Abstract:
Groundwater age contains critical information about groundwater circulation and evolutionary processes, which is an important hydrogeological parameter. A systematic bibliometric analysis of 1,804 papers published from 1975 to 2024 related to groundwater age with tracers was conducted to sort the current research status and analyze development trends. The result reveals that the number of publications in this field has generally exhibited an exponential upward trend, with the United States, China, and Germany contributing the most publications. Co-occurrence network analysis identifies three key research themes: groundwater quantity, paleoclimate, and groundwater quality. Temporal trends show relatively balanced development across these three themes from 1990 to 2001. An obvious emphasis on groundwater quantity research to guide groundwater resource management was demonstrated during the period from 2002 to 2013, while research focus shifted toward paleoclimate studies to address climate change challenges from 2014 to 2024. Over the past two decades, breakthroughs in Atom Trap Trace Analysis (ATTA) technology have enabled the application of long-lived radioactive noble gas isotopes, creating new opportunities for constructing continuous groundwater chronology sequences over 1.4 million years. Important developmental trends in groundwater chronology were included, but not limited to: improvement of single-tracer age correction models, multi-tracer combination approaches, and coupling with groundwater numerical models. These advancements contribute to enhancing the precision and accuracy of groundwater age dating, providing theoretical support and technical guidance for groundwater resource management and climate change adaptation.