Table 1.  Pre-Andean orogenies — duration, cause(s) and affected areas.

Major orogenic events	Duration	Possible cause(s)	Affected areas	

Pampean Orogeny	

Late Precambrian to Cambrian (?Ordovician).	
Has been linked to the collision between the Arequipa-Antofalla microplate (semi-autochthonous terrane from eastern Laurentia) and Gondwana, which resulted in closure of the Puncoviscan Ocean.
More recently, this collisional event is viewed as being confined to the Precambrian, with the Pampean Orogeny related to the Early Cambrian collision of the Pampean Terrane against the proto-Andean margin (Rapela et al. 1998, and references therein).	Magmatism, metamorphism and polyphase folding associated with this event are identifiable in north Argentina and south Bolivia and Peru. During the Cambro-Ordovician, the majority of the western flank of South America was a passive continental margin.  An exception to this was in southern Peru and Bolivia, where a retro-arc extensional setting was established between the Arequipa Massif in the west and the Brazilian Shield to the east.
In the Eastern Sierras Pampeanas, the Pampean Orogeny spanned the Cambrian and resulted in MORB-type ophiolite obduction, combined with widespread anatexis and S-type granite magmatism (Rapela et al. 1998).	

Famatinian Orogeny
(Caledonian Phase)

Ocloyic Orogeny

Precordilleran Orogeny	
Latest Cambrian to Early Ordovician

Late Ordovician to Early Silurian

Early Devonian	
Started with subduction ca. 490-470 Ma (Rapela et al. 1998).

The Late Ordovician to Early Silurian Ocloyic compressional event has been linked to the collision and accretion of a terrane from the eastern margin of Laurentia with the western margin of South America (Pampean Ranges in Argentina; Ramos 1988b).  Referred to as the Precordilleran Terrane by Astini et al. (1995; Precordillera Terrane by Rapela et al. 1998), this may be equivalent to the Cuyania Terrane of Ramos et al. (1996).  Until very recently, most workers (e.g., Dalla Salada et al. 1992, Astini et al. 1995, Dalziel 1997, Ramos et al. 1996) have suggested that the timing of collision of the Precordillera Terrane with Gondwana occurred during the Middle Ordovician of the Famatinian Orogeny.  However, arguments presented by Rapela et al. (1998) may suggest that the collision is later, sometime during the Silurian to Early Devonian.  They suggest that because this timing overlaps with that of the postulated accretion of the Chilenia Terrane (see Ramos & Basei 1997), ‘Chilenia’ basement outcrops may actually represent translated slivers of the Precordillera Terrane ― not a distinct terrane in its own right!
	
This produced a wide continental arc and ensialic retro-arc basin.  The Famatinian Magmatic Arc may have extended the entire length of the southeastern Gondwana margin.

Ocloyic compressional event led to closure of the retro-arc basin.

Responsible for magmatism and folding in Chile, eastern and northwestern Argentina and Colombia. During this period, a retro-arc extensional regime is thought to have resumed in southern Peru and Bolivia.  This setting was affected by strike-slip deformation probably associated with oblique collision.  Clastic sediments are thought to have been derived from the west, possibly sourced by the Arequipa Massif and Puna Arch.	

chanic orogeny
(Early Hercynian Phase)	

Late Devonian to Early Carboniferous	The cause of this orogeny is debatable and has been attributed to several events.  These include collision of the Mejillones Terrane in Peru and the Chilenia Terrane in Chile, and stresses developed along the western margin of the Arequipa Massif.  The widespread nature of this deformation suggests that it was related to the development of subduction along the entire length of the South American western margin.	
Large areas of South America (particularly Bolivia and Peru) were affected by this event.  Exceptions occur in Colombia and northwestern Argentina. This led to inversion of Early Paleozoic basins; as expressed by a regionally widespread unconformity.	
Gondwanide
San Rafael Orogeny
(Late Hercynian Phase)	
Late Permian to Early Triassic	
May represent the suturing of the Patagonia Terrane to the Gondwana margin, resulting in the formation of a magmatic arc (Ramos et al. 1984).	This event is expressed in Peru, Bolivia, southern and eastern Argentina (e.g., Sierra de la Ventana), and Chile.  The San Rafael orogenic phase of the Gondwanide Orogeny was responsible for crustal shortening and folding, and is represented by a strong angular unconformity between the Permo-Triassic and Upper Carboniferous to Lower Permian successions.	

Juruá Orogeny	
?Triassic	This event has been tied to strong inversion tectonics in the Permo-Triassic graben systems of this area.  This orogenic event could represent the first phase of “Andean” deformation, linked to the initial stages of Gondwana breakup (see below).	
It is confined to central South America, not extending southwards beyond Peru, or northwards beyond Ecuador, and represents one of the most significant erosional events in this area.	

Nevadan Orogeny	

Mid to Late Jurassic	

Possibly related to increased rates in subduction along the western margin and the start of rifting in the South Atlantic.	
Particularly in the NW of the continent, leading to the emergence of the proto-Andean cordillera.  Carbonate sedimentation was replaced by clastic and evaporitic sequences in the foreland trough.  At the climax of the orogeny (Late Jurassic), sedimentation stopped, and widespread uplift and erosion took place across Colombia, Ecuador, Peru and Bolivia.	

