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Exquisitely preserved fossils of a new reef-building vermetid species from shallow-marine lower Miocene (Burdigalian) deposits of the Chilcatay Formation and upper Miocene (Tortonian) sediments of the Pisco Formation of Peru are here reported and described in detail for the first time. These finds are assigned to the living genus Thylacodes and recognized as representatives of a new species, Thylacodes devriesi sp. nov. This new taxon is known by long, almost straight tube-like shells that display peculiar ornamentations in form of striated lamellae and are arranged in an organ-pipe fashion. This discovery represents an important addition to the knowledge of the systematics and distribution of Thylacodes in South America in the geological past. Paleoenvironmental and taphonomic inferences drawn by the fossil remains of this reef-forming species are herein discussed for both the Chilcatay and Pisco Formations in the broader framework of the South American fossil record of Vermetidae.

We report 130 vertebrate fossils preserved as bony elements and the co-occurring assemblage of fish teeth and spines from the lower strata of the Pisco Formation exposed along the western side of the lower Ica Valley (East Pisco Basin, Peru). Geological mapping at 1:10,000 scale reveals that all these fossils originate from the Langhian–Serravallian P0 allomember. In the study area, P0 is up to ∼40 m thick and features a sandy lower portion, reflecting shoreface deposition, that fines upwards into a package of offshore silts. Marine vertebrates only occur in the lower sandy layers and include whales, dolphins, reptiles, birds, and bony and cartilaginous fishes. The reconstructed paleoenvironment is consistent with a warm-water, marginal-marine setting with a strong connection to the open ocean. This work helps to elucidate the rich yet still poorly understood middle Miocene portions of the Pisco Formation, and highlights the need to conserve this outstanding Fossil-Lagerstätte.

Tephra layers are a unique tool for stratigraphy. Their geologically instantaneous deposition together with their dispersion on wide areas make them a powerful instrument for dating and correlating simultaneous events at different localities. In this paper, we present and discuss the application of tephra fingerprinting in the upper Miocene portion of the Pisco Formation. The Pisco Formation is an important marine vertebrate Fossil-Lagerstätte that crops out in the Ica Desert, on the Peruvian Coast. The paleontological relevance of this formation has entailed the necessity of reconstructing a chronostratigraphic framework, using 40Ar/39Ar dating and correlations on volcanic ashes. Tephra layers from the volcanic activity of the Peruvian Andes are very frequent in the Pisco Formation and many represent a primary air-fall deposition on the sea floor. Therefore, many samples from tephra layers within measured stratigraphic sections at different sites in the study area were fingerprinted with a combined approach, using petrographic and chemical analyses on phenocrysts and volcanic glasses, as well as glass shard morphology and granulometric analyses, performed on 53 selected samples, collected from different localities. Based on the results obtained, we correlate some tephra layers in two localities at several km distance, where the correlation between the measured sections was previously only hypothetical. Major element chemistry of biotite proved a valuable tool to discriminate different tephra in the upper Miocene portion of the Pisco Formation, due to the presence of peraluminous as well as metaluminous compositions. This work shows that it is possible to apply tephra fingerprinting and tephrostratigraphy in a complex situation such as that represented by the Pisco Formation, where a high number of apparently similar volcanic ash layers were deposited in a shallow marine environment. The application of this correlation method allows us to increase the chronostratigraphic detail in the studied interval of the Pisco Formation, providing an accurate framework in which fossil marine vertebrates are stratigraphically located. The obtained high-resolution chronostratigraphy will greatly clarify the evolutionary history of Cetaceans.

