S. Piazolo

University of Leeds · School of Earth and Environment, Institute for Tectonics and Geophysics

Fabrics, also known as textures or crystallographic preferred orientations, reveal information about the deformation history of the flow of polycrystalline materials, including glacial ice, olivine in the mantle, and feldspar and quartz in the crust. Ice fabrics can have an order‐of‐magnitude effect on the ease of flow in ice sheets. However, due t...

Electron backscatter diffraction (EBSD) analysis enables a unique perspective of the internal microstructure of foraminiferal calcite. Specifically, EBSD provides crystallographic data from within the test, highlighting the highly organised “mesocrystal” structure of crystallographically aligned domains throughout the test, formed by sequential dep...

The heavily faulted Martian terrains of Ceraunius Fossae and Tractus Fossae, south of the Alba Mons volcano, have previously only been considered as parts of larger tectonic studies of Alba Mons, and the complexity of the faulting remains consequently unclear. As these terrains are in midst of the large Tharsis’ volcanoes, the study of their surfac...

Numerous graben features transect the Tempe Terra plateau in the northeastern Tharsis Rise, Mars, making it one of the most heavily structured regions of Tharsis. The origin of the complex fault geometries, generated over three distinct stages of tectonic activity, is poorly understood. This work distinguishes between Tempe Terra structures of loca...

Grain growth can modify the microstructure of natural ice, including the grain size and crystallographic preferred orientation (CPO). To better understand grain-growth processes and kinetics, we compared microstructural data from synthetic and natural ice samples of similar starting grain sizes that were annealed at the solidus temperature (0 ∘C) f...

Here, we study the relationships of titanite-hosting microdomains, intragrain chemical variations, microstructure and fluids with the aim of deciphering the reliability of titanite U-Pb dating to constrain the age of deformation in mylonitic rocks. We investigate these relationships in a post-Variscan amphibolite-facies shear zone developed in the...

Numerous graben features transect the Tempe Terra plateau in the northeastern Tharsis Rise, making it one of the most heavily structured regions of Tharsis. The origin of the complex fault geometries, generated over three distinct stages of tectonic activity, is still poorly understood. This work distinguishes between locally-sourced and regionally...

Ulysses Fossae is a faulted region surrounded by lava flows that sits between the major volcanoes of the Tharsis Rise volcanic province on Mars. This area is unique, as it is the only exposure of extensional faulting which can be related to the Olympus Mons volcano and one of the only a few faulted areas relating to the Tharsis Montes. In order to...

In this study, we report field, microstructural and geochronological evidence for localized and dynamically evolving fluid flux associated with the syntectonic intrusion of the Caçapava do Sul Granitic Complex into the dolomitic marbles of the Passo Feio Metamorphic Complex (Dom Feliciano Belt, southern Brazil). The marbles were intruded by mafic i...

Grain growth can modify the microstructure of natural ice, including the grain size and crystallographic preferred orientation (CPO). To understand better grain-growth processes and kinetics, we compared microstructural data from synthetic and natural ice samples that were annealed at ice-solidus temperature (0ºC) to successfully long durations. Th...

Melt migration through high-strain zones in the crust fundamentally influences their rheological behaviour and is important for the transfer of fluids to upper crustal regions. The inference of former melt-present deformation, based on field observations, may be hampered if the high-strain zone experience a low time-integrated melt flux or high mel...

Melt migration through high-strain zones in the crust fundamentally influences their rheological behaviour and is important for the transfer of fluids to upper crustal regions. The inference of former melt-present deformation, based on field observations, may be hampered if the high-strain zone experience a low time-integrated melt flux or high mel...

The structurally complex region of Tempe Terra, located in the northeast of the Tharsis Rise on Mars, preserves deformation related to the growth of Tharsis and lies along the trendline formed by the Tharsis Montes volcanoes. We characterise the spatiotemporal tectonic evolution of Tempe Terra based on comprehensive structural mapping. From this ma...

Ice fabrics – the distribution of crystal orientations in a polycrystal – are key for understanding and predicting ice flow dynamics. Despite their importance, the characteristics and evolution of fabrics produced outside of the deformation regimes of pure and simple shear flow has largely been neglected, yet they are a common occurrence within ice...

