Groundwater and Paleoclimate - Research
Groundwaters constitute not only the globally most important water resource, but also record information about the paleoclimate. Environmental tracer methods provide important quantitative foundations for the sustainable management of these resources, and enable the reconstruction of the recorded climate history. Tracer research in groundwater therefore touches two of the big current and future environmental problems: The increasing scarcity of drinking water and climate change.
Isotope and environmental tracer methods for groundwater dating (e.g. 3H-3He, 4He, CFCs, SF6, 14C) provide characteristic time scales of the renewal of groundwater bodies and the transport of (contaminating) substances. Important research topics concern the self-cleaning potential of polluted aquifers, the contamination risk of wells, and the sustainable use of groundwater resources in arid regions. The primary information that can be obtained from tracer data is the residence time of groundwater in the subsurface, the so-called water age. From this further paramaters are derived, such as recharge rate, flow velocity, permeability, mixing ratios, degradation rates, etc. Often tracer data are used to constrain such parameters in numerical flow and transport models.
From the dissolved noble gases in groundwater, reliable quantitative paleo recharge temperatures can be derived. In contrast to other temperature proxies such as the stable isotopes, for which groundwater is also an appropriate archive, there is no need to rely on empirical relationships. For this reason noble gas temperatures are useful for the calibration of other proxies. A difficulty in the calculation of noble gas temperature is the phenomenon of "excess air" in groundwater. On the other hand it seems that excess air also contains information on the infiltration conditions. The processes and environmental conditions that are relevant for the formation of excess air, as well as the applicability of excess air as a new paleoclimate proxy will be investigated in collaboration with the soil physics group.
In co-operation with the respective research grous at the IEP Heidelberg, the applicability of noble gases in other climate archives (e.g. ice, pore waters, cave deposits) shall be investigated.
Current Research Projects
4. Advancing the use of noble gases as paleoclimate indicators - Projekt unseres EU Marie-Curie-Fellows Laszlo Palcsu
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