Trace elements in medium-temperature (40鈥?0聽掳C) thermal waters from the Mura basin (North-Eastern Slovenia)
| 详细信息 | 推荐本文 | |
- 作者：Peter Kralj
- 关键词：Thermal waters ; Hydrogeochemistry ; Trace elements ; Mura basin ; Slovenia
- 刊名：Environmental Geology
- 出版时间：September 2004
- 出版年：2004
- 期刊代码：40_0943-0105
- 类别：ear
- 卷：46
- 期：5
- 页码：622-629
- 数据来源：sp
摘要
Medium-temperature thermal waters in the Mura basin occur in hydrogeological systems different in age, burial depth, temperature, porosity and permeability, and the presence of free carbon dioxide which penetrates through the fractures from pre-Tertiary basement. The waters commonly belong to sodium-bicarbonate hydrogeochemical facies, but may have significantly different amounts of total dissolved solids, including trace elements. Thermal waters occurring in low-permeable, well-compacted and moderately fractured Tertiary sediments older than Upper Pliocene are the richest in trace elements, although their abundance may be very variable from one aquifer to another. The ratios of major alkaline and alkaline earth elements (Na, K, Ca) and trace elements (Li, Rb, Cs, Ba, Sr) commonly show relative enrichment in highly mineralised waters with respect to the waters with lower mineralisation. Rare earth elements (REEs) and Y show only minor fractionation in the highly mineralised waters, whereas in the waters with lower mineralisation strong fractionation of heavy rare earth elements (HREEs) over light rare earth elements (LREEs) occurs, along with a pronounced positive europium anomaly. Positive Th/U ratios are commonly observed, although both actinide elements occur in the range of some hundredths of ppb to some ppb. Trace elements were particularly useful in the study of well cycling in two hydraulically interconnected geothermal wells in the town of Murska Sobota, which produce a mixture of low- and high-mineralised waters.