WESTERN PACIFIC TECTONICS AND THE SUGGESTED SIERRA SEVEN SUTURE SAGA

Diverse pre-batholithic rocks within the northern Sierra Nevada and vicinity define at least two western Pacific-like island arc complexes, variously deformed by both east- and west-vergent faults and isoclinal folds, as well as possibly numerous strike-slip faults. From west to east these rocks include the Coast Range-Great Valley Ophiolite, the western Jurassic or Smartville belt, a lower-middle Jurassic rifted island arc/ophiolite; the Paleozoic-Mesozoic Central Belt of diverse metamorphosed sedimentary, volcanic, plutonic, and ophiolitic rocks, the Devonian-Triassic Feather River/Devils Gate complex of metamorphosed peridotite and ophiolitic rocks; a Carboniferous-Triassic metasedimentary/volcanic unit of possible Klamath-affinity, at times called the "Cedar" rocks; and the Ordovician-Jurassic Eastern Belt: Devonian-Mississippian, Permian, and Jurassic arc sequences underlain by and interbedded with metasedimentary rocks.

In the western Pacific, ophiolite/arc sequences may result from complex intra-arc rifting and closure (e.g. Philiippines: e.g., Encarnacion, 2004) or multiple ophiolites, sutures, collisions, rapid Neogene plate margin changes, and extensive transform faulting (Indonesia and Philippines: e.g., Hall and Wilson, 2000) . The rapidity of western Pacific tectonic changes complicates comparison with older terranes. Some active collisional sutures, e.g, arc-arc, may be difficult or even impossible to detect when completed, especially in older deformed belts.

Application of western Pacific models to the northern Sierra Nevada and vicinity suggests a "thought experiment" proposing the possible existence of seven sutures, several involving westward subduction, from west to east: 1.Coast Range-Great Valley Ophiolite/Western Jurassic belt; 2. Western Jurassic Belt/Central Belt; 3. Central Belt/Feather River Peridotite; 4. Feather River Peridotite/"Cedar" rocks; 5. "Cedar" rocks/Eastern Belt, and two within the Eastern Belt: 6. A pre late Devonian ophiolite emplacement and 7. A possible suture within Jurassic volcanic rocks. .

Insights from the Western Pacific suggest that the effort to understand the US Pacific margin may benefit more from use of a model-deductive than simply an inductive approach.