Daniela Rubatto

• PhD Earth Science, ETH Zurich
• Professor at University of Bern

Subducted serpentinites are important for recycling water and fluid mobile elements into the deep Earth. Here we present a texturally controlled in situ oxygen and boron isotope and trace element study of the Erro-Tobbio ultramafic rocks (Western Alps, Italy) that have experienced exhumation to the seafloor, hydration and subsequent dehydration upo...

Constraining the timescales of metamorphic processes is critical to understanding geodynamics on Earth. It is generally accepted that the rates of metamorphic reactions in regional metamorphism, where fluids are limited or transient, are several orders of magnitude slower than in laboratory experiments. This discrepancy is attributed to several rat...

Exhumation rates of high-pressure rocks are paramount in determining plate tectonic processes, which requires absolute chronology of metamorphic stages. U-Pb geochronology of zircon and other accessory minerals has proven successful in dating different metamorphic stages, thus constraining geological rates. A common strategy to link U-Pb ages to me...

Relicts of subducted oceanic lithosphere provide key information for the tectonic reconstructions of convergent margins. In the Central Alps, such relicts occur as isolated mafic–ultramafic lenses within the migmatites of the southern Adula nappe and Cima-Lunga unit. Analysis of the major-, minor-, and accessory minerals of these ophiolitic relicts...

Partial melting and melt evolution and migration play an important role in the differentiation of continental crust. These processes affect metal transport and concentration, volatile cycling, and the mechanical properties of the crust. The study of nanorocks, i.e. crystallised melt inclusions [1], has emerged in recent decades as a key approach in...

Paleogeographic reconstructions show that the Ligurian‐Piedmont Ocean (LPO) was a relatively narrow oceanic basin but the actual amount of oceanic lithosphere generated and the timing of magmatic accretion are still subjects of debate. New U–Pb dating of zircon from two pairs of FeTi‐oxide metagabbro and metaplagiogranite s.l. of the Susa and Lanzo...

The trace-element and isotope geochemistry of rutile are robust tools to determine metamorphic temperatures, age, and host-/source lithologies. The use of rutile as single grain indicator for pressure, temperature, time and composition (P–T–t–X) of the host rock, which is vital in the use of detrital rutile to trace plate-tectonic regimes throughou...

Fluid–rock interaction within the altered oceanic crust and across the slab–mantle boundary during subduction facilitates element transfer, but the dynamics of fluid transport and fluid–rock exchange during upward fluid migration are still unclear. A study of metamorphic fluid–rock interaction within a section of subducted oceanic crust was carried...

Modern-style continental subduction is the main carrier of rifted margins to mantle depths (> 90 km) where ultra-high pressure (UHP) metamorphism above coesite stability is attained[1,2]. An open question is why exhumed UHP rocks, a key feature of modern-style continental orogens, only appeared and became common late in Earth’s history. The long-st...

Did exhumation of ultrahigh-pressure (UHP) rocks proceed at comparable rates in the Neoproterozoic and in modern collisional orogens? We address this question with a multi- mineral geochronological study of UHP rocks from the Gourma fold-and-thrust belt in Mali. Integrated petrology and zircon U-Pb geochronology reveal peak metamorphic conditions o...

A well‐preserved remnant of the middle crust of the former Adriatic passive margin is exposed in the Southern Alps (Italy). The Dervio‐Olgiasca Zone is located south of the Insubric Line along the northern part of Como lake and, because of the lack of Alpine overprint, provides favourable conditions to investigate the pre‐Alpine (rift‐related) hist...

Converging lines of evidence suggest that, during the late Archean, Earth completed its transition from a stagnant-lid to a plate tectonics regime, although how and when this transition occurred is debated. The geological record indicates that some form of subduction, a key component of plate tectonics—has operated since theMesoarchean, even though...

Carbonated ultramafic rocks (i.e., ophicarbonates) form by peridotite serpentinization and carbonation at the seafloor. Their metamorphic evolution is linked to that of serpentinites, hence dating deformation and metamorphism in ophicarbonates will add constraints to the P-T-t history of the subducted ultramafic lithosphere. A potential, yet undere...

