Neotectonics of the São Pedro ridge region and surroundings

Abstract

During the project evaluation period (Regular Research Grant) "Geomorphological-Pedological Evolution of Cuesta Escarpment Foothills in the State of São Paulo" (Fapesp Process 2016/08722-3), which is tied to the present proposal, the reviewer asked for the revision of some aspects of the proposal then submitted. The main change referred to the need for the project to include also the investigation of the tectonic influence, especially Neotectonics, in the genesis of the relief of the area investigated, to the detriment of the initial proposal which contemplated only the relation of the materials (soils, deposits and rocks) with morphogenesis. Attending to this request, the investigation of the structural influence on relief was added in the project, including taking advantage of the team members experience in this kind of research and the recently establishment of an international partnership with other professional specialists in the question. As we already have today a partnership with specialists in the area, with the Laboratory of Quantitative Geodynamics and Remote Sensing of the Roma Tre University - UniRoma3 (Italia), which has resulted in a internship by one of the project´s researchers in that institution in 2016, we propose the coming of a researcher of that institution, PhD. in Structural Geology Paola Cianfarra. She will be allocated to the Pedology Laboratory of Geography Department of the FFLCH-USP, our project´s dwelling institution, for a 30 day period, between 15 November and 15 December 2017.Considering such a large experience of Prof. Paola Cianfarra and the needs of our research project, we propose the following plan of activities for the researcher´s stay with USP.1) Analysis of satellite images (e.g. ASTER, Landsat 8, Sentinel) and terrain digital models (e.g. SRTM, ASTERGDEM) to carry out a reconnaissance of the main structures (lineaments, dykes and probable faults) which cut the São Pedro region and surroundings to identify signs of neotectonic deformation, which will aid selection of the best points for field control. The lineaments will be identified automatically in the SID software, developed by Professor Francesco Salvini (UniRoma3), who is ex-adviser and partner of Prof. Cianfarra, and has been collaborating with the extant project. The data will be analyzed statistically by Daisy software, also developed by Prof. Salvini and should point to the directions of the main structures in the regional context, according to Anderson Theory principles. 2) Analysis of geophysical data gravity and aeromagnetic anomaly maps) to evaluate the possible deformations of the basin bedrock and compare the structural line and gravity anomalies with the lineaments mapped in remote sensing images. The geophysical data of the area investigated are recent (2012) and have already been asked for from the ANP - National Petroleum Agency. 3) Description, measurement and interpretation of primary structures in the field, in order to identify possible tendencies of block tilting. Moreover, data about joints and faults will be surveyed, with the aim of identifying eventual families of faults or great fracturings, which data will aid the determination of the tension fields from the kinematic indicators and/or geometry of the structures. The field survey will be done with Clar type compasses, while the structural data will be analyzed statistically in Daisy software. 4) Analysis of the seismicity of the area and comparison of stress data inferred from lineaments with the seismic-related stress. The seismicity data will be extracted from the data bank of the Brazilian Seismographic Network, already available for public access, and which includes also the historic earthquakes that occurred in the region. 5) Data integration, comparison with the most recent data and construction of a tectonic model for the area studied. (AU)