Different analysis of sediment core GeoB13823-2, GeoB13824-1 and GeoB13861-1 from the Argentine continental margin

• Main Authors: Warratz, Grit, Henrich, Rüdiger, Voigt, Ines, Chiessi, Cristiano Mazur, Kuhn, Gerhard, Lantzsch, Hendrik
• Format: Dataset
• Language: English
• Published: PANGAEA 2017
• Subjects: Center for Marine Environmental Sciences; MARUM; Antarctic; Argentine; Antarc*
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.874957; https://doi.org/10.1594/PANGAEA.874957

The deep southern component water (SCW), comprising Lower Circumpolar Deep Water (LCDW) and Antarctic Bottom Water (AABW), is a major component of the global oceanic circulation. It has been suggested that the deep Atlantic water mass structure changed significantly during the last glacial/interglacial cycle. However, deep SCW source-proximal records remain sparse. Here we present three coherent deep SCW paleo-current records from the deep Argentine continental margin shedding light on deep-water circulation and SCW flow strength in the Southwest Atlantic since the Last Glacial Maximum (LGM). Based on coherently increased sortable silt values, we propose enhanced deep SCW flow strength from 14 to 10 cal ka BP relative to the early deglacial/LGM and the Holocene. We propose a direct influence of deep northern component water (NCW) on deep SCW flow strength due to vertical narrowing of deep SCW spreading concurrent with a migration of the high-energetic LCDW/AABW interface occupying our core sites. We suggest a shoaled NCW until 13 cal ka BP, thereby providing space for deep SCW spreading that resulted in reduced carbonate preservation at our core sites. Only from 13 cal ka BP on, increased carbonate content indicates that NCW expanded vertically leading to a deeper NCW-SCW interface. This NCW expansion changed deep-water properties in the deep Southwest Atlantic causing enhanced carbonate preservation at our core sites. We further show that southern-sourced terrigenous sediment-supply to our core sites was uninterrupted since the LGM due to a persistent deep SCW flow leading to contourite drifts at the Argentine continental margin.