Pre‐Mesozoic basements of the Alpine belt commonly contain kilometre‐scale folds with steeply inclined axial planes and fold axes, which are named “Schlingen” folds. The structural evolution of Schlingen folds and their geodynamic significance for the Variscan evolution are unclear. To close this gap, this study investigates a well-preserved Schlin...

Knowledge of oxygen diffusion in garnet is crucial for a correct interpretation of oxygen isotope signatures in natural samples. A series of experiments was undertaken to determine the diffusivity of oxygen in garnet, which remains poorly constrained. The first suite included high-pressure (HP), nominally dry experiments performed in piston-cylinde...

Secondary Ion Mass Spectrometry (SIMS) extracts chemical, elemental, or isotopic information about a localized area of a solid target by performing mass spectrometry on secondary ions sputtered from its surface by the impact of a beam of charged particles. This primary beam sputters ionized atoms and small molecules (as well as many neutral particl...

The Oisans–Pelvoux massif belongs to the Paleozoic basement of the External western Alps and records high temperature (HT) metamorphism associated with intense migmatization during the syn to post-collisional stages of the Variscan orogeny. Metamorphic assemblages related to the early collision stages have been obliterated making it difficult to co...

The modern hydrological cycle includes precipitation of ¹⁸O-depleted meteoric water over continental crust exposed above sea-level. How far back in the geological record can continental exposure be documented remains uncertain, particularly for the Archean. To investigate the extent of Archean continental exposure, we document a newly discovered lo...

Dehydration reactions in the subducting slab liberate fluids causing major changes in rock density, volume and permeability. Although it is well known that the fluids can migrate and interact with the surrounding rocks, fluid pathways remain challenging to track and the consequences of fluid-rock interaction processes are often overlooked. In this...

Collisional orogens commonly include mono-metamorphic and poly-metamorphic units, and their different evolution can be difficult to recognise and reconcile. The Theodul Glacier Unit (TGU) in the Western Alps consists of an association of metasedimentary and metamafic rocks embedded within the Zermatt-Saas tectonic unit. In spite of recent petrologi...

The age and P‐T conditions of Variscan high pressure (HP) metamorphism in the Paleozoic basement of the western Alps remain poorly constrained, but is nevertheless crucial to build a consistent tectonic scenario for the southeastern domain of the Variscan Belt. We report here the results of a structural, petrological, thermobarometric and geochrono...

Epidote – here defined as minerals belonging to the epidote–clinozoisite solid solution – is a low-μ (μ=238U/204Pb) mineral occurring in a variety of geological environments and participating in many metamorphic reactions that is stable throughout a wide range of pressure–temperature conditions. Despite containing fair amounts of U, its use as a U-...

Above subduction zones, magma production rate and crustal generation can increase by an order of magnitude during narrow time intervals known as magmatic flare-ups. However, the consequences of these events in the deep arc environment remain poorly understood. Here we use petrological and in-situ zircon dating techniques to investigate the root of...

The Belomorian Province of the Fennoscandian Shield exposes numerous Precambrian eclogites, which makes it significant for the study of early tectonic processes. The age of these eclogites has been discussed for more than 15 years and regarded as either Archean or Paleoproterozoic. In the Kuru-Vaara quarry within the northern Belomorian Province, t...

An amendment to this paper has been published and can be accessed via the original article.

Microscale dating of distinct domains in minerals that contain relics of multiple metamorphic events is a key tool to characterize the polyphase evolution of complex metamorphic terranes. Zircon and allanite from five metasediments and five metaintrusive high-pressure (HP) rocks from the Eclogite Micaschist Complex of the Sesia Zone were dated by S...

Subduction zones represent one of the most critical settings for fluid recycling as a consequence of dehydration of the subducting lithosphere. A better understanding of fluid flows within and out of the subducting slab is fundamental to unravel the role of fluids during burial. In this study, major and trace element geochemistry combined with oxyg...

Ion probe 208Pb/232Th fissure monazite ages from the Argentera External Massif and from the high-pressure units of the Western Alps provide new insights on its Cenozoic tectonic evolution. Hydrothermal monazite crystallizes during cooling/exhumation in Alpine fissures, an environment where monazite is highly susceptible to fluid-mediated dissolutio...

