Salvatore Milli

Sequence Stratigraphy and Depositional Setting of the Tiber Delta: Integration of High-resolution Seismics, Well Logs, and Archeological Data

ABSTRACT Using archeological evidence, radiocarbon data, well logs, and high-resolution seismic profiles, we applied sequence-stratigraphic analysis to sediments deposited during the last glacio-eustatic cycle on the Tyrrhenian continental margin embracing the Tiber River months. These sediments form a high-frequency sequence of fifth order that has developed over the last 20,000 yr since the last lowstand, hereafter referred to as the Tiber Depositional Sequence (TDS). The TDS is still evolving and lies on a Type 1 sequence boundary that has been identified both on the shelf and below the present delta plain. This sequence consists of lowstand, transgressive, and highstand systems tracts. The lowstand deposits are not present on the shelf but are found on the continental slope, where they constitute the last progradation set of the continental margin. A network of gullies, active when the river mouth was at the shelf break, is present within the lowstand deposits. The transgressive-systems-tract (TST) deposits lie directly on the basal unconformity. Landwards the TST is represented by a retrogradational parasequence set of fluvial, coastal barrier-lagoon, and lagoonal delta facies. Seaward, on the shelf, these parasequences merge into a seismically transparent deposit that forms a condensed section. The flooding surfaces that bound the parasequences are marked by peat layers that were dated by 14C. The radiometric ages were used to draw a carve of sea-level rise for the last 11,000 yr. The top of the transgressive systems tract (maximum flooding surface) is represented by the last peat layer, which was formed about 4700-5000 yr BP and buried 4-5 m below the present upper delta plain. The highstand systems tract is made up of deposits of the present Tiber wave-dominated delta, i.e., upper and lower delta plain, delta front, and prodelta slope. The aligned beach ridges mark the position of the prograding coastline, which for the last 2500 yr can be dated by archeological and historical data. The recent very fast progradation of the Tiber delta, during the last 500 years, is consistent with historical data on floods of the city of Rome and the suspended load of the Tiber River.

The new chronology of the Ceprano calvarium (Italy)

IntroductionThe fossil human calvarium known as Ceprano (Latium, Italy) iscommonly dated to 800e900 ka, on the basis of geological andstratigraphical inferences (Ascenzi et al., 1996, 2000). This chro-nology appeared somehow consistent with the “archaic”morphology of the calvarium and its peculiar combination offeatures, which gave rise to a controversial taxonomic identity(Ascenzietal.,1996,2000;Clarke,2000;Manzietal.,2001;Mallegniet al., 2003; Bruner and Manzi, 2005, 2007). A re-evaluation of thislate Early Pleistocene chronology has been advanced by Muttoniet al. (2009) on the basis of paleomagnetic data. This hypothesis istested here, based on the combined evaluation of the multidisci-plinary evidence collected during recent systematic excavations.The specimen was discovered on 13 March 1994 within a claylevel partly destroyed by bulldozers working for a new road ina locality known as Campogrande (Fig. 1), about 3 km SW ofCeprano and 100 km SE of Rome, in Central Italy (for review andreferences see Manzi, 2004). The sediment containing the cranialfragments yielded more than 50 fragments. However, the craniumremainedincompletebecauseneitherportionsof thefacenorteethwere retrieved.The geological history of the Campogrande area was initiallyreferred to two main stratigraphic complexes (Ascenzi et al., 1996,2000; Ascenzi and Segre, 1997a,b): 1) upper fluvio-colluvialdeposits, with variable occurrence of volcanoclastic products (lateEarly to Middle Pleistocene); 2) lower lacustrine deposits, withoutvolcanoclastic products (roughly predating 1.0 Ma). The layercontaining the human calvarium was considered to belong to thelower portion of the upper stratigraphic complex. Its chronologywas inferred as more ancient than the Acheulean site of FontanaRanuccio, near Anagni (458 5.7 ka; Segre and Ascenzi, 1984),possiblyolderthan700ka,adatecorrespondingtothebeginningofthe volcanic activity in the region (Fornaseri, 1985).Given the presence in the Ceprano basin of various LowerPaleolithic assemblages, the archaic features of the calvarium andits hypothetical chronological position were considered in associ-ation with Mode 1, or Oldowan, techno-complexes (Biddittu,1984;Ascenzietal.,1996,2000).Mode1Paleolithicintheareacomefromvarious localities, including Arce, Castro de’ Volsci, Fontana Liri(Biddittu, 1972, 1974), as well as from the Campogrande area itself(see SOM-1), whose assemblages are characterized by flint orlimestone pebble-tools (mostly choppers, chopping-tools andpercussion tools), by debitage with hammerstone flakes, and byrelatively frequent cores, with a low degree of exploitation, mostoften unifacial, and high frequencyof cortical striking platforms. Asfor Mode 2 or Acheulean assemblages, new recent data (excava-tions 2001e2006; see below) have made it possible to bettercharacterize the material from Campogrande. These materials arenot numerically rich, but they yield evidence of each production

