Circulation changes and nutrient concentrations in the late Quaternary Aegean Sea: A nonsteady state concept for sapropel formation

摘要: sapropel-forming conditions, we identify the start of ‘‘seasonal’’ stratification and highlight a lag in d 18 O response planktonic foraminifer N. pachyderma to termination T1b as identified record G. ruber. By use simple model determine that this offset cannot be function bioturbation effects. The is order 1 kyr suggests isolation intermediate/deep water preceded sapropel formation by up 1.5 kyr. Using discovery, propose an explanation for major unresolved problem studies, namely, source nutrient supply required export productivity reach levels needed sustained deposition. We suggest nutrients had been accumulating astagnant basin 1–1.5 these accumulated resources wereutilized duringthe deposition S1. In addition, provide first quantitative estimate diffusive (1/e) mixing timescale eastern Mediterranean its ‘‘stratified’’sapropel mode, which 450 years. INDEX TERMS: 1050 Geochemistry: Marine geochemistry (4835, 4850); 3030 Geology Geophysics: Micropaleontology; 3339 Meteorology Atmospheric Dynamics: Ocean/atmosphere interactions (0312, 4504); 4267 Oceanography: General: Paleoceanography; 4870 Biological Chemical: Stable isotopes; KEYWORDS: sapropel, Mediterranean, Holocene, foraminifera, climate variability