Peruvian Orogeny	
Late Jurassic to Mid Cretaceous	Subduction, transpression and tectonic thickening transformed the Central Andes into a ‘convergent arc’ setting.  This resulted from a marked increase in the rate of westward movement of the South American Plate across the mantle, possibly due to the early Aptian separation of North Africa and South America in the equatorial Atlantic region.	
This started Peruvian orogenesis in the northern Central Andes, led to closure of the Chile back-arc, and resulted in compressive deformation affecting the continental rift basins of central Argentina.	

Table 2.  Andean orogenies — duration, cause(s) and affected areas.

Major orogenic events	Duration	Possible cause(s)	Affected areas	

(Sub-Hercynian Phase)

Late Cretaceous	In the ?Campanian, the Central Cordillera was loaded by the accretion of the Amaime-Chaucha Terrane.
After this accretion episode, continued South American - Caribbean Plate convergence resulted in the eastward subduction of Caribbean crust outboard of the Amaime Terrane.
A general decrease in subsidence rates in a large number of the Sub-Andean foredeep basins during this period has been related to a relative decrease in Peruvian compressional deformation.  However, in the north, the Pacific Volcanic Arc collided with the South American margin. 	This created the Umir (Middle Magdalena) - Colon (Maracaibo) Basin to the east with asymmetric foredeep geometry.

This resulted in foredeep and forebulge development in the Maracaibo and Barinas Basins, respectively.	

Laramide Orogeny	
Early to Mid Eocene	The northern and northwestern South American margin was subjected to further loading by accreted components of the Caribbean nappe system (southeastern Caribbean Plate).	
This produced a northward deepening foredeep geometry, particularly in the Maracaibo area.	

Incaic Orogeny	
Late Eocene to Early Oligocene
	
An increase in the westward acceleration of South America across the mantle, resulted in an increase in subduction rates and an intensification of the convergent arc tectonics along most of the length of the Andes.	
Eastward and westward thrusting at the flanks of the Andean chain produced considerable uplift, particularly in the northern and central Andes.	

Quechua 1
(Early Andean Phase)
	
Early Miocene	
Galapagos Rift separates Farallon Oceanic Plate into Nazca and Cocos Plates, increasing rate of convergence along the length of the Andes.	
Intensification of magmatism and tectonic thickening.  Dextral strike-slip displacements along major faults such as the Oca-El Pilar Fault System increase along the northern South American margin.	

Quechua 2-3
(Late Andean Phase)

Mid Miocene to Recent	

Increased westwards advance of South America across the mantle, led to yet another increase in subduction rate, particularly along the Peru-Chile Trench System.	This rejuvenation resulted in rapid uplift associated with large-scale crustal thickening, foredeep development, local eastward propagation of foredeep deformation and extensive magmatic activity.  The Andean Orogeny culminated in the Pliocene.  Crustal shortening concentrated in southern Peru, Bolivia and northern Chile creating the Bolivian Orocline, resulting in counterclockwise crustal block rotation in southern Peru and clockwise in northern Chile.	

Table 3.  Summary of the tectonic evolution of the Northern Margin of South America.

