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Process of fossilisation (or of conservation)

Taphonomic process always occur from T0 to T1 (which corresponds to the entry of the Individual into the fossil register). The responsible factors are generally abiotic (including the sediment), which are external to individuals, populations and biocenoses and delimit their extension and ecological evolution. Biotic factors, such as predation, bioturbation, organic degradation, etc., can occur independently or in synergy (positive or negative) with abiotic factors.
There are alteration processes, due to biotic and abiotic factors, and conservation or fossilisation processes due mainly to abiotic factors. Both types of taphonomic processes are dynamic and non-linear, permanently from T0 to T1, governed by the changes and evolution of the biocenosis in which a dead individual undergoes taphonomy.

The actions of these processes should be analysed and interpreted from “actuodata”, the limits of which depend on the relevance to transpose to the past and the reliability of the paleoecological data obtained from the fossil layer, including the validity of species identification. There is no model, even in the Actual; each fossil layer needs an acute analysis, especially of its particularities and of its situation.

The knowledge of the death factors, or at least the occurrence of ecological conditions at that moment, should be considered as basic taphonomic data with which to perform a paleoecological analysis.

One of the aims of a paleoecological interpretation of a fossil layer is to identify the factors at T0 in order to establish the prevailing environmental conditions when the death of individuals occurred, perhaps to discriminate the time interval between the death of the different individuals. As in ecology, the paleoecological approaches have to take into account the multiplicity and the insertion of space and time scales, as well as the interactions of physical, chemical and biological features in relation to the organisation levels of the biological and ecological systems.
Within a fossil assemblage, the thickness of which is sometimes centimetrical, time and space insertions may develop over several tens of thousands of years, so that the conditions at T0 can be very different over a long period



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