Ingeous Petrology MPI
MPI-01 General contributions to igneous petrology Brian Robins, Marjorie Wilson
The symposium will include novel contributions to important and topical aspects of magmatic systems on the Earth and other terrestrial planets. The main focus of the symposium will be the fundamental causes of igneous activity, the interplay between tectonic environment and magmatic activity, and the nature of the physical and chemical processes that take place during the generation, extraction, movement and crystallisation of magma, as well as their duration. Contributions that explore the role of various types of mixing at different stages in magmatic systems and their significance for the composition of magmas and their subsequent evolution are particularly welcome.
MPI-02 Integrated perspectives on the accretion of oceanic crust Yildirim Dilek, Jeffrey A. Karson
Investigations of the processes associated with the accretion of oceanic crust come from several different perspectives, all of which contribute significantly to the current perception of seafloor spreading. This session is designed to bring together presentations that will represent these various perspectives in order to provide an up-to-date assessment of progress toward a comprehensive understanding of the genesis of the oceanic crust. Major topics will include investigations of oceanic crust at spreading centers and subduction zone environments, from deep crustal drilling, and in "tectonic windows", the seismic structure of oceanic crust and spreading centers at mid-ocean ridges and in backarc basins, and field and geochemical investigations of ophiolite complexes. Presentations will focus on the interplay of tectonic, magmatic, and hydrothermal processes in the formation and evolution of modern and ancient oceanic crust across a broad spectrum of spreading rates, magma budgets, mantle dynamics, and tectonic settings.
MPI-03 Granite classification - a never-ending problem Bernard Bonin, Tapani Rämö, Tom Andersen (IUGS Subcommission of Systematics on Igneous Rocks (SSIR) and UNESCO - IGCP 510)
Granites are simple quartz feldspar rocks but there is no consensus about how and where granitic magmas originate and how and where they evolve. In this session devoted to granite classification, two major issues will be addressed: * use and significance of chemical diagrams. In the SSIR nomenclatural scheme, plutonic rocks are classified using the QAP diagram, while the TAS diagram is the simplest way to discriminate volcanic rocks. Is the TAS diagram a chemical equivalent of the modal QAP diagram? Can it be used for plutonic rocks? * fate of alphabet classification. This genetic classification never gained a worldwide consensus. We wish to examine parameters describing granite and to discuss whether it is possible to obtain answers to the genetic conundrum. Other issues include: * generation of migmatites vs. granites: is it only a problem of scale? * relationships of granites with volcanic rocks: are there always volcanoes above granite plutons? Contributions are expected in the fields of rock-forming minerals, igneous petrology, experimental petrology, element and isotope geochemistry, in order to provide a more robust frame for granite classification.
MPI-04 Mafic dyke swarms: A global perspective Rajesh K. Srivastava, Wouter Bleeker, Richard Ernst
Because of great depth and lateral extent, mafic dyke swarms provide the most complete record of short-lived, mantle-generated magmatic events through time and space. Our increasing ability to date mafic dyke rocks precisely has greatly enhanced their importance as high-resolution markers in time. Collectively, the record of mafic dyke swarms provides information on “the pulse of the Earth”—that is, the rhythm of mantle melting events through time, from minor rift-related events, to the largest known igneous events (LIPs) on the planet extruding millions of km3 of basaltic melt over short intervals of time (<1 my). Linked with precise ages, mafic dykes swarms become an unparalleled source of diverse and high-quality information: on tectonics and secular evolution, age and location of igneous centres, paleo-stress directions, strain gradients, key paleomagnetic poles, paleo-intensities of the core dynamo, plume frequency, mantle sources, and much more. Successive short-lived dyke events define “bar codes” that identify a piece of crust and its original “nearest neighbours”. Thus they are the key to paleogeographic reconstructions. “Bar coding” the geological record will allow, in principle, a full reconstruction of Earth’s paleogeography, back to ca. 2.6 Ga. This session will bring together all those interested in these and other aspects of mafic dyke swarms.
MPI-05 Large Igneous Provinces: Initiation, evolution and origin Lothar Viereck-Goette, Sverre Planke
The events during initiation of some mafic Large Igneous Provinces (North Atlantic, Ferrar, and Karoo Igneous Province) were studied recently, with spectacular results and new (?) concepts. In all cases we see that early emplacement occurred as sills in a shallow crustal environment with abundant magma-wet sediment interaction and diatreme formation. However, this initial character may be due to the local geology of young unconsolidated sediments overlying crystalline basement. We can neither identify an initial phase of small volume magma emplacement, nor a regular early involvement of molten continental crust. In the Ferrar Province, we recognize that the magmas belong to the tholeiitic differentiation series with the early intrusive andesitic magmas being more evolved than the later plateau forming basaltic andesitic lavas. Which of these observations are of general relevance for LIP formation and are crucial pieces in the big puzzle? How are Silicic Large Igneous Provinces initiated, do they start with a mafic initial phase? We invite any geoscientist working on the topic of initiation of mafic or silicic LIP to present his/her new data from other LIPs on earth in order to gain a more precise understanding of the early processes during production, evolution and emplacement of such catastrophic volumes of magma.
MPI-06 Layered intrusions and the evolution of magma chambers - a tribute to J. Richard Wilson Christian Tegner, Bernard Charlier, Brian Robins
Magma slowly cools, crystallizes and interacts with crustal country rocks in magma chambers. These processes generate the known diversity of volcanic rocks and plutonic roots, some containing important mineralisations. We invite contributions from all fields of research that addresses magma chamber processes including field relations, petrography, petrology, geophysics and geochemistry. This symposium is a tribute to J. Richard Wilson for his contributions to the understanding of processes in mafic magma chambers from investigations of layered mafic intrusions. This symposium complements excursions no. 2 (The Skaergaard Intrusion, ), no. 26 (Magma Geopark: The Rogaland Anorthosite Province) and no.33 (The Fongen-Hyllingen Layered Intrusion).
MPI-07 Alkaline and carbonatite magmatism and related ore deposits Lia Kogarko, Tom Andersen, Kathryn Moore
The symposium "Alkaline and carbonatitic magmatism and related ore deposits" is dedicated to the problems of the origin, differentiation and ore potential of alkaline and carbonatitic magmatic systems in diverse geodynamic regimes and regions. The mineralogy, petrology, geochemistry and genesis of alkaline and peralkaline rocks, phoscorites, carbonatites, associated rare metallic deposits (Nb, Ta, Zr, Hf, U, Sr etc) and other types of ore lodes will be presented. The formation of igneous layering and superlarge rare metallic deposits in alkaline and peralkaline intrusions will be discussed. Special attention will be paid to the physical and chemical conditions (T, P, fO2) of rock formation, assessed by thermodynamic analysis, microinclusion investigations and experimental petrology. The application of new isotope systems (Lu-Hf, Re-Os etc) to the problems of sources of alkaline and carbonatitic magmatism will also be discussed as well as the elucidation of the role of plume and lithospheric magmatism in the origin of parental magmas. Multidisciplinary research is welcomed to elucidate the role and origin of enriched mantle reservoirs, large alkaline provinces of continents and oceans, and the alkaline rocks and carbonatites of the oceanic regions. The role of metasomatism will be discussed, from the early phases of the formation of alkaline, carbonatitic and phoscoritic magmatic rocks to the final stages of hydrothermal and carbohydrothermal activity.
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