Fosdick Mountains, Antarctica

Valhalla Complex, British Columbia, Canada

Crustal Melting and Orogeny

Gneiss domes, metamorphic core complexes, and orogenic plateaux

Gneiss domes cored by migmatites occur worldwide in collisional orogens of all ages. Typically, more than one dome is present, they are elongate, and they are characterized by a core of migmatites and granite surrounded by high-grade metasedimentary rocks. Some unresolved questions about gneiss domes include:

--What is the thermal and/or mechanical significance of gneiss domes in orogeny?

--What are the internal dynamics of domes? (and can this information be retrieved from the fabrics/petrology of dome rocks?)

--How do dome rocks relate (structurally, thermally) to their overlying metamorphic rocks and structures (which in many cases are detachment faults of metamorphic core complexes)?

--Why do domes typically occur in swarms or belts, and what is the significance of their size, spacing, and distribution?

--What are the pressure-temperature-time paths of metamorphic rocks within and beyond the dome?

--What is the significance of migmatites in the cores of domes?

--Is there a characteristic timing of partial melting and deformation relative to dome formation?

--Is there a characteristic timing or rate of exhumation of the high-grade cores of domes?

People: Christian Teyssier, Donna Whitney, Jennifer Wright, Patrice Rey (U Sydney), Stacia Gordon (U of Nevada-Reno), Seth Kruckenberg (PhD 2009), Rory McFadden (PhD 2009)