Discriminating Solar vs. Ocean Forcing of Holocene Climate From Observations of 14C in the Ocean Mixed Layer

Konrad Hughen, Marine Chemistry & Geochemistry

OCCI Project Funded: 2005

Proposed Research

What are the primary questions you are trying to address with this research? (Or, if more appropriate, is there a hypothesis or theory that you are trying to prove or disprove?)
What processes act to amplify the Holocene climate response to possible solar forcing? 

What is the significance of this research for others working in this field of inquiry and for the broader scientific community?

The signature of radiocarbon change in the surface ocean relative to the atmosphere should change depending on whether the forcing is from variability in solar irradiance or deep-ocean ventilation.  Identifying these 14C signatures in the same sediments as Holocene climate shifts will provide evidence of potential climate forcing mechanisms. 

What is the significance of this research for society?
Identifying the mechanisms responsible for causing abrupt climate fluctuations is critical to our ability to predict such changes in the future. 

When and where will this investigation be conducted? (For instance, is this new fieldwork, or a new analysis of existing data?)

The investigation will involve new analyses of existing sediment cores from the Cariaco Basin.

What are the key tools or instruments needed to conduct this research?
We will use the brand-new scanning-XRF Facility at WHOI, and also conduct ultra-high resolution 14C dating (~10-yr temporal resolution) across several rapid climate shifts to identify D14C excursions in the ocean mixed-layer. 

What are the greatest challenges - physical or intellectual - to conducting this investigation?
Resolving annual-scale laminations for counting will be critical to constructing high-quality floating varve chronologies. 

Is this research part of a larger project or program?
This is part of a larger effort to provide accurate 14C calibration for marine records during the Holocene, as well as accurate calibration for marine and atmospheric records beyond the age of tree ring chronologies back to ~13 ka.

Websites

http://www.ngdc.noaa.gov/paleo/pubs/hughen2004/hughen2004.html
http://www.ngdc.noaa.gov/paleo/pubs/hughen2000/hughen2000.html
http://www.ngdc.noaa.gov/paleo/pubs/hughen1998/

Research Interests

My research interests involve the application of inorganic and organic geochemical and sedimentological techniques toward constructing and interpreting high-resolution, multi-proxy paleoenvironmental records in order to understand the mechanisms controlling global climate change at a variety of time scales.