scholarly journals Airborne geophysical surveys of the lower Mississippi Valley demonstrate system-scale mapping of subsurface architecture

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Burke J. Minsley ◽  
J. R. Rigby ◽  
Stephanie R. James ◽  
Bethany L. Burton ◽  
Katherine J. Knierim ◽  
...  
Keyword(s):  
Groundwater Age ◽  
Regional Scale ◽  
The United States ◽  
Shallow Aquifer ◽  
Mississippi Valley ◽  
Seismic Zone ◽  
Lower Mississippi Valley ◽  
Shallow Subsurface ◽  
Aquifer Systems ◽  
Geophysical Surveys

AbstractThe Mississippi Alluvial Plain hosts one of the most prolific shallow aquifer systems in the United States but is experiencing chronic groundwater decline. The Reelfoot rift and New Madrid seismic zone underlie the region and represent an important and poorly understood seismic hazard. Despite its societal and economic importance, the shallow subsurface architecture has not been mapped with the spatial resolution needed for effective management. Here, we present airborne electromagnetic, magnetic, and radiometric observations, measured over more than 43,000 flight-line-kilometers, which collectively provide a system-scale snapshot of the entire region. We develop detailed maps of aquifer connectivity and shallow geologic structure, infer relationships between structure and groundwater age, and identify previously unseen paleochannels and shallow fault structures. This dataset demonstrates how regional-scale airborne geophysics can close a scale gap in Earth observation by providing observational data at suitable scales and resolutions to improve our understanding of subsurface structures.

Closing a scale-gap in Earth observation using regional-scale airborne geophysics in the lower Mississippi Valley

2021 ◽  
Author(s):  
Burke Minsley ◽  
James Rigby ◽  
Stephanie James ◽  
Bethany Burton ◽  
Katherine Knierim ◽  
...  
Keyword(s):  
United States ◽  
Groundwater Resources ◽  
Regional Scale ◽  
The United States ◽  
Shallow Aquifer ◽  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Aquifer Systems ◽  
Regional Hydrogeology ◽  
New Madrid

<p>Critical groundwater resources and hidden seismic hazards underly much of the Mississippi Alluvial Plain. Spanning nearly 100,000 square kilometers across seven states, this region hosts one of the most prolific shallow aquifer systems in the United States that supports a $12 billion agricultural economy amidst chronic groundwater decline. Further, underlying fault structures of the Reelfoot Rift and New Madrid Seismic Zone represent an important and poorly understood hazard with a complex pattern of historical impacts. Despite its societal and economic importance, mapping of shallow subsurface architecture with spatial resolution needed for effective management is insufficient. Here, we report the results of 40,000 flight-line-kilometers of electromagnetic, magnetic, and radiometric data collectively providing a system-scale snapshot of an entire aquifer system, the first such effort in the United States. This survey enables new understanding of the regional hydrogeology while also revealing previously unseen large vertical displacements (exceeding 50 m) in the uppermost Tertiary units within the New Madrid Seismic Zone.</p>

Assessing and Managing Geologic Hazards in the Appalachian Region of the United States

2019 ◽  
Author(s):  
Martin P. Derby ◽  
Bailey Theriault
Keyword(s):  
United States ◽  
Regional Scale ◽  
Appalachian Basin ◽  
The United States ◽  
Rapid Expansion ◽  
Phase Iii ◽  
Geophysical Surveys ◽  
Geologic Hazards ◽  
Basin Region ◽  
Best Fit

Abstract Geohazards have the potential to adversely affect the operation or integrity of an existing pipeline, or the routing, design, and construction of a proposed pipeline. Identifying, characterizing, evaluating, and if necessary, mitigating and monitoring geologic hazards have become critical steps to successfully and safely building and operating pipelines in the Appalachian Basin region of the United States. The recent, rapid expansion of pipeline construction and operation in the region, along with natural geologic and geographic conditions which are conducive to landsliding and ground subsidence, have resulted in a recent increase in geohazard-related incidences both during and post-construction of pipelines. As such, there is an increasing need to recognize, understand, and closely manage geohazards in this region, prior to, during, and post-construction of pipelines. This paper will provide an overview of essential tools that have proven most useful in this region, to identify, characterize, and ultimately mitigate and monitor potential geohazards. This paper will also provide insight on how to evaluate specific project needs and best-fit approaches and solutions for the project at hand, to reduce the operator’s risk. A case study will be presented from the Appalachian Basin region, including how a phased approach was used to assess and manage geohazards. The phased approach includes (1) Phase I Assessments, which consist of a regional-scale desktop assessment to identify, initially characterize, and qualitatively classify (e.g., low, moderate, high hazards) geohazards; (2) Phase II Assessments, which consist of a non-intrusive ground reconnaissance completed at targeted sites; and (3) Phase III Assessments, which consist of subsurface investigations such as drilling, test pitting, or geophysical surveys to further characterize specific hazards. The information obtained from the phased approach can be used for the design of mitigation and/or monitoring, if deemed necessary. Overall approaches to selecting and utilizing best-fit mitigation and monitoring options, both during and post-construction, fit for the regional conditions and to the individual project, will also be discussed.

