Micro-Analysis, Processes, Time (MAPT)

Session Titles and Conveners

Outlines of Sessions

1. Advances in the application of accessory mineral analysis to understanding crustal processes.

Conveners: Simon L Harley (Edinburgh), Jean-Marc Montel (LMTG Toulouse and CRNS Nancy), Lutz Nasdala (Vienna)

Accessory minerals such as zircon, monazite, titanite and rutile have been widely used to provide age data constraining, for example, the thermal histories of cooling igneous and metamorphic rocks. However, these minerals not only contain age information but also may, as active witnesses of processes occurring at high temperatures in the crust, preserve evidence as to the nature and timing of those processes. This session will aim to complement others in MAPT that focus on such large-scale themes as metamorphic P-T-t paths, formation and growth of crust, and exhumation, by assessing how the variety of chemical and microstructural signatures preserved in accessory minerals reflect the chemical and/or physical processes occurring the crust. Contributions will be welcomed on such issues as: accessory mineral chemical, textural and microstructural signatures of mineral-melt and mineral-fluid interactions; accessory mineral behviour during deformation and its consequences for Pb isotope chronometers; approaches to recognising the causes and consequences Pb isotopic disturbance in zircon, monazite and other accessories; zircon-rutile systems and the use / abuse of Ti-Zr thermometries; zircon-garnet and –pyroxene systems and the use / abuse of REE distribution data.

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2. Decoding polymetamorphism in mountain belts: from P-T-t-d records to geodynamic models.

 Conveners: Clare Warren, Tom Argles (Open University), Mark Caddick (ETH Zurich)

 Metamorphic records of orogenesis are complex, and studies of mountain belt evolution therefore require not only sophisticated analytical petrography, but also careful integration of data from several related disciplines: metamorphic petrology, structural geology, geochronology, and geophysics. In recent years, orogenic studies have benefitted increasingly from the formulation of ever more sophisticated models of the thermal and/or mechanical processes that shape collisional mountain belts. This session seeks to bring together researchers from all parts of the spectrum of orogenic study between field-based work, through laboratory analysis of mineral data, to theoretical modelling. We will aim to explore the essential tools for resolving the complex metamorphic signals of mountain belt rocks, how to construct and interpret increasingly detailed pressure-temperature-time-deformation (P-T-t-d) paths, and how records of polymetamorphism fit into the orogenic puzzle. We welcome contributions on topics such as: geochronological insights into orogenic processes; tracking prograde and retrograde portions of P-T paths; predictions from orogenic models; the significance of overprinting relationships; resolving polymetamorphic signals.

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3. Deep subduction and exhumation of continental and oceanic crust.

 Conveners: Simon Cuthbert (West of Scotland), Cees-Jan de Hoog (Oxford), Gaston Godard (Paris 7) & Paddy O'Brien (Potsdam)

This session explores the materials, processes and rock record of subduction systems. Our emphasis will focus on studies at the grain and intragrain scale at high and ultra-high pressures, ultimately leading to insights on the scale of entire crustal slab and the surrounding mantle. Important new insights into subduction systems are now coming from recent advances in microbeam analytical and sample preparation methods (down to the nano-scale and up to high beam energies), high-pressure experimental techniques, geochemical and phase-petrological modeling, microstructural analysis, continuing improvements in the precision and spatial resolution of isotopic analysis and geochronology, and new field data. The rewards include improved understanding of the physical properties of the crustal slab, rates of processes, thermal evolution and phase changes, strain patterns, generation and fluxes of fluids and melts, magma genesis in arcs and collision zones, seismogenic processes, mantle evolution and the genesis of ore deposits including diamond. We seek contributions on both oceanic and continental subduction systems, on crust-mantle interactions, and on processes operating during both subduction and exhumation. Sophisticated new numerical models of subduction systems are now becoming available, and the techniques explored in this session will provide important tools for testing and improving them.

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4. Mantle processes: insights from peridotite massifs, xenoliths, xenocrysts and diamonds.

Conveners: Gilles Chazot (Brest, France), Graham Pearson (Durham, UK), Thomas Stachel (Alberta, Canada).

