ISSN:
1573-0417
Keywords:
Stable isotopes
;
strontium isotopes
;
hydrology
;
paleolimnology
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
Notes:
Abstract Reconnaissance δ18O,, δD, and δ87Sr data for fifteen lakes in the Western Lakes Region of the Sand Hills of Nebraska indicate dynamic hydrologic systems. The rather narrow range of δ87Sr from lake water (1.1 to 2.1) and groundwater (0.9 to 1.7) indicates that the groundwater is generally unradiogenic. Groundwater residence times and relatively unradiogenic volcanic ash within the dune sediments control the δ87Sr values. Based on the mutual variations of δ18O and δD, the lakes can be divided into three groups. In Group 1, both δ18O and δD values increase from spring to fall. The δ18O and δD values in Group 2 decreased from spring to fall. Group 3 are ephemeral lakes that went dry some time during 1992. The data and isotopic modeling show that variations in the ratio of evaporation relative to groundwater inflow, local humidity conditions, and the δa has substantial influence on the isotopic composition. In addition, isotopic behavior in ephemeral lakes can be rather unusual because of the changing activities of water and mineral precipitation and redissolution. The annual and interannual isotopic variability of these lakes which is reflected in the paleonvironmental indicators may be the rule rather than the exception in these types of systems.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1007913010057
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