Hydrochemical interpretation of groundwater flow systems in Quaternary sediments of southern Ontario

1986 ◽  
Vol 23 (7) ◽  
pp. 938-947 ◽  
Author(s):  
K. W. F. Howard ◽  
P. Beck
Keyword(s):  
Major Ions ◽  
Regional Scale ◽  
Shallow Aquifer ◽  
Sediment Geochemistry ◽  
Quaternary Sediments ◽  
Southern Ontario ◽  
Water Types ◽  
Regional Flow ◽  
Aquifer Systems ◽  
Composite Flow

Shallow aquifer systems in surficial Quaternary sediments are geometrically complex, with highly variable hydraulic characteristics. Consequently these systems are extremely difficult to assess hydrogeologically using conventional investigation techniques and are often poorly understood. In a 500 km2 area of southern Ontario, hydrochemical techniques were used to investigate the hydraulic integrity and regional flow behaviour of 14 aquifer systems defined within 100 m of Quaternary overburden. This type of approach had been used successfully in more extensive bedrock aquifer systems but had not previously been applied on a regional scale to shallow Quaternary systems where sediment geochemistry and flow conditions are highly variable and rarely known. The study involved analysis of over 260 well waters for pH, major ions (Ca, Mg, Na, K, HCO3, Cl, and SO4) and subsidiary ions (NO3, I, Br, and F). Selected samples were analyzed for tritium.The groundwaters are classified into eight water types, two of which are sodium chloride in character and of bedrock origin. Of the remaining six, four are related by a chemical evolutionary sequence showing transition from a tritiated (> 30 TU), low-iodide (< 5 μg/L) CaHCO3 recharge water to an ion-exchanged, NaHCO3 water low in tritium (< 15 TU) and enriched in iodide (> 15 μg/L). The existence of this sequence implies a regional, composite flow system involving seven supposedly discrete aquifer systems.The two remaining water types are recent tritiated waters (> 20 TU) contaminated by road salt (Cl > 40 mg/L) and agricultural nitrate (NO3 > 10 mg/L). Together with the CaHCO3 waters these clearly delineate major areas of recharge and show that the covering of Halton Till is extensively permeable.

2 The Development of Archaeological Knowledge in the Lower Mississippi Valley

1964 ◽  
Vol 18 ◽  
pp. 3-15 ◽  
Author(s):  
Robert E. Greengo
Keyword(s):  
United States ◽  
The United States ◽  
Thomas Jefferson ◽  
Mississippi Valley ◽  
Lower Mississippi Valley ◽  
Archaeological Knowledge ◽  
Plausible Argument

Observations having some bearing on the archaeology of the Lower Mississippi Valley are to be found in the writings of the early travelers. As the country became settled, accounts of local and regional historical interest often included remarks or occasional papers devoted to the local antiquities. My purpose here is to sketch the conceptualization of prehistory as it was developed through the most significant writings.A plausible argument may be submitted in support of the contention that Thomas Jefferson was the first scientific archaeologist in the United States. Curiously enough, his archaeological influence extended to the Lower Mississippi Valley. This was through H. M. Brackenridge, who went into the Louisiana Territory soon after it was purchased and wrote a number of descriptive accounts of the country.

scholarly journals Assessing Decadal Trends of a Nitrate-Contaminated Shallow Aquifer in Western Nebraska Using Groundwater Isotopes, Age-Dating, and Monitoring

