High-resolution paleomagnetic investigations were performed on Río Valdez outcrop at the Fagnano Lake, central Isla Grande de Tierra del Fuego, southernmost South America. Our aims were to develop a full-vector paleomagnetic secular variation (PSV) record and establish paleomagnetic chronostratigraphy for the outcrop based on radiocarbon dating and the correlation of the PSV record with other dated PSV records in the region. We detected two distinct anomalous directional intervals at 35,400 and 33,800 cal. years BP and at 41,500 and 39,000 cal. years BP, which could be associated with Mono Lake and Laschamp excursions. Rock magnetic investigations revealed slight changes in concentration, mineralogy, and magnetic grain size along the sedimentary sequence, but the reconstruction of past direction and relative paleointensity variations in the geomagnetic field remained feasible. The record provides new insights into the behavior of the geomagnetic field at high latitudes in the Southern Hemisphere, about which very little is currently known.

对南美洲最南端的火地岛大岛中部的法尼亚诺湖的 Río Valdez 露头进行了高分辨率古地磁调查。我们的目标是开发全矢量古地磁长期变化 (PSV) 记录，并基于放射性碳测年以及 PSV 记录与该地区其他 PSV 记录的相关性，建立露头的古地磁年代地层学。我们在 35,400 和 33,800 卡路里处检测到两个不同的异常方向间隔。年 BP 和 41,500 和 39,000 cal。年 BP，这可能与莫诺湖和拉尚远足有关。岩石磁性调查揭示了沿沉积序列的浓度、矿物学和磁性粒度的轻微变化，但是重建过去的方向和地磁场的相对古强度变化仍然是可行的。该记录提供了对南半球高纬度地磁场行为的新见解，目前对此知之甚少。