Subduction zones represent one of the most critical settings for fluid recycling as a consequence of dehydration of the subducting lithosphere. A better understanding of fluid flows within and out of the subducting slab is fundamental to unravel the role of fluids during burial. In this study, major and trace element geochemistry combined with oxyg...

Monoclinic epidote is a low-µ (µ = 283U / 204Pb) mineral occurring in a variety of geological environments, participating in many metamorphic reactions and stable throughout a wide range of pressure–temperature conditions. Despite containing fair amounts of U, its use as a U–Pb geochronometer has been hindered by the commonly high contents of initi...

The structural and chemical properties of zircon inclusions in garnet megablasts from the Dora Maira Massif (Western Alps, Italy) were characterized in detail using charge contrast imaging, Raman spectroscopy, and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The aim of this work is to determine to what extent the degree...

Garnet is one of the most robust and ubiquitous minerals that record element zoning during crustal metamorphism. In addition to major elements, zoning in trace elements can provide a wealth of information to document the changing conditions of garnet growth and modification. However, mapping trace elements at low concentrations, over large areas an...

Thorium–lead (Th-Pb) crystallization ages of hydrothermal monazites from the western, central and eastern Tauern Window provide new insights into Cenozoic tectonic evolution of the Tauern metamorphic dome. Growth domain crystallization ages range from 21.7 ± 0.4 to 10.0 ± 0.2 Ma. Three major periods of monazite growth are recorded between ∼ 22–20 (...

Accurate ion microprobe analysis of oxygen isotope ratios in garnet requires appropriate reference materials to correct for instrumental mass fractionation that partly depends on the garnet chemistry (matrix effect). The matrix effect correlated with grossular, spessartine and andradite components was characterised for the Cameca IMS 1280HR at the...

Oxygen isotope geochemistry is a powerful tool for investigating rocks that interacted with fluids, to assess fluid sources and quantify the conditions of fluid–rock interaction. We present an integrated modelling approach and the computer program PTLoop that combine thermodynamic and oxygen isotope fractionation modelling for multi-rock open syste...

Elevated δ¹⁸O is used as a marker for the presence of continents and surficial alteration in the Eoarchean and Hadean. This study establishes a timeline for δ¹⁸O enrichment in Eoarchean metasedimentary rocks of the Isua supracrustal belt in Greenland. The source-rocks for the protolith of these metasedimentary rocks are mafic to intermediate magmat...

The knowledge of the fractionation behaviour between phases in isotopic equilibrium and its evolution with temperature is fundamental to assist the petrological interpretation of measured oxygen isotope compositions. We report a comprehensive and updated internally consistent database for oxygen isotope fractionation. Internal consistency is of par...

To understand the temporal sequence of geological processes such as magmatism, water‐rock interaction, and metamorphism in fossil continental rifts, a combined study of petrography, mineral geochemistry, in situ garnet O isotopes, in situ zircon U‐Pb ages and O isotopes, and pseudosection calculations was conducted for metagranites from a Neoproter...

Abstract. Thorium-Pb crystallization ages of hydrothermal monazites from the western, central and eastern Tauern Window provide new insights into Cenozoic tectonic evolution of the Tauern metamorphic dome. Growth domain crystallization ages range from 22.3 ± 0.6 Ma to 7.7 ± 0.9 Ma. Three major periods of monazite growth are recorded between ~ 22–19...

Oxygen isotope geochemistry is a powerful tool for investigating rocks that interacted with fluids, to assess fluid sources and quantify the conditions of fluid-rock interaction. We present an integrated modelling approach and the computer program PTLOOP that combine thermodynamic and oxygen isotope fractionation modelling for multi-rock open syste...

Microscale oxygen isotope analysis (¹⁸O/¹⁶O) of minerals can identify distinct events of fluid-rock interaction. This method is, however, still limited to a few major and accessory minerals of which most are anhydrous minerals. We present the systematic study of oxygen isotope distribution in white mica by Secondary Ion Mass Spectrometry (SIMS). Te...

