Groundwater age categories based on tritium concentrations in samples collected from the Mississippi River Valley alluvial aquifer and aquifers of the Mississippi embayment principal aquifer system

The Mississippi River Valley alluvial aquifer (MRVA) overlies and is bounded by several regional aquifers that make up the Mississippi embayment aquifer system (MEAS)...密西西比河谷冲积含水层（Mississippi River Valley alluvial aquifer, MRVA）覆于多个构成密西西比凹陷含水层系统（Mississippi embayment aquifer system, MEAS）的区域含水层之上，并以这些区域含水层为边界。