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A terrane in
Older usage of terrane simply described a series of related rock formations or an area having a preponderance of a particular rock or rock groups.
A tectonostratigraphic terrane is not necessarily an independent
A tectonostratigraphic terrane is a fault-bounded package of rocks of at least regional extent characterized by a geologic history which differs from that of neighboring terranes. The basic characteristics of these terranes is that the present spatial relations are not compatible with the inferred geologic histories. Where terranes which lie next to each other possess strata of the same age, it must be demonstrable that the geologic evolutions are different and incompatible, and there must be an absence of intermediate
The concept of tectonostratigraphic terrane developed from studies in the 1970s of the complicated
It was soon determined that these exotic crustal slices had in fact originated as "suspect terranes" in regions at some considerable remove, frequently thousands of kilometers, from the
orogenic beltwhere they had eventually ended up. It followed that the present orogenic belt was itself an accretionary collage, composed of numerous terranes derived from around the circum- Pacificregion and now sutured together along major faults. These concepts were soon applied to other, older orogenic belts, e.g. the Appalachian beltof North America.... Support for the new hypothesis came not only from structural and lithological studies, but also from studies of faunal biodiversityand palaeomagnetism.
When terranes are composed of repeated accretionary events, and hence are composed of subunits with distinct history and structure, they may be called superterranes.