Soatá.^[1]

Regional setting

See also: Altiplano Cundiboyacense § Prehistory, and Ocetá Páramo § Geology

The Soatá Formation was deposited in a glacial lacustrine environment, in a narrow elongated deep paleolake

The Altiplano Cundiboyacense, in the Eastern Ranges of the Colombian Andes, was formed late in the regional uplift of the Andean orogeny. It is estimated that the main stage of uplift happened during the Plio-Pleistocene. The Western and Central Ranges were submerged much earlier, leaving a corridor to the Caribbean in the Neogene.

The compression in the Andean orogenic belt caused the formation of fold and thrust belts in the Eastern Ranges, where Cretaceous and Jurassic normal faults were inverted as thrust faults lifting up the Paleozoic (Floresta and Cuche Formations), Mesozoic and Paleogene strata. A hiatus existed on the Altiplano between the Late Eocene and Late Miocene, in several parts of the Altiplano continuing until the Pleistocene.

During the glacials and interglacials of the Pleistocene ("ice ages"), several paleolakes formed on the Altiplano Cundiboyacense, of which Lake Humboldt on the Bogotá savanna was the most extensive (approximately 4,500 square kilometres (1,700 sq mi)). Rivers were restricted during the drier glacial periods and the vegetation changed from páramo to Andean forest between the glacials and stadials and interglacials and interstadials.^[2]

Description

Fossils of the gomphothere Haplomastodon waringi were found in the Soatá Formation

Lithologies

The Soatá Formation consists of whitish calcareous claystones and sandy siltstones with plagioclase, hematite, zircon, green and reddish biotite, hornblende and crystalline calcite in its upper, older terrace. This unit also contains foraminifera and fragments of shells.^[1]

The middle, younger unit is composed of basal greyish claystones with non-uniform matrix-supported conglomerates at the upper section. The uppermost layer contains siltstones, probably of volcaniclastic origin.^[3]

The youngest sediments are found deepest in the basin and consist of claystones and greenish matrix-supported conglomerates. Rootlets and mammal fossils are more abundant in this layer.^[3]

Stratigraphy

The Soatá Formation unconformably overlies the Cretaceous Capacho Formation, and is overlain by the Holocene infill sediments of the Chicamocha River, the course of which severely eroded and fragmented the Soatá formation.^[4] The formation is subdivided into three units of different lithological character and sedimentary dip in a terrace setting. The Soatá Formation is time-equivalent with the upper part of the Sabana Formation on the Bogotá savanna and the Chinauta deposits near Fusagasugá in the southwest of the Altiplano.^[5][6] Two samples were analysed for radiometric dating and provided ages of 45,900 ± 1,600 and 39,600 ± 800 years BP.^[7] This corresponds to the Chicagota interstadial and the Tagua stadial, when the glaciations were at their maximum extent.^[8][9]

Depositional environment

The depositional environment has been interpreted as lacustrine (Lake Soatá) and fluvio-deltaic. Contrasting with the wide and shallow Lake Humboldt on the Bogotá savanna, Lake Soatá was probably close to 400 metres (1,300 ft) deep.^[10] The paleolake was approximately 30 kilometres (19 mi) long and widest between Soatá and Boavita at 7 kilometres (4.3 mi).^[11]

Fossil content

In the Soatá Formation, fossils of Haplomastodon waringi, Neochoerus sp. and Odocoileus cf. salinae have been found.^[12] The fossil content is fragmentary.^[13]

Outcrops

Type locality of the Soatá Formation to the northeast of the Altiplano Cundiboyacense. The Chicamocha River valley is clearly visible.

The Soatá Formation is apart from its type locality Portugalete found around Soatá (Jútua), and stretches to the north near the border of Boyacá and Santander, northeast of Tipacoque. To the south, the formation may have reached until Socotá.^[10]

