Tectonically-triggered sediment and carbon export to the Hadal zone

TitleTectonically-triggered sediment and carbon export to the Hadal zone
Publication TypeJournal Article
Year of Publication2018
AuthorsBao, R, Strasser, M, McNichol, AP, Haghipour, N, McIntyre, C, Wefer, G, Eglinton, TI
JournalNature Communications
Date PublishedJan-12-2018

Sediments in deep ocean trenches may contain crucial information on past earthquake history
and constitute important sites of carbon burial. Here we present 14C data on bulk organic
carbon (OC) and its thermal decomposition fractions produced by ramped pyrolysis/oxidation
for a core retrieved from the >7.5 km-deep Japan Trench. High-resolution 14C measurements,
coupled with distinctive thermogram characteristics of OC, reveal hemipelagic
sedimentation interrupted by episodic deposition of pre-aged OC in the trench. Low δ13C
values and diverse 14C ages of thermal fractions imply that the latter material originates from
the adjacent margin, and the co-occurrence of pre-aged OC with intervals corresponding to
known earthquake events implies tectonically triggered, gravity-flow-driven supply. We show
that 14C ages of thermal fractions can yield valuable chronological constraints on sedimentary
sequences. Our findings shed new light on links between tectonically driven sedimentological
processes and marine carbon cycling, with implications for carbon dynamics in hadal