Heron Reef Mid-Holocene Porites and Acropora Sr/Ca Data Sadler, J.; Webb, G.E. Sadler, J. Webb, G.E. earth science/paleoclimate/corals and sclerosponges earth science/paleoclimate/corals and sclerosponges (Heron Island Reef>LATITUDE -23.45>LONGITUDE 151.92) The tropical and subtropical oceans of the Southern Hemisphere are poorly represented in present-day climate models, necessitating an increased number of paleoclimate records from this key region to both understand the Earth's climate system and help constrain model simulations. Here we present a site-specific calibration of live collected massive Porites Sr/Ca records against concomitant in situ instrumental water temperature data from the fore-reef slope of Heron Reef, southern Great Barrier Reef (GBR). The resultant calibration, and a previously published Acropora calibration from the same site, was applied to subfossil coral material to investigate Holocene water temperatures at Heron Reef. U-Th-dated samples of massive Porites suggest cooler water temperatures with reduced seasonal amplitude at ~5.2 ka (2.76–1.31°C cooler than present) and ~7 ka (1.26°C cooler than present) at Heron Reef. These results contrast the previous suggestion of a mid-Holocene Thermal Maximum in the central GBR around 5.35 ka and 4.48 ka, yet may be explained by differences in temperature of the shallow ponded reef flat (central GBR) and the deeper reef slope waters (this study) and potential large reservoir correction errors associated with early radiocarbon dates. Combining coral-based water temperature anomaly reconstructions from the tropical and subtropical western Pacific indicates a coherent temperature response across the meridional gradient from Indonesia and Papua New Guinea down to the southern GBR. This similarity in reconstructed temperature anomalies suggests a high probability of an earlier expression of a mid-Holocene Thermal Maximum on the GBR between ~6.8 and 6.0 ka. STUDY NOTES: Modern and mid-Holocene Sr/Ca data from Porites colonies and Acropora inter-branch skeleton collected from Heron Reef, southern GBR. Water depths <= 23m. Provided Keywords: Porites, Acropora, inter-branch skeleton, Sr/Ca, mid-Holocene, southern GBR NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Sadler, J. Investigator : Webb, G.E. 2016-03-17 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/19902 https://www1.ncdc.noaa.gov/pub/data/paleo/coral/west_pacific/sadler2016/sadler2016-heron.txt https://www1.ncdc.noaa.gov/pub/data/paleo/coral/west_pacific/sadler2016/sadler2016-heron.txt English https://www.ncdc.noaa.gov/paleo/study/19902 https://www1.ncdc.noaa.gov/pub/data/paleo/coral/west_pacific/sadler2016/sadler2016-heron.txt Sadler, J., G.E. Webb, N.D. Leonard, L.D. Nothdurft, and T.R. Clark2016Reef core insights into mid-Holocene water temperatures of the southern Great Barrier ReefPaleoceanography311410.1002/2016PA002943 START YEAR: 6962 cal yr BP * END YEAR: -64 cal yr BP 151.92 -23.45 151.92 -23.45