Carboniferous to Permian.  During the Carboniferous to Permian, several continental blocks surrounded large areas of the modern Caribbean Sea as part of the western Gondwana supercontinent.  These included: (a) the Florida Straits-Bahamas Block located to the north and northwest; (b) the Chortis-Nicaragua-Jamaica Block to the southwest underlying Middle America, south of the Motagua Fault Zone; (c) the Yucatan Block situated in the west; and (d) the Guayana Block in the south, which extends from Colombia through Venezuela to the Brazilian Atlantic coast.
Triassic to Early Jurassic.  Along the northern South American margin, passive marginal rifting and intra-continental rifting associated with the opening of the Proto-Caribbean Seaway occurred between Venezuela and Yucatan.  The timing of initial rifting is indicated to be of Late Triassic to Early Jurassic age.  This continental attenuation created several major NE-SW trending intra-cratonic rift basins, and it has been suggested that the rifted margin had a re-entrant/salient geometry.  Several re-entrants are recognized: (a) northeastern Lake Maracaibo (Trujillo Trough); (b) Serrania del Interior Oriental (Gulf of Barcelona); and (c) Trinidad (Gulf of Paria).  Further inland, from the true continental slope province, several intra-continental rifts are recognized: the subsurface Espino Graben and smaller associated rifts in the southern part of the Maturin Basin.  The Espino Graben appears to continue SW to at least the Colombian border, and may continue northwestwards beneath the Serrania del Interior; the Uribante and Trujillo Troughs which underlie, respectively, the southwest and northeast Merida Andes; and the Machiques Trough which now forms part of the Perija Range.  The Espino Graben appears to have remained relatively stable whereas the other rifts have undergone inversion during Andean orogenesis.
Middle to Late Jurassic.  By the Middle to Late Jurassic an Atlantic-type passive margin existed from the Guajira Peninsula eastward to Trinidad.  Sediments deposited at this time, along the actual continental margin of northern South America, have been disrupted and obscured by the effect of Cenozoic overthrusting of allochthonous terranes related to movement of the Caribbean Plate.  During the Middle Jurassic, between 180-160 Ma, Africa and South America were rifting from North America, resulting in the initial development of the Central Atlantic Ocean.  This rifting propagated northwestwards into the Gulf of Mexico and Central Florida along the North Bahamas Fracture Zone.  At approximately 145 Ma it has been proposed that the spreading in the Gulf of Mexico had stopped.  The spreading jumped southwards between the southern margin of the Yucatan Block and South America; both of which behaved as passive margins during this time.  This was the onset of the generation of Proto-Caribbean oceanic crust.
Early Cretaceous.  During the Early Cretaceous (approximately 145-120 Ma), passive marginal rift basins developed along the northern margin of South America as spreading continued with the production of the Proto-Caribbean crust.  Eastward-dipping subduction of the Farallon Plate along the west coast of Central America generated the Proto-Greater Antilles Arc Complex.
Mid Cretaceous.  At approximately 100 Ma, the subduction zone beneath the Proto-Greater Antilles island arc switched polarity, becoming west-dipping.  This resulted in the insertion of the Farallon Plate between North and South America, in so doing, subducting the oceanic crust of the Proto-Caribbean as the Greater Antilles island arc advanced northeastwards.  Several studies suggest that this switch in subduction polarity was triggered by the collision of anomalously thickened oceanic crust with the Proto-Antilles island arc.  The northeastward movement of the Greater Antilles Arc system had a profound effect on the geotectonic evolution of the Colombian and Venezuelan margins.  The northern Venezuela-Trinidad area is composed of several distinct tectonic blocks or terranes, which are: (a) the Serrania del Interior, an autochthonous passive margin of Venezuela; (b) metamorphic rocks of the Precambrian to Cretaceous Cordillera de la Costa metamorphic belt; and (c) metavolcanic rocks of the Cretaceous Villa de Cura Group.  The latter two major tectonic blocks are interpreted as being allochthonous or exotic terranes.  All three blocks form a single complexly deformed metamorphic terrane known as the Margarita Block.  Many models explaining the emplacement of these exotic terranes have been proposed, but are not discussed in this contribution.
Late Cretaceous to Paleocene.  As the Greater Antilles Arc continued to move northeastwards, during the latest Cretaceous to Early Tertiary, it collided with the Yucatan Block in the Campanian, and later with the Bahamas Platform.  This northeastwards movement of the arc was accommodated in the north on left-lateral transform faults developed along the southern margin of the Chortis Block (Hess Escarpment) and the Nicaragua Rise, and the eastern edge of the Yucatan Block.  To the south, a right-lateral transform fault developed in northern South America to accommodate the movement.  The eastward advance of the Farallon Plate resulted in the collision and accretion of the Western Cordillera Ophiolite Complex to northwest Colombia.  In the south, the transform fault stepped to the left around the Colombian margin.  This led to the development of a new ‘segment’ of subduction zone, which resulted in consumption of the Farallon Plate beneath America.
The collision of the Farallon Plate with the Bahamas Platform in the latest Cretaceous to earliest Paleocene had the effect of halting insertion of the plate between North and South America.  However, the Pacific part of the Farallon Plate could not be stopped from moving northeastwards resulting in the development of a new subduction zone along the western margin of the Panamanian Arc.  This subduction zone essentially separated the ‘Caribbean Plate’ from its Pacific counterpart (the Farallon Plate).
Late Eocene to Early Oligocene.  Drag along the southern edge of the Caribbean plate boundary may have produced a component of differential shear, which was accommodated by extensional, and transtensional strains resulting in the development of the Falcon and Bonaire Basins.
Late Oligocene to Early Miocene.  In the Late Oligocene to Early Miocene, changes in the relative motion of the Caribbean Plate led to oblique collision and overthrusting of the Margarita Block with the autochthonous northern Venezuelan margin.  This transpressional deformation may have produced the NE-SW-trending folds and thrusts of the Sierra del Interior and Central Range areas of Venezuela and Trinidad.  This thrust loading may have induced flexural downwarping of the Eastern Venezuela Basin.  With continued eastward migration of the Caribbean Plate, part of the Margarita Block was translated eastwards.  This resulted in internal fracturing and extension along the northern Venezuelan margin, leading to Early Oligocene extension in the Falcon and Bonaire Basins.  In the Late Oligocene to Early Miocene, a minor change in South American-Caribbean plate motion caused the Moron, and possibly the San Sebastian Faults, to right step, resulting in the development of the Cariaco pull-apart basin.
Mid Miocene to Present.  From the Mid Miocene to present day, the Caribbean Plate and associated deformation front have propagated eastwards.

References 

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Dalla Salada, L., Cingolani, C. A. & Varela, R. 1992. Early Paleozoic belt of the Andes and southwestern South America: Result of Laurentia-Gondwana collision? Geology, 20, 617-620.
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