Application of growth strata and detrital-zircon geochronology to stratigraphic architecture and kinematic history

Abstract

Growth strata analysis and detrital-zircon geochronology are useful applications of stratigraphy to tectonic problems. Whereas both tools can contribute to kinematic analyses of supracrustal rock bodies, growth strata are also useful for analyzing the influence of tectonics on stratigraphic architecture. This study reports: (1) a conceptual model for growth strata development; (2) stratigraphic and kinematic analyses of growth strata architectures from growth structures in southeastern Utah, the Gulf of Mexico, and northeastern Spain; and (3) the detrital-zircon geochronology of the Salinian block of central coastal California. Kinematic sequence stratigraphy subdivides growth strata into kinematic sequences that are separated by kinematic sequence boundaries. Kinematic sequences can be further partitioned into kinematic domains based on the termination patterns of strata within a kinematic sequence. Salt-related fluvial growth strata from the Gulf of Mexico and southeastern Utah contain stratigraphic architectures that are unique to different kinematic domains. Offlap kinematic domains contain fluvial strata indicative of high slopes, low accommodation rates, and strong structural influence on paleocurrent direction. Onlap kinematic domains contain fluvial strata indicative of moderate slopes, high accommodation rates, and decreased structural influence on paleocurrent direction. The stratigraphic architecture of alluvial-fan thrust-belt growth strata in northeastern Spain does not display a marked correlation with kinematic domain, and is most easily interpreted using existing models for autocyclic alluvial-fan evolution. Detrital-zircon (U-Pb) geochronologic data from basement and cover rocks of Salinia suggest that Salinia originated along the southwestern margin of North America, likely in the vicinity of the Mojave Desert. The presence of Neoproterozoic and Late Archean detrital zircons in Salinian basement rocks also suggest that Salinian sediments were recycled from miogeoclinal sediments of the western margin of North America.