Quantification Quantification of Central Andes growth and erosion in relation to sedimentation in the Neuquén and Colorado basins - a Source-to-Sink- approach
This project follows a “Source to Sink” approach relating Central Andes growth with sedimentation in Neuquén and Colorado basins (Fig. 1). The working hypothesis is that tectonic mountain growth produces large volumes of eroded rocks and subsidence in the foreland basins that catches those sediments. While contractional tectonics accelerates subsidence rates of foreland basins, periods of neutral tectonics produce low to no accommodation space in the retroarc. On those cases, large portion of sediments will bypass the continent toward the offshore basins, therefore controlling overburden and petroleum generation.
To accomplish this aim, we investigate the Río Grande foreland basin, which relates to the generation of the Malargüe fold and thrust belt. The basin is located in the northern part of the Neuquén basin (Fig. 1).
We collected new data during a field campaign to build stratigraphic columns for a regional correlation and combination with available seismic data (Fig. 2). We took samples from key places for a better coverage of the area. In addition, samples from borehole have been acquired and will be analyzed to integrate the outcrop and subsurface information. Furthermore, to better constrain the Late Cenozoic tecto-sedimentary evolution of the area, we will use three different methodologies:
- First, sedimentation rates and depositional ages will be characterized by correlating outcrop samples to the interpreted seismic horizons, using U-Pb dating for minimum depositional ages.
- Second, this analysis will be complemented with petrographic studies in sandstone thin sections for a complete provenance study.
- Third, we started to work on the tectonic reconstruction of the study area using available and newly data to integrate the last deformation phase with the tectonics and sedimentation known in the area (Fig. 3).
Finally, we will determine periods of sediment bypass from the Andean foreland basin towards the Colorado offshore basin by comparing periods of sedimentation and non-deposition or erosion in the different basins from the source region of sediments in the mountains to their sink region in the Atlantic Ocean. And by doing this we look forward to elucidate the interaction between the Andean uplift, erosion, sediment transport and deposition in the Argentinian offshore.
