The Neogene-Quaternary Guadix-Baza basin in southeast Spain offers a good scenario to analyze the links between fluvial erosion, uplift, and fault activity. The basin is divided in two sub-basins by a major active structure, the Baza normal fault. The Guadix sub-basin is located on the footwall block of the fault, and the Baza sub-basin on the hanging-wall. In this area, fluvial erosion is especially intense since the Late Pleistocene when the lacustrine drainage network of the basin was captured by a major river: the Guadalquivir River. The capture point was located in the Guadix sub-basin, which meant that a higher amount of sediment was removed from the footwall block of the fault. However, erosion on the hanging-wall basin was not as intense. Sediment remobilization caused load release on the basin, and subsequent surface uplift (isostatic rebound). Differential erosion between sub-basins resulted in differential uplift, as well as deformation concentration along the boundary between both sub-basins (the Baza fault), and the fault slip. Fernandez-Ibanez et al. show the importance of erosion in basin evolution, and the controls on fault activity. This has important implications for the analysis of old basins and the quantification of basin extension rates.
Climate and Antarctic Intermediate Water coupling during the late Holocene
Christine Euler and Ulysses S. Ninnemann, Dept. of Earth Science, University of Bergen, 5007 Bergen, Norway. Pages 647-650.
The ratio of oxygen isotopes in shells of planktonic and bottom-dwelling foraminifera (single celled marine organisms) were used to document natural variations in the southeast Pacific Ocean temperature and salinity during the first 1300 years A.D. The data presented by Christine Euler and Ulysses Ninnemann of
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Geological Society of America