Understanding the climate-tectonic interaction in Western Amazonia (Acre Basin) during the Quaternary using luminescence techniques
Universidade de São Paulo/FAPESP, 2020-2022
Though some numerical ages are available for the Quaternary sedimentary record for the Solimões and Amazonas Basins, the Quaternary stratigraphic record and its timing in the Acre Basin is poorly known. This is critical to evaluate if landscape changes driven by tectonics and/or climate influenced species distribution in Amazonia during the Quaternary, the critical period for biotic diversification. To understand the relationship between tectonism and climate and their role for landscape changes in lowland Amazonia during the Quaternary, it is mandatory to obtain a detailed chronology of the sedimentary record and the sediment source areas that allow to correlate the studied sedimentary deposits from the Acre Basin with nearby basins and tectonic phases. With this post-doctoral proposal, we aim to use different luminescence signals to produce a detailed age model of the sedimentary record from selected locations in the Acre Basin and to obtain exhumation rates from the sediment source areas from the Andes. This will be accomplished collecting samples from outcrops and from drill cores extracted under the Trans-Amazon Drilling Project (International Continental Scientific Drilling Project, ICDP). For determination of sedimentation ages, we will use diverse luminescence dating techniques, including dating protocols recently developed, that allow to increase the age limit of the dating method to time scales of 10^5 to 10^6 years. Low temperature thermochronology analysis using luminescence signals from bedrock samples from the Andes Cordillera and from samples collected during drilling will provide exhumation and subsidence rates for the Andes Cordillera and the Acre Basin, respectively, for the Quaternary.
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Characterization of the origin of the interfluve of the Orinoco and Amazon rivers and its influence on paleoenvironments and biota diversification
Universidade Federal de São Paulo/FAPESP, 2021-2022
Despite the growing recognition that fluvial dynamics play an important role in shaping the Amazonian landscape and driving biota diversification, there is a lack of information on the timing and mechanisms controlling changes in the Amazonian fluvial system over time. This knowledge gap arises from the absence of robust dating for Late Cenozoic (Neogene and Quaternary) geological records and the lack of suitable proxies for comparing ancient and modern fluvial systems. This is particularly true for the plains and sub-Andean regions of northwestern Amazonia, encompassing the Caquetá and Guaviare rivers, which drain the interfluve of the Amazon and Orinoco basins, respectively. This research project employs an integrated approach based on geological, geochronological, and phylogeographic methods to reconstruct the paleogeographic history of northwestern Amazonia and its effects on biotic evolution during the Neogene and Quaternary. By incorporating new techniques, we aim to produce one of the most detailed records ever generated on the landscape evolution of the fluvial system draining the Amazon-Orinoco interfluve. This record will enable us to address fundamental questions about (1) the timing and mechanisms of the separation between the Amazon and Orinoco basins, (2) the response of fluvial systems to climatic and tectonic changes, and (3) how changes in floodplains impact the evolution of birds and plants at different temporal scales. An important aspect of our proposal is to deepen existing collaborations between Brazilian and Colombian researchers, who use geological and biogeographical data to test and refine landscape evolution models. The data generated will significantly improve these models, ultimately contributing to more accurate predictions of future changes in rivers and Amazonian biodiversity. It will also support scientists and decision-makers in devising intelligent and effective conservation strategies and mitigating environmental impacts.
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The potential of quartz and feldspar for luminescence dating of sediments of the Atacama Desert
Universidad Católica del Norte/CIGIDEN, 2016-2019
Numerical dating is of great importance to understand the climatic and tectonic evolution of the Atacama Desert during the Quaternary. However, due to the hyperaridity, some dating material is not available. Quartz and potassium feldspar are ubiquitous in the Atacama Desert and therefore, optical dating techniques as optically stimulated luminescence present a great opportunity. Here, we aim to describe the luminescence properties of quartz and potassium feldspar to evaluate their suitability for OSL dating. Obtaining reliable ages offer the possibility to better understand the Late Quaternary evolution of the Atacama Desert as well as to improve the knowledge about natural hazards that affect northern Chile.
Late Quaternary evolution of the tectonic uplift in northern Chile
Universidad Católica del Norte/CIGIDEN, 2014-2019
The geomorphology of the Mejillones Peninsula, northern Chile, evidences a Quaternary tectonic uplifting and normal faulting process. The upper plate faults located closer to the peninsula show undifferentiated Quaternary activity. However, there is no consensus about the uplift rate of the Mejillones Peninsula and numeric ages allowing to establish the most recent geologic history of the upper plate faults are scarce. The main aim of this project is to contribute to a better knowledge of the subduction process and upper plate deformation relationship through the quantification of the coastal uplift and the upper plate fault activity in the Mejillones Peninsula for the Late Quaternary applying luminescence dating techniques.