The Sestola Vidiciatico tectonic Unit (SVU) accommodated the early Miocene convergence between the subducting Adriatic plate and the overriding Ligurian prism, and has been interpreted as a field analogue for the shallow portion of subduction megathrusts. The SVU incorporated sediments shortly after their deposition and was active down to burial depth corresponding to temperatures around 150 °C. Here, we describe the internal architecture of the basal thrust fault of the SVU through a multi-scale structural analysis and investigate the evolution of the deformation mechanisms with increasing burial depth. At shallow depth, the thrust developed in poorly lithified sediments which deformed by particulate flow. With increasing depth and lithification of sediments, deformation was accommodated in a meter scale, heterogeneous fault zone, including multiple strands of crack-and-seal shear veins, associated with minor distributed shearing in clay-rich domains and pressure solution. In the last stage, slip localized along a sharp, 20 cm thick shear vein, deactivating the fault zone towards the footwall. The widespread formation of crack-and-seal shear veins since the first stages of lithification indicates that failure along the thrust occurred at high fluid pressure and low differential stress already at shallow depth. Progressive shear localization occurs in the last phases of deformation, at temperatures typical of the transition to the seismogenic zone in active megathrusts.

The Ediacaran–Cambrian (E-C) boundary is based on the first appearance of the ichnofossil Treptichnus pedum. Investing an ichnotaxon with such biostratigraphic pre-eminence has been the focus of criticism. Points of contention have revolved around four main issues: (1) ichnotaxonomy, (2) behavioural significance, (3) facies controls and (4) stratigraphic occurrence. First, confusion results from the fact that Treptichnus pedum was originally referred to as Phycodes pedum and, more recently, some authors have placed it in Trichophycus or Manykodes. However, the overall geometry of these burrows indicates they belong in Treptichnus. Second, regardless of its precise mode of feeding, the behaviour involved is iconic of the Cambrian explosion. Third, objections are based on the idea that trace fossils show a closer link to facies than body fossils. Notably, in contrast to common assumptions, T. pedum is not only present in the low-energy offshore of wave-dominated marine settings, but it occurs at considerably shallower water in intertidal and shallow-subtidal zones of tide-dominated systems, as well as in mouth bars of deltaic systems and lower shoreface to offshore transition zones of wave-dominated marine settings. Its broad environmental tolerance supports evolutionary innovations rather than facies controls as the main mechanism underlying the observed vertical pattern of distribution of T. pedum in most E-C successions comprising shallow-marine deposits. Fourth, although treptichnids have been documented below the E-C boundary, T. pedum is not known from Ediacaran rocks. The delayed appearance of T. pedum in E-C successions should be analysed on a case-by-case basis.

The author apologizes that the FirstView publication of this article (Selim, 2016) included a figure (Fig. 12) for which permission had not been granted by the owners, Dana Gas PJSC.

The article has been recast, replacing the original Fig. 12 with a new version.

Reassessment of key geological sections, field relationships and petrographical characteristics of the Northern Ireland ‘Clay-with-Flints’ and ‘Donald's Hill Ignimbrite Formation’ show they formed dominantly by sedimentary processes. The involvement of a previously postulated pyroclastic flow during early Paleocene time is not recognized and, as such, the Donald's Hill Ignimbrite Formation stratigraphic term is discounted. Instead a multistage model of formation by sedimentary accumulation and remobilization is presented and the term Clay-with-Flints is retained. Regionally, two dominant facies are recognized in most Clay-with-Flints sections. Facies 1 was formed by an initial accumulation of flints on a chalk landscape undergoing karstification, and involved deposition of a clay matrix derived predominantly from contemporaneous erosion of subtropical soil horizons formed mainly on basalt. In Facies 2, evidence is observed for widespread remobilization of Facies 1 deposits by high-density mudflows driven by the advancement of the Antrim Lava Group, which caused the blockage of subsurface and marginalization of surface drainage. A stratigraphical constraint imposed by the presence of a supposed ignimbrite in this part of the North Atlantic Igneous Province has been problematic, but this is resolved by its identification as a diachronous, sedimentary deposit that formed until buried by either the lower or upper formations of the Antrim Lava Group.

