A Konso Silver Tuff correlative found offshore the East African Rift

Offshore the Horn of Africa, volcanic ash layers preserved in deep-sea sediments have played a crucial role in establishing and refining chronologies for paleontological sites in the East African Rift System (EARS). However, no such layers younger than 750 ka have been identified, despite evidence for major eruptions during this interval. Here, we investigate the 166-150 ka interval in marine sediment core MD96-2073, retrieved near Socotra Island. We constructed an age-depth model based on δ 18 O tie-points and 14 C dates, using Bayesian statistics (BACON software). This core spans at least 250 kyr, with a mean chronological uncertainty of ± 3.5 ka (95% confidence interval). Although no visible tephra layers were identified, glass-shard counting revealed a distinct cryptotephra horizon dated to 154.6 ka (13 ka as whole 95% confidence interval). Major and trace element analyses of glass shards allow correlation of this cryptotephra with the Konso Silver Tuff, which is considered to derive from the Shala volcano, making it the youngest EARS-derived tephra currently correlated with marine deposits. This cryptotephra represents a widespread tephrostratigraphic marker and provides a new chronological anchor for sediments of comparable age, including lacustrine, paleontological, and archaeological records.