The session covers the breadth of research on natural rocks and minerals concerning the origin and the evolution of lithospheric mantle, including cratonic keels and their diamond source regions, and peridotite massifs exposed in orogenic belts. Following the broader theme of the conference, we particularly encourage contributions utilizing or establishing advances in micro-analytical techniques and their application to mantle studies.

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5. Deep Earth Mineral Physics and Experimental Petrology I: Probing geochemical and physical processes (recent developments from nano-beam and in-situ techniques)

Conveners: Anne-Line Auzende (Paris), Chrystele Sanloup (Edinburgh), David Dobson (University College London), Falko Langenhorst (Bayreuth)

The current picture of the Earth’s deep interior is evolving as seismology, geochemistry, fluid dynamics and mineral physics converge to provide geochemical and dynamical models. Recent discoveries suggest that large mantle heterogeneities can be linked to: spin transition of iron in the oxides, chemical composition of the mantle phases, phase transitions, melt presence, or temperature variations among others. High-pressure experimentation has largely contributed to this movement, thanks to numerous investigations of “mineral physics” and experimental petrology which provide information on the chemical and physical properties of the mantle phases down to core-mantle boundary conditions. Nanotechnologies (e.g. ATEM, FIB, NanoSIMS, STXM) have seen major improvements in recent years, allowing petrological investigations and mass transport measurements on samples recovered from extreme pressures. Additionally, coupling high P-T techniques to in-situ probes (e.g. optical spectroscopy, XRF, XANES, EXAFS) provides new insights on geochemical issues such as element partitioning, kinetics or phase relationships in the inner Earth. We invite contributions on mineral physics and/or experimental petrology dealing with high-pressure phase properties (elastic, transport), element/isotope partitioning in the mantle/ core, melting processes at the CMB, phase transitions providing results that can trace geodynamic processes and reveal a new chemistry of Earth’s materials at depth. Papers from other fields (e.g. geochemistry, seismology, fluid dynamics) that bridge multiple disciplines and/or original approaches to infer the deep Earth complexity are also encouraged.

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6. Deep Earth Mineral Physics and Experimental Petrology II:  The fate of subducted material from lithosphere to core.

Conveners: Falko Langenhorst (Bayreuth), Anne-Line Auzende (Paris), Chrystele Sanloup (Edinburgh), David Dobson (University College London)

Subduction of cold oceanic crust into the Earth´s mantle at convergent plate boundaries is arguably the central process in the chemical and physical evolution of our planet. At the Earth´s surface the subduction process is manifested as volcanism and earthquakes, while in the interior it leads to mantle convection and geochemical cycling of elements. The fate and behaviour of subducted material in Earth´s interior is largely determined by the complex thermal, chemical and mechanical structure of the descending oceanic lithosphere and its strong thermal and chemical disequilibrium with the surrounding mantle. To understand the deep-seated phenomena in subduction zones it is essential to know the physical and chemical properties of the subducted material and the kinetics of reactions at high pressure and high temperature. This session will hence address issues such as phase stabilities and relations in slab-related compositions, kinetics and mechanisms of phase transformations and mineral reactions (including dehydration), as well as elastic (equation of state data), rheological (deformation mechanisms and flow laws), and transport (diffusivity, viscosity) properties of subducted materials. Both experimental and computational (atomistic and geodynamic modelling) studies to these subjects are highly welcome to be presented at the session.

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7. Pushing the limits of high-precision radioisotope geochronology: techniques, tools and applications.

Conveners: Dan Condon (British Geological Survey), Blair Schoene (Geneva), and Simon Kelley (Open University)

High-precision geochronology is revolutionizing our understanding of earth and planetary history, from the timing of condensation and accretion of protoplanetary material to the causes of mass extinctions to rates of geological processes and climate change. Our ability to measure very small amounts of radiogenic daughter products with high precision, combined with the development of microbeam techniques with high spatial resolution, has exposed new sources of geological complexity and the revelation of systematic error at the sub per mil level that hinder inter-chronometer comparisons. We seek contributions that address the ultimate resolving power of different geochronological techniques from cosmogenic isotopes to extinct nuclides, highlighting technique development to the applications driving them.

