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RESEARCH PROGRAM

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Research Units
Similar research programs:
Scientific and education field classification
International Patent Classification
  • CHEMISTRY; METALLURGY
  • 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
PETROLOGY; GRANULITE; STABLE ISOTOPES; CARBON; METAPELITE; FLUID INCLUSIONS; MELT INCLUSIONS; CRUSTAL ANATEXIS; GRANITE

Petrologic and isotopic study of fluid-melt-rock interactions during crustal anatexis: comparative application to the pelitic xenoliths of the Neogene Volcanic Province of SE Spain, and to the granulites of the Kerala Khondalite Belt (India)

Università degli Studi di Padova
Abstract
The aim of this research Program is to increase the knowledge on fluid-melt-rock interactions during the partial melting of graphitic metasediments.
The approach will be based on petrographic, fluid and melt inclusion, stable isotope studies performed on natural samples, as well as on thermodynamic and theoretical modelling based on both original data and knowledge already available.
The natural samples belong to well characterized geological settings including anatectic graphitic metapelites: the xenoliths in the dacites of the Neogene Volcanic Province of SE Spain, and the granulites (khondalites) of the Kerala Khondalite Belt (India). The former are very rare fragments of partially melted crust, rapidly brought to the Earth's surface by volcanic eruption; as such, they preserve at best the microstructural and geochemical fatures of HT rocks, in particular the presence of fresh glass (quenched anatectic melt). The latter are among the most intensely studied examples of granulitic terranes exposed on large scales. Owing to their slow cooling and exhumation, these rocks underwent various processes of microstructural and chemical reequilibration, with the complete crystallization of the anatectic melt. The complementary features of the two settings will provide useful information to be merged in an integrated framework.
The research will be organised along four main lines:
1: PETROLOGY OF PARTIAL MELTING OF GRAPHITIC METAPELITES
On >>>

Principal Investigator
Bernardo CESARE Università degli Studi di PADOVA
Research Objectives
Having recognized that:
- many locations in the Earth expose large outcrops of granulites derived from graphitic metasediments,
- graphitic metapelites are one of the main carriers of carbon in the continental lithosphere,
- graphite presence imposes the existence of complex C-O-H fluids in the rocks,
- there is a lack of systematic studies on the partial melting of graphitic rocks,
the aim of the present Project is to contribute to a better understanding of the partial melting of graphitic metapelites, by means of: a) the characterization of fluid-melt-rock interactions, b) the modelling of the behaviour of C-O-H fluids and c) the implications on the behaviuor of some stable isotopes, first of all carbon.
The objectives can be grouped within four main research themes by which, through the study of natural rocks, we aim at:
1- Characterizing the processes of partial melting of graphitic metasediments from a petrologic point of view. By a comparative study of residual xenoliths and metapelitic granulites, we will characterize: i) the microstructural features, ii) the microchemical features of different parageneses, iii) the thermobarometric conditions, iv) the mass balances in the main melting reactions, and v) we will compare these results with thermodynamic simulations based on pseudosections. This part of the research will put constraints to the main petrologic variables (P-T-X) in the studied anatectic >>>

Timescale
24 months
National and international background
Because it is our purpose to study the melting of graphitic metapelites utilizing well-suited samples of (i) peculiar xenoliths in dacitic volcanics (Spain) and (ii) metapelitic granulites of the Kerala Khondalite Belt (India), the following description will consist of three parts: the first deals with the state of the art of knowledge on anatectic processes in graphitic rocks, the second and third with the petrologic features of the two rock suites to be studied.
(i) Partial melting of the Continental Crust is one of the main mechanisms for the generation of granitic magmas, and commonly accompanies high grade metamorphism in the formation of granulite and migmatite terrains. It follows that the reconstruction of phenomena which characterize anatexis is fundamental for the understanding of the geodynamic evolution in the mid-to-deep crust and at the crust-mantle boundary. A genetic link between granulites and crustal melting has been evidenced already in the early 70's, when granulites were interpreted as remnants (restites) after melt extraction (e.g., Fyfe 1973). Many granulite terrains are now interpreted as residual rocks produced by anatexis, whereas granites would represent the counterpart melts, extracted and emplaced in the upper crust (Clemens & Vielzeuf, 1987).
The origin and the behaviour of rocks subjected to partial melting (granulites and migmatites) have been extensively studied in the last three decades, by means of field (e.g. >>>