Palaeoloxodon and Human Interaction: Depositional Setting, Chronology and Archaeology at the Middle Pleistocene Ficoncella Site (Tarquinia, Italy)

The Ficoncella site in northern Latium (Italy) represents a unique opportunity to investigate the modalities of a short occupation in an alluvial setting during the Lower Palaeolithic. The small excavation area yielded a lithic assemblage, a carcass of Palaeoloxodon antiquus, and some other faunal remains. The main objectives of the study are to better characterize the depositional context where the Palaeoloxodon and the lithic assemblage occur, and to evaluate with greater precision the occupation dynamics. A 25 m-long well was drilled just above the top of the terrace of the Ficoncella site and faunal and lithic remains were analyzed with current and innovative techniques. The archaeological site contains floodplain deposits as it is located next to a small incised valley that feeds into a larger valley of the Mignone River. A tephra layer capping the site is 40Ar/39Ar dated to 441± 8 ka. Collectively, the geochronologic, tephrochronologic and geologic data, suggest the site was occupied during MIS 13. The new results should prompt further research at Ficoncella in order to improve our understanding of the dynamics of human settlement in Europe during the Early to Middle Pleistocene.

THE MIDDLE PLEISTOCENE DEPOSITS OF THE ROMAN BASIN (LATIUM, ITALY):AN INTEGRATED APPROACH OF MAMMAL BIOCHRONOLOGY AND SEQUENCE STRATIGRAPHY

The biochronological setting proposed for the Plio-Pleistocene large mammal faunas of the Italian peninsula is based on the definition of faunal units (FUs) and mammal ages (MAs). Many evidences suggest that a multidisciplinary approach could enable us to better understand the actual meaning of a given faunal assemblage taking into account sedimentological and physical stratigraphic studies of the sedimentary successions in which local mammal faunas occur. The Pleistocene deposits of the Roman Basin can be considered a significant model to test this integrated approach. The detailed study of this sedimentary succession, in terms of facies analysis and sequence stratigraphy, sets some physical and temporal constrains to the occurrence of faunal complexes because the allocyclic control (climate and eustatic variations) on both landscape and stratigraphical evolution can affect the association type of mammal faunas. A correlation scheme between the Roman Pleistocene sequence-stratigraphic units and the mammal biochrons has been proposed; this approach constitutes a first tentative to connect the mammal fauna remains to the sedimentary processes which are responsible of their transport, stock and potential preservation in the depositional environments and to collocate this fauna in the systems tracts of the fourth-order depositional sequences recognised in the local Roman Basin Pleistocene succession.

The Laga Basin: stratigraphic and structural setting

Most of the ancient turbidite systems are known being deposited in foredeep basins at the front of active thrust belt. Differently from fluvio-deltaic systems generally lacated in the more internal portion of these basins, the turbidite systems occur at different depth in the more deeper portions of these basins (foredeep turbidite systems) or in the relatively shallower tectonically confined depressions occurring on top of the thrust belt (wedge-top turbidite systems) (see discussion in Mutti et al. 2002, 2003). Foredeep turbidite systems represent the classical sedimentation in a broad and flat basin plain, showing thick to thin parallel and continuous sandstone beds with the Bouma-type depositional division. Wedge-top turbidite systems are directly fed by fluvio-deltaic systems and more clearly record both climate changes affecting the source areas and tectonic activity of the orogenic wedge. Messinian turbidite deposits of the northern and central Apennines show many characters indicating sedimentation in confined basins, formed since the upper Tortonian in relation to the segmentation of the Langhian-lower Tortonian Marnoso- Arenacea foredeep basin (inner stage of the Marnoso-Arenacea, Ricci Lucchi, 1986). In these last years, detailed facies and physical stratigraphic analyses as a well as structural and thermal analyses, conducted on the Laga and Argilloso-Arenacea Fms (central Apennines), demonstrate as these basins were located at the hinge between foredeep and wedge-top depozones of the Messinian Apennine thrust belt (Milli and Moscatelli, 2000, 2001; Bigi et al., 2003; Moscatelli, 2003; Milli et al., 2004; Falcini et al., 2006; Stanzione et al., 2006; Casero and Bigi, 2006; Aldega et al., 2006; Critelli et al., 2007; Milli et al., 2007). Anisotropy of the subducted plate and thrust propagation rate deeply controlled the onset of complex basins at the top of the orogenic wedge (Casero and Bigi 2006; Bigi et al., 2006). The resulting topography of these basins and the concomitant climate changes exerted a strong control on turbidite sedimentation and on the stratigraphic organization of these deposits.