کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5783048 1637523 2017 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Differences in groundwater and chloride residence times in saline groundwater: The Barwon River Catchment of Southeast Australia
ترجمه فارسی عنوان
تفاوت در زمانهای اقامت زمین و کلراید در آبهای زیرزمینی شور: دره رود باروون در جنوب شرقی استرالیا
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
چکیده انگلیسی


- Chloride and groundwater residence times are not necessarily equal in semi-arid regions.
- Elevated groundwater salinity is primarily due to recycling of solutes in saline lakes.
- Calculated 14C mean residence times vary with flow model and input function.
- 36Cl ratios in rainfall were higher in the past due to environmental change.
- Enrichment in δ13C suggests increasing evaporation over the past 20 ka or longer.

The residence times of groundwater and chloride and the processes contributing to the development of saline (total dissolved solids (TDS) up to 45,379 mg/L) groundwater within the Barwon River Catchment of southeast Australia were investigated using major ion, stable isotope (δ18O, δ2H, and δ13C) and radioactive isotope (3H, 14C, 36Cl) geochemistry. The elevated groundwater salinity in the region is primarily due to evapotranspiration and recycling of solutes in saline lakes with minor contributions from weathering of halite, silicate and calcite minerals. Groundwater residence times estimated from 14C vary from modern to ~ 20 ka; for groundwater with lower 14C activities, the estimated residence times vary significantly depending on the assumed flow model and the 14C activity of recharge. Chloride residence times downgradient of Lake Murdeduke (a saline through-flow lake in the centre of the catchment) are greater than the corresponding groundwater residence times due to the recycling of Cl within the lake. Precise estimates of chloride residence time could not be determined using 36Cl due to R36Cl in precipitation being lower than that of groundwater. This is most likely due to R36Cl values in rainfall having been higher in the past than they are at present due to climate variability. δ18O, δ2H, and δ13C values also suggest that the region has experienced increasingly more evaporative conditions with time. The results of this study demonstrate that, while Cl is a useful tracer of hydrological processes, it must be applied carefully in arid and semi-arid regions of the world. In particular, recharge rates calculated using chloride mass balance may be underestimated where recycling of Cl has occurred.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Geology - Volume 451, 20 February 2017, Pages 154-168
نویسندگان
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