The Plio-Pleistocene Calvello-Anzi Basin (CAB) represents a synorogenic shallow marine to alluvial succession deposited during the late phase of the Apennine Orogenic event. While the stratigraphy and sedimentary cycles are well known, the precise role and timing of the tectonic phases affecting this area are unclear. In this paper we report the major findings from a study aimed at unraveling the signatures of the Plio-Quaternary tectonic events affecting the CAB and this portion of the Southern Apennines by using a field integrated approach characterized by facies analysis, structural surveying, and basin architecture. The CAB is located in the axial portion of the Southern Apennine chain and has a roughly E-W orientation which is at a high angle with respect the main NW-SE striking regional tectonic structures controlling the foreland-directed migration of the compression. In the study area, an approximately 1,200-meter-thick package of Zanclean (early-middle Pliocene) to Santernian (middle Pleistocene) shelf, shallow marine, and alluvial deposits accumulated during the late stages of the Apennine orogenic evolution. Within the CAB deposits we recognize two main depositional motifs which roughly correspond to previously established regional cycles that are genetically linked to two corresponding tectonic phases of the Southern Apennine chain. Our results reveal how these two main tectonic phases played a primary role in controlling the depositional architecture, facies, depocenter distribution, and the basin shape throughout the CAB's lifespan. In the proposed model, during the first depositional stage (Zanclean), the CAB formed as a wedge-top basin, controlled by the subsurface propagation of NW-SE-trending thrusts related to the main NE-SW directed shortening of the Apennines. This stage is recorded in the basal units of the CAB infill by progressive unconformities, the development of syn-tectonic shallow marine sedimentary wedges along a high gradient tectonically controlled depositional surface, and a marked SE migration of the main depocenter. During the second depositional stage (upper Piacenzian to Santernian), the CAB was controlled by a series of roughly E-W-trending normal faults which crosscut the preexisting compressional structural fabric. Syndepositional activity along these faults played a direct role in creating an E-W oriented tectonic depression and controlling the accommodation space for the upper portion of the CAB infill. This second stage is marked by two points of evidence. The first point is revealed by a southwestward migration of the CAB depocenter driven by ~90-degree rotation from a roughly NW-SE elongated pattern to roughly elongated W-E transverse to the Pliocene regional structural fabric. This depocenter drift also coincides with an abrupt change in depositional regime from shallow marine to continental sedimentation. The second and most important point of evidence is the presence of several basin-bounding extensional fault zones which cut the lower Pliocene basin-fill units. We relate these features to the middle upper Pleistocene transition to along-strike extension, widely reported in the Southern Apennines, which is related to the overall extensional regime that is acting on the chain also at present. Data from this study provide additional insight into the evolution of the Southern Apennine chain, the formation of the Plio-Pleistocene CAB, and the debated role of Quaternary tectonics on the basin's development during the post-collision orogenic phases. Given the proximity of the study area with several oil fields and considering that hydrocarbon traps in Southern Apennines are Plio-Quaternary in age, the constraints provided on the timing and the style of the regional deformation may improve the definitions of hydrocarbon traps in the buried Apulian platform.

Bedforms and resulting sedimentary structures of interpreted upper-flow-regime origin are fairly common in various ancient and modern depositional settings, yet outcrop examples of shallow-water strata dominated by sedimentary structures arising from such flow conditions are rarely documented. This outcrop-based study presents the first detailed analysis of mid-Pleistocene beachface-shoreface strata containing sedimentary structures interpreted to have been formed by storm-generated backwash flows during the transition in flow regime from supercritical to subcritical. Here we propose that moving down the steep beachface, backwash flows rapidly accelerated and became thinner, experienced abrupt deceleration and flow thickening passing through an erosional hydraulic jump in the trough at the toe of the beachface, and then waned to thicker and subcritical conditions just downflow of the hydraulic jump. In this frame, landward-dipping backset laminae deposited on the downflow side of the trough evolved into thinner, upper-stage plane-parallel laminae further downstream. The transition from the proximal to the distal upper shoreface records a significant increase of preserved wave ripples and burrowed intervals, in concert with a progressive decrease in thickness and grain-size of individual sets of plane-parallel laminae and increase of gravel-filled gutter casts.

International audience; wo-mica—biotite and muscovite—volcanics are particularly rare in the geological record. One of the several dozen volcanic ash layers from Central Andes volcanoes found in the upper Miocene marine succession of the Pisco Formation (Ica Desert, Peru) contains juvenile biotite and muscovite, sillimanite/andalusite, feldspars, and rhyolitic glass. 39Ar–40Ar dating on biotite and muscovite concordantly constrain an age of 7.96 Ma for this two-mica ash layer. A second tephra in the Pisco Formation has a similar biotite composition and an age between 7.45 and 6.93 Ma. The peculiar mineral assemblage and the chemical composition of biotite indicate a strongly peraluminous composition of the erupted magmas and, together with the 39Ar–40Ar ages, suggest to consider a correlation of these ash layers to the eruptions of the Miocene Macusani (Peru) or Morococala (Bolivia) volcanic complexes in the Eastern Cordillera of Central Andes. The major and trace element composition of glass supports the correlation with Macusani. A provenance from Morococala seems less likely given the large distances involved. These results provide new data on the volcanic activity of the Eastern Cordillera revealing ash that dispersed to over 500 km to the west, in the forearc marine basins. This finding highlights that the exhumed forearc East Pisco Basin is highly promising as an archive of distal ash for the reconstruction of the volcanic activity of Central Andes during the Miocene silicic flare-ups.