Late Eocene deposits of the Samlat Formation, south of Ad-Dakhla city, southwestern Morocco, have yielded a mixed marine and terrestrial vertebrate fauna. Abundant and diversified chondrichthyans and archaeocete whales have been found, as well as the remains of sirenians and proboscideans. Here we describe the rest of this fossil assemblage which includes actinopterygians, turtles, palaeophiid snakes, crocodiles and pelagornithid seabirds. Actinopterygians are represented by at least two large-sized taxa, a scombroid probably close to the extant Acanthocybium or to the Eocene Aramichthys, and a siluriform related to the Ariidae. Turtles include at least four species represented by shell fragments. This mixed coastal and continental turtle fauna includes one littoral species of Podocnemididae, one or two deep-sea species of Dermochelyidae and one deep-sea species of Cheloniidae. Another turtle species is assigned to the terrestrial Testudinidae. Fragmentary crocodilian remains indicate the presence of undetermined eusuchians tentatively referred to Gavialidae and/or to Crocodylidae. Snake vertebrae are tentatively attributed to the genus Pterosphenus (Palaeophiidae) pending the discovery of new material. Avian remains belong to a large pseudo-toothed bird (Pelagornithidae). Pseudo-tooth morphology resembles that of the late Oligocene – Neogene genus Pelagornis. Additional bird remains are needed for a more precise taxonomic assignment. The fossil assemblage and palaeoenvironment of the upper Eocene deposits of the Samlat Formation appear closely related to those of the upper Eocene – lower Oligocene deposits of the Fayum (Egypt). The initial overview of this fauna provides an important contribution to the study of vertebrate evolution in North Africa near the Eocene–Oligocene transition.

Garnetiferous pelitic to psammopelitic migmatites widespread across the central and eastern part of the Aravalli–Delhi Fold Belt in NW India record two distinct orogenies, e.g. the Aravalli Orogeny (1.7–1.6 Ga) and the Delhi Orogeny (1.0 Ga). In this study, we integrate field geological studies with textural and mineral–chemical analyses, P–T pseudosection modelling and in situ monazite dating in anatectic migmatites in the Aravalli Supergroup occurring along the Deoli–Shahpura segment. The study reveals formation of peak assemblages of garnet + sillimanite + biotite + K-feldspar + melt and garnet + muscovite + K-feldspar + melt in two anatectic migmatite samples. P–T pseudosection modelling suggests that anatexis in the gneisses occurred at ~8 kbar and 700–800°C along a tight-loop clockwise P–T path. Monazite ages from the migmatites indicate that the anatexis occurred at ~1.73–1.74 Ga. This age is similar to the Palaeoproterozoic anatexis (at 7–8 kbar) and charnockite emplacement in the Sandmata and the Mangalwar complexes, the subsolidus amphibolite-facies metamorphism in the Rajpura–Dariba and Pur–Banera supracrustal belts, and the A-type granite magmatism in the North Delhi Fold Belt. We propose that the Palaeoproterozoic migmatites in central and eastern Rajasthan are part of the one crustal unit that underwent anatexis during an accretion event along the NE–SW-trending Aravalli orogenic belt.

The link between lithosphere thinning and formation of world-class gold deposits is well established in the Jiaodong Peninsula within the eastern North China Craton (NCC). However, the timing of initiation and duration of the lithospheric thinning process as well as the depth of formation of the mineralization remain uncertain. Since these parameters are fundamental to formulate exploration strategies, in this study we perform fission track (FT) analysis on zircon and apatite grains in Late Mesozoic granitoid samples from the Jiaodong Peninsula and provide new constraints for the mode and duration of lithospheric evolution and mineralization depth. The zircon FT ages range from 64.3 to 90.9 Ma and those of apatite show a range of 32.8–50.9 Ma. The data collectively display age peaks at ~60–80 and ~30–50 Ma. Reverse modelling of the apatite FT results indicates rapid crustal uplift during ~30–80 Ma in the Jiaodong Peninsula. This period coincides with the timing of maximal sedimentation in the neighboring basins and voluminous basaltic eruptions in the eastern NCC. We suggest that the Jiaodong Peninsula has experienced two stages of crust uplift in the Late Cretaceous and Paleogene as a consequence of the continuing lithosphere thinning, together with the surrounding basins, forming the horst–graben system in the eastern NCC. The Late Mesozoic granitoids are the main wall rocks for gold deposits in Jiaodong, and thus the crust denudation history gathered from the FT data suggest that the gold mineralization formed at depths of c. 6–11 km.

