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RESEARCH PROGRAM

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Research Units
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Scientific and education field classification
International Patent Classification
  • CHEMISTRY; METALLURGY
  • HUMAN NECESSITIES
    • MEDICAL OR VETERINARY SCIENCE; HYGIENE
      • FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
  • PHYSICS
    • MEASURING (counting G06M); TESTING
      • INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (separating components of materials in general B01D, B01J, B03, B07; apparatus fully provided for in a single other subclass, see the relevant subclass e.g. B01L; measuring or testing processes other than immunoassay, involving enzymes or micro-organisms C12M, C12Q; investigation of foundation soil in situ E02D1/00; sensing humidity changes for compensating measurements of other variables or for compensating readings of instruments for variations in humidity, see G01D or the relevant subclass for the variable measured; testing or determining the properties of structures G01M; measuring or investigating electric or magnetic properties of materials G01R; systems or methods in general, using reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; determining sensivity, graininess, or density of photographic materials G03C5/02; testing component parts of nuclear reactors G21C17/00; [N: controlling or regulating non-electric variables G05D; measuring degree of ionisation of ionised gases, i.e. plasma H05H1/00A; testing electrographic developer properties G03G15/08H6])
Geographical classification
Keywords
CRUSTAL ANATEXIS, PETROLOGY, MELT AND FLUID INCLUSIONS, MIGMATITES AND GRANULITES, MELT INTERACTION AND CHAOTIC MIXING

Crustal Anatexis: Natural evidence, Experiments and Modelling (C.A.N.E.M)

Università degli Studi di Padova
Abstract
This Research Project will study in detail the processes accompanying crustal melting in its early stages of high-grade metamorphism and beginning of anatexis, and in the following stages during which anatectic melts segregate from the source region, migrate through the continental crust, and emplace as plutonic or volcanic bodies. We will use a multidisciplinary approach integrating metamorphic and igneous petrology, microstructural analysis, thermodynamic and geochemical modelling, also using techniques based on Chaos Theory and fractal Geometry, studies of melt and fluid inclusions, and experimental petrology simulations,
The Project is focused on the following objectives, of fundamental petrological importance but still poorly known or constrained.
Pre-anatectic phases ('gestation’)
-to understand the development of anatectic processes in the source region determining the thermo-baric conditions during the prograde phase of high temperature metamorphism and the onset of melting reactions, by studying the chemical composition of mineral phases at the beginning and after the onset of melting, and the microstructures related to the localization of the anatectic melt in the source region and during the segregation process.
-to quantify melting reactions and their melt productivity by detecting microstructures indicative of melting, and by performing mass balance calculations based on the composition of analysed mineral phases.
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Principal Investigator
Bernardo Cesare Università degli Studi di PADOVA
Research Objectives
Due to the lack of a specific section, citations in the following texts are referred to those reported in the B Model of each Research Unit. In particular, the prefix “a” and “b” is utilised to indicate citations given in the Research Unit of Padova and Perugia, respectively.

The target of this Research Project is the detailed understanding of the processes accompanying crustal melting in its early stages of high-grade metamorphism and beginning of anatexis, and the successive stages during which anatectic melts segregate from the source region, migrate through the continental crust, and emplace as plutonic or volcanic bodies. To this aim, a multidisciplinary study integrating metamorphic and igneous petrology, microstructural analysis, thermodynamical and geochemical modelling, also using techniques based of Chaos Theory and Fractal Geometry, studies of melt and fluid inclusions, and experimental simulations, will be carried out.
The main objectives, of fundamental petrological importance but still poorly known or constrained, are:

Pre-anatectic phases ('gestation’)
- to understand the development of anatectic processes in the source region by characterizing the behaviour of natural metapelitic systems during the prograde phase of high temperature metamorphism and the onset of melting reactions. The researches will be focused on the determination of anatectic thermobaric conditions, on the study of the >>>

First Results
The expected results are the advancement of knowledge relative to the main objectives of the Research Project [further details can be found in section 11 of this A Model and in the B Model of each Research Units (R.U.)]. These are synthetically listed as follows:

Pre-anatectic stages ('gestation’)
- comprehension of anatectic processes in the source region by characterising the behaviour of natural metapelitic systems.
- quantification of melting reactions and their melt productivity.

Syn-anatectic stages ('birth’)
- understanding of the causes of compositional heterogeneities of natural anatectic melts.
- construction of the first geochemical database for natural anatectic melts.
- comprehension of the petrological significance of fluid inclusions coexisting with melt inclusions.
- execution of thermodynamic modelling of the studied rocks.
- understanding of the interaction mechanisms among anatectic melts, on both small and large length scale.

Post-anatectic stages ('migration and emplacement’)
- understanding of the influence of interaction processes among anatectic melts on their original geochemical compositions.
- comprehension of the influence of transport and coalescence on the composition of anatectic melts during their migration through fracture networks.
- understanding of the mechanisms associated with >>>

Timescale
24 months
National and international background
In his recent review about the state of the art and problems related to crustal anatexis, Brown (2007) concludes: “We have come far in our understanding of melt generation and extraction from anatectic lower crustal sources, and magma ascent and emplacement into the upper crust of large hot orogens, but much remains to be done”.
Anatexis (partial melting) of the middle-lower crust is tightly associated and connected with granulite facies metamorphism and with the genesis of migmatites [a1,b1,a2]. By generating granitoid magmas [a3,a4,b11], which can segregate from the source region and migrate toward shallower crustal levels [a5-a9,b12,b13], anatexis represents one of the most important agent of the differentiation of the continental crust [a10,a4], influencing its rheological behaviour [a11-a13,a7] and, hence, its geodynamic evolution [a14,a6,b1].
The emplacement of anatectic melts, both in plutonic and volcanic environments, marks the final stage of formation of magmatic bodies [e.g. a7,b13]. These bodies are the product of aggregation of compositionally different melts: i) heterogeneous primary melts due to different degrees of partial melting and/or source variability; ii) interaction among such melts during segregation and ascent processes; iii) interaction in magma chambers and/or in volcanic conduits [e.g. b3,b27,b28]. Aggregation and interaction among the different melts can occur with different efficiencies, masking or completely obliterating the >>>