User:Sietecolores/sandbox4

Version 1
At the latitudes of 32–36° S —that is Central Chile and most of Mendoza Province— the Andean orogeny proper begun in the Late Cretaceous when backarc basins were inverted. Immediately east of the early Andes foreland basins developed and their flexural subsidence caused the ingression of waters from the Atlantic all the way to the front of the orogen in the Maastrichtian. At more southern latitudes (36–39° S) various Jurassic and Cretaceous marine transgressions from the Pacific are recorded in the sediments of Neuquén Basin. In the Late Cretaceous conditions changed. A marine regression occurred and the fold and thrust belts of Malargüe (36°00 S), Chos Malal (37° S) and Agrio (38° S) started to develop in the Andes and did so in until Eocene times. This meant an advance of the orogenic deformation since the Late Cretaceous that made the western part of Neuquén Basin to stack in the Malargüe and Agrio fold and thrust belts. In the Oligocene the western part of the fold and thrust belt was subject to a short period of extensional tectonics whose structures were inverted in the Miocene. After a period of quiescence the Agrio fold and thrust belt resumed limited activity in the Eocene and then again Late Miocene. From the Eocene to the early Miocene sediments accumulated in the Abanico Extensional Basin, a north-south elongated basin in Chile from that spanned from 29° to 38° S. Tectonic inversion from 21 to 16 million years ago made the basin to collapse and the sediments to be incorporated to the Andean cordillera.

The Andes at the latitudes of 32–36° S experienced a sequence of uplift in the Cenozoic that started in the west and spread to the east. Beginning about 20 million years ago in the Miocene the Principal Cordillera (Argentina-Chile border) begun an uplift that lasted until about 8 million years ago. Before this uplift was over the Frontal Cordillera to the east started a period of uplift that lasted from 12 to 5 million years ago. Further east the Precordillera was uplifted in the last 10 million years and the Sierras Pampeanas has experienced a similar uplift in the last 5 million years. The more eastern part of the Andes at these latitudes had their geometry controlled by ancient faults dating to the San Rafael orogeny of the Paleozoic. The Sierras de Córdoba (part of the Sierras Pampeanas) where the effects of the ancient Pampean orogeny can be observed, owes it modern uplift and relief to the Andean orogeny in the Tertiary. Similarly the San Rafael block east of the Andes and south of Sierras Pampeanas was raised in the Miocene during the Andean orogeny. In the south of Mendoza Province the Guañacos fold and thrust belt (36.5° S) appeared and grew in the Pliocene and Pleistocene consuming the western fringes of the Neuquén Basin.

Version 2 (incomplete)
At the latitudes between 17 and 39° S the Late Cretaceous and Cenozoic development of the Andean orogeny is characterized by an eastward migration of the magmatic belt and the development of several foreland basins. The eastward migration of the arc is thought to be caused by subduction erosion.

From the Eocene to the early Miocene sediments accumulated in the Abanico Extensional Basin, a north-south elongated basin in Chile from that spanned from 29° to 38° S. Tectonic inversion from 21 to 16 million years ago made the basin to collapse and the sediments to be incorporated to the Andean cordillera.

Late Cretaceous to Eocene deformation along the Andes eastern border (32–39° S) consumed the western fringes of Neuquén Basin incorporating sedimentary strata into fold and thrust beltS. In the Oligocene and early the fold and thrust belts were subject to a period of extensional tectonics.

The Andes at the latitudes of 32–36° S experienced a sequence of uplift in the Cenozoic that started in the west and spread to the east. Beginning about 20 million years ago in the Miocene the Principal Cordillera (Argentina-Chile border) begun an uplift that lasted until about 8 million years ago. Before this uplift was over the Frontal Cordillera to the east started a period of uplift that lasted from 12 to 5 million years ago. Further east the Precordillera was uplifted in the last 10 million years and the Sierras Pampeanas has experienced a similar uplift in the last 5 million years. The more eastern part of the Andes at these latitudes had their geometry controlled by ancient faults dating to the San Rafael orogeny of the Paleozoic. The Sierras de Córdoba (part of the Sierras Pampeanas) where the effects of the ancient Pampean orogeny can be observed, owes it modern uplift and relief to the Andean orogeny in the Tertiary. Similarly the San Rafael block east of the Andes and south of Sierras Pampeanas was raised in the Miocene during the Andean orogeny. In the south of Mendoza Province the Guañacos fold and thrust belt (36.5° S) appeared and grew from the Pliocene into the present consuming the western fringes of the Neuquén Basin.