Orogenic gold deposits are comprised of complex quartz vein arrays that form as a result of fluid flow along transcrustal fault zones in active orogenic belts. Mineral precipitation in these deposits occurs under variable pressure conditions, but a mechanism explaining how the pressure regimes evolve through time has not previously been proposed. H...

To study the ore mineralization at the outcrop scale we merge an advection–diffusion simulation with the geochemical software iphreeqc to model the mixing of two realistic fluids. We simulate the infiltration of a metal-rich fluid into a rock that is saturated with pore fluid. We test the feedback effects with a number of scenarios based on an outc...

Melt transfer and migration occurs through both supra- and sub-solidus rocks. Mechanisms of melt transfer include dyking, mobile hydrofracturing and diffuse porous melt flow where melt flow may or may not be channelized via instabilities or into high-strain zones of active deformation. Here, we highlight the microstructural- and outcrop-scale signa...

Antigorite serpentinite is expected to occur in parts of subduction plate boundaries, and may suppress earthquake slip, but the dominant deformation mechanisms and resultant rheology of antigorite are unclear. An exhumed plate boundary shear zone exposed near Nagasaki, Japan, contains antigorite deformed at 474°C ± 30°C. Observations indicate that...

Deformation is a near ubiquitous process that is observed within nearly all naturally forming rocks. Electron backscatter diffraction (EBSD) is a technique that enables slip-systems (a form of plastic deformation) to be inferred from intra-crystalline misorientations at a comparable scale to representative CPO analysis (≥300 crystals for the nakhli...

The Martian nakhlite meteorites, which represent multiple events that belong to a single magma source region represent a key opportunity to study the evolution of Martian petrogenesis. Here 16 of the 26 identified nakhlite specimens are studied using coupled electron backscatter diffraction (EBSD) and emplacement end-member calculations. EBSD was u...

Local variations of metamorphic record from compositionally heterogeneous rocks: Inferences on exhumation processes of (U)HP-HT rocks (Cima di Gagnone, Adula-Cima Lunga unit) Stefania Corvò1,2, Matteo Maino1,2, Antonio Langone2, Filippo Luca Schenker3, Leonardo Casini4, Sandra Piazolo5, and Silvio Seno1,3 1Department of Earth and Environmental Sc...

The Earth’s subsurface not only provides a wide range of natural resources but also contains large pore volume that can be used for storing both anthropogenic waste and energy; these resources will be critical for decarbonising our economy. For example, geothermal energy may be extracted from hot water contained or injected into deep reservoirs; CO...

Structural and metamorphic analyses from the works under discussion (Ramírez-Salazar et al., 2021; Zuo et al., 2021a) show that the Isua supracrustal rocks can be interpreted to record one single deformation and metamorphic event featuring quasi-homogeneous deformation and amphibolite facies metamorphism, followed by late static retrogression or th...

The formation of shear zones is crucial to understand the deformation of the crust and the evolution of rifted margins. However, despite their intrinsic importance, a detailed characterization of the compositional and structural patterns of shear zones is often lacking, resulting in poorly constrained models of shear initiation. In this contributio...

During grain growth in 2D systems triple junction kinetics may significantly influence not only the rate of grain growth but also the geometric evolution of the grain boundary network. In this contribution we analyse results from in-situ heating experiments coupled with electron backscatter diffraction analysis using a columnar Al foil. It is shown...

Processes that enrich rocks in oxides, such as ilmenite, are controversial. Current models include magmatic accumulation, crystallisation of veins from immiscible liquids and syntectonic differentiation. In this contribution, we investigate examples of oxide enrichment in both the oceanic and continental crust. The oceanic samples are of oxide gabb...

Pressure and temperature change simultaneously in the Earth’s crust from surface to depth. Joint pressure and temperature changes influence many different physical properties. There are many studies on samples at elevated pressure, where the influence of open cracks, fractures, voids and pores have been studied. Applying confining pressure has a di...