New age estimates obtained via Strontium Isotope (87Sr/86Sr) Stratigraphy and new paleoclimatic data are here presented for the Miocene Chilcatay and Pisco formations exposed in the East Pisco Basin, an Andean forearc basin of southern Peru, which is renowned worldwide for its exceptional content of fossil marine vertebrates. Mollusk and barnacle shells, carbonate nodules, and shark teeth were collected along three stratigraphic sections for applying Strontium Isotope Stratigraphy on both carbonates and phosphates. To avoid diagenetic biases, mollusk and barnacle shells were analyzed in detail by means of optical and scanning electron microscopy, cathodoluminescence, and inductively coupled plasma-optical emission spectrometry, whereas only the enameloid from the best-preserved shark teeth was sampled. The obtained 87Sr/86Sr ages confirm a late early Miocene (Burdigalian) age for the Chilcatay strata, and reveal middle Miocene (Langhian to Serravallian) ages for the lower Pisco unit (i.e., the P0 sequence) – a result that matches the relatively archaic aspect of its cetacean fossil assemblage. New and literature data about the fossil assemblage of the lower Pisco beds highlight the presence of several thermophilic invertebrates and vertebrates, thus suggesting a warm-water, tropical paleoenvironment for this middle Miocene sequence. Such a paleoenvironmental scenario recalls the warm conditions associated with the Chilcatay Formation, rather than the cooler setting inferred for the remainder of the Pisco Formation (i.e., the P1 and P2 sequences). This pattern likely reflects the late Miocene trend of global cooling, as well as a middle to early late Miocene strengthening of the Humboldt Current.

International audience; The Miocene Pisco Formation, broadly exposed in the Ica Desert of southern Peru, is among the most outstanding Cenozoic marine Fossil-Lagerstä tten worldwide. It is renowned for its exceptional preservation and abundance of vertebrate fossils, including a rich assemblage of whales and dolphins (Cetacea). Here, we integrate taphonomic data on 890 marine vertebrate fossils, gathered through 16 different localities. Our observations range from the taxonomic distribution, articulation, completeness, disposition and orientation of skeletons, to the presence of bite marks, associations with shark teeth and macroinvertebrates, bone and soft tissue preservation, and the formation of attendant carbonate concretions and sedimentary structures. We propose that the exceptional preservation characterising many Pisco vertebrates, as well as their exceptionally high abundance, cannot be ascribed to a single cause like high sedimentation rates (as proposed in the past), but rather to the interplay of several favourable factors including: (i) low levels of dissolved oxygen at the seafloor (with the intervention of seasonal anoxic events); (ii) the early onset of mineralisation processes like apatite dissolution/recrystallisation and carbonate mineral precipitation; (iii) rapid burial of carcasses in a soupy substrate and/or a novel mechanism involving scour-induced self-burial; and (iv) original biological richness. Collectively, our observations provide a comprehensive overview of the taphonomic processes that shaped one of South America's most important fossil deposits, and suggest a model for the formation of other marine vertebrate Fossil-Lagerstä tten.

Exceptionally preserved delicate baleen microstructures have been found in association with the skeleton of a late Miocene balaenopteroid whale in a dolomite concretion of the Pisco Formation, Peru. Microanalytical data (scanning electron microscopy, electron probe microanalysis, X-ray diffraction) on fossil baleen are provided and the results are discussed in terms of their taphonomic and paleoecological implications. Baleen fossilization modes at this site include molding of plates and tubules, and phosphatization. A rapid formation of the concretion was fundamental for fossilization. We suggest that the whale foundered in a soft sediment chemically favorable to rapid dolomite precipitation, allowing the preservation of delicate structures. Morphometric considerations on the baleen plates and bristles coupled with the reconstructed calcification of the latter permit speculation on the trophic preferences of this balaenopteroid whale: the densely spaced plates and the fine and calcified bristles provide evidence for feeding on small-sized plankton, as does the modern sei whale.

Large discordant breccia bodies (LDBBs) are important record keepers of the tectonic and gravitational evolution in platform-to-basinal settings, and have important implications for fluid-flow migration and compartmentalization of tight carbonate reservoirs. In the Gargano Promontory of southern Italy, LDBBs occur within a Cretaceous slope and basinal carbonate succession. We use field mapping and Unmanned Aerial Vehicle (UAV) -based Structure from Motion (SfM) Photogrammetry to document otherwise inaccessible cliff-side exposures of seismic-to subseismic-scale vertical discordant breccias. LDBBs are up to 50 m in width, more than 80 m in height and display internal chaotic or aligned clast fabrics. The formation which generally contains the LDBBs is characterized by beds of cherty pelagic limestone intercalated with calcarenites, calciturbidites and horizons of mass transport deposits. The mass-transport deposits can be correlated across the chaotic breccia bodies, indicating only slight or no vertical displacement across the adjacent walls. The bases of the breccia bodies are always hidden below current sea level, while the rarely exposed tops are capped by bedded intervals of the host rock formation. Timing and origin of the studied breccias were determined using several lines of evidence, such as stratigraphic provenance of clasts in breccias, mutual relationships of structural and sedimentologic features, and previous studies which establish that the age of dolomitizing cements in the LDBBs formed at different times and by different processes (fault shearing and solution collapse). This work investigates the size, shape and geometry of these breccia bodies whilst also providing cm-scale detail of the textural features in otherwise inaccessible outcrops. We suggest that breccias formed as a result of solution exploiting a pre-existing fracture network characterized by large-scale vertical strike-slip or oblique-slip faults. Initial displacement along these faults created a wide fault damage zone, where fluid migration was later focused to create a zone highly susceptible to solution and subsequent periodic sidewall collapse.

