MARGO-D-24-00269
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Data of Marine Geology article : Coral reef boulders as recorders of cyclone activity over the last 3,500 years (Fakarava Atoll, Tuamotu, French Polynesia) Table 1. Uranium-thorium dating of selected coral samples from top surface reef boulders, south-eastern reef rim, Fakarava Atoll. Ages are given in calendar years before present (cal. yr BP), relative to 2024 and in years BC (Before Jesus Christ) or AD (Anno Domini). Age discrepencies betwwen the dated coral samples are given. See Table S1 (supplementary mayerial) for error ranges associated with ages. Table 2. Morphometric attributes (length, width, height, volume, weight and distance of location relative to the reef front line) of the 19 U/Th dated reef boulders, south-eastern reef rim, Fakarava Atoll, partly based on photogrammetric imagery analysis. Table 3. Pre-displacement setting and flow velocities (m/s) of four selected boulders, from the south-eastern reef-rim side, Fakarava Atoll (north-west Tuamotu). As the bed angle of the boulders at the pre-displacement location was assumed to be θ=0, there is no difference between the values of lifting motion for both joint-bounded and non-joint bounded boulders Table S1. Supplementary material: uranium–thorium dating of coral samples extracted from reef boulders, south-eastern reef rim, Fakarava Atoll. Are given successively laboratory sample codes, field sample (F, FAK) numbers, uranium and thorium contents, isotopic composition with statistical errors – two standard deviations of the mean – and ages. Uranium and thorium contents and isotopic ratios δ234UM = {[(234U/238U)sample / (234U/238U)eq]-1} x 1000, where (234U/238U) sample is the measured atomic ratio and (234U/238U)eq is the atomic ratio at secular equilibrium. δ234U(T) is the initial value and is calculated by the equation: δ234U(0) = δ234Umeans exp(λ234t), where t is the age in years and λ234 is the decay constant for 234U. Ages were corrected for authigenic 230Th using 230Th/232Th) of the detrital fraction = 10 ± 5. Ages are expressed in both calendar years before present (BP), relative to 2024, corrected for detrital content using a 230Th/232Th isotopic ratio = 7 ± 50% and in conventional ages BP (Before Present, relative to 1950).
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Table S1. Supplementary material: uranium–thorium dating of coral samples extracted from reef boulders, south-eastern reef rim, Fakarava Atoll. Are given successively laboratory sample codes, field sample (F, FAK) numbers, uranium and thorium contents, isotopic composition with statistical errors – two standard deviations of the mean – and ages. Uranium and thorium contents and isotopic ratios δ234UM = {[(234U/238U)sample / (234U/238U)eq]-1} x 1000, where (234U/238U) sample is the measured atomic ratio and (234U/238U)eq is the atomic ratio at secular equilibrium. δ234U(T) is the initial value and is calculated by the equation: δ234U(0) = δ234Umeans exp(λ234t), where t is the age in years and λ234 is the decay constant for 234U. Ages were corrected for authigenic 230Th using 230Th/232Th) of the detrital fraction = 10 ± 5. Ages are expressed in both calendar years before present (BP), relative to 2024, corrected for detrital content using a 230Th/232Th isotopic ratio = 7 ± 50% and in conventional ages BP (Before Present, relative to 1950).