Abstract
We present measurements of Sr/Ca, δ18O, and spectral luminescence ratios (G/B) from a mid-Holocene Porites sp. microatoll recovered from the nearshore Great Barrier Reef (GBR). These records were used as proxies to reconstruct sea surface temperature (SST), the δ18O of surrounding seawater (δ18Osw), and riverine influence, respectively, and compared with records from a modern Porites sp. microatoll growing in the same environment. Strong riverine influence in the mid-Holocene record is indicated by (1) an increased annual δ18Osw range in the mid-Holocene record, (2) negative peaks in δ18O characteristic of flood events, and (3) a higher G/B luminescence ratio. Seasonal cycles in G/B suggest that humic acid inputs were elevated for a longer portion of the year during the mid-Holocene. The seasonal cycle of δ18Osw peaked earlier in the year in the mid-Holocene record relative to the modern, while mean δ18Osw values from the mid-Holocene record were similar to modern values. These records provide an insight into the oceanographic conditions the nearshore GBR experienced during mid-Holocene climatic shifts and are consistent with a strong Australian–Indonesian Summer Monsoon (AISM) system at ~ 4700 cal. yr BP.
Highlights
The mid-Holocene (~ 6000–4000 yr BP) is a period where rapid shifts in global climate patterns and monsoon systems occurred (Duprey et al, 2012; Greer and Swart, 2006)
Palynological data from north-eastern Australia indicate generally wetter conditions and suggest that a shift occurred in ENSO system state at ~ 5000 yr BP from a La Niña type with higher precipitation, to an El Niño-dominated state with lower precipitation associated with modern ENSO conditions (Rodbell et al, 1999; Sandweiss et al, 1996; Shulmeister and Lees, 1995)
We present a multi-proxy skeletal δ18O, Sr/Ca, and spectral luminescence record of seasonal to interannual variability in riverine influence obtained from nearshore Great Barrier Reef (GBR) coral microatolls
Summary
The mid-Holocene (~ 6000–4000 yr BP) is a period where rapid shifts in global climate patterns and monsoon systems occurred (Duprey et al, 2012; Greer and Swart, 2006). The GBR is one of the most studied reef provinces, with numerous studies focusing on determining the relationship between coral geochemical proxies and modern SSTs (Alibert et al, 2003; Cardinal et al, 2001; Fallon et al, 2003; Marshall and McCulloch, 2002). Mid-Holocene proxy records from the GBR are rare, further limiting our understanding of oceanographic conditions during the Holocene period of reef-building
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
