Labrador and Nunavut Mg/Ca and d18O Data from Coralline Algae covering 1745-2014 CE Light, T.; Williams, B.; Halfar, J.; Hou, A.; Zajacz, Z.; Tsay, A.; Adey, W. Light, T. Williams, B. Halfar, J. Hou, A. Zajacz, Z. Tsay, A. Adey, W. earth science/paleoclimate/corals and sclerosponges (magnesium/calcium,Clathromorphum compactum,null,mole per mole,null,corals and sclerosponges,interpolated,electron probe x-ray microanalysis,N,Annually interpolated microprobe Mg/Ca data.) earth science/paleoclimate/corals and sclerosponges (magnesium/calcium,Clathromorphum compactum,null,mole per mole,null,corals and sclerosponges,interpolated,inductively-coupled plasma mass spectrometry|laser ablation,N,Monthly interpolated LA-ICP-MS Mg/Ca data for a replicate transect.) earth science/paleoclimate/corals and sclerosponges (age,null,null,year Common Era,null,corals and sclerosponges,null,null,N,Age assigned to OES C Mg/Ca data visually using growth bands) earth science/paleoclimate/corals and sclerosponges (age,null,null,year Common Era,null,corals and sclerosponges,null,null,N,Age assigned to Mg/Ca data visually using growth bands) earth science/paleoclimate/corals and sclerosponges (age,null,null,year Common Era,null,corals and sclerosponges,null,null,N,Age assigned to OES A Mg/Ca data visually using growth bands) earth science/paleoclimate/corals and sclerosponges (age,null,null,year Common Era,null,corals and sclerosponges,null,null,N,Age assigned to delta 18O data visually using growth bands) earth science/paleoclimate/corals and sclerosponges (delta 18O,Clathromorphum compactum,null,per mil VPDB,null,corals and sclerosponges,interpolated,isotope ratio mass spectrometry,N,Annually interpolatedd18o data) earth science/paleoclimate/corals and sclerosponges (age,null,null,year Common Era,null,corals and sclerosponges,null,null,N,Age assigned to MS A Mg/Ca data visually using growth bands) earth science/paleoclimate/corals and sclerosponges (magnesium/calcium,Clathromorphum compactum,null,mole per mole,null,corals and sclerosponges,interpolated,inductively-coupled plasma mass spectrometry|laser ablation,N,Monthly interpolated LA-ICP-MS Mg/Ca data for one transect.) earth science/paleoclimate/corals and sclerosponges (age,null,null,year Common Era,null,corals and sclerosponges,null,null,N,Age assigned to MS B Mg/Ca data visually using growth bands) earth science/paleoclimate/corals and sclerosponges (age,null,null,year Common Era,null,corals and sclerosponges,null,null,N,Age assigned to OES B Mg/Ca data visually using growth bands) earth science/paleoclimate/corals and sclerosponges (magnesium/calcium,Clathromorphum compactum,null,mole per mole,null,corals and sclerosponges,interpolated,inductively-coupled plasma atomic emission spectroscopy|laser ablation,N,Monthly interpolated LA-ICP-OES Mg/Ca data for a replicate transect.) earth science/paleoclimate/corals and sclerosponges (delta 18O,Clathromorphum compactum,null,per mil VPDB,null,corals and sclerosponges,interpolated,isotope ratio mass spectrometry,N,Annually interpolated d18o data) earth science/paleoclimate/corals and sclerosponges (age,null,null,year Common Era,null,corals and sclerosponges,null,null,N,Age assigned to microprobe Mg/Ca data visually using growth bands) earth science/paleoclimate/corals and sclerosponges (magnesium/calcium,Clathromorphum compactum,null,mole per mole,null,corals and sclerosponges,interpolated,inductively-coupled plasma atomic emission spectroscopy|laser ablation,N,Monthly interpolated LA-ICP-OES Mg/Ca data for one transect.) earth science/paleoclimate/paleocean earth science/paleoclimate/paleocean (Qikiqtarjuaq>LATITUDE 67.560556>LONGITUDE -64.031389) (Kingitok Island 2013-15(4)>LATITUDE 55.398056>LONGITUDE -59.846667) High-latitude climate reconstructions are essential for discerning anthropogenic climate change from natural climate variability. Since observational high-latitude climate records are rare prior to the satellite era, climate proxies such as the coralline algae Clathromorphum compactum are needed to generate these reconstructions. C. compactum is distributed across the northern high latitudes and documents environmental variability in the magnesium-to-calcium ratio (Mg/Ca) and d18O composition of its calcite skeleton. Therefore, paired Mg/Ca and d18O analyses in C. compactum are a promising new tool for reconstructing historic high-latitude climate change. Here a new method for C. compactum Mg/Ca analysis, laser ablation-inductively coupled plasma-optical emission spectroscopy (LA-ICP-OES), was verified through comparisons with parallel Mg/Ca transects using established techniques in a specimen from Labrador, Canada. Next, LA-ICP-OES Mg/Ca analysis in two specimens from Nunavut, Canada, was paired with d18O analyses. While Mg/Ca data across all specimens captured seasonal sea surface temperature (SST) variability, Mg/Ca values differed in replicate transects within skeleton formed at the same time regardless of technique used. This reduces the effectiveness of C. compactum Mg/Ca as a SST proxy on interannual time scales. Mg/Ca values and d18O composition differed between the two Nunavut specimens, and only one of them documented local SST, sea ice cover, and sea surface salinity. This indicates that climate archive verification is required for each unique coralline algal specimen. In the specimen from Nunavut verified here, paired Mg/Ca and d18O analyses produced more robust sea ice cover/sea surface salinity reconstructions than d18O analyses alone, supporting further development of this proxy system. STUDY NOTES: Mg/Ca and d18O data for 3 coralline algae specimens Provided Keywords: Coralline algae, LA-ICP-OES, Arctic SST, Mg/Ca, d18O NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Light, T. Investigator : Williams, B. Investigator : Halfar, J. Investigator : Hou, A. Investigator : Zajacz, Z. Investigator : Tsay, A. Investigator : Adey, W. 2018-09-10 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/25111 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/light2018/light2018-qk-b.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/light2018/light2018-2013-15.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/light2018/light2018-qk-a.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/light2018/light2018-qk-b.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/light2018/light2018-2013-15.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/light2018/light2018-qk-a.txt English https://www.ncdc.noaa.gov/paleo/study/25111 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/light2018/light2018-qk-b.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/light2018/light2018-2013-15.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/light2018/light2018-qk-a.txt Light, T., Williams, B., Halfar, J., Hou, A., Zajacz, Z., Tsay, A., and Adey, W.2018Advancing Mg/Ca Analysis of Coralline Algae as a Climate Proxy by Assessing LA-ICP-OES Sampling and Coupled Mg/Ca-d18O AnalysisGeochemistry, Geophysics, Geosystems1910.1029/2018GC007504 START YEAR: 1745 AD * END YEAR: 2015 AD -64.031389 55.398056 -59.846667 67.560556