U.S. Geological   Survey Professional Paper 16262000

**Phanerozoic  Tectonic Evolution of the Circum-North Pacific**

***By***

**Warren J. Nokleberg, Leonid M. Parfenov, James W.H. Monger, Ian O. Norton, Alexander I. Khanchuk, David B. Stone, Christopher R. Scotese, David W. Scholl, and Kazuya Fujita**

| **ABSTRACT**

The Phanerozoic         tectonic evolution of the Circum-North Pacific is recorded mainly in the         orogenic collages of the Circum-North Pacific mountain belts that separate         the North Pacific from the eastern part of the North Asian Craton and         the western part of the North American Craton. These collages consist         of tectonostratigraphic terranes that are composed of fragments of igneous         arcs, accretionary-wedge and subduction-zone complexes, passive continental         margins, and cratons; they are overlapped by continental-margin-arc and         sedimentary-basin assemblages. The geologic history of the terranes and         overlap assemblages is highly complex because of postaccretionary dismemberment         and translation during strike-slip faulting that occurred subparallel         to continental margins.We analyze the complex tectonics of this region         by the following steps. (1) We assign tectonic environments for the orogenic         collages from regional compilation and synthesis of stratigraphic and         faunal data. The types of tectonic environments include cratonal, passive         continental margin, metamorphosed continental margin, continental-margin         arc, island arc, oceanic crust, seamount, ophiolite, accretionary wedge,         subduction        zone, turbidite basin, and metamorphic. (2) We make correlations between         terranes. (3) We group coeval terranes into a single tectonic origin,         for example, a single island arc or subduction zone. (4) We group igneous-arc         and subduction- zone terranes, which are interpreted as being tectonically         linked, into coeval, curvilinear arc/subduction-zone complexes. (5) We         interpret the original positions of terranes, using geologic, faunal,         and paleomagnetic data. (6) We construct the paths of tectonic migration.         

Six processes         overlapping in time were responsible for most of the complexities of the         collage of terranes and overlap assemblages around the Circum-North Pacific,         as follows. (1) During the Late Proterozoic, Late Devonian, and Early         Carboniferous, major periods of rifting occurred along the ancestral margins         of present-day Northeast Asia and northwestern North America. The rifting         resulted in the fragmentation of each continent and the formation of cratonal         and passive continental-margin terranes that eventually migrated and accreted         to other sites along the evolving margins of the original or adjacent         continents. (2) From about the Late Triassic through the mid-Cretaceous,         a succession of island arcs and tectonically paired subduction zones formed         near the continental margins. (3) From about mainly the mid-Cretaceous         through the present, a succession of igneous arcs and tectonically paired         subduction zones formed along the continental margins. (4) From about         the Jurassic to the present, oblique convergence and rotations caused         orogenparallel sinistral and then dextral displacements within the upper-plate         margins of cratons that have become Northeast Asia and North America.         The oblique convergences and rotations resulted in the fragmentation,         displacement, and duplication of formerly more nearly continuous arcs,         subduction zones, and passive continental margins. These fragments were         subsequently accreted along the expanding continental margins. (5) From         the Early Jurassic through Tertiary, movement of the upper continental         plates toward subduction zones resulted in strong plate coupling and accretion         of the former island arcs and subduction zones to the continental margins.         Accretions were accompanied and followed by crustal thickening, anatexis,         metamorphism, and uplift. The accretions resulted in substantial growth         of the North Asian and North American Continents. (6) During the middle         and late Cenozoic, oblique to orthogonal convergence of the Pacifi c plate         with present-day Alaska and Northeast Asia resulted in formation of the         modern-day ring of volcanoes around the Circum-North Pacific. Oblique         convergence between the Pacific plate and Alaska also resulted in major         dextral-slip faulting in interior and southern Alaska and along the western         part of the Aleutian-Wrangell arc. Associated with dextral-slip faulting         was crustal extrusion of terranes from western Alaska into the        Bering Sea. |
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URL of this page:   https://pubs.usgs.gov/pp/2000/1626/  Maintained by: Michael Diggles  Created: December 15, 2000  Last modified: May 18, 2006 (mfd)