The Terrane Puzzle: New Perspectives on Paleontology and Stratigraphy from the North American Cordillera

Displaced or tectonostratigraphic terranes have been on the horizon of geology from popular books to technical papers. Terranes are now well recognized and compose a large portion of estate in the North American Cordillera. They are discrete, fault-bounded blocks of regional “mappable” extent whose rocks and fossils differ to a great degree from those of adjacent blocks. When mapped in detail, the terranes resemble a collage of mixed rock types and tectonic styles, metamorphism, and volcanic origin—each part resembling the pieces of a puzzle. The allochthonous nature of terranes, as compared with the craton and with each other, has been suspected ever since the term was fi rst used in this sense by Irwin (1972). Terrane studies are at the heart of discussions on the geological evolution of western North America from Mexico to the western Great Basin to the blocks, tectonic slices, and faults making up most of Alaska. Since the initiation of the terrane concept (Jones et al., 1977), terrane research continues to proliferate as a major agenda in geology. It also has spawned many new ideas in disparate areas of geology. Research continues to generate new hypotheses to test and solve terrane puzzles, and this research stimulates new directions of geological research.