A variety of host-fabric elements (HE) cut by cross-cutting elements (CE) in rocks defines flanking structures (FS) on mesoscopic and microscopic scales. There has been renewed interest in studying and classifying the FS for their morphologies, useful as shear sense indicators and geneses. Existing non-genetic morphologic parameters for the FS are reviewed, and two new classification schemes are presented. One of these is based on the nature of the CE and whether HE penetrates it. The other scheme takes account of all the potential combinations of drag/no drag and slip/no slip of the HE. Deciphering the shear sense of the rock body from FS is complicated because the angular relationship between the CE and the primary shear planes might be opposite to what is found between S- and C- ductile shear fabrics. Further, single CEs can curve and several similar FS occur in reverse forms. As with mineral fish, the shape asymmetries of microscopic CEs indicate the shear sense. Conjugate FS (with non-parallel CEs) with interfering perturbation fields around the CEs are more reliable shear-sense indicators than FS with single CE. During low but increasing bulk strains, FS may evolve from one type to another, e.g. from a- to s-type. At high strain, FS can resemble intrafolial or sheath fold. Whether the drag is normal or reverse depends fundamentally on the initial angle between the HE and the CE and the relative magnitudes of throw and vertical separation.

Fifteen sandstone samples taken from pre-Cretaceous strata of the Yangtze Block are analysed to constrain the evolution of the South China Block, especially the assembly between the Yangtze and Cathaysia blocks. The results show that the maximum depositional age of the Neoproterozoic Lengjiaxi Group adjacent to the Cathaysia Block is c. 830 Ma, differing from that of the Kunyang and Dahongshan groups (> 960 Ma) on the southwestern margin of the Yangtze Block. The detrital zircons from Palaeozoic samples from the Yangtze Block have similar age populations to those in the Cathaysia Block, and they may originate from the Cathaysia Block according to palaeogeographic, palaeocurrent and former research data. The detrital zircons of Middle–Upper Jurassic sandstones in the southwestern and central Yangtze Block yield dominant age populations at 2.0–1.7 Ga and subordinate groups of 2.6–2.4 Ga, 0.8–0.7 Ga and 0.6–0.4 Ga. The Upper Triassic strata may be derived from the southern Yangtze and North China blocks due to the collisions between the Indosina, South China and North China blocks, whereas the Jurassic sediments may be partly derived from uplift and erosion of the Jiangnan Orogen due to an intracontinental orogeny induced by Pacific subduction towards the Eurasia Plate. The detrital age spectra and provenance data for basement in the South China Block are analysed and compared with each other. The South China Block has affinity with Australia not only in the Columbia supercontinent but also in the Rodinia supercontinent. We infer the existence of an ancient orogen under the western Jiangnan Orogen, which may have occurred during the Columbia age, earlier than the Sibao orogeny. This is supported by seismic profile proof from the SinoProbe.

New magnetic and seismic datasets offer a unique opportunity to document the geometry of the Appalachian front in a poorly studied segment of the orogen. Interpretation of high-resolution magnetic data allows, for the first time, the documentation of the contact between the autochthonous St Lawrence Platform and the Appalachians and highlights the regional significance of previously poorly documented ENE faults that experienced post-Ordovician strike-slip motion. Seismic data reveal tectonic slices in the foreland domain underlying the Appalachians and show that the depth of the décollement at the base of the Appalachian tectonic wedge varies significantly. Taken together, geological, magnetic and seismic data suggest that the geometry of the Appalachian front exhibits significant variations in map and cross-section views and recorded a polyphased structural history.

This study reports on a ~ 150 m thick macrofossil-barren sequence of siliciclastic sediments from a Burdigalian age (Early Miocene) freshwater lake. The lake was located within an incipient rift system of the Most Basin in the Ohře (Eger) Graben, which was part of the European Cenozoic Rift System, and had an original area of ≈ 1000 km2. Sediments from the HK591 core that cover the entire thickness of the lake deposits and some of the adjacent stratigraphic units were analysed by X-ray fluorescence spectroscopy (a proxy for element composition) and magnetic polarity measurement. The element proxies were subjected to frequency analysis, which provided estimated sedimentation rates, and allowed for sediment dating by magnetostratigraphy and orbital tuning of the age model. Based on the resulting age model and the known biostratigraphy, the lake was present between 17.4 and 16.6 Ma, which includes the onset of the Miocene Climatic Optimum in the latest Early Miocene. The identification of orbital forcing (precession, obliquity and short eccentricity cycles) confirms the stability of the sedimentary environment of the perennial lake in an underfilled basin. The dating allowed the sediment record to be interpreted in the context of the current knowledge of the European climate during that period. The stability of the sedimentary environment confirms that precipitation was relatively stable over the period recorded by the sediments.

