TY - JOUR T1 - Permafrost Organic Carbon Mobilization From the Watershed to the Colville River Delta: Evidence From 14C Ramped Pyrolysis and Lignin Biomarkers JF - Geophysical Research Letters Y1 - 2017 A1 - Zhang, Xiaowen A1 - Bianchi, Thomas S. A1 - Cui, Xingqian A1 - Rosenheim, Brad E. A1 - Ping, Chien‐Lu A1 - Hanna, Andrea J. M. A1 - Kanevskiy, Mikhail A1 - Schreiner, Kathryn M. A1 - Allison, Mead A. KW - Arctic KW - carbon cycling KW - Colville River KW - Lignin KW - permafrost KW - pyrolysis AB - The deposition of terrestrial‐derived permafrost particulate organic carbon (POC) has been recorded in major Arctic river deltas. However, associated transport pathways of permafrost POC from the watershed to the coast have not been well constrained. Here we utilized a combination of ramped pyrolysis‐oxidation radiocarbon analysis (RPO 14C) along with lignin biomarkers, to track the linkages between soils and river and delta sediments. Surface and deep soils showed distinct RPO thermographs which may be related to degradation and organo‐mineral interaction. Soil material in the bed load of the river channel was mostly derived from deep old permafrost. Both surface and deep soils were transported and deposited to the coast. Hydrodynamic sorting and barrier island protection played important roles in terrestrial‐derived permafrost POC deposition near the coast. On a large scale, ice processes (e.g., ice gauging and strudel scour) and ocean currents controlled the transport and distribution of permafrost POC on the Beaufort Shelf. VL - 44 UR - https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL075543 IS - 22 ER - TY - JOUR T1 - Late Holocene sedimentation in a high Arctic coastal setting: Simpson Lagoon and Colville Delta, Alaska JF - Continental Shelf Research Y1 - 2014 A1 - Hanna, Andrea J. M. A1 - Allison, Mead A. A1 - Bianchi, Thomas S. A1 - Marcantonio, Franco A1 - Goff, John A. AB - Arctic coastal environments near major river outfalls, like Simpson Lagoon, Alaska and the adjacent Colville River Delta, potentially contain high-resolution sediment records useful in elucidating late Holocene Arctic sediment transport pathways and coupled terrestrial-ocean evidence of paleoclimate variability. This study utilizes a multi-tracer geochronology approach (137Cs, 239,240Pu, and 14C) tailored for high-latitude environments to determine the age models for cores collected from Simpson Lagoon, and to date seismic boundaries in shallow acoustic reflection data (CHIRP) to examine late Holocene infill patterns. Modern (~100 y) sediment accumulation rates range from 5 m of late Holocene interbedded sediments, likely derived primarily from the Colville River, with onset of accumulation occurring prior to ~3500 y BP. A paleo-high in central Simpson Lagoon, separating the two depocenters, was subaerially exposed prior to ~600 y BP. The millimeters-per-year sedimentation rates across the lagoon, coupled with the undisturbed, interbedded sediment record, indicate that these settings hold great potential to develop new Arctic paleoenvironmental records. VL - 74 UR - http://www.sciencedirect.com/science/article/pii/S0278434313004056 JO - Late Holocene sedimentation in a high Arctic coastal setting: Simpson Lagoon and Colville Delta, Alaska ER -