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Geological group in the Venezuelan Andes From Wikipedia, the free encyclopedia
The Río Cachirí Group (Spanish: Grupo Río Cachirí, PZc) is a geological group of the Cesar-Ranchería Basin, Colombia and the Serranía del Perijá of the northernmost Colombian and Venezuelan Andes. The group of shales, sandstones and limestones is of Devonian age and has a maximum thickness in the Venezuelan section of 2,438 metres (7,999 ft). The group contains abundant fauna; crinoids, bryozoa, brachiopods and molluscs have been found in the group.
Río Cachirí Group | |
---|---|
Stratigraphic range: Devonian | |
Type | Geological group |
Unit of | Cesar-Ranchería Basin, Serranía del Perijá |
Sub-units | Caño Grande Fm., Caño del Oeste Fm., Campo Chico Fm., Los Guineos Fm. |
Underlies | Carboniferous sequence |
Overlies | Perijá Formation |
Thickness | ~1,100 m (3,600 ft) (Colombia) 2,438 m (7,999 ft) (Venezuela) |
Lithology | |
Primary | Shale, sandstone |
Other | Limestone |
Location | |
Coordinates | 10°50′03″N 72°14′23″W |
Region | Cesar, La Guajira Zulia |
Country | Colombia Venezuela |
Extent | ~110 km (68 mi) (Venezuela) |
Type section | |
Named for | Río Cachirí |
Named by | Liddle |
Location | Mara |
Year defined | 1928 |
Coordinates | 10°50′03″N 72°14′23″W |
Region | Zulia |
Country | Venezuela |
Thickness at type section | 2,438 m (7,999 ft) |
Paleogeography of the Middle Devonian 380 Ma, by Stampfli & Borel |
The formation was defined by Liddle in 1928 in Río Cachirí, part of Mara, Zulia, in the Venezuelan part of the Serranía del Perijá, and the same author subdivided the group into three formations in 1943. In 1972, Bowen added a fourth formation to the group.[1]
The group contains black, grey and red shales, grey micaceous sandstones, quartzitic sandstones and red and bluish grey limestones.[1]
The Río Cachirí Group, dated to span the Devonian, is subdivided into the Caño Grande, Caño del Oeste, Campo Chico and Los Guineos Formations. The maximum thickness has been recorded in Venezuela, with 2,438 metres (7,999 ft), while the thickness on the Colombian side of the range does not exceed 1,100 metres (3,600 ft).[1] The group is recognised along a section of approximately 110 kilometres (68 mi) in the Venezuelan terrain.[2] The group unconformably overlies the Perijá Formation and is overlain by an unnamed Carboniferous sequence. The Río Cachirí Group is time-equivalent with the Floresta and Cuche Formations of the Floresta Massif, Altiplano Cundiboyacense and the Quetame Group of the Eastern Ranges.[3] The sediments of the Río Cachirí Group were deposited in an epicontinental sea at the edge of the Paleo-Tethys Ocean.[1]
The group contains abundant fossils of crinoids, bryozoa, brachiopods and molluscs as Acrospirifer olssoni, Spirifer kingi, Leptaena boyaca, Fenestella venezuelansis, Neospirifer latus, Composita subtilita, Phricodrotis planoconvexa and Pecten sp.[4]
Apart from its type locality on the eastern flank of the Serranía del Perijá in Zulia, Venezuela, the formation is also found in other parts of the mountain range, on the Colombian western side in the east of San Diego and Curumaní, Cesar.[5][6]
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) | [7][8][9][10] | |||
2.6 | Pliocene | Pliocene volcanism Andean orogeny 3 GABI | Subachoque | ||||||||||
5.3 | Messinian | Andean orogeny 3 Foreland | Marichuela | Caimán | Honda | [9][11] | |||||||
13.5 | Langhian | Regional flooding | León | hiatus | Caja | León | Lacustrine (León) | 400 m (1,300 ft) (León) | Seal | [10][12] | |||
16.2 | Burdigalian | Miocene inundations Andean orogeny 2 | C1 | Carbonera C1 | Ospina | Proximal fluvio-deltaic (C1) | 850 m (2,790 ft) (Carbonera) | Reservoir | [11][10] | ||||
