**5. Conclusion**

The complexity of tectonic processes controlling the evolution of foreland basins resulted in highly complex basins. The more that is known about these processes and their consequences, the more complex our models become and the more each basin appears to be unique [9].

During the first evolutionary stage of the foreland basin that developed during the middle to upper Eocene in north‐western Argentina, the basin had an elongated configuration, was par‐ allel to the Andean uplift, and did not extend to the external sector of the Cordillera Oriental (**Figure 14a**).

The uplift of the margins of the basin and the increase in the relief of the edge of the Puna plateau associated with the Leon Muerto Range are reflected in three depositional sequences that are interpreted to represent three tectonic episodes. Consequently, the main controls over the ephemeral fluvial system were the interactions between tectonics and basin subsidence and the constant arid climatic conditions (**Figure 14a**).

At the beginning of the second evolutionary stage of the foreland basin, an initial elongated depocenter parallel to the orogen developed at ∼17 Ma. This depocenter featured the devel‐ opment of playa lake deposits and paleocurrent directions to the north (along the Umbral de Los Gallos). Over time, the depocenter migrated to the eastern edge of the basin by ∼15 Ma (**Figure 14b**).

Integrated Stratigraphy of the Cenozoic Andean Foreland Basin (Northern Argentina) http://dx.doi.org/10.5772/intechopen.69985 149

*4.3.1. Facies and depositional architecture of the Piquete Formation*

148 Seismic and Sequence Stratigraphy and Integrated Stratigraphy - New Insights and Contributions

[59] (**Figure 13**).

**5. Conclusion**

(**Figure 14a**).

(**Figure 14b**).

tane Calchaquí Basin [42, 59].

based on its morphology [67], have also been found.

and the constant arid climatic conditions (**Figure 14a**).

The paleoenvironment of the Piquete Formation has been interpreted as relatively small allu‐ vial fans distributed on the flanks of structural depressions and dominated by debris flows (**Table 3**). If these alluvial fans would have been more, had developed in the eastern sector, and away from the thrust fronts, flood plains with small lake systems would have developed

The conglomerates in the Piquete Formation contain slabs of limestone from the Yacoraite Formation, slate from the Precambrian basement of the Puncoviscana Formation, and clasts of reddish sandstone and limestone from the Salta Group. The change in the conglomeratic clast composition from the Guanaco Formation to the Piquete Formation suggests that between ∼5 and 2 Ma, thick sediments from the eastern edge of the Puna were trapped in the intermon‐

The paleontological content of the Piquete Formation at present is very limited and includes fragmentary remains of vertebrates, notably including abrocomid rodents and plates of Dasypodidae. In the Xibi Xavi river, in the city of Jujuy, complete remains of a glyptodont (*Cranithlastus xibiensis*) and megatherium teeth [66] have been found. Alligatoroid remains from Rosario de la Frontera (south of Salta province), assigned to the species *Caiman latirostris*

The complexity of tectonic processes controlling the evolution of foreland basins resulted in highly complex basins. The more that is known about these processes and their consequences, the more complex our models become and the more each basin appears to be unique [9].

During the first evolutionary stage of the foreland basin that developed during the middle to upper Eocene in north‐western Argentina, the basin had an elongated configuration, was par‐ allel to the Andean uplift, and did not extend to the external sector of the Cordillera Oriental

The uplift of the margins of the basin and the increase in the relief of the edge of the Puna plateau associated with the Leon Muerto Range are reflected in three depositional sequences that are interpreted to represent three tectonic episodes. Consequently, the main controls over the ephemeral fluvial system were the interactions between tectonics and basin subsidence

At the beginning of the second evolutionary stage of the foreland basin, an initial elongated depocenter parallel to the orogen developed at ∼17 Ma. This depocenter featured the devel‐ opment of playa lake deposits and paleocurrent directions to the north (along the Umbral de Los Gallos). Over time, the depocenter migrated to the eastern edge of the basin by ∼15 Ma

**Figure 14.** Schematic diagram models for Cenozoic foreland basins showing the evolution of the study area from Eocene (a) to Pliocene (d) time (not to scale).

The second evolutionary stage of the foreland basin (15–10 Ma) featured a new restructur‐ ing of the broken foreland basin with the development of thick sedimentary deposits in the Calchaquí basin area that thin toward the eastern basin margin. The same pattern in sedimen‐ tation and development is observed in the Metán Subgroup basin to the east (**Figure 14c**).

The contact between the Los Colorados and Angastaco formations is a paraconformity grad‐ ing into an unconformity. Tectonics and subsidence were the fundamental controls on the evolution of the fluvial style, the deposit thickness, and the paleocurrent variability. The red sandstone clasts (Lumbrera Formation) and gray sandstone clasts (Maíz Gordo Formation) in the Tonco Valley, which are associated with easterly paleocurrents, suggest that the Sierra León Muerto to the east of the Angastaco basin was uplifted (**Figure 14c**).

The Metán Subgroup deposits are interpreted to have accumulated at ∼14.9 Ma in an arid paleoenvironment characterized by a sandy ephemeral fluvial system associated with dune fields and playa lake deposits, with sand flats, mud flats, an ephemeral saline lake, and a per‐ manent saline lake and sporadic marine incursions from the south‐east (**Figure 14c**). At ∼12 Ma, a new basin restructuring event began and the Metán Subgroup deposits began to be eroded.

During the third stage of evolution in the foreland basin (∼10–5 Ma), the western part of the basin experienced at least three episodes of tectonic reactivation, which are reflected in varia‐ tions in the rate of sedimentation in the Palo Pintado Formation. Paleocurrents from the south and south‐east indicate tectonic reactivation of the depositional area from the Sierra León Muerto‐Sierra Los Colorados (**Figure 14d**).

The Guanaco Formation is characterized by alluvial fans deposits dominated by flowing streams and a braided fluvial system. The sedimentary paleoenvironment, provenance, and paleocurrent data suggest that the foreland basin evolved at a different time and rhythm than the Calchaquí basin, with the connection of first‐ and second‐order river systems transported material from the eastern edge of the Puna and the area of the El Toro Lineament (**Figure 14d**).

The San Felipe Formation is characterized by braided fluvial fan and a shallow gravel‐braided fluvial system. The provenance and abundant clasts in different levels of the Salta Group and the association with paleocurrents from the north‐east, east, and south‐east suggest a reactivation of the Sierra León Muerto and the Sierra Los Colorados in the depositional area (**Figure 14e**).

The Piquete Formation lies in marked unconformity over the deposits of the Guanaco Formation or older deposits. They accumulated as a series of alluvial fans of limited dimensions and are distributed on the flanks of structural depressions and dominated by debris flows. The compo‐ sition of the clasts of conglomerates from the Piquete Formation suggests that between ∼5 and 2 Ma, the basin was isolated from the basin of the San Felipe Formation (**Figure 14d**).
