RICERCA ITALIANA     

Palaeoclimatic forcing on building organism communities, carbonate productivity and depositional systems of some Italian Meso-Cenozoic shelf deposits.

Università degli Studi di Ferrara

Abstract

The forecast amplitude of the present-day atmospheric change is triggering an increasing interest for a longer time perspective, that only the palaeoclimatic study can provide. Only the stratigraphy can indeed understand an extended temporal record, quite relevant for both the interpretation of the modern modifications and the understanding of the ancient geological history. This research proposal is aimed at improving the palaeoclimatic interpretation of Tertiary and Middle Triassic times, through the multidisciplinary, co-ordinated analysis of selected carbonate platform cases history from Italy. The calcareous production supporting the platforms growth is indeed so strongly related to the biological processes that these stratigraphic bodies can be thought as the end product of an ancient ecological dynamics. Due to the strong genetic linkage between climatic fluctuations, depositional, geochemical and biological processes, the research on carbonate platforms needs the interdisciplinary integration of sedimentological and palaeontological analysis, performed by the four involved research teams. The very same carbonate platform outcrops will therefore be analysed from both sedimentological and palaeontological points of view. To make a more comprehensive palaeoclimatic reconstruction, palaeobotanic information preserved within basinal successions and correlative Tertiary continental deposits and palaeosoils will also be investigated. The sedimentological and physical >>>

Principal Investigator

Alfonso BOSELLINI Università degli Studi di FERRARA

Research Objectives

The forecast amplitude of the present-day climatic change is triggering a new awareness and an increasing interest toward palaeoclimatic modification. The stratigraphy can provide a long temporal record useful both in the interpretation of the modern modifications and to the understanding of the ancient geological history. The research project hereafter proposed is aimed at reconstructing the dynamic relationships between palaeoclimatic fluctuations, carbonate production and depositional dynamics of selected carbonate platform systems form the Meso-Cainozoic of Italy. To achieve a more comprehensive view of the palaeoclimatic record, a few terrigenous and mixed terrigenous carbonate systems will be also analysed. The research is based on the interdisciplinary integration of physical stratigraphy, sedimentology, macro- and micro-palaeontology and selected geochemical analysis, to achieve a somewhat holistic approach to the palaeoenvironmental dynamic reconstruction. The sedimentological analysis will be performed both through field work and microfacies analysis, the palaeontological investigation will be mainly focused on the palaeoecological interpretation of taxa sensitive to environmental fluctuations, such as corals and terrestrial plants. To improve the lateral tracing of palaeoclimatic events, selected intervals will be analysed also from a biostratigraphic point of view (ammonoids, conodonts or planctonic foraminifera). Integrated through workshops involving the whole >>>

First Results

Coordination between the various units and definition of a common schedule;
Construction of a preliminary database based on the previous bio-cronostratigraphical knowledges;
Definition of priorities and methodologies in the approach to the areas and the sections key to study;First acquisition of paleontological data in order to define a high resolution biostratigraphic framework for paleoclimatic signals. Refinig of facies analyses and preliminary outline of depositional geometries of chosen terrigenous-carbonatic systems. First semi-quantitative models of designated areas and of preliminary carbonate productivity estimates.Reconstruction of facies associations and of fossil tanatocenosis: palaeoecological characterization of the analized systems.Organization of the stratigraphic successions analyzed in respect of existing biozonation standards and/or sharpening of existing biozonations. First isotopic curves and their use for high resolution correlations and to give estimations of the productivity and paleo-temperature. Acquisition of geochronological data in the Middle and Upper Triassic successions for temporal quantification of the duration of biozone with the consequent possibility to estimate with great precision the aggradational and progradational rates in various paleoclimatic contexts.Integration of acquired field data with synthetic stratigraphic models.
Integration between acquired data and the sequence stratigraphy framework.
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Timescale

24 months

National and international background

The scientific attention for the dynamic relationships between palaeoclimatic fluctuation, eustatic variation and carbonate production has been growing through the last 10-20 years, both because of the importance for fossil fuel research and under of the pressure of the present day climatic fluctuations, generating a strong impact on human activity and economics. Good palaeoclimatic information is provided by the integrated sedimentological analysis of carbonate platform and the palaeoecological interpretation of the associated fossil content. The calcareous precipitation supporting the carbonate platforms growth is largely associated with and supported by biological processes, such as the direct biocontrolled growth of skeletal parts or the bioinduced precipitation supported by biological macromolecule. The carbonate sediments are therefore much strongly related to the biological processes to the point that carbonates are said to be born and not made. This intimate association with biological processes makes the carbonate systems much more sensitive to palaeoclimatic fluctuations than their terrigenous counterparts. A carbonate platform can be thus considered as the end product of an ecological system dynamic, and the depositional processes can be therefore understood only within an accurate palaeobiologic and palaeoclimatic framework.

MESOZOIC PALAEOCLIMATE
The available sedimentological, palaeontological and isotopic evidence suggests that during >>>