Noble gas signatures in the Island of Maui, Hawaii: Characterizing groundwater sources in fractured systems
| Autor: | Yi Niu, Rohit B. Warrier, M. Clara Castro, Chris M. Hall, Stephen B. Gingerich, Martha A. Scholl |
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| Rok vydání: | 2017 |
| Předmět: |
Hydrology
geography geography.geographical_feature_category 010504 meteorology & atmospheric sciences Noble gas Aquifer Groundwater recharge 010502 geochemistry & geophysics 01 natural sciences Rainwater harvesting Infiltration (hydrology) Sedimentary rock Precipitation Groundwater Geology 0105 earth and related environmental sciences Water Science and Technology |
| Zdroj: | Water Resources Research. 53:3599-3614 |
| ISSN: | 0043-1397 |
| Popis: | Uneven distribution of rainfall and freshwater scarcity in populated areas in the Island of Maui, Hawaii, renders water resources management a challenge in this complex and ill-defined hydrological system. A previous study in the Galapagos Islands suggests that noble gas temperatures (NGTs) record seasonality in this fractured, rapid infiltration groundwater system rather than the commonly observed mean annual air temperature (MAAT) in sedimentary systems where infiltration is slower thus, providing information on recharge sources and potential flow paths. Here, we report noble gas results from the basal aquifer, springs, and rainwater in Maui to explore the potential for noble gases in characterizing these complex fractured hydrologic systems. Most samples display a mass-dependent depletion pattern with respect to surface conditions consistent with previous observations both in the Galapagos Islands and Michigan rainwater. Basal aquifer and rainwater noble gas patterns are similar and suggest direct, fast recharge from precipitation to the basal aquifer. In contrast, multiple springs, representative of perched aquifers, display highly variable noble gas concentrations suggesting recharge from a variety of sources. The distinct noble gas patterns for the basal aquifer and springs suggest that basal and perched aquifers are separate entities. Maui rainwater displays high apparent NGTs, incompatible with surface conditions, pointing either to an origin at high altitudes with the presence of ice or an ice-like source of undetermined origin. Overall, noble gas signatures in Maui reflect the source of recharge rather than the expected altitude/temperature relationship commonly observed in sedimentary systems. |
| Databáze: | OpenAIRE |
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