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)		[14][15][16][17]
2.6	Pliocene		Pliocene volcanism Andean orogeny 3 GABI		Subachoque
5.3	Messinian		Andean orogeny 3 Foreland		Marichuela			Caimán	Honda				[16][18]
13.5	Langhian		Regional flooding	León	hiatus	Caja	León			Lacustrine (León)	400 m (1,300 ft) (León)	Seal	[17][19]
16.2	Burdigalian		Miocene inundations Andean orogeny 2	C1		Carbonera C1		Ospina		Proximal fluvio-deltaic (C1)	850 m (2,790 ft) (Carbonera)	Reservoir	[18][17]
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	[15][18]
25				C6		Carbonera C6				Distal fluvio-lacustrine (C6)		Seal
28	Early Oligocene			C7		C7		Pepino	Gualanday	Proximal deltaic-marine (C7)		Reservoir	[15][18][20]
32	Oligo-Eocene			C8	Usme	C8	onlap			Marine-deltaic (C8)		Seal Source	[20]
35	Late Eocene			Mirador		Mirador				Coastal (Mirador)	240 m (790 ft) (Mirador)	Reservoir	[17][21]
40	Middle Eocene				Regadera				hiatus
45
50	Early Eocene			Socha		Los Cuervos				Deltaic (Los Cuervos)	260 m (850 ft) (Los Cuervos)	Seal Source	[17][21]
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	[14][15][18][17][22]
65	Maastrichtian		KT extinction	Catatumbo	Guadalupe				Monserrate	Deltaic-fluvial (Guadalupe)	750 m (2,460 ft) (Guadalupe)	Reservoir	[14][17]
72	Campanian		End of rifting	Colón-Mito Juan									[17][23]
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	[14][17][24]
93	Cenomanian		Rift 2
100	Albian				Une	Une		Caballos		Deltaic (Une)	500 m (1,600 ft) (Une)	Reservoir	[18][24]
113	Aptian			Capacho	Fómeque			Motema	Yaví	Open marine (Fómeque)	800 m (2,600 ft) (Fómeque)	Source (Fóm)	[15][17][25]
125	Barremian		High biodiversity	Aguardiente	Paja					Shallow to open marine (Paja)	940 m (3,080 ft) (Paja)	Reservoir	[14]
129	Hauterivian		Rift 1	Tibú- Mercedes	Las Juntas	hiatus				Deltaic (Las Juntas)	910 m (2,990 ft) (Las Juntas)	Reservoir (LJun)	[14]
133	Valanginian			Río Negro	Cáqueza Macanal Rosablanca					Restricted marine (Macanal)	2,935 m (9,629 ft) (Macanal)	Source (Mac)	[15][26]
140	Berriasian			Girón
145	Tithonian		Break-up of Pangea	Jordán	Arcabuco	Buenavista Batá		Saldaña		Alluvial, fluvial (Buenavista)	110 m (360 ft) (Buenavista)	"Jurassic"	[18][27]
150	Early-Mid Jurassic		Passive margin 2	La Quinta	Montebel Noreán	hiatus				Coastal tuff (La Quinta)	100 m (330 ft) (La Quinta)		[28]
201	Late Triassic			Mucuchachi				Payandé					[18]
235	Early Triassic		Pangea		hiatus							"Paleozoic"
250	Permian
300	Late Carboniferous		Famatinian orogeny						Cerro Neiva ()				[29]
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)		[26][30][31][32][33]
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)				[34][35][36]
488	Late Cambrian		Regional intrusions	Chicamocha (490-515)	Quetame ()	Ariarí ()		SJ del Guaviare (490-590)	San Isidro ()				[37][38]
515	Early Cambrian		Cambrian explosion										[36][39]
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	[40][41]
600	Neoproterozoic		Cariri Velhos orogeny	Bucaramanga (600-1400)				pre-Guaviare					[37]
800			Snowball Earth										[42]
1000	Mesoproterozoic		Sunsás orogeny			Ariarí (1000)			La Urraca (1030-1100)				[43][44][45][46]
1300			Rondônia-Juruá orogeny			pre-Ariarí	Parguaza (1300-1400)		Garzón (1180-1550)				[47]
1400				pre-Bucaramanga									[48]
1600	Paleoproterozoic						Maimachi (1500-1700)		pre-Garzón				[49]
1800			Tapajós orogeny				Mitú (1800)						[47][49]
1950			Transamazonic orogeny				pre-Mitú						[47]
2200			Columbia
2530	Archean		Carajas-Imataca orogeny										[47]
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)^[50], García González et al. (2009),^[51] and geological report of Villavicencio^[52]
2. based on Duarte et al. (2019)^[50] and the hydrocarbon potential evaluation performed by the UIS and ANH in 2009^[53]