In situ analysis of a garnet porphyroblast from a granulite facies gneiss from Sør Rondane Mountains, East Antarctica, reveals discontinuous step‐wise zoning in phosphorus and large δ¹⁸O variations from the phosphorus‐rich core to the phosphorus‐poor rim. The gradually‐decreasing profile of oxygen isotope from the core (δ¹⁸O = ~15 ‰) to the rim (δ¹...

Fissure monazite-(Ce) (hereafter called monazite) commonly crystallizes during deformation at low metamorphic grade and offers the possibility to date protracted deformation over several millions of years and to identify distinct deformation phases. We performed Th-Pb geochronology at the microscale on 10 samples of fissure monazite from two Alpine...

Heat flow studies suggest that the lower crust has low concentrations of heat-producing elements. This could be due to either (i) greater fractions of basaltic rock at depth or (ii) metamorphic depletion of radioactive elements from rocks with more evolved (andesitic to granodioritic) compositions. However, seismic data suggest that lower crust is...

Eclogites are commonly seen as markers of subduction and thus their presence in Proterozoic and Archean orogenic provinces is crucial information for determining the initiation of modern plate tectonic. The Belomorian province hosts some of the oldest known eclogite-facies rocks. Here we present new garnet Lu–Hf geochronology that constrains the pr...

In order to resolve inter- and intracrystalline oxygen isotopic heterogeneities in olivine crystals encountered in mantle peridotites, basaltic lavas, chondritic meteorites and metamorphic rocks, in situ techniques such as ion microprobes are needed. Accurate ion microprobe analysis requires not only well-characterised reference materials, but also...

Oxygen and iron isotope variations have been investigated in three compositionally distinct garnet samples to assess natural variations and search for suitable reference material. We report in situ major, trace element and O isotope analyses for mantle-derived garnet xenocrysts from Kakanui, New Zealand, as well as magmatic and hydrothermal garnets...

We present the first investigation of in situ oxygen isotopes in serpentine minerals by sensitive high‐resolution ion microprobe (SHRIMP). Chemically homogeneous samples of antigorite (δ¹⁸O = 8.30 ± 0.12‰), chrysotile (δ¹⁸O = 4.37 ± 0.02‰) and lizardite (δ¹⁸O = 5.26 ± 0.20‰) analysed by laser fluorination are identified as potential reference mater...

Reconstructing the evolution of Gneiss domes within orogenic belts poses challenges because domes can form in a variety of geodynamic settings and by multiple doming mechanisms. For the North Himalayan gneiss domes (NHGD), it is debated whether they formed during shortening, extension or collapse of the plateau, and what is the spatial and temporal...

In the Dent Blanche Tectonic System, the Mont Morion biotite-bearing granite is a km-scale intrusion preserved in a low-strain volume. Zircon saturation thermometry suggests that it crystallised from a melt that reached about 800 °C. U–Pb zircon and allanite geochronology indicates crystallization of the magma in the Permian (290 ± 3 Ma; 280 ± 8 Ma...

The identification of markers of subduction zones in orogenic belts requires the estimation of paleo-geothermal gradients through pressure-temperature-time (P-T-t) estimates in mafic rocks that potentially derive from former oceanic units once. However, such markers are rare in supracrustal sequences specially in deeply eroded and weathered Pre...

Monazite is a key accessory mineral for metamorphic geochronology, but interpretation of its complex chemical and age zoning acquired during high-temperature metamorphism and anatexis remains a challenge. We investigate the petrology, pressure–temperature and timing of metamorphism in pelitic and psammitic granulites that contain monazite from the...

Most monazite reference materials (RMs) for in situ U-Pb geochronology are rich in Th, however, many hydrothermal ore deposits contain monazite that is low in trace element contents including Th, U and Pb. Because of potential problems with matrix effects and lack of appropriate matrix-matched RMs, such variations can bias dating of hydrothermal de...

Garnet and zircon geochronology combined with trace element partitioning and petrological studies provide tight constraints on evolution of the UHT-(U)HP terrain of the Orlica-Śnieżnik Dome (OSD) in the NE Bohemian massif. Lu-Hf dating of peritectic garnet from two mesocratic granulites constrained the time of its initial growth at 346.9 ± 1.2 and...

