Magnetic susceptibility scanning of a composite sediment core from Laguna Vogt, central west Patagonia

A 3 m-long sediment composite record was retrieved from Laguna Vogt (46.74º S, central west Patagonia) using a UWITEC gravity corer (for the uppermost 70 cm depth) and a modified Livingstone piston corer (for the remaining depths) during march, 2020. Several analytical techniques were applied to the sediment records. Firstly, X-ray fluorescence and magnetic susceptibility scanning were done at 1 mm and 1 cm resolution, respectively. Afterwards, subsampling was carried out at a 1 cm depth resolution. Exceptionally, the resolution was changed to 0.5 cm for sections with contrasting lithologies. Bulk chemistry measurements for elements C, N, and S were performed on the subsamples at intervals between 4 and 0.5 cm. Finally, grain size distributions for the subsamples were measured using a 4 cm step protocol. Results are presented with respect to depth and age. Ages were derived from an age-depth model based on 9 samples taken for radiocarbon dating from the composite profile.

2020年3月，研究团队从巴塔哥尼亚中西部的沃格特湖（Laguna Vogt，南纬46.74°）获取了总长3米的沉积岩芯复合记录：其中顶部70厘米采用UWITEC重力采样器采集，剩余层段则使用改良型利文斯通活塞采样器获取。针对该沉积记录，研究人员采用了多项分析技术：首先分别以1毫米和1厘米的分辨率开展X射线荧光（X-ray fluorescence）扫描与磁化率扫描测试；随后以1厘米的深度分辨率进行分样，对于岩性差异显著的层段，分辨率调整为0.5厘米以开展针对性分样。对上述分样开展碳（C）、氮（N）、硫（S）元素的体相化学测试，测试间隔介于0.5至4厘米之间；最后，采用4厘米步长的测试方案，对分样进行粒度分布测定。所有测试结果均以深度与年代为基准呈现；年代数据则基于该复合岩芯剖面中9个放射性碳测年样品所构建的年代-深度模型推导得出。