CO2 Release from Pockmarks on the Chatham Rise‐Bounty Trough at the Glacial Termination.

Stott, Lowell , Davy, Bryan , Shao, Jun , Coffin, Richard, Pecher, Ingo , Neil, Helen, Rose, Paula and Bialas, Joerg (2019) CO2 Release from Pockmarks on the Chatham Rise‐Bounty Trough at the Glacial Termination. Open Access Paleoceanography and Paleoclimatology, 34 (11). pp. 1726-1743. DOI 10.1029/2019PA003674.

[thumbnail of Stott_et_al-2019-Paleoceanography_and_Paleoclimatology.pdf]
Preview
Text
Stott_et_al-2019-Paleoceanography_and_Paleoclimatology.pdf - Accepted Version

Download (2MB) | Preview
[thumbnail of Stott_et_al-2019-Paleoceanography_and_Paleoclimatology.pdf]
Preview
Text
Stott_et_al-2019-Paleoceanography_and_Paleoclimatology.pdf - Published Version

Download (107MB) | Preview

Supplementary data:

Abstract

Seafloor pockmarks of varying size occur over an area of 50,000 km2 on the Chatham Rise, Canterbury Shelf and Inner Bounty Trough, New Zealand. The pockmarks are concentrated above the flat‐subducted Hikurangi Plateau. Echosounder data identifies recurrent episodes of pockmark formation at ~100,000yr frequency coinciding with Pleistocene glacial terminations. Here we show that there are structural conduits beneath the larger pockmarks through which fluids flowed upward toward the seafloor. Large negative Δ14C excursions are documented in marine sediments deposited next to these subseafloor conduits and pockmarks at the last glacial termination. Modern pore waters contain no methane and there is no negative δ13C excursion at the glacial termination that would be indicative of methane or mantle‐derived carbon at the time the Δ14C excursion and pockmarks were produced. An ocean general circulation model equipped with isotope tracers is unable to simulate these large Δ14C excursions on the Chatham Rise by transport of hydrothermal carbon released from the East Pacific Rise as previous studies suggested. Here we attribute the Δ14C anomalies and pockmarks to release of 14C‐dead CO2 and carbon‐rich fluids from subsurface reservoirs, the most likely being dissociated Mesozoic carbonates that subducted beneath the Rise during the Late Cretaceous. Because of the large number of pockmarks and duration of the Δ14C anomaly, the pockmarks may collectively represent an important source of 14C‐dead carbon to the ocean during glacial terminations.

Document Type: Article
Keywords: Pockmarks, deglaciation, carbon cycle, geologic carbon
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
Open Access Journal?: No
Publisher: AGU, Wiley
Related URLs:
Expeditions/Models/Experiments:
Date Deposited: 24 Oct 2019 07:08
Last Modified: 31 Jan 2022 09:13
URI: https://oceanrep.geomar.de/id/eprint/48063

Actions (login required)

View Item View Item