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The Late Pleistocene/Holocene Tiber delta succession represents the most recent and one of the best preserved, high-frequency/low-rank depositional sequences developed along the Latium continental margin of the Italian peninsula. Several previous studies have established a robust data set from which it has been possible to describe the stratigraphic architecture of the entire Tiber depositional sequence from the landward to seaward sectors and over a distance of 60 km. The Tiber depositional sequence shows many characteristics found in other Late Pleistocene to Holocene deltaic and coastal successions of the Mediterranean area. The stratigraphic architecture of the Tiber depositional sequence is controlled mainly by glacioeustasy, although factors such as tectonic uplift, volcanism and subsidence, exert an influence at a local scale. The resulting depositional model allowed discussion of some important points such as: (1) the genesis of the Tiber mixed bedrock-alluvial valley, extending from the coastal plain to the innermost portion of the shelf, recording (i) multiple episodes of incision during relative sea-level fall, and (ii) a downstream increase of depth and width of the valley during the base-level fall and the subsequent base-level rise; (2) the different physical expression of the Tiber depositional sequence boundary from landward to seaward, and its diachronous and composite character; (3) the maximum depth reached by the Tiber early lowstand delta at the end of the sea-level fall is estimated at ca 90 m below the present sea-level and not at 120 m as suggested by previous works; (4) the backward position of the Tiber late lowstand delta relative to the deposit of early lowstand; (5) the change of the channel pattern and of the stacking pattern of fluvial deposits within the Lowstand Systems Tract, Transgressive Systems Tract and Highstand Systems Tract. All of these features indicate that the Late Pleistocene/ Holocene Tiber delta succession, even if deposited in a short period of time from a geological point of view, represents the result of the close interaction among many autogenic and allogenic factors. However, global eustatic variations and sediment supply under the control of climatic changes can be considered the main factors responsible for the stratigraphic architecture of this sedimentary succession, which has been heavily modified by human activity only in the last 3000 years. 1886

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This study documents the stratigraphic evolution of the Castagnola ponded turbidite mini-basin through analysis of a detailed base-to-top section measured in the central part of the basin. thickness population suggests that the turbidite system was no longer obstructed frontally, and could step forward onto a healed topography. In order to assess whether the documented trends of turbidite bed characteristics indicative of the 'fill to spill' transition could be recognised from wireline log data alone, synthetic logs were prepared by up-scaling the field data to resolutions typical of borehole geophysical log data. Vertical trends of average bed thickness and net/gross recognisable in the synthetic data suggest that the transition from ponded to spill-dominated situations should be resolvable in geophysical log data.

8The assessment and meaning of turbidite thickness statistics represent open research questions 9 for both applied and pure sedimentology. Yet thickness data collected in the field are often 10 incomplete and/or biased toward or against certain thickness classes due to bed geometry, erosion 11 and/or operational filed constraints, which largely undermine tackling such questions. However, in 12 situations where turbidity currents are ponded by basin topography so to deposit basin-wide 13 tabular beds and erosion is negligible, some of the variables of the 'bed thickness equation' can be 14 relaxed, making easier to investigate what the primary controls on turbidite thickness statistics are. 15This study reviews the bed thickness statistics of the non-channelized parts of the infill of four 16 tertiary basins of Central-Northern Apennines (Italy), where bed geometry and sedimentary 17 character have been previously assessed. Though very different in terms of size and, arguably, 18 character of feeder system and source area, these basins share a common evolution to their 19 turbidite fill with upward transition from an early ponded to a late unconfined setting of deposition. 20Based on comparison of thickness subsets from diverse locations and stratigraphic heights within 21 the basin fills of the case studies, this paper seeks to answering the following questions: i) how 22 data collection choices and field operational constraints (e.g. location, outcrop quality, use of 23 thickness from single vs. multiple correlative sections, length of the stratigraphic section from which 24 thicknesses were retrieved) can affect statistics of an empirical distribution of turbidite thicknesses? 25 ii) how depositional controls of confined vs. unconfined basins can modify the initial thicknesses 26 distribution of turbidites?; iii) is there in turbidite thickness statistics a 'flow confinement' signature 27 2 which can be used to distinguish between confined and unconfined depositional settings? Results 28 suggests that: i) best practices of data collection are crucial to a meaningful interpretation of 29 turbidite thickness data, especially in presence of stratigraphic and spatial trends of bed thickness; 30 ii) a systematic bias against cm-thick Tcd Bouma sequence turbidites deposited by small volume 31 low density flows exists, which can significantly modify the low-end tail of an empirical frequency 32 distribution of bed thickness; iii) thickness statistics of beds starting with a basal Ta/Tb Bouma 33 division bear a coherent relationship to the transition from ponded to unconfined depositional 34 settings, consisting in a reduction of variance and mean and, consequently, modification of the 35 initial thickness-frequency scaling relationship. This research highlights the role of flow stripping, 36 sediment by-pass and bed geometry in altering the initial thickness distribution of ponded turbidites 37 suggesting how, on the contrary, fully ponded mini-basins represents the ideal setting for further 38 research link...