Dissecting 20 million years of deep-water forearc sediment routing using an integrated basin-wide Bayesian chronostratigraphic framework

作者：Daniel S. Coutts, Stephen M. Hubbard, Rebecca G. Englert, Peter D. Ward, W. A. Matthews · 发表于：Geological Society of America Bulletin · 年份：2024 · DOI：10.1130/b37194.1 · 被引用次数：8 · 研究领域：Geological formations and processes、Geology and Paleoclimatology Research、Geological and Geophysical Studies

Abstract Sedimentary deposits along convergent margins contain a record of sediment transfer and coupled tectonic processes. Deciphering the evolution of ancient convergent margins, both spatially and temporally, is challenging as their stratigraphic successions are often locally deformed, which makes it difficult to correlate stratigraphic units over large distances, and they may have limited age constraints. Here, we construct a novel Bayesian chronostratigraphic framework for Late Cretaceous–Paleocene units of the Nanaimo forearc basin in western British Columbia, Canada, which reveals unparalleled detail into long-term sedimentation processes along an active deep-water margin. The Upper Nanaimo Group outcrop belt features ~2000 m of forearc basin fill that includes the deposits of multiple submarine channel systems along a 160-km-long depositional strike-oriented cross section of the ancient continental margin. The age and longevity of individual slope-channel systems was determined by constructing a Bayesian Monte Carlo numerical model in which biostratigraphic and magnetostratigraphic measurements were used to further constrain 37 detrital zircon maximum depositional ages. Important context for the refined maximum depositional ages is provided by a detailed stratigraphic dataset composed of 2199 m of measured stratigraphic section and 4207 paleoflow measurements, which demonstrate the facies, architecture, distribution, and orientation of 12 slope-channel systems. In co...