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Constraining the Age and Evolution of the Tuaheni Landslide Complex, Hikurangi Margin, New Zealand, Using Pore‐Water Geochemistry and Numerical Modeling
Author(s) -
Luo Min,
Torres Marta E.,
Kasten Sabine,
Mountjoy Joshu J.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl087243
Subject(s) - geology , sedimentary depositional environment , landslide , pore water pressure , sediment , margin (machine learning) , geochemistry , methane , geomorphology , paleontology , geotechnical engineering , structural basin , machine learning , computer science , ecology , biology
The Tuaheni Landslide Complex (TLC) on the Hikurangi Margin is subject to reactivation, yet the timing of slide emplacement remains unknown. Here we modeled pore‐water data collected from the TLC during the International Ocean Discovery Program (IODP) Expedition 372 in 2017/2018 using a transient‐state reaction‐transport modeling approach. Our simulations reveal that the TLC was formed by two separate depositional events and that the most recent one occurred 12.5 ± 2.5 ka as a coherent ~40 m sediment block that carried its initial pore‐water signature. In addition, we show that the rapid burial of pore‐water SO 4 2− in the pre‐slide sediments consumed an additional ~5.6 × 10 9 mole of CH 4 over the entire Tuaheni South following the most recent depositional event. These findings provide significant insights into the nature and timing of the TLC and highlight the role of slope failure on subsurface methane cycling on millennial timescales.