Banca de DEFESA: Michele Andriolli Custódio

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : Michele Andriolli Custódio
DATE: 19/12/2023
TIME: 11:00
LOCAL: Auditório do Instituto de Geociências
TITLE:

The Cenozoic sedimentary evolution of the AndesAmazon-South America Equatorial Margin Source to Sink system

KEY WORDS:

Paleogene; northern South American plate; Foz do Amazonas Basin; paleogeography; sediment provenance.

PAGES: 324
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUBÁREA: Geologia
SUMMARY:

The Andes-Amazon-South American Equatorial Margin (AAMESA) sourcesedimentation system (S2S), which extends for around 3,200 km and is located north of the South American platform, is one of the largest S2S systems in the world. Currently, the AAMESA system is controlled by the Andes from a sedimentary point of view, as 95% of the average annual flow of suspended sediment supplied by the Amazon to the Atlantic Ocean comes from Andean tributaries. Despite scientific advances detailing the influences of Andean construction and erosion processes on the origin, evolution and sedimentary record of the S2S AAMESA system from the end of the Cretaceous to the beginning of the Paleocene in Western Amazonia and the establishment of the transcontinental Amazon River at the end of the Miocene (Neogene) in Eastern Amazonia, the geological history and, in particular, the pre-Neogene and Pliocene configurations of the AAMESA system have yet to be clarified. The main objective of this thesis is to propose a paleogeographic reconstruction of the Andes-AmazonEquatorial Margin system during the Cenozoic, based on new stratigraphic, sedimentological and sedimentary provenance data obtained from one of the basins that make up the foreland basin system of the Amazonian backarc (Huallaga Basin, northern Peru) and the main basin of the Amazonian equatorial margin (Foz do Amazonas Basin). We show that, from the Paleocene to the Lower Eocene (Danian - Ypresian) (66 - 43.5 Ma), a depositional hiatus developed in the basins of the Amazonian backarc linked to an episode of tectonic quiescence in the Andes. This tectonic quiescence is contemporaneous with the formation of the "South American" laterite surfaces in Central Amazonia and the low sedimentation rates in the Foz do Amazonas Basin. The resumption of uplift and erosion of the Peruvian Andes in the middle to late Eocene (Lutetian - Bartonian) (43.5 - 37.6 Ma) was recorded in the sedimentation of the foreland basin of the Amazonian backarc by the presence of debris from the magmatic arcs of the Cordillera Occidental and by a Bartonian transgression marked by the presence of tidal deposits in continental lacustrine deposits. The beginning of the rise of the Eastern Cordillera is recorded in the sediments of the foreland basin of the Amazonian backarc (Huallaga Basin) 30 Ma ago, in the Rupelian. From the Rupelian to the Middle Miocene, the Eastern Cordillera continued to rise, creating a topographic relief capable of acting as an orographic barrier to atmospheric flows from the Atlantic Ocean. This continuous elevation may have led to the presence of wetter climates in western Amazonia, which could have favored the formation of laterite surfaces in central Amazonia between the Oligocene and the Lower Miocene, in relation to the intense phase of alteration that occurred between 30 and 18 Ma. Our provenance data record a new period of exhumation of the Cordillera Oriental from the Upper Miocene to the present day. This period of rejuvenation of the relief of the Eastern Cordillera is linked to a period of propagation of the Amazonian orogenic prism towards the craton. This led to a reorganization of the Amazon drainage network and is probably one of the driving forces behind the transcontinentalization of Amazonia in the Middle-Upper Miocene. Finally, the AAMESA system did not exist in "source-tosink" (S2S) terms until the late Miocene, with the transcontinental establishment of the Amazon River. The preceding period was marked by the dominance of two different systems, represented by the Eastern Amazon craton and the NE region of South America (Borborema province, São Luís craton, Gurupi belt).

COMMITTEE MEMBERS:
Externa à Instituição - DILCE DE FÁTIMA ROSSETTI - INPE
Externo ao Programa - 3342517 - ADRIANO DOMINGOS DOS REIS - nullInterno - 1178074 - GUILHERME DE OLIVEIRA GONCALVES
Externo à Instituição - JÉRÔME VIERS - UPS
Presidente - 418662 - ROBERTO VENTURA SANTOS