Fossil bones, together with teeth, are the most common remains of vertebrates that could manage to get preserved over geological times, providing information on the diagenetic and fossilization processes that occurred in the depositional paleoenvironment. Fossil bones from the marine vertebrate Konservat-Lagerstatte in the East Pisco Basin and Sacaco area (Peru) show a high variety of different textural and chemical features, suggestive of different processes variably contributing to the fossilization path. At the macroscopic scale, bone samples can be grouped into six different categories on the basis of the color (red to gray to white) and hardness (which relates to the mineralization degree); a variety of case studies can be found between these categories. Microscopically, the original microstructure of the bone tissue, both compact and cancellous, is well preserved in all the studied samples, with differences in cavity fillings, distribution of microcracks, and presence of Fe oxides in the diverse bone types. The bone composition and mineralogy correspond to fluorapatite. Differences in color, mineralization degree and geochemistry can be interpreted in terms of different fossilization paths, from burial at the seafloor to exposure in the present-day desert environment. The fossilization paths are strongly conditioned by the factors controlling the interplay of the mechanisms of apatite dissolution-recrystallization and dolomite precipitation (formation of carbonate concretions) as well as the fixation of iron in finely disseminated sulfides in the very early stages of fossilization.

Lepidocyclinids are one of the most common group of Cenozoic large benthic foraminifera and, thanks to their clear evolutionary patterns, they are extensively used in biostratigraphy. They originated during the Eocene in the American region and then spread eastward, reaching a worldwide distribution in the Oligocene. This paper investigates the southernmost population of lepidocyclinids ever found along the Pacific coast of South America, located in the lower part of the Paracas Formation (Los Choros Member) of the East Pisco Basin of Peru. The examined Los Choros strata are composed of mixed siliciclastic-bioclastic coarse-grained deposits. The skeletal assemblage is dominated by large benthic foraminifera and mollusks with subordinate echinoids and barnacles, suggesting a deposition in a shallow, tropical, shelf environment with a moderate nutrient supply. The large benthic foraminiferal assemblage is largely dominated by Lepidocyclina rdouvillei. This species is extremely primitive, exhibiting ancestral characters such as a straight wall separating the protoconch and deuteroconch, very large principal auxiliary chambers and a poorly organized equatorial plane. The presence of common and primitive L. rdouvillei, supported by the associated occurrence of Polylepidina, suggests an age comprised between 43.6 Ma and 40.5 Ma for the Los Choros Member in the study area. This range is confirmed by nannofossil assemblages that indicate an age between 42.37 Ma and 40.34 Ma for the base of the overlying Yumaque Member of the Paracas Formation. These results highlight the potential of lepidocyclinids for biostratigraphy and paleoenvironmental reconstructions in South America.

The Miocene Gorgoglione Flysch Formation records the stratigraphic product of protracted sediment transfer and deposition through a long‐lived submarine channel system developed in a narrow and elongate thrust‐top basin of the Southern Apennines (Italy). Channel‐fill deposits are exposed in an outcrop belt approximately 500 m thick and 15 km long, oriented oblique to the palaeoflow, which was roughly south‐eastward. These exceptional exposures of channel‐fill strata allow the stacking architectures and the evolution of the channel system to be analyzed at multiple scales, enabling the effects of syn‐sedimentary thrust tectonics and basin confinement on the depositional system development to be deciphered. Two end‐member types of elementary channel architecture have been identified: high‐aspect‐ratio, weakly‐confined channels, and low‐aspect‐ratio, incisional channels. Their systematic stacking results in a complex pattern of seismic‐scale depositional architectures that determines the stratigraphic framework of the deep‐water system. From the base of the succession, two prominent channel‐complex sets have been recognized, namely CS1 and CS2, consisting of amalgamated incisional channel elements and weakly‐confined channel elements. These channelized units are overlain by isolated incisional channels, erosional into mud‐prone slope deposits. The juxtaposition of different channel architectures is interpreted to have been governed by regional thrust‐tectonics, in combination with a high subsidence rate that promoted significant aggradation. In this scenario, the alternating ‘in sequence’ and ‘out of sequence’ tectonic pulses of the basin‐bounding thrusts controlled the activation of coarse‐clastic inputs in the basin and the resulting stacking architectures of channelized units. The tectonically‐driven confinement of the depositional system limited the lateral offset in channel stacking, preventing large‐scale avulsions. This study represents an excellent opportunity to analyze the stratigraphic evolution of a submarine channel system in tectonically‐active settings from an outcrop perspective. It should find wide applicability in analogous depositional systems, whose stratigraphic architecture has been influenced by tectonically‐controlled lateral confinement and associated lateral tilting.

