Many ancient settings differ from Holocene shallow seas, and studies on quantitative taphonomy carried out in modern shell beds do not necessarily answer all questions that the fossil record may raise. In order to help characterize past environments, sedimentological shell beds from a Lower Pleistocene fan-delta system are analyzed. The studied sandstone intervals, cyclically alternated with a mudstone facies, were deposited in a tectonically active setting during phases of advance of fan deltas. High-density flows triggered by river floods mixed skeletal remains from different shallow-water communities. Standardized quantitative taphonomic procedures tested in modern settings are applied for the first time to fossil bivalves. The study shows that intrinsic factors did not overprint the pattern dictated by extrinsic agents. Damage levels are inversely related to sedimentation rate and directly related to the volume of high-density flows, although the influence of other agents cannot be eliminated. The most revealing taphonomic variables are fine-scale alteration, edge modification, fragmentation, and discoloration, while bioerosion and encrustation were insignificant, due to generally high rates of sedimentation. The study suggests different sources of skeletal remains. Fine-scale alteration, edge modification, and fragmentation are higher in shells from aerobic muddy sediments, and it is suggested that these remains came from erosion of older, tectonically exposed sediments of the mudstone biofacies. The majority of shells are fresh and came from nearshore sandy and muddy biofacies. These are interpreted as contemporary, or nearly so, to the depositional events. The overall results underline the importance of active tectonics in causing repeated burial/exhumation cycles and episodic burial of articulated, or otherwise pristine, skeletal remains, causing the frequent mixing of taphonomic signatures through lateral transport. This situation may be characteristic of other fan-delta systems from ancient structurally confined basins.

Sequence biostratigraphic analyses from five industry wells in the Northern Carnarvon Basin (NCB), Western Australia, are tied to seismic stratigraphic interpretations from a set of 3D and 2D seismic data. Distribution patterns of ∼286 benthic and 73 planktonic foraminiferal taxa in sidewall cores and ditch cuttings from Eocene to Pliocene intervals are documented and supplemented with observations of other fossil groups (e.g., fragments of ostracodes, bryozoans, corals, and mollusks) and lithological components such as calcite cement and quartz sand.

Preservation of foraminiferal assemblages is extremely variable in latest Eocene to Pliocene stratigraphy, depending upon the location of wells and the interval investigated. Nonetheless, consistent, detectable faunal signals correlate between wells and with prominent seismic horizons and sequences. The late Oligocene to middle Miocene is characterized by deeper-water benthic assemblages dominated by infaunal taxa and a high planktonic abundance. Stratigraphic events in the middle Miocene, including turnover in benthic foraminifera, are interpreted to record a regional flooding event (equivalent to cycle Tejas B (TB) 2.3) at the beginning of the mid-Miocene climatic optimum (∼16–14.5 Ma). Following this event, seismically defined geomorphic features include karstification on the shelf and incision on the clinoform front.

All wells show a major transition to shallow-water, warm conditions on the shelf in the middle and late Miocene, with benthic assemblages dominated by larger foraminifera. This transition appears higher in more-basinward wells and appears to be a result of progradation. Geomorphic features in the late middle Miocene (∼12 Ma) identified from 3D seismic analyses show an intensification of earlier gully formation, resulting in the development of submarine canyons. Detailed analyses of faunal patterns also provide evidence of higher-frequency sea-level fluctuations (0.5–3 Ma), not detected in the seismic stratigraphic patterns.

Taphonomic, paleobiological, and paleoecological analyses have been conducted on a rich bone accumulation on Poggio Rosso in the Upper Valdarno basin (Tuscany, central Italy). Fossil mammalian remains from the Upper Valdarno, including the type specimens of important European Villafranchian taxa, have been collected from the Renaissance through the present, mostly with little concern for stratigraphy. Because the specimens, elements, skeletal parts, and even entire skeletons generally were found in isolation, a great deal of information on taxonomic co-existence, population dynamics, proportions of limb segments, and other metrics, was precluded. The discovery of the latest Pliocene Poggio Rosso site, where bones are preserved in a sandy floodplain bed, has provided opportunity to rectify these omissions. The bone accumulation largely consists of limb bones (mostly articulated) and skulls, many of which are associated with mandibles. Axial skeletal elements are strongly underrepresented. Several bones were bimodally oriented. The specimens are slightly weathered, and have common bite and gnaw marks. Some coprolites also occur.

Because of its complex genesis, Poggio Rosso does not match conventional taphonomic categories. The bimodal arrangement of the elements and sedimentologic evidence indicate that an unconfined flood flow contributed to the assemblage's final arrangement. The role of carnivores, however, was far more substantial. The occurrence of skulls, limb bones, bite and gnaw marks, and coprolites and the comparative rarity of axial skeletal parts, attest to the presence and activity of carnivores—hyenas in particular, represented in the Upper Valdarno by Pachycrocuta brevirostris. Poggio Rosso thus is a sort of den with characteristics of a kill site. The proportionally high amount of carnivore remains, especially skulls, intimates that the hyaenids might have had cubs at the time. General wastage and incompletely consumed carcasses indicate surplus killing as well as actively transported prey elements; all of which, along with specific paleobiological speculations, suggest that the bone accumulation was formed by a cooperative group of hyenas preying on debilitated game populations in a moment of great environmental stress (possibly a period of drought). Sedimentological and palynological analyses confirm arid environmental conditions and reveal that the bones accumulated over a short time. Moreover, these same data indicate that the changes in the floodplain occurred during a major climatic fluctuation, with an increasingly arid phase that ended close to the fossil-bearing layer, which was then followed by wetter conditions.

