I´m working on a granulite that has an associated tonalite, probably they are the products of a partial fussion but I would like to have more evidences other than field relationships.
Search for thin section evidence of partial melting according to Sawyer 1999 and 2001 Criteria on the granulite.
Sawyer 1999 Criteria for the recognition of partial melt
Sawyer 2001 Melt segregation in the continental crust
Also you can look if you have partial melting under static and dinamic conditions on thin sections.
Rosenberg & Riller 2000 Partial-melt topology in statically and dynamically recrystallized granite
But have also to look to leucosome if have some features of syntectonic parcial melting, with a detailed structural geology analysis of leucosomes and tonalite.
Michel Brown are one of geologist that contribute on the relationship between partial melting and granite genesis, but from the structural geology point of view.
Brown & Solar 1998 Granite ascent and emplacement during contractional deformation in convergent orogens
Brown 1994 The generation, segregation, ascent and emplacement of granite magma
Brown 2001. Orogeny, migmatites and leucogranites a review
Also you can compare convencional geochemistry, isotope geochemistry and detaled geochronology from the leucosome-tonalite-granulite to look if they have chemical and chronological relationship.
In situ U-Pb dating (with SHRIMP or laser ablation) and a detaled textural analysis on zircons (overgrowths, dynamic recrystallization, etc) of these rocks could help a lot.
I hope this information could help to your research