The red-bed deposits in northern Iraq are situated in an active foreland basin adjacent to the Zagros Orogenic Belt, bound to the north by the Iranian plate thrust over the edge of the Arabian plate. The red-bed successions are composed of alternating red and brown silty mudstones, purplish red calcareous siltstone, fine- to coarse-grained pebbly sandstone and conglomerate. The red beds in the current study can be divided into four parts showing a trend of upward coarsening with fine-grained deposits at the top. A detailed petrographic study was carried out on the sandstone units. The clastic rocks consist mainly of calcite cemented litharenite with rock fragments (volcanic, metamorphic and sedimentary), quartz and minor feldspar. The petrographic components reflect the tectonic system in the source area, laterally ranging from a mixed orogenic and magmatic arc in Mawat–Chwarta area to recycled orogenic material rich in sedimentary rock fragments in the Qandel area. The Cretaceous–Palaeogene foreland basin of northern Iraq formed to the southwest of the Zagros Suture Zone and the Sanandaj–Sirjan Zone of western Iran. During Palaeogene time deposition of the red beds was caused by renewed shortening in the thrust sheets overlying the Arabian margin with uplift of radiolarites (Qulqula Formation), resulting in an influx of radiolarian debris in addition to continuing ophiolitic detritus. Mixed sources, including metamorphic, volcanic and sedimentary terranes, were present during deposition of the upper part of the red beds.

At the southern boundary of the Rhodope Massif, NE Greece, the Kavala Shear Zone (KSZ) represents an example of the Eastern Mediterranean deep-seated extensional tectonic setting. During Miocene time, extensional deformation favoured syntectonic emplacement and subsequent exhumation of plutonic bodies. This paper deals with the strain-related changes in macroscopic, geochemical and microstructural properties of the lithotypes collected along the KSZ, comprising granitoids from the pluton, aplitic dykes and host rock gneisses. Moreover, we investigated the evolution of seismic anisotropy on a suite of granitoid mylonites as a result of progressive strain. Isotropic compressional and shear wave velocities (Vp, Vs) and densities calculated from modal proportions and single-crystal elastic properties at given pressure–temperature (P–T) conditions are compared to respective experimental data including the directional dependence (anisotropy) of wave velocities. Compared to the calculated isotropic velocities, which are similar for all of the investigated mylonites (average values: Vp ~ 5.87 km s−1, Vs ~ 3.4 km s−1, Vp/Vs = 1.73 and density = 2.65 g cm−3), the seismic measurements give evidence for marked P-wave velocity anisotropy up to 6.92% (at 400 MPa) in the most deformed rock due to marked microstructural changes with progressive strain, as highlighted by the alignment of mica, chlorite minerals and quartz ribbons. The highest P- and S-wave velocities are parallel to the foliation plane and lowest normal to the foliation plane. Importantly, Vp remains constant within the foliation with progressive strain, but decreases normal to foliation. The potential of the observed seismic anisotropy of the KSZ mylonites with respect to detectable seismic reflections is briefly discussed.

Gold-bearing mineral deposits occur over a strike distance of >300 km within the Grampian Terrane of Scotland and Ireland. This terrane consists of Neoproterozoic–Lower Ordovician rocks of the Dalradian Supergroup that were polyphase deformed and metamorphosed during the c. 470 Ma Grampian Orogeny. Sulphide-rich Au–Ag deposits occur in Scotland at Calliachar–Urlar Burn, Tombuie, Tyndrum and Cononish, and in Ireland at Curraghinalt (Omagh), Cavanacaw, Croagh Patrick, Cregganbaun and Bohaun. They are hosted by 0.1–6 m thick quartz veins and have a similar overall mineralogy, including native gold, As, Cu, Fe, Pb and Sn sulphides, with hessite, tetrahedrite and electrum present in the first six localities above. The mineralized quartz veins, which are characterized by open-space textures, crystallized at c. 3–5 km depth in the crust. All of the deposits were structurally controlled and, apart from Curraghinalt, occur within second-order Riedel R, R′ and T fractures resulting from a regional N–S-trending maximum principal stress. These deposits are of Upper Silurian to Lower Devonian (post-Scandian) age, and are inferred to have crystallized from hot, silica-rich metamorphic fluids derived from dehydration reactions at the greenschist/amphibolite-facies boundary. Curraghinalt is an older, Grampian, thrust-related deposit. Plutonic igneous rocks (mainly granitoid) contributed in part to the fluids, which were channelled into major orogen-parallel, strike-slip faults, to be injected by fault-valve pumping into the damage zones and fault breccias of newly formed Riedel fractures. Any residual fluid probably percolated to the ground surface to form Rhynie chert-type hot-springs.