Historically, sandy paleochannel deposits of the 2,000 m- thick Ferris (Maastrichtian–Danian: 66–62 Ma) and overlying 3,000 m-thick Hanna Formation (Danian–Thanetian: 62–55 Ma) in southern Wyoming's Hanna and Carbon basins have been interpreted as fluvial channel fills. New selachian paleofaunas from both formations are concentrated in stratigraphic intervals that also exhibit an abundance of mechanical tidal indicators and low-diversity marine ichnofossil assemblages (indicating brackish-water). Their presence in these two continental formations supports the reinterpretation of some sandy paleochannel deposits and shaly intervals as brackish-water estuaries, tidally influenced distributary channels, and interdistributary bays. Cederstroemia and Cretorectolobus are reported for the first time from Maastrichtian deposits (they previously have been documented only from Campanian and older strata). A new species of dasyatid is preserved in the middle Ferris Formation (earliest Paleocene: 64 Ma) and awaits fuller description. Prior interpretations of the Hanna Basin area as being far removed from the influences of the Western Interior Sea (WIS) during the latest Cretaceous and Paleocene must now be re-evaluated. New paleogeographic reconstructions of the western shoreline of the WIS, based in part on the stratigraphic and geographic distribution of selachian teeth in the Hanna Basin area, suggest that a complete marine regression and continental draining at the end of the Cretaceous did not occur. When combined with sedimentological and ichnological data, selachian tooth assemblages are useful tools for interpreting depositional environments and for basin-scale research.

Through a detailed regional study of the Lower Triassic (Nammalian) Sinbad Limestone Member of the Moenkopi Formation in southeastern Utah, previously qualitative paleoecological observations on Early Triassic gastropods have been quantified. Paleocommunities of the Lower Triassic Sinbad Limestone Member are dominated by gastropod juveniles and small-size adult gastropods (99% of the gastropods are smaller than 1 cm) that form numerous microgastropod packstones and grainstones that were deposited subtidally. The results from this case study of the Sinbad Limestone Member reflect a global Early Triassic phenomenon of microgastropod-dominated open-shelf environments. These characteristics of the paleoecology of Early Triassic gastropod faunas are non-actualistic since, during Ecological Evolutionary Units (EEUs), larger gastropods and normal-marine communities are invariably common somewhere contemporaneous with the occurrence of microgastropod-dominated faunas. Early Triassic microgastropods behaved as repopulation-interval opportunists during the aftermath of the end-Permian mass extinction, proliferating into vacated ecospace after most groups became extinct or dropped to very low numbers as a result of the end- Permian mass extinction. Small-sized adults and numerous juveniles are characteristics of opportunists and of groups inhabiting physiologically and/or chemically harsh environments. The characteristics of the Early Triassic microgastropod fauna indicate prolonged environmental stresses related to the causes of the end-Paleozoic biotic crisis.

The rosetted trace fossil Dactyloidites ottoi (Geinitz) commonly has been associated with shallow-water, high-energy marine environments, although detailed sedimentological analyses of the host deposits are unfortunately few. The Aptian–Albian Otoio Formation (Basque-Cantabrian Basin) provides an excellent opportunity to test the paleobathymetric and paleoenvironmental controls on the restricted distribution of D. ottoi. The Otoio Formation records a great variety of shallow-water marine environments, but D. ottoi occurs only in intervals interpreted as fluvial-dominated deltas (Gilbert-type and mouth bar-type deltas). Moreover, detailed facies analysis and geometric relationships of the deltaic deposits suggest the following main controls on the distribution of D. ottoi: (1) paleodepth between 0 and 3 m, quantified from the foreset heights of Gilbert-type deltas; (2) siliciclastic and organic matter-rich sandy substrate; (3) high and discontinuous sedimentation rates; and (4) reduced salinity, responsible for the small size of the trace from the Otoio Formation. These observations are in agreement with published data from other localities.

Bioerosion was a common process affecting corals and stromatoporoids in reef and off-reef facies on the carbonate ramp that spanned the Ordovician–Silurian boundary on Anticosti Island. The probable worm boring Trypanites was the dominant macroboring, penetrating more than 40% of 2,500 massive tabulate corals and stromatoporoids examined, occasionally in dense concentrations. The frequency of macroboring was influenced by conditions at the facies level reflected by changes in grain size, water depth, storm reworking of sediments, and the nature of the skeletal mass bored. These factors regulated exposure time of the host-substrate surface to the watermass and thus influenced bioerosion. Bored specimens are most common in muddy off-reef facies, moderate in sandy off-reef facies, and less common in reefs. In off-reef facies, storm-enhanced deposition and reworking of sediments were most important in the burial of eligible host substrates. In reefs, the high competition for space by encrusting epizoans, combined with sedimentation, limited macroborers that preferred to excavate dead skeletal substrates. Skeletal density was the most important property of the host substrate in controlling boring frequency. Macroborers favored a dense host skeleton likely for its enhanced mechanical strength and adaptability for unlined borings, despite requiring greater energy for excavation. High-relief host skeletons were bored more frequently than tabular forms, since their greater capacity to shed sediment would have resulted in more prolonged exposure above the seafloor. The probable bivalve boring Petroxestes pera is rare. Temporal changes in boring frequency appear to reflect local shifts in facies and relative sea level. Mass-extinction events near the O/S boundary, which eliminated some host corals and stromatoporoids, had no apparent effect on boring frequency.