Water-level changes in the Hammock River marsh palaeovalley, Connecticut between 13,000 and 6000 (C) yrs B.P. |
| |
Authors: | Orson van de Plassche Sytze van Heteren W Roland Gehrels Willem G Mook |
| |
Institution: | a Faculty of Earth Sciences, Free University, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands b Centre for Isotope Studies, RUG, Westersingel 34, 9718 CM, Groningen, The Netherlands |
| |
Abstract: | Detailed analysis of basal organic deposits underlying Hammock River marsh, Connecticut allowed documentation of water-level changes that occurred between 13,000 and 6000 yrs B.P. Four main periods of groundwater- and lake-level movements and related environmental changes can be identified. 1. (1) 12,500-10,200 yrs B.P. (lake stage): very rapid rise of the groundwater table of about 2 to 3 m, resulting in a shallow lake, followed by a more gradual rise of about 2.5 to 1.5 m. 2. (2) 10,200-7000 yrs B.P. (freshwater marsh, stage 1): slow overall rise of the water table interrupted by a drop of at least 1 m between about 9500 and 9000 yrs B.P. and of at least 0.8 m between about 8000 and 7500 yrs B.P., each event leading to oxidation and maceration of organic material. 3. (3) 7000-6400 yrs B.P. (complete desiccation of the swamp): rapid fall of the water table of at least 3.9 m. causing large-scale down-wasting of the accumulated peat. 4. (4) After 6400 yrs B.P. (freshwater marsh, stage 2): rapid rise of the water table.
The water-table rise of period 1 and the lowering of period 3 are attributed to predominantly local causes, while the groundwater fluctuations during period 2 are probably climate-related. The final water-level increase reflects the influence of Holocene relative sea-level rise. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|