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8. LA-ICPMS isotope and trace element analyses: techniques and applications to solid Earth studies

Conveners: Craig Storey (Bristol), Matt Horstwood (NIGL) and Franck Poitrasson (LMTG Toulouse)

Laser Ablation ICP-MS is now a widely used technique for in-situ measurements of trace element concentrations and isotope ratios in the Earth Sciences. Its popularity and flexibility means that the state-of-the-art is continuously being updated. This is both from a technological (e.g. low nanosecond Excimer and femtosecond lasers and rapid scanning sector field mass spectrometers) and a methodological perspective (e.g. radiogenic isotopes (Nd, Sr, Hf) and non-traditional stable isotopes (Si, Fe, Mg)). At the same time, more mature methods, such as U-Pb geochronology and trace element analysis, are continuously being improved and the community is seeking collaborative agreement on best practice regarding measurement protocols, data handling, uncertainty propagation and data reporting. We are therefore seeking contributions for this session that report new or improved techniques and/or applications in any area of Earth Sciences.

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9. Light element isotopes: analysis and applications to mass fluxes in the Earth.

Conveners: Simone Kasemann (Edinburgh) and Tim Elliott (Bristol)

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10. Fingerprinting exhumation: advances in thermochronology and sediment provenance analysis.

Conveners: Fin Stuart (SUERC, UK) and Connie Spiegel (University of Bremen, Germany)

The application of multiple mineral thermochronometers is widely used to quantify the thermal history of orogenic belts in order to decipher the tectonic histories.  Improvements in understanding of low-temperature thermochronometry, i.e. ⁴⁰Ar/³⁹Ar, fission-track and (U-Th)/He, and the application of established thermochronometers to detrital minerals have emerged as two major developments in the field.  This session aims to bring together researchers who are interested in the application of techniques for establishing chronology and thermal history construction.  We welcome contributions where the application of thermochronology provides information about styles and rates of orogenic growth, tectonic exhumation and erosion, palaeo-relief, deformation within the source and the sink coupled system and basin burial temperatures. Particular emphasis will be given to the application of innovative techniques for establishing chronology/thermochronology, the use of multiple thermochronometers, and the determination of sediment source using the detrital mineral record.

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11. Recent advances in metamorphic and igneous petrology.

Conveners: Horst Marschall (Bristol) and Mark Jessell (LMTG)

Petrology plays a central role in the investigation of processes operating in the Earth's crust and mantle. Detailed unravelling of the structure, chemistry, texture and mineralogy of rocks has provided unparalleled insight into large-scale processes, such as oceanic and continental subduction and exhumation, continental collision, rifting and orogenesis. The petrology of intrusive and extrusive magmatic rocks provides the basis for our models on crustal differentiation and of magma-chamber processes on the way to an understanding and prediction of volcanic eruptions. On the boundary between metamorphic and magmatic processes, crustal anatexis is playing an increasingly important role in retracing and predicting geothermal gradients, the formation of granites and the mechanical stability of mountain belts. Detailed petrology including microstructural, mineralogical, chemical and geochronological analyses is currently advancing our knowledge in these fields. In this session, we welcome contributions presenting a modern approach to igneous and/or metamorphic petrology.

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12. The role of microanalysis and microtextures in understanding magmatic processes.

Conveners: Jon Davidson (Durham), Marian Holness (Cambridge) and Dan Morgan (Leeds)

The study of petrographic textures has always been a key part of igneous petrology, and the microscope remains a fundamental tool in understanding magmatic systems. In recent years, though, a range of technological and analytical advances has opened up new frontiers in petrographic research. We can now investigate microscopic textures at ever-smaller scales, and even in 3-D.  Furthermore, we can integrate in situ geochemical analyses of elements and their isotopes to trace petrogenetic timescales and processes. These opportunities have led to significant advances in our understanding of magmatic processes.

This session will welcome contributions on the application of microanalysis and microtextural studies to igneous rocks. Examples may include microgeochemical analysis; in situ dating; micro-scale analysis of textures and structures in magmatic rocks; and the use of microscopic features in understanding rates and timescales of magmatic processes.

