TOPICS

Welcome to the Granites Summer School 2019 

MAGMATIC DIFFERENTIATION

Since the nineteen century, the physico-chemical evolution of magmatic systems is intimately  linked to the notion of magmatic differentiation:

 “In petrographical literature in recent years attention has repeatedly been drawn to the fact, that igneous rocks, which are closely connected geographically and in age, are also chemically related to one another, showing a certain " consanguinity "-to use Iddings'" very fitting expression-a relationship which makes them form a distinct "petrographical province " (Judd) when compared with igneous rocks of other parts of the world”

Bäckström 1893

(Bäckström H. (1893) The Journal of Geology, Vol. 1, No. 8, 773-779; Iddings (1892) Bull. Phil. Soc. of Washington, 12, 89-214.)

In 1915, Bowen laid the foundation of modern igneous petrology:

“The decision is reached that differentiation is controlled entirely by crystallization. The sinking of crystals and the squeezing out of residual liquid are considered the all-important instruments of differentiation”

Bowen, 1915

(Bowen N. L. (1915) American Journal of Science, 39, 175–191.)

Since Bowen (1915), Several subsequent research results were published on magmatic differentiation, further enhancing our understanding. Many processes have been suggested to explain the magmatic differentiation. These processes are:

-          Distinct melting events from from different sources region and composition.

-          Various degree of partial melting

-          Crystal fractionation by either crystal settling/floating or melt extraction from crystal mushes

-          Mixing / migling of different magmas

-          Liquid immiscibility

-          Assimilation of surrounding rocks

It is now recognized that all these processes act together to cause change in magma composition during deep melt production, transfer and final emplacement at depth and at the surface. Recent advances discuss the importance of each process and their potential implication in the still debated different models actually proposed to describe the crustal magmatic plumbing systems: channeled vertical pathways, diapirism and magma mush column. “Magma fluxes between the different portions of [theses] plumbing system, and the variation of the chemical and physical properties of magma as it rises through the crust, exert essential controls on the eruptive modalities of volcanoes and the geochemistry of their products” (Caricchi and Blundy, 2015, Geological Society, London, Special Publications, 422, 1–15).

The main objectives of the Granite 2019 Summer school are:

-     Bring together young scientists, PhD students and Post-Doc, and senior researchers to provide a strong learning and research environment for promote a respectful but critical dialogue.

-   To summarize present knowledge and most recent scientific advances on all processes responsible for the magmatic differentiation.

-    To open the way towards the new frontiers for futures studies both in terms of scientific challenges and applications.

Magma mixing and migling (dacite and andesite; Santorini volcano, Greece)