A newly discovered elasmobranch assemblage from the fossil-bearing area of Zamaca (Chilcatay Formation, southern Peru) is described herein, providing a first comprehensive view on the early Miocene shark and ray paleocommunities of the East Pisco Basin, whose sedimentary infill represents one of the most important Cenozoic Fossil-Lagerstatten worldwide. The studied assemblage includes at least twenty-two species attributed to twelve families and five orders. Thirteen taxa are recorded for the first time from the Chilcatay Formation, and four of them are recorded for the first time from the Pacific coast of South America. The reconstructed paleoenvironmental scenario is consistent with a shallow-marine coastal area, representative of a sheltered shelfal setting, influenced by both brackish and open-ocean waters. This paleoenvironment was inhabited by a community of small mesopredator elasmobranchs that exploited the Zamaca area as a nursery ground and recruitment area. The structure of the Zamaca assemblage is mainly explained by three key-features: 1) a taxonomic composition dominated by two shark lineages, Lamniformes and Carcharhiniformes, the former being predominant; 2) the leading role played by two species, Carcharhinus brachyurus and †Cosmopolitodus hastalis, accounting for about 60% of the analyzed specimens; 3) the distinctly juvenile imprint of the entire assemblage. Striking similarities emerge between the elasmobranch assemblage from Zamaca and the late Miocene one from Cerro Colorado (Pisco Formation, East Pisco Basin), thus suggesting the persistence of a peculiar “biological enclave” driven by the concurrence of the ecological, environmental, and oceanographic factors that characterized the coast of present-day Peru during the Neogene.

International audience; The taphonomy and palaeoecology of the early Miocene (Burdigalian) vertebrate assemblage of Ullujaya (East Pisco Basin, Peru) is here described. Vertebrate remains are concentrated in marine facies (Ct1a association) of the exposed Chilcatay Formation (dated 19-18 Ma) deposited within a 30-40 m deep, semi-enclosed, offshore environment. Coupled with ichnological observations, the size distribution of pyrite framboid relics reveals fluctuation of euxinic and oxic-dysoxic conditions at the seafloor. The assemblage is dominated by toothed cetaceans (kentriodontids, squalodelphinids, physeteroids, and the eurhinodelphinid-like Chilcacetus), together with a large dermochelyid turtle, some bony fish, and diverse elasmobranchs, mostly juveniles of Carcharhinus brachyurus and Cosmopolitodus hastalis. The vertebrate assemblage comprises a coastal community, dominated by mesopredators, representative of a warm-temperate, sheltered embayment connected with riverine and open-ocean environments. Vertebrate skeletons are typically disarticulated and incomplete, and some bone elements display shark bite marks. Microborings are observed at the bone surface. Bones exhibit a good degree of apatite mineralisation and bone cavities are locally filled by Ca-Mg carbonates. Our taphonomic observations suggest prolonged flotation of carcasses during which they were subject to biogenic and physical processes of partial destruction (including scavenging by sharks), before final deposition on a soft compact substrate. Preservation was favoured by the oxygen-deficient bottom conditions that inhibited the action of benthic macro-scavengers.

This outcrop-based study reports diffuse joints and veins, normal to strike-slip fault zones and minor folds that developed, from Miocene to Quaternary, within the clastic to siliceous sedimentary record of the forearc Pisco Basin of southern Peru. Patterns, orientations, dimensional parameters and other outcrop-scale characteristics of the various deformation features are illustrated and their genetic mechanisms and timing of development are inferred. These new structural data and interpretations allow a better constraint of the structural style and evolution of the Pisco Basin, and can represent useful guidelines for characterizing the outcrop-scale deformation affecting similar forearc basins along the Peruvian coast. Major results of this study are that the development of the documented deformation features, their patterns, dimensional parameters and kinematics seem influenced by local perturbations of the paleostress field by mechanic processes partly independent of plate tectonics forces. These processes include strain localization on both pre-existing and progressively forming new structural discontinuities, and cyclic switches of the horizontal, principal stress axes σ2 and σ3. In particular, we discuss how different normal fault patterns, from sub-parallel to multidirectional/polygonal, could form in a same deformation phase in response of the local σ2/σ3 magnitude ratio, as an evolution of stratabound, mutually orthogonal vein sets.

Field mapping and sedimentological study of outcrop sections exposed along the Ica River valley permitted the establishment of a regional allostratigraphic framework for the upper Miocene portion of the Pisco Formation. The stratigraphy of the studied interval is illustrated using a new 1:20,000-scale geological map which reveals that this formation is a cyclical sedimentary succession composed of three fining-upward allomembers. The bounding surfaces defining each allomember are transgressively modified subaerial unconformities. They converge and merge landward into a single composite surface representing the time-transgressive lower boundary of the Pisco Formation. Accordingly, the extent of the stratigraphic gap associated with the basal unconformity varies significantly throughout the basin and increases toward the basin margins. The timing of allomember-bounding surfaces coincides with that of major oxygen-isotope maxima in the deep-sea oxygen isotopic record and matches the ages of eustatic sequence boundaries identified elsewhere, indicating glacio-eustatic falls due to the growth of Antarctica ice sheets as a viable mechanism for their development.