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13. Electron microscopy, microstructural analysis and grain scale processes: insights and frontiers.

Conveners: Kate Brodie (Manchester), Alan Boyle (Liverpool), Florian Heidelbach (Bayreuth), David Mainprice (Montpellier)

Recent advances in analytical techniques in electron microscopy (SEM, TEM and electron microprobe) have greatly enhanced our understanding of grain-scale processes during deformation and metamorphism of minerals and rocks. Backscattered and orientation-contrast electron imaging combined with electron backscatter diffraction (EBSD), cathodoluminescence imaging, charge-contrast imaging, electron microprobe analysis and TEM and optical microscopy have facilitated detailed microstructural and microchemical studies of microstructures developed  under a range of metamorphic conditions, strain rates and strain geometries. These provide better, and in some cases new, understanding of deformation mechanisms in geological materials and their potential interplay with microgeochemistry. Focussed-ion beam (FIB) techniques have opened the possibility of direct selection and preparation of TEM samples inside the SEM as well as serial sectioning of specimens such that 3-D structures become accessible for microstructural/chemical analysis. In-situ heating and deformation experiments are also becoming possible inside SEMs with possibilities for on-line observation and analysis.

This session aims to bring together a broad range of researchers using imaging and microanalytical techniques to investigate deformed and  metamorphosed minerals, rocks and materials. Contributions covering SEM, EBSD and TEM investigations, combined with optical and microchemical studies or other novel techniques are especially invited.

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14. New advances in transmission electron microscopy characterisation and preparation of minerals

Conveners: Patrick Cordier (Lille 1), Falko Langenhorst (Universität Bayreuth) and Michael Carpenter (Cambridge)

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15. Mineral microstructures: their implications and applications.

Conveners: Ian Parsons (Edinburgh), Alain Baronnet (Paul Cézanne University and Centre Interdisciplinaire de Nanoscience de Marseille), Rainer Abart (Freie Universität Berlin)

No crystal is structurally perfect and many important rock forming and accessory phases contain a rich inventory of defect microstructures which affect their chemical reactivity and provide clues to events in their geological history.  The convenors would welcome work involving intracrystal microstructures of all types and at all scales, ranging from point defects, embracing lattice-scale dislocations, stacking faults, domain textures, exsolution textures and twins, up to the scale of gross imperfections such as subgrains, pores, chemical zoning and features related to replacement reactions.  We would like to explore the role of these microstructures in controlling the chemical reactivity of minerals, with respect to major and trace elements and isotopic exchange, and to review the ways in which microstructures can be used to obtain information on the history of crystals over both short and long periods of geological time.  We welcome contributions ranging from the deep Earth to surface phenomena including biominerals.

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16. New advances in mineral deposit geology

Conveners: Martin Smith (Brighton), Gawen Jenkin (Leicester)

New analytical and microanalytical techniques have revolutionised our understanding of mineralisation processes in recent years. These include laser ablation ICPMS for the direct chemical analysis of fluid inclusions and intragrain variations in trace element concentrations and isotope ratios, development of the Re-Os geochronometer for direct dating of ore phases alongside other microanalytical technqiues for geochronology, and the use of multicollector ICPMS for the analysis of transition metal isotopes as tracers of metal source.  This session invites contributions detailing both new analytical techniques applied to ore deposits and studies where such techniques have provided new insights in ore forming processes in all environments. Contributions should not be limited to the indicative areas outlined above.

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17. Mineralogy of Nuclear Wastes.

Conveners: Fergus Gibb (Sheffield) and Ian Farnan (Cambridge)

 Many countries have a legacy of nuclear wastes. Not only do these urgently require dealing with safely but they constitute a serious obstacle to nuclear 'new build', with all this implies for future energy supplies and climate change. Solutions to the radioactive waste problem are crucially dependent on the mineralogical and materials sciences with minerals, glasses, cements and ceramics central to the recovery, immobilisation, storage and eventual geological disposal of the wastes. This session aims to bring together researchers and practitioners in these disciplines to present and discuss some of the most recent outcomes of analytical, experimental and modelling studies in mineralogy of particular relevance to radioactive wastes.

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