Benjamin W. Hallett
 Ben's Vitae
|
ResearchMy research involves a multi-faceted approach to understanding and solving tectonic problems related to the development of continental orogenic belts. I am interested in the metamorphic conditions and chemical reactions that cause partial melts to form, and in how partially molten (migmatitic) rocks can change their overall strength to deform ductilely. Metamorphic mineral zoning patterns (growth and diffusional) provide powerful information on the P-T conditions experienced by a particular rock. Using isotopic and chemical dating techniques on well-known geochronometric minerals to determine the melting history of a migmatite zone rock allows the conditions of melting to be put into a tectonic context (a P-T-t-D path). This helps improve our understanding of compressional (and extensional) metamorphic terranes and how to reconstruct their histories.
One tectonic problem that has recieved considerable focus recently is that of the exhumation of ultrahigh pressure (UHP) metamorphic rocks in continental orogens. Commonly, structures that may have acted to bring these rocks up from depths over 100 km are not exposed or are significantly overprinted. This problem is not specific to UHP terranes, as many regional metamorphic belts do not show obvious exhumation structures and/or only part of their retrograde history is recorded. Melt-crystallizing reactions occur in all migmatitic rocks and generally record retrograde conditions, providing key information about the exhumation path.
Teaching
Personal