Concordant paleolatitudes for Neoproterozoic ophiolitic rocks of the Trinity Complex, Klamath Mountains, California

Abstract

New paleomagnetic results from the eastern Klamath Mountains of northern California show that Neoproterozoic rocks of the Trinity ophiolitic complex and overlying Middle Devonian volcanic rocks are latitudinally concordant with cratonal North America. Combining paleomagnetic data with regional geologic and faunal evidence suggests that the Trinity Complex and related terranes of the eastern Klamath plate were linked in some fashion to the North American craton throughout that time, but that distance between them may have varied considerably. A possible model that is consistent with our paleomagnetic results and the geologic evidence is that the Trinity Complex formed and migrated parallel to paleolatitude in the basin between Laurasia and Australia–East Antarctica as the Rodinian supercontinent began to break up. It then continued to move parallel to paleolatitude at least through Middle Devonian time. Although the eastern Klamath plate served as a nucleus against which more western components of the Klamath Mountains province amalgamated, the Klamath superterrane was not accreted to North America until Early Cretaceous time.

The microstructure of layered ultramafic cumulates: Case study of the Bear Creek intrusion, Trinity ophiolite, California, USA

“…Although its precise tectonic setting and emplacement history are poorly constrained, its association with arc-derived volcano-sedimentary formations together with geochemical and geochronological data suggest that it is a dismembered fragment of a former arc-related ocean basin that may have opened between Rodinia and Laurentia; the Trinity ophiolite itself could represent the youngest remnant of this oceanic domain (Brouxel et al, 1988;Coleman, 1986;Mankinen et al, 2002;Wallin et al, 1988;Wallin and Metcalf, 1998).…”