The Upper Jurassic to Lower Cretaceous platform-slope to basinal carbonate strata cropping out in Gargano Promontory (southern Italy) are partly dolomitized. Fieldwork and laboratory analyses (petrographic, petrophysical and geochemical) allowed the characterization of the dolomite bodies with respect to their distribution within the carbonate succession, their dimensions, geometries, textural variability, chemical stability, age, porosity, genetic mechanisms and relation with tectonics. The dolomite bodies range from metres to kilometres in size, are fault-related and fracture-related, and probably formed during the Early Cretaceous at

The development of emerging digital technologies that allow the collection and analysis of field data represents a significant innovation in field-based geological studies. The integration of these digital techniques with traditional sedimentological field methods facilitates considerable improvements in outcrop characterization. An example of this integrated modern approach for geological data collection is employed for the detailed characterization of a turbidite channel-lobe system of the Gorgoglione Flysch Formation in Southern Italy. The study area, exposed above the village of Castelmezzano, has been measured and described in detailed stratigraphic sections, providing data for both sedimentological analysis and correlation of the stratigraphy. In order to gain a complete perspective on the exposure and stratigraphic elements, analysis of physical outcrop data was enhanced by the use of high-resolution Gigapixel imagery and 3D photogrammetric outcrop reconstructions. The Santa Maria section has been assessed in terms of vertical and lateral facies stacking arrangements and subdivided into two component facies associations separated by a prominent concave-up erosional boundary. The lower facies association, interpreted as a frontal lobe complex, consists of tabular, thick-bedded coarse sandstones interbedded with persistent heterolithic packages of thin-bedded sandstones and mudstones, and minor soft-sediment deformed strata. The upper facies association represents the infill of a channel-form and consists of a basal conglomerate, passing gradually upwards into massive amalgamated sandstones overlain by large-scale cross-laminated sandstones. The excellent exposure of the Santa Maria section records the complete evolution of a channel-lobe system, transitioning from frontal lobe deposition through channel incision and bypass, to progressive backfilling. This study shows how facies characterization, stratigraphic correlations and reconstruction of the depositional architectures have been substantially enhanced by the use of emerging digital techniques for geological data collection.

The life history strategies of sharks often include the use of protected nursery areas by young-of-the-year and juveniles. Nursery areas can be primary (i.e., grounds where the sharks are born and spend the very first part of their lives) or secondary (i.e., grounds inhabited by slightly older but not yet mature individuals). Criteria utilized to recognize these strategic habitats include: high concentration of young sharks, high food availability, and low predation risk. Since the fossil record of sharks consists mainly of isolated teeth, identification of paleonurseries involves a series of problems due to difficult application of actualistic criteria. A rich shark tooth-bearing level (ST-low1) has recently been discovered in the upper Miocene deposits of the Pisco Formation exposed at Cerro Colorado (southern coast of Peru). Most of the teeth collected from this level belong to the extant copper shark Carcharhinus brachyurus. These teeth are small and compatible with those of extant juveniles. This observation, coupled with other paleoenvironmental considerations, indicates that the ST-low1 horizon could have represented a nursery ground for juvenile individuals of C. brachyurus. The absence of very small-sized teeth (i.e., referable to young-of-the-year) suggests a secondary nursery ground inhabited by immature copper sharks. Observations on the tooth size of other Lamniformes, Carcharhiniformes, and Myliobatiformes occurring along with C. brachyurus point to a significantly juvenile structure of this elasmobranch assemblage, thus supporting the hypothesis of a communal use of the Cerro Colorado paleonursery.

New knowledge on patterns of fibrous gypsum veins, their genetic mechanisms, deformation style and weathering is provided by a field- and laboratory-based study carried out on the Neogene to Quaternary Pisco Basin sedimentary strata exposed in the Ica desert, southern Peru. Gypsum veins vary considerably in dimensions, attitudes and timing, and can develop in layered and moderately fractured rocks also in the absence of evaporitic layers. Veins occur both as diffuse features, confined to certain stratigraphic levels, and localized within fault zones. Arrays formed by layer-bounded, mutually orthogonal sets of steeply dipping gypsum veins are reported for the first time. Vein length, height and spacing depend on the thickness of the bed packages in which they are confined. Within fault zones, veins are partly a product of faulting but are also inherited layer-bounded features along which faults are superimposed. Owing to the different petrophysical properties with respect to the parent rocks and their susceptibility to textural and mineralogical modifications, water dissolution and rupture, gypsum veins may have a significant role in geofluid management. Depending on their patterns and grade of physical and chemical alteration, veins may influence geofluid circulation and storage, acting as barriers to flow and possibly also as conduits.