In this study we report field, microstructural and geochronological evidence for multistage localized and episodic fluid flux associated with the syntectonic intrusion of the Caçapava do Sul Granitic Complex into the dolomitic marbles of the Passo Feio Metamorphic Complex (Dom Feliciano Belt, southern Brazil). The marbles were intruded by mafic and...

Strain distribution across the Eoarchean Isua supracrustal belt, Earth’s oldest 10s-of-km2 supracrustal fragment, is disputed. Resolving whether strain here is concentrated in shear zones or distributed quasi-uniformly offers tests of plate tectonic and non-plate tectonic models, and thus bears on the question: is plate tectonics required to unders...

Low carbon energy infrastructure, such as wind and solar farms, are crucial for reducing greenhouse gas emissions and limiting global temperature rise to 1.5°C. During 2020, 5.2GW of offshore wind capacity went into operation worldwide, taking the total operational capacity of global offshore wind to 32.5GW from 162 offshore windfarms, and over 200...

Replacement reactions during fluid infiltration into porous media, rocks and buildings are known to have important implications for reservoir development, ore formation as well as weathering. Natural observations and experiments have shown that in such systems the shape of reaction fronts can vary significantly ranging from smooth, rough to highly...

As a petrofabric indicator, anisotropy of magnetic susceptibility (AMS) can potentially be used to infer seismic properties of rocks, and in particular seismic anisotropy. To evaluate the link between AMS and seismic anisotropy we present laboratory measurements of elastic wave velocities and anisotropy of magnetic susceptibility (AMS) for eight sa...

Studies of populations of gold particles are becoming increasingly common; however, interpretation of compositional data may not be straightforward. Natural gold is rarely homogenous. Alloy heterogeneity is present as microfabrics formed either during primary mineralization or by modification of pre-existing alloys by chemical and physical drivers...

Shear zones localise most of deformation in narrow areas and provide efficient ways to mobilize significant volumes of fluids and melts up and down the crust. Deformation may localise if a specific domain focuses higher differential stress or strain rate with respect the host rocks. This concentration is commonly associated with variations in rock...

We report compositional, microstructural and seismic properties from 24 samples collected from the Middle Allochthon (Seve Nappe) of the central Scandinavian Caledonides, and its bounding shear zones. The samples stem both from field outcrops and the continental drilling project COSC-1 and include quartzofeldspathic gneisses, hornblende gneisses, a...

The paradigm for hydrous high-strain zones that cut dry host rocks is for fluid-rock interaction to have involved aqueous fluids. However, the role of silicate melt is increasingly recognised. This contribution examines the formation of glimmerite (biotitite) bands during melt migration in the Gough Dam shear zone, a high-strain zone in central Aus...

The paradigm for hydrous high-strain zones that cut dry host rocks is for fluid-rock interaction to have involved aqueous fluids. However, the role of silicate melt is increasingly recognised. This contribution examines the formation of glimmerite (biotitite) bands during melt migration in the Gough Dam shear zone, a high-strain zone in central Aus...

Pressure and temperature system changes in the earth crust from surface to a deeper depth. These pressure and temperature changes can influence the physical properties of rocks. There are many studies on samples at elevated pressure, where the influence of open cracks, fractures, voids and pores are introduced. It is expected that applying confinin...

Titanite is a useful accessory mineral for understanding crustal processes because is considered as a powerful petrochronometer that allows to determine both age (U-Pb isotopes) and pressure-temperature (P–T) conditions (trace-element composition: Zr, rare earth elements (REE)). However, titanite has a propensity to recrystallize during metamorphis...

!!!Free download from author link valid for 50 days: https://authors.elsevier.com/c/1cy9t,Ig4NUng Replacement reactions during fluid infiltration into porous media, rocks and buildings are known to have important implications for reservoir development, ore formation as well as weathering. Natural observations and experiments have shown that in suc...

Aqueous fluids play an important tectonic role in terrain retrogression and crustal softening of deep to mid crustal rocks during metamorphism. Moreover, the role of a wide compositional spectrum of fluids is essen- tial in mineral system science as a medium of mass transfer. High strain zones, shear zones and faults are Earth’s primary crustal-sca...

