Short-lived Radioisotope (SLR) data are generated for selected core sub-samples at 2mm sampling intervals for “surficial unit” and 5mm sampling resolution intervals to base of cores. SLR data generated include sample activity (dpm/g) of: 1) Excess 234Th activity, which is calculated by measuring the total 234Th activity and the subtraction of the measured or estimated “background” 234Th activity, 2) Excess 210Pb activity, which is calculated by measuring the total 210Pb activity and subtraction of the measured background 210Pb activity (average of 214Pb; 295keV, 214Pb: 351keV, and 214Bi; 609keV), 3) 137Cs activity, and 4) 7Be activity. Where appropriate, age dating is calculated in calendar years for 234Th and 210Pb activity profiles, as well as linear accumulation rates (LAR) expressed as cm/yr, and mass accumulation rates (MAR) expressed as g/cm2/yr.
Brooks, Gregg. 2015. Short-lived radioisotope geochronology. Distributed by: Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC), Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7VT1Q1Z
Total 234Th (63keV) activity (dpm/g) Total 210Pb (46keV) activity (dpm/g) 214Pb (295keV) activity (dpm/g) 214Pb (351keV) activity (dpm/g) 214Bi (609keV) activity (dpm/g) 137Cs (661keV) activity (dpm/g) 7Be (477keV) activity (dpm/g) CRS Age dating (yrs) and MAR (g/cm2/yr) 210Pb and 234Th
Data were corrected for counting time, detector efficiency and varying geometry using the IAEA RGU-1 standards for calibration, as well as for the fraction of the total radioisotope measured yielding activity in dpm/g. CRS (Constant Rate of Supply) Model applied to assign a date to each individual sample and calculate LAR. LAR = linear accumulation rate (cm/yr) MAR (g/cm2/yr) = dry bulk density (g/cm3) x LAR (cm/yr) CRS (Constant Rate of Supply) Model applied to assign a date to each individual sample
Series HPGe (High-Purity Germanium) Coaxial Planar Photon Detectors