The formation of accessory allanite, monazite and rutile in amphibolite facies rocks across the Barrovian sequence of the Central Alps (Switzerland) was investigated with a combination of petrography and geochemistry and related to the known structural and metamorphic evolution of the Lepontine dome. For each of these minerals a specific approach w...

A mineral that forms under conditions as variable as diagenesis to deep subduction, melt crystallization to low temperature alteration, and that retains information on time, temperature, trace element and isotopic signatures is bound to be a useful petrogenetic tool. The variety of conditions under which zircon forms and reacts during metamorphism...

The Main Central Thrust (MCT) is a prominent continental-scale fault within the Himalaya. Its definition has been the topic of some debate in the literature. After a brief consideration of the state of discussion to clarify the definition we use in this work, we report features from the field- to the microstructural- scale of a particularly well-ex...

One of the enduring debates in the study of the Himalayan orogen (and continental collision zones in general) is whether the salient observed features are explained (a) by localized deformation along discrete, narrow fault zones/ductile shear zones separating individual blocks or slices (e.g. critical taper or wedge tectonic models), or (b) by dist...

In Western Bhutan Himalayas leucogranite dykes emplaced in sub-­‐vertical hybrid fractures that cut across the high-­‐grade rocks of the upper Greater Himalayan Sequence just below to the South Tibetan Detachment. The granitic dykes dip to the North often showing a mylonitic deformation with a top-­‐down to-­‐the-­‐N sense of shear. The high-­‐angl...

Abundant multiphase solid inclusions (MSI) were found in garnet in an ultrahigh-pressure (UHP) paragneiss from the Kokchetav complex, Kazakhstan. The MSI are composed of mineral associations that include rock-forming and accessory minerals, which crystallized during exhumation. We present experimental and analytical protocols for how such inclusion...

Garnet is commonly encountered in a variety of rocks and tectonic settings and its chemical and isotopic zoning is regularly used to unravel the P-T-t-Xfluids evolution of the crust. However, the correct interpretation of oxygen isotopic signatures measured in natural rocks as well as the understanding of timescales and rates of fluid-rock interact...

We investigated a contractional shear zone located in central Nepal, known as Kalopani shear zone. This high-temperature shear zone triggered the early exhumation of the metamorphic core in the Himalayan belt and deeply affected the tectono-metamorphic history of the crystalline rocks soon after the collisional stage. Pseudosection modeling and inv...

We investigated a contractional shear zone located in central Nepal, known as Kalopani shear zone. This high-temperature shear zone triggered the early exhumation of the metamorphic core in the Himalayan belt and deeply affected the tectono-metamorphic history of the crystalline rocks soon after the collisional stage. Pseudosection modeling and inv...

In the Kali Gandaki valley (central Nepal), a ductile, high-temperature, contractional shear zone with a top-to-the-SW sense of shear, known as Kalopani Shear zone, is located within the uppermost part of the Greater Himalayan Sequence (GHS). We mapped and investigated this shear zone in in detail, in order to unravel its age and role in the evolut...

The lesser and greater Himalayan sequences (LH and GH) in Sikkim have been studied in detail recently. The LH consists mainly of pelitic lithologies with detrital zircon ages >1800 Ma and εNd(0) of -27.7 to -23.4 (with intercalated calcsilicates, metabasites and a sheared granite gneiss - the Lingtse gneiss). The metamorphic sequence is characteriz...

The Barchi-Kol terrain is a classic locality of ultrahigh-pressure (UHP) metamorphism within the Kokchetav metamorphic belt. We provide a detailed and systematic characterization of four metasedimentary samples using dominant mineral assemblages, mineral inclusions in zircon and monazite, garnet zonation with respect to major and trace elements, an...

The Dora-Maira whiteschists derive from metasomatically altered granites that experienced ultrahigh-pressure metamorphism at ~750 °C and 40 kbar during the Alpine orogeny. In order to investigate the P–T–time–fluid evolution of the whiteschists, we obtained U–Pb ages from zircon and monazite and combined those with trace element composition and oxy...