The upper Neogene Pisco Formation of Peru is known worldwide as one of the most significant Cenozoic\ud marine vertebrate Konservatt-Lagerstätten, even featuring cetacean specimens that retain remains of soft tissues or\ud stomach contents. Previous works showed that biomediated precipitation of dolomite concretions around large-sized\ud decaying carcasses was one of the most relevant processes responsible for exceptional fossil preservation. In turn, little is\ud known about the modes of fossilization of well-preserved small-sized vertebrates, which are rather common in the Pisco\ud Formation, but mostly do not exhibit dolomite concretions. We report on a cetacean specimen, identified as belonging\ud to the extinct short-snouted, small dolphin species Brachydelphis mazeasi (Pontoporiidae), preserved within a late\ud Miocene sandy deposit at the site of Pampa Corre Viento. This specimen consists of a moderately disarticulated partial\ud skeleton exhibiting well-mineralized bones; it is not enclosed within a dolomite concretion, being however delimited\ud by an evident dark boundary in the host sediment. Scanning electron microscopy and microanalytical investigations\ud identify Mn-oxides and apatite as early diagenetic minerals around the skeleton. We argue that a rapid burial of the\ud specimen was pivotal for the preservation of the bones, and allowed the early establishment of anoxic processes for\ud degradation of organic matter. Coupled with availability of P in porewater, the reducing conditions and the lowered\ud pH allowed precipitation of Ca-phosphate while increasing Mn solubility close to the pontoporiid carcass. Mn-oxides\ud precipitated at the redox boundary, the latter defining the outer edge of the volume of sediment affected by altered\ud chemical conditions due to the decaying processes. The permeability of the sediment and the small size of the carcass\ud were possible factors unfavorable to extensive sulfate reduction, thus preventing the formation of a dolomite concretion\ud and allowing bone phosphatization. This record emphasizes the role of conditions favorable to bone mineralization in\ud absence of an isolating carbonate concretion, in cases of high quality preservation of small-sized vertebrates observed\ud in the Pisco Formation. The observation of patterns in the distribution of diagenetic minerals in the sediment enclosing\ud vertebrate remains without, or with limited carbonate concretions provides insights into early taphonomic processes.

A 25 m-thick outcrop section exposed at Torre Mucchia, on the sea-cliff north of Ortona, eastern central Italy, comprises a rare Middle Pleistocene succession of shallow-water and paralic sediments along the western Adriatic Sea. An integrated study of the section, including facies and microfacies analyses, and characterization of paleobiological associations (mollusks, fishes, ostracods, foraminifers and pollen), enable a detailed reconstruction of the paleoenvironmental and paleoclimatic conditions during deposition. The shallow-water deposits include a transgressive, deepening- and fining-upward shoreface to offshore-transition facies succession overlain by a regressive shoreface-foreshore sandstone body with an erosive base and a rooted and pedogenically altered horizon at the top that imply deposition during sea-level fall. This forced regressive unit is overlain by paralic strata forming a transgressive succession comprising palustrine carbonates and back-barrier lagoonal mudstones. The palustrine carbonates exhibit some of the typical features encountered in palustrine limestones deposited within seasonal freshwater wetlands (marl prairies). Following the sea-level rising trend, the freshwater marshes were abruptly replaced by a barrier-lagoon system that allowed deposition of the overlying mud-rich unit. Within these deposits, the faunal assemblages are consistent with a low-energy brackish environment characterized by a relatively high degree of confinement. The pollen record documents the development of open forest vegetation dominated by Pinus and accompanied by a number of mesophilous and thermophilous tree taxa, whose composition supports a tentative correlation with Marine Oxygen Isotope Stage 17. The new pollen record from Torre Mucchia improves our understanding of the vegetation development in the Italian Peninsula during the Middle Pleistocene and sheds new light on the role played by the most marked glacial periods in determining the history of tree taxa.

