Production and distribution of greenhouse gases in Hong Kong and East Asian continental shelf sediments since the Middle Pleistocene climatic transition

Professor Yim, Wai Shu Wyss   (Principal Investigator (PI))

Professor Ridley Thomas William Nigel   (Co-Investigator)

Dr Yang Shouye   (Co-Investigator)

Dr Switzer Adam Douglas   (Co-Investigator)

30

2006-07-01

300000

Production and distribution of greenhouse gases in Hong Kong and East Asian continental shelf sediments since the Middle Pleistocene climatic transition

greenhouse gases, Middle Pleistocene, shelf sediments

Earth Sciences,Environmental

HKU 7058/06P

General Research Fund (GRF)

2006

Completed

(1) To use selected boreholes within the Hong Kong continental shelf to provide clues concerning the production of greenhouse gases in the past 500,000 years particularly during the little known episodes of sub-aerial exposure.(2)To identify and map areas affected by sub-surface gas on the Hong Kong continental shelf, the adjacent Pearl River mouth region and selected continental shelves in eastern Asia covered by the EGS (Asia) Limited database.(3) To apply integrated sedimentological and chronological techniques to better confine the episodes of sub-aerial exposure. (4) To examine the broader implications of the findings by comparison with regional and global data including South China Sea coral reef records, deep sea records, ice core records and speleothem records.(5) Issues/problems (a) What is the role of greenhouse gas production from sub-aerially exposed muddy continental shelves at the termination of ice ages? (b) What can be learnt from the Hong Kong continental shelf based on evidence from seismic profiles and boreholes? (c) What can be learnt from other continental shelves in eastern Asia using the unpublished surveying database of EGS (Asia) Limited? (d) Refining of the offshore geological model of Yim (1994) using sequence stratigraphy and state-of-the-art dating methods including radiocarbon, optically-stimulated luminescence (OSL), uranium-series and amino-acid racemization (AAR). (e) To test the implications of the findings using sequence stratigraphy and land-sea correlation. (6) Outcomes/significance/value The findings on greenhouse gas production from sub-aerially exposed continental shelves should generate valuable new knowledge on glacial periods and make an important contribution to the following 5 international projects: (a) The CHANGES (Carbon Hydrology ANd Global Environmental Changes) co-initiative of the International Union of Geological Sciences and the International Council of Scientific Union. The PI’s role as one of the co-managers is to lead carbon cycle research on the neglected continental shelf environment. (b) The 3-year project on ‘Sub-aerially exposed continental shelves since the Middle Pleistocene climatic transition’ submitted through the Commission on Coastal and Marine Processes and funded by the International Union for Quaternary Research (INQUA) for 2005-2007. The PI is the proposer and leader. Note that the funding is entirely for annual meetings including the international workshop in Hong Kong during May 2005, a field meeting in Western Australia in August 2006 and a symposium at the 17th INQUA Congress in Cairns, Australia in July 2007. (c) International Geoscience Programme Project No. 464 ‘Continental shelves during the last glacial cycle’. This project provides a key medium for continental shelf researchers to interact. (d) Past Global Changes (PAGES) project of the International Geosphere-Biosphere Programme (IGBP). (e) Land-ocean Interaction in the Coastal Zone (LOICZ) project of IGBP.