This study is focused on slide blocks including oceanic lavas associated with pelagic sediments within the eastern part of the Ankara Mélange. A detailed petrological characterization of the volcanic rocks and a detailed biochronological investigation of the associated radiolarian cherts in eight sections (east of Ankara) was carried out. The volcanic rocks are largely represented by basalts and minor ferrobasalts and trachytes. They show different geochemical affinities and overlapping ages including: (a) Late Jurassic – Early Cretaceous garnet-influenced MORB (middle late Oxfordian to late Kimmeridgian–early Tithonian and early–early late Tithonian; late Valanginian–early Barremian); (b) Early Cretaceous enriched-MORB (middle late Barremian–early early Aptian; Valanginian to middle Aptian–early Albian); (c) Middle Jurassic plume-type MORB (early–middle Bajocian to late Bathonian–early Callovian); (d) Late Jurassic – Early Cretaceous alkaline basalts (middle–late Oxfordian to late Kimmeridgian–early Tithonian; late Valanginian to late Hauterivian). All rock types show a clear garnet signature, as testified to by their high MREE/HREE (middle rare earth element/heavy rare earth element) ratios. The coexistence of chemically different rock types from Middle Jurassic to Early Cretaceous times suggests that they were formed in a mid-ocean ridge setting from partial melting of a highly heterogeneous mantle characterized by the extensive occurrence of OIB-metasomatized portions, which were likely inherited from Triassic mantle plume activity associated with the continental rift and opening of the Neotethys branch.

The Drumian Wheeler Formation preserves one of the most diverse exceptionally preserved faunas of the Cambrian period. Here we describe Messorocaris magna gen. et sp. nov., a new non-biomineralizing arthropod from this formation tentatively assigned to the family Sanctacarididae. The new taxon exhibits a vaulted axial region, and wide pleural regions forming sickle-shaped lateral extensions in the trunk, a character particularly distinctive within the Sanctacarididae. This description provides an opportunity to stress the fact that the ‘Wheeler fauna’ encompasses two distinct assemblages, as confirmed by similarity analysis. These contemporaneous faunas lived at different bathymetries, and should be treated as separate entities.

Remains of a coelacanth specimen are described from Rhaetian deposits of the Var Department, southeastern France. They comprise the lower part of a branchial apparatus associated with a left lower jaw and a basisphenoid. Osteological features of the angular and basisphenoid and the teeth ornamentation allow the inclusion of the specimen in the mawsoniid family, genus and species indeterminate. Mawsoniids are known in freshwater environments from the Triassic of North America and from the Cretaceous of Western Gondwana and Europe, as well as from Late Jurassic marine environments from Europe. The new discovery here reported represents the first coelacanth from the marine Triassic of France and improves the understanding of the palaeobiogeography of the Mawsoniidae.

The Central-Southern Apennines are the result of the collision between Europe and Africa. Despite the volume of existing literature, many problems remain unsolved such as the presence of Tertiary conglomerates containing exotic basement clasts. The lack of basement rocks in the Central-Southern Apennines implies that the origin of these clasts has to be sought in areas where the basement is extensively exposed. These include the Calabro–Peloritani arc and the Sardinia–Corsica block, which in Cenozoic time were connected to the Central-Southern Apennines. In this work we present the results of sedimentary, geochemical and petrographic analyses performed on the exotic basement-derived clasts. These analyses include lithological, major- and minor-element and rare Earth element compositions which are compared to analogous rocks from Calabria and Sardinia basements. Results indicate Eastern Sardinia as the primary source area for the studied conglomeratic units, linking the Central-Southern Apennines sedimentary cover to the Mesozoic carbonates of Eastern Sardinia prior to the opening of Tyrrhenian Sea. The Cilento unit (Campania) was directly fed by an uplifting Cenozoic orogen, and the Filettino, Gavignano (Latium) and Ariano Irpino (Campania) units were produced by the successive reworking of ‘Cilento-like’ sedimentary units. These results may imply that part of the Central-Southern Apennines represented a portion of the European margin of the Tethys.