Facies anatomy and large-scale stratigraphic organization of mid-Pleistocene strata (Qm2 Unit) exposed near the town of Ortona, eastern central Italy, have been defined through an integrated outcrop and subsurface dataset, and record sedimentation within a long-term low-accommodation setting. The studied interval can be subdivided into nine facies associations, reflecting a range of continental, marginal marine, nearshore and innermost shelf environments, and contains a well-preserved record of high-frequency relative sea-level changes in the form of a stack of three unconformity-bounded sequences. Each of the three sequences, designated Qm23, Qm22, and Qm21 from oldest to youngest, consists of a specific subset of the nine identified facies associations as a function of preserved depositional systems and systems tracts. Typically, the following architectural elements occur in ascending stratigraphic order: i) a basal unconformity, molded by fluvial incision and subaerial exposure during sea-level fall and shoreface erosion during subsequent rise; ii) a maximum regressive surface, which is coincident with the sequence boundary; iii) a transgressive systems tract including braided-river conglomerates and floodplain fines within the confines of an incised-valley, palustrine carbonates and back-barrier lagoon mudstones, and a deepening- and fining-upward shoreface to offshore-transition facies succession bounded at the base by a wave ravinement surface; iv) a sharp regressive surface of marine erosion produced by shoreface incision during relative sea-level fall; and v) a prograding, downstepping, and offlapping sharp-based lithofacies assemblage of either beach conglomerates or sandstones, ascribed to the falling stage systems tract, overlain by a rooted paleosol marking subaerial exposure. Sequences were deposited on the uplifting palaeo–Adriatic shelf in response to repeated high-frequency and high-amplitude eustatic changes in sea level that would promote the creation of accommodation space. By subtracting space to deposition, the contemporaneous regional uplift of the basin margin may be accounted for the shingled, downstepping configuration of individual sequences to form a falling stage sequence set of a larger composite sequence. In dip view, the erosional contact at the base of the Qm2 falling stage sequence set is a composite regressive surface, resulting from the downdip convergence and amalgamation of multiple erosional surfaces produced by the progressive basinward translation of successive sequences. Results from this study have direct implications for the oil and gas field development and exploration when making predictions of reservoir and seal geometries within shallow-marine, marginal-marine, and nonmarine sediments emplaced in similar long-term limited-accommodation settings.

The assessment of deformation types within the slope of a carbonate platform can be complicated by the possible interaction of rooted (tectonically-induced) and superficial (gravity-driven) structures. An ideal case study to document and distinguish tectonically- and gravity-driven structures is provided by the Cretaceous slope-to-basin carbonates exposed in the Gargano Promontory, southern Italy. These carbonates formed adjacent to the Apulian platform margin, which was oriented approximately NE–SW to NW–SE along the southern and northern edges of the promontory, respectively. Slump-related folds are characterised by axial planes typically oriented either sub-parallel or at small angles to the strike of the inferred paleoslope. In fact, the strike of folds is roughly NE–SW in the southern portion of the study area, whereas it is NW–SE in the northern part. Correspondingly, gravity-driven normal and reverse faults strike sub-parallel and at acute angles to the adjacent Apulian paleoslope. Cretaceous tectonic faults in the slope-to-basin carbonates form two principal sets striking NW–SE and WNW-ESE. The former set is made up of normal faults and the latter one includes mainly oblique-slip normal faults. Neither normal nor oblique-slip normal faults show any relationship with the geometry of the paleoslope. The results obtained from this study may help the interpretation of subsurface data in those geological contexts in which the interplay of gravitational and tectonic processes is responsible for deformation.

An up to 1500 m-thick clastic succession, the late Zanclean Baronia Synthem, has been analysed in detail in the Ariano wedge-top Basin (southern Apennine, Italy). In the Baronia Mountains the studied sediments are well exposed and laterally mappable due to young uplift and exhumation and rest unconformably on a complexly deformed pre-Pliocene substratum formed by Triassic to Miocene allochthonous units. The Baronia Synthem has been resolved into seven facies associations that are representative of distinct fluvial, deltaic, nearshore and offshore depositional environments and can be grouped into lowstand, transgressive, and highstand systems tracts. Using an integrated approach comprising original geological field mapping at 1:10,000 scale, conventional sedimentary facies analysis and a sequence stratigraphic approach, this paper provides a detailed description and interpretation of facies associations and new insights on the stratigraphic architecture and the geological history of this portion of the basin fill.

Middle Pleistocene continental sediments in central Italy ("Qc Unit") record the oldest fluvial accumulation along the uplifting margin of the Peri-Adriatic basin. The architecture of the sediment body can be divided into two unconformity-bounded, fining-upward cycles interpreted as genetically related depositional sequences. These sequences highlight the systematic adjustment of the fluvial system to changes in the ratio between accommodation space and sediment supply (A/S ratio) and from base to top, comprise the following surfaces and stratal components: (i) a regionally correlative sequence boundary resulting from an A/S ratio ≤ 0; (ii) a low-accommodation systems tract characterized by conglomerate-rich, amalgamated channel fills and recording an A/S ratio < 1; (iii) an expansion surface marking the turnaround point from low-accommodation systems tract to high-accommodation systems tract deposits; (iv) a high-accommodation systems tract dominated by floodplain fines encasing lens-like, fluvial channel deposits and denoting an A/S ratio > 1; and (v) a mature red argillic paleosol. To constrain the climatic signal for paleosols formation, the two sequence-capping mature paleosols have been investigated. The results of these studies suggest that they were developed under humid and warm climatic conditions associated with interglacial phases, which have been correlatively attributed to Marine Oxygen Isotope Stages 11 and 9.