Magnetic, mineralogical, geochemical and sedimentological properties of sediments from the Gulf of San Jorge, Patagonia, Argentina

DESIAGE, P-A; MIGUEL HALLER; MONTERO-SERRANO, JC; ERICA GIARRATANO; ST-ONGE, G; GIL MÓNICA

San Francisco

Encuentro; AGU Fall Meeting - American Geophysical Union; 2016; 2016

American Geophysical Union

In 2014, ~2000 km of geophysical data (multibeam bathymetry, subbottom profiler and sparker), as well as 62 sediment and 28 suspended particulate matter (SPM) samples were collected on board the R/V Coriolis II as part of the MARGES (Marine Geology of the Gulf of San Jorge) and MARES (Marine Ecosystem health of the San Jorge Gulf) Expeditions in the Gulf of San Jorge (Patagonia, Argentina). The SPM was collected using Niskin bottles mounted on a rosette, whereas sediment samples were collected using a grab sampler, box, gravity and piston core in order to reconstruct climatic, oceanographic, aeolian and geomagnetic variations during the Late Pleistocene and Holocene. Here, we present a multi-proxy approach with a focus on the magnetic properties. The new data include mineralogical, geochemical, sedimentological and magnetic properties of surface sediments, SPM and sediment cores and shed light on the sedimentary processes in the Gulf of San Jorge, while geochronological (14C and 210Pb) analyses in conjunction with rock magnetic signatures and other proxies provide insights into the chronostratigraphy and environmental changes since the last glaciation in Patagonia. Our results reveal very low recent sedimentation rates and the importance of dust and coastal erosion as a major sediment source in the Gulf during the Holocene, while the last glaciation and deglaciation were marked by important relative sea-level changes and meltwater inputs.