Gray value determination from sediment core of Lake Alchichica in Mexico@en

The grey values were measured from a 57-cm-long sediment core retrieved from Lake Alchichica (19° 24' 38 N, 97° 24' 14 W, 2322 masl) at a water depth of ~ 60 m using a Uwitec® coring device equipped with a 9-cm coring tube. The core structure was revealed by a Siemens Somatom Definition +128 CT-scanner at the INRS Centre Eau Terre Environnement with a 0.31 mm resolution in the stratigraphic direction. Grey levels are expressed in Hounsfield units (HU): light (dark) grey levels represent dense (light) sediments. The analysis was performed at the INRS Centre Eau Terre Environnement in Canada.