Boron content of core samples from alliance-28, Surinam, as an indicator of paleosalinity

Abstract

The boron content of the clay fraction of 66 samples from the 338-m deep core hole Alliance-28 in Northern Surinam, indicates a marine palaeosalinity in the Paleocene-Eocene interval at about 295, 240 and 223 m depth, in the Pleistocene interval at about 80 m depth and also in the larger part of the Holocene interval. It furthermore suggests deposition in (almost) fresh water in the upper and lower part of the Paleocene-Eocene interval and in the Pliocene interval. Brackish water is indicated for some parts of the Paleocene-Eocene and the larger part of the Pleistocene intervals. The boron content is relatively high (60-140) ppm) in the clay fraction of calcareous and/or glauconitic sediments, markedly less (30-60 ppm) in sediments intercalated with brown coal and generally lowest (1040 ppm) in white kaolin layers.