This project aims to understand how the allogenic and autogenic factors control the final sand composition within the depositional sequences starting from their petrographic and paleontological characters. This project comprises two research approaches, carried out by two research teams that will analyze the sedimentary successions of our study through facies and sequence¿stratigraphic analysis and through a quantitative and qualitative sand compositional analysis.
The sedimentary sequences that will be investigated include some of the Messinian siliciclastic deposits of the central-southern Apennines (Arenarie di Manciano, Flysch della Laga, and Flysch di Agnone) and the Upper Pleistocene- Holocene deposits of the Po and Tiber river deltaic systems. In these areas, such sedimentary successions have just a robust sequence-stratigraphic interpretation that constitutes a strong point to constrain the several new sections that will be measured, sampled and correlated to integrate stratigraphic, sedimentologic, biostratigraphic and chemostratigraphic data. Particular attention will be addressed to quantitative sand composition and microfacies analysis; this in order to determine changes in arenite composition across and within the different depositional sequences. One of the main expected results of the proposed study is to illustrate, how arenite petrofacies and microfacies can be utilized as a tool for sequence-stratigraphic interpretation of continental to marine clastic sedimentary successions.
As discussed above sand and mud composition may constitute an excellent tracer of sediment production and transport through source-to-sink systems that can be utilized to evaluate the role of the allogenic and autogenic factors in the developing of the depositional sequences. Some questions arise regarding the application of these concepts to sequence stratigraphy: 1) Can sand composition be used to better characterize the sequence stratigraphic framework of a sedimentary succession? and 2) At what physical and temporal scales of depositional sequences may sand composition provide a significant contribution to the sequence-stratigraphic interpretation? Bearing this in mind we maintain that this research project can contribute to answer to the previous questions as it addresses these issues by investigating sedimentary successions deposited in different geological and environmental contexts where the interaction between auto- and allogenic processes occurs at different spatial and temporal scales, thus allowing to evaluate the weight they have on the final composition of the depositional sequences. This appears to be particularly true for better preserved Quaternary sequences where compositional signals are clearer when analyzing stratigraphic units developed on a long temporal scale (high-rank sequences, about one million years), whereas the interpretation of compositional trends is more complex when considering stratigraphic units developed on short temporal scales (low-rank sequences, 100 ka or less) due to the major influence of the local processes, which affect the final sand and mud composition. In this light, this research project can contribute to the advancement of knowledge on this subject; at the same time, it may be very useful for applied purposes, because textural and compositional analysis has an important economic impact for the characterization of physical characteristic of petroleum reservoirs and aquifers, as well as to assess sandstones and shale capability to host and transmit fluids at the surface (water, oil, gas, and CO2).