Is orogeny simple?
Marnie Forster and Gordon Lister Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia Orogeny is not a simple process, whether it is regarded as progressive or as episodic, complex sequences of events occur throughout the evolution of orogens (Fig. 1). These sequences of events include periods of quiescence, deformational events, and mineral growth events (metamorphism), and thermal events often short in duration, with characteristically complex overprinting of events. As we endeavour to understand the timing of these sequences we must understand how the events that we are dating fit into complex tectonic sequences within the region and/or orogen. D1, D2 … Dn schemes are used by structural geologists and metamorphic petrologists to define sequences of events, however these schemes do not reflect the complexity of deformation and metamorphism. In part the problem relates to the way such schemes are constructed (and/or debated). There is ofte
