To account for the high reservoir ages (up to 1,200 years) in high latitude (polar) regions an additional offset of ΔR=700 ±100 ¹⁴C years was introduced (following multiple iterations) to the existing R=405 ¹⁴C years (pre-setting Marine 13 calibration curve), resulting in a total reservoir effect of 1,105 ¹⁴C years.