Geological Society of America

T242 Ice-Sheet and Sea-Ice Paleo-Reconstructions from the Arctic, Antarctica, and the Southern Ocean

Friday, 30 October 2020
10:00 AM - 2:00 PM
Meeting Rooms

GEOCHEMICAL EVIDENCE FOR THE DISCHARGE OF METEORIC FLOW TO THE CHUKCHI SEA SUGGESTIVE OF A SUBSURFACE FLOW PULSE DURING THE EARLY HOLOCENE THERMAL MAXIMUM (EHTM)

Paper number: T242-1
Program: Technical Sessions
Time: 10:00 AM – 10:15 AM

Authors

Marta Torres Presenting Author
Oregon State UnivCEOAS, Corvallis, OR
Dong-Hun Lee
Hanyang University ERICA Campus, Ansan
Kwangchul Jang
Korea Polar Research Institute, Incheon
James Rae
University of St Andrews, St Andrews
Meilian Chen
Guangdong Technion-Israel Institute of Technology, Shantou
JiHoon Kim
Korea Institute of Geoscience and Mineral Resources, Daejeon
Wei-li Hong
Stockholm University, Stockholm
Jong-Sik Ryu
Pukyong National University, Busan
Moo-Hee Kang
Korea Institute of Geoscience and Mineral Resources, Daejeon
Dukki Han
Jeju Special Self-Governing Province
Seung-Il Nam
Korea Polar Research Institute, Incheon
Dong-Chan Koh
Korea Institute of Geoscience and Mineral Resources, Daejeon
Frank Niessen
Alfred Wegener Institute, Bremerhaven, N/A

Abstract

The impact of permafrost thaw on the discharge of subsurface flow in the Arctic Ocean and its connection to (bio-) geochemical interactions in this critical zone of our planet are still poorly understood. We present geochemical data collected on the Chukchi Shelf, where chloride and water isotope data reveal a meteoric source enriched in cations with a radiogenic fingerprint. The postulated subsurface fluid is enriched in dissolved inorganic carbon and methane; the isotopic composition of the carbon reservoirs is consistent with discharge of fluids affected by diagenetic reactions in a closed system. This scenario is in accordance with published reports of high abundance of a terrestrial humic-like fluorescent dissolved organic matter at this shelf site. These fluid characteristics are in stark contrast with those from other sites in the Chukchi Sea, where fluid discharge does not impact regional biogeochemical reactions in marine sediment. Numerical simulations indicate that the observed data at the investigated site in the shelf cannot be attributed to a water discharge that occurred during the past centuries and thus suggest no association with anthropogenically-induced climate change. Alternatively, we attribute our observations to paleo-subsurface flow resulting from permafrost thaw during the Early Holocene Thermal Maximum (EHTM).

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-356187

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