New petrological and U–Pb zircon geochronological information has been obtained from intrusive plutonic rocks and migmatites from the Cap de Creus massif (Eastern Pyrenees) in order to constrain the timing of the thermal and tectonic evolution of this northeasternmost segment of Iberia during late Palaeozoic time. Zircons from a deformed syntectonic quartz diorite from the northern Cap de Creus Tudela migmatitic complex yield a mean age of 298.8±3.8 Ma. A syntectonic granodiorite from the Roses pluton in the southern area of lowest metamorphic grade of the massif has been dated at 290.8±2.9 Ma. All the analysed zircons from two samples of migmatitic rocks yield inherited ages from the Precambrian metasedimentary protolith (with two main age clusters at c. 730–542 Ma and c. 2.9–2.2 Ga). However, field structural relationships indicate that migmatization occurred synchronously with the emplacement of the quartz dioritic magmas at c. 299 Ma. Thus, the results of this study suggest that subduction-related calc-alkaline magmatic activity in the Cap de Creus was coeval and coupled with D2 dextral transpression involving NNW–SSE crustal shortening during Late Carboniferous – Early Permian time (c. 299–291 Ma). Since these age determinations are within the range of those obtained for undeformed (or slightly deformed) calc-alkaline igneous rocks from NE Iberia, it follows that the Cap de Creus massif would represent a zone of intense localization of D2 transpression and subsequent D3 ductile wrenching that extended into the Lower Permian during a transitional stage between the Variscan and Cimmerian cycles.

During Early, as proposed by the International commission on stratigraphy Pleistocene times, interacting fluvial and aeolian processes constructed wide alluvial plains over an evaporite-dominated Miocene substratum in the central Ebro Basin. An exceptional site where these deposits show faults, folds, diapirs, karst structures and unconformities has been studied in detail. Analysis of particular structures demonstrates the interaction by that time of tectonic faulting, diapirism, karstification and sedimentation in an area where deformation was traditionally linked to the presence of underlying evaporites, without proposing any precise mechanism. Multiple approaches (sedimentology, structural geology and geophysics) have been used in order to discriminate the origin of each type of structure as well as to understand the interaction between different processes. Numerous normal faults and fractures of variable size are consistent with the regional stress field. Pleistocene deposits are pierced by diapirs of Miocene evaporites and disrupted by karst structures with different geometries (tubular, funnel and vault), both partially controlled by tectonics. The example described is proposed as an analogue model that could successfully illustrate evolution patterns of basins of potential interest for petroleum geology where similar processes have actuated, resulting in complex stratigraphical architectures.

The role of travertine fissure-ridges in reconstructing tectonics and related earthquakes is a challenging issue of recent debate directed at delineating historical/prehistorical seismic records. Indeed, direct measurements on a travertine fissure-ridge immediately after a seismic event have never been previously performed. We describe the co- and post-seismic effects of a M = 3.6 earthquake on fluid flow and travertine deposition in a geothermal area of Tuscany (Italy). Direct observation allows us to demonstrate that thermal spring (re)activation is directly influenced by transient seismic waves, therefore providing a basis for reconstructing seismic events in the past.

C. R. M. Butt comments: In their recent paper, Lacinska & Styles (2013) described in detail the geological setting, mineralogy and petrology of ‘silicified serpentinite’ in the Hajar Mountains, United Arab Emirates (UAE). They note that their ‘silicified serpentinite’ is essentially the same unit as ‘birbirite’ and other informally named quartz-rich outcrops that overlie ultramafic rocks in this and other regions. Some authors have suggested such silicification to be hydrothermal in origin, but it is now generally accepted to be due to weathering. Lacinska & Styles (2013) concluded that ‘silicified serpentinite’ is a silcrete; this is correct, but it is a purely descriptive term and, without qualification, has no specific genetic implications other than being silica-cemented regolith (Butt & Zeegers, 1992; Eggleton, 2001). The materials illustrated are more correctly termed a silicified saprolite as they preserve the fabric of the protolith.

Alicja M. Lacinska and Michael T. Styles reply: We appreciate the comment by C. R. M. Butt on the publication by Lacinska & Styles (2013) on the silicified serpentinites described from the Hajar Mountains in the United Arab Emirates. This comment is based on his very extensive knowledge of laterites and regoliths from ancient shield areas around the world; the degree to which this knowledge is directly applicable to the rocks formed at the margins of a recently uplifted mountain range, as described in the original paper, is debatable.