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 | [8][11] | |||||
25 | C6 | Carbonera C6 | Distal fluvio-lacustrine (C6) | Seal | |||||||||
28 | Early Oligocene | C7 | C7 | Pepino | Gualanday | Proximal deltaic-marine (C7) | Reservoir | [8][11][13] | |||||
32 | Oligo-Eocene | C8 | Usme | C8 | onlap | Marine-deltaic (C8) | Seal Source | [13] | |||||
35 | Late Eocene | Mirador | Mirador | Coastal (Mirador) | 240 m (790 ft) (Mirador) | Reservoir | [10][14] | ||||||
40 | Middle Eocene | Regadera | hiatus | ||||||||||
45 | |||||||||||||
50 | Early Eocene | Socha | Los Cuervos | Deltaic (Los Cuervos) | 260 m (850 ft) (Los Cuervos) | Seal Source | [10][14] | ||||||
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 | [7][8][11][10][15] | |||
65 | Maastrichtian | KT extinction | Catatumbo | Guadalupe | Monserrate | Deltaic-fluvial (Guadalupe) | 750 m (2,460 ft) (Guadalupe) | Reservoir | [7][10] | ||||
72 | Campanian | End of rifting | Colón-Mito Juan | [10][16] | |||||||||
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 | [7][10][17] | |||
93 | Cenomanian | Rift 2 | |||||||||||
100 | Albian | Une | Une | Caballos | Deltaic (Une) | 500 m (1,600 ft) (Une) | Reservoir | [11][17] | |||||
113 | Aptian | Capacho | Fómeque | Motema | Yaví | Open marine (Fómeque) | 800 m (2,600 ft) (Fómeque) | Source (Fóm) | [8][10][18] | ||||
125 | Barremian | High biodiversity | Aguardiente | Paja | Shallow to open marine (Paja) | 940 m (3,080 ft) (Paja) | Reservoir | [7] | |||||
129 | Hauterivian | Rift 1 | Tibú- Mercedes | Las Juntas | hiatus | Deltaic (Las Juntas) | 910 m (2,990 ft) (Las Juntas) | Reservoir (LJun) | [7] | ||||
133 | Valanginian | Río Negro | Cáqueza Macanal Rosablanca | Restricted marine (Macanal) | 2,935 m (9,629 ft) (Macanal) | Source (Mac) | [8][19] | ||||||
140 | Berriasian | Girón | |||||||||||
145 | Tithonian | Break-up of Pangea | Jordán | Arcabuco | Buenavista Batá | Saldaña | Alluvial, fluvial (Buenavista) | 110 m (360 ft) (Buenavista) | "Jurassic" | [11][20] | |||
150 | Early-Mid Jurassic | Passive margin 2 | La Quinta | Montebel Noreán | hiatus | Coastal tuff (La Quinta) | 100 m (330 ft) (La Quinta) | [21] | |||||
201 | Late Triassic | Mucuchachi | Payandé | [11] | |||||||||
235 | Early Triassic | Pangea | hiatus | "Paleozoic" | |||||||||
250 | Permian | ||||||||||||
300 | Late Carboniferous | Famatinian orogeny | Cerro Neiva () | [22] | |||||||||
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) | [19][23][24][25][26] | ||||||
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 () | [27][28][29] | ||||||
488 | Late Cambrian | Regional intrusions | Chicamocha (490-515) | Quetame () | Ariarí () | SJ del Guaviare (490-590) | San Isidro () | [30][31] | |||||
515 | Early Cambrian | Cambrian explosion | [29][32] | ||||||||||
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 | [33][34] | |||||
600 | Neoproterozoic | Cariri Velhos orogeny | Bucaramanga (600-1400) | pre-Guaviare | [30] | ||||||||
800 | Snowball Earth | [35] | |||||||||||
1000 | Mesoproterozoic | Sunsás orogeny | Ariarí (1000) | La Urraca (1030-1100) | [36][37][38][39] | ||||||||
1300 | Rondônia-Juruá orogeny | pre-Ariarí | Parguaza (1300-1400) | Garzón (1180-1550) | [40] | ||||||||
1400 | pre-Bucaramanga | [41] | |||||||||||
1600 | Paleoproterozoic | Maimachi (1500-1700) | pre-Garzón | [42] | |||||||||
1800 | Tapajós orogeny | Mitú (1800) | [40][42] | ||||||||||
1950 | Transamazonic orogeny | pre-Mitú | [40] | ||||||||||
2200 | Columbia | ||||||||||||
2530 | Archean | Carajas-Imataca orogeny | [40] | ||||||||||
3100 | Kenorland | ||||||||||||
Sources |
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