Igneous and metamorphic petrology in the last decades
of the twentieth century exploded into a broad, multifaceted,
increasingly quantitative science. Advances
in physical and field petrology and geochemistry have
forever changed our thinking about the origin and evolution
of magmas, their dynamic behavior, and the way in
which they are intruded and explosively extruded. Developments
in geochronology, quantitative evaluation
of the role of heat and fluid transfer in crustal rocks,
and new field discoveries have impacted our understanding
of the evolution of metamorphic systems and
their dynamic interaction with tectonic processes. Geophysics
and mineral physics have provided new insights
into the nature of the convecting mantle and its role as
a giant heat engine driving magmatic and metamorphic
processes. New tools of all kinds allow new ways of
gathering petrologic data, while phenomenal developments
in computers and computer software permit
data to be stored, processed, and modeled in ways
unimaginable as recently as a couple of decades ago.