Geochemical and isotopic evidence for upward flow of saline fluid to the Mississippi River Valley alluvial aquifer, southeastern Arkansas, USA

Groundwater from the Quaternary Mississippi River Valley Alluvial (MRVA) aquifer in southeasternArkansas (SE AR), USA, has higher salinity compared to other MRVA groundwater. Previous studieshave argued for infiltration of evaporated soil water as a primary source for the elevated salinity, althoughseepage from local rivers and deep groundwater sources also have been considered. Geochemical andisotope data from irrigation, public supply, and industrial wells, as well as subsurface geologic data, areused to demonstrate that upward flow of saline water along regional faults is the primary source of salinityin MRVA aquifer groundwater in SE AR. Sodium, chloride (Cl-) and bromide (Br-) concentrationsillustrate mixing relationships between MRVA aquifer groundwater and Jurassic Smackover Formationbrine, with mixing percentages of <1% Smackover brine being the source of anomalously high Cl-, Br-, andother ions in MRVA groundwater with elevated salinity. Stable oxygen and hydrogen isotope data suggestsubstantial mixing of Paleogene Wilcox Formation water with that of the MRVA aquifer groundwater andvarying degrees of evaporative concentration. Radiocarbon and helium isotope data argue for contributionsof chloride-rich, pre-modern and relatively fresh modern water for recharge to the MRVA aquifer.Chloride concentration in MRVA aquifer waters closely follows the spatial distribution of earthquake-inducedliquefaction features and known or suspected geologic faults in SE AR and northeastern Louisiana.A conceptual model is developed where deep-seated basinal fluids in overpressured reservoirs migrateupward along faults during and following Holocene earthquakes into the overlying MRVA over 100s to1,000s of years

A Storied Place: Jonathan Carver’s Travel Narrative and the Indigenous Map of the Upper Mississippi River Valley

This essay recognizes the totality of practices by which Native peoples of the upper Mississippi River valley for centuries oriented themselves to place as an Indigenous map. After limning the map and its material and nonmaterial components, I then place it at the center of a comparative Indigenous-colonizer literary analysis and argue that the manuscript of Euro-American Jonathan Carver’s 1760s travel narrative written in the region is in constitutive relationship to the map. I conclude by turning to printed versions of his narrative to consider how they extend and shape colonialist orientations to the Indigenous map. Attending to how the land has been shaped in partnership with Indigenous text making transforms American literary studies by demonstrating one way that Euro-American texts always were, are, and will be in relation to Native genres.