Calculating anisotropy and better understanding this physical effect is one of the main challenges in geophysics, whether in the size of the field or micro scale. one of the very common methods of calculating seismic anisotropy is to take into account the bulk properties of the material, in a micro-scale, this is based on the average value of Cryst...

Ice fabrics are key for understanding and predicting ice flow dynamics. Despite its importance, the characteristics and evolution of ice fabrics beyond pure and simple shear flow has largely been neglected. However, 80 % of the flow of ice in Antarctica is outside the regimes of pure and simple shear. We use a new validated numerical model (SpecCAF...

The Volgo-Uralia segment, which constitutes one fourth of the East European Craton, is covered by sedimentary deposits. From geophysical studies and examination of thousands of drillcores, Volgo-Uralia has been recognised as a vast high-grade terrain with a complex crustal history extending from the Palaeoarchaean to the Palaeoproterozoic. Our rece...

The Ivrea Verbano Zone (IVZ, Western Alps) is an exhumed section of the pre-Alpine middle to lower continental crust made of (ultra-)mafic rocks intruded into high grade metapelites and metabasites that escaped Alpine subduction. Following the Variscan orogeny, indeed, the IVZ was affected by post-orogenic extension and subsequently, in the Triassi...

When hydrated, phosphides such as the mineral schreibersite, (Fe,Ni)3P, allow for the synthesis of important phosphorus-bearing organic compounds. Such phosphides are common accessory minerals in meteorites; consequently, meteorites are proposed to be a main source of prebiotic reactive phosphorus on early Earth. Here, we propose an alternative sou...

The record of metamorphic conditions is commonly highly heterogeneous in spatially close rocks of different composition and rheology. The well-studied Cima di Gagnone area in the Central Alps represents such an example, as relatively small, 1– to 100 s-meter scale, ultrahigh–pressure and high–temperature ultramafic lenses are enveloped within amphi...

Archean geological records are increasingly interpreted to indicate a ≤3.2 Ga initiation of plate tectonics on Earth. This hypothesis contrasts with dominant plate tectonic interpretations for the Eoarchean (ca 4.0‐3.6 Ga) Isua supracrustal belt (southwest Greenland). Alternatively, recent work shows the belt could have formed via heat‐pipe tectoni...

The toolbox is developed in the framework of COMSOL multi-physics which is a well established commercial software that is available to a wide range of researchers; it can be used to investigate the compositional and non-compositional effects of minerals on seismic response properties.

The Eoarchean Isua Supracrustal Belt (ISB) has been interpreted as one of the earliest records of subduction processes, leading to the conclusion that a plate tectonic geodynamic system was likely operating since the early Archean. However, proposed tectonic models remain difficult to evaluate as our understanding of the metamorphic and structural...

As seismic data from the lower crust becomes more readily available, it is important to link seismic properties to the ongoing processes within lower crustal evolution. This includes high temperature, pre‐ and post‐migmatization solid state deformation as well as melt‐present deformation. We selected two tonalitic migmatites with variable former me...

There remains a significant challenge to model ice crystal fabrics both accurately and efficiently within ice-sheet models. We develop the first fully constrained continuum model, validated against experiments, able to predict the evolution of a crystal fabric for any flow field or temperature. For this, we apply a mesoscopic continuum model descri...

In this policy brief, we introduce a suite of technologies which use underground assets to store heat and energy, or provide a low carbon means of energy generation. These present regional authorities with an opportunity for low carbon economic regeneration which is sympathetic to local industrial heritage.

Abstract Metamorphic differentiation, resulting in segregated mineral bands, is commonly recorded in metamorphic rocks. Despite the ubiquitous nature of compositionally layered metamorphic rocks, the processes that are responsible for metamorphic differentiation receive very little attention. Here, detailed petrography, quantitative mineral chemist...

Seismology offers valuable information about the nature of lithosphere and asthenosphere. Seismic waves are used to investigation the Earth’s crust and upper mantel and to understand their placement and depth. In this respect, outcrop samples’ thin sections provide a wealth of information about the rocks seismic properties. A numerical toolbox is p...