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1047 ◽  
Author(s):  
Martin Wells ◽  
Troy Gilmore ◽  
Aaron Mittelstet ◽  
Daniel Snow ◽  
Steven Sibray
Keyword(s):  
Groundwater Age ◽  
Small Region ◽  
The United States ◽  
Nitrate Contamination ◽  
Age Dating ◽  
Shallow Aquifer ◽  
United States Geological Survey ◽  
Biogeochemical Processes ◽  
Mean Values ◽  
Recharge Rates

Shallow aquifers are prone to nitrate contamination worldwide. In western Nebraska, high groundwater nitrate concentrations ([NO3−]) have resulted in the exploration of new groundwater and nitrogen management regulations in the North Platte Natural Resources District (NPNRD). A small region of NPNRD (“Dutch Flats”) was the focus of intensive groundwater sampling by the United States Geological Survey from 1995 to 1999. Nearly two decades later, notable shifts have occurred in variables related to groundwater recharge and [NO3−], including irrigation methods. The objective of this study was to evaluate how changes in these variables, in part due to regulatory changes, have impacted nitrate-contaminated groundwater in the Dutch Flats area. Groundwater samples were collected to assess changes in: (1) recharge rates; (2) biogeochemical processes; and (3) [NO3−]. Groundwater age increased in 63% of wells and estimated recharge rates were lower for 88% of wells sampled (n = 8). However, mean age and recharge rate estimated in 2016 (19.3 years; R = 0.35 m/year) did not differ significantly from mean values determined in 1998 (15.6 years; R = 0.50 m/year). δ15N-NO3− (n = 14) and dissolved oxygen data indicate no major changes in biogeochemical processes. Available long-term data suggest a downward trend in normalized [NO3−] from 1998 to 2016, and lower [NO3−] was observed in 60% of wells sampled in both years (n = 87), but median values were not significantly different. Collectively, results suggest the groundwater system is responding to environmental variables to a degree that is detectable (e.g., trends in [NO3−]), although more time and/or substantial changes may be required before it is possible to detect significantly different mean recharge.

Astronomy and U.S. Expansion in the Lower Mississippi Valley

2018 ◽  
pp. 129-161
Author(s):  
Cameron B. Strang
Keyword(s):  
United States ◽  
Scientific Community ◽  
The United States ◽  
Mississippi Valley ◽  
Scientific Practices ◽  
Lower Mississippi Valley ◽  
William Dunbar

U.S. expansion into the lower Mississippi Valley from 1795 to 1810 evinced and inspired many of the ways that officials and experts in the early United States used astronomy to promote territorial growth. Yet Anglo-Americans did not simply export scientific practices to the United States’ new territories. Peaceful and violent encounters among Spaniards and Anglos, masters and slaves, inhabitants and administrators, and whites and Indians all shaped the practice of astronomy in the Gulf South and, moreover, influenced how astronomy and imperialism overlapped in the United States on the whole. Geopolitical competition motivated the work of the Spanish and U.S. commissions of the Florida boundary survey (1798–1800), violence against slaves enabled astronomers like William Dunbar to perform disciplined observations, and interimperial exchanges of data made José Joaquín de Ferrer y Cafranga a prominent figure in the United States’ scientific community.

Personal Empires: Mapping, Local Networks, and the Control of Land in the Lower Mississippi Valley

2021 ◽  
Vol 10 (2) ◽  
pp. e021
Author(s):  
Matthew E. Franco
Keyword(s):  
United States ◽  
Eighteenth Century ◽  
United States Of America ◽  
The United States ◽  
Spatial Representations ◽  
Mississippi Valley ◽  
Way Of Life ◽  
Local Networks ◽  
Property Ownership ◽  
Lower Mississippi Valley

The Louisiana and Florida territories sat at the intersection of empires in the late eighteenth century. Between 1750 and 1820 the area was controlled by the French and Spanish empires, the emerging United States of America, as well as the Choctaw, Creek, and Seminole nations. While political surveys produced images of the moving borders between sovereign powers, cadastral surveys show the constancy of local landowners. Landowners superseded national distinction and were a constant in an area in the midst of great change. As control of the region shifted, landowning families continued their way of life. The continued circulation of Spanish cadastral surveys after the transfer of the region to the United States of America shows how Spanish spatial representations of property ownership shaped the image of the Lower Mississippi Valley.

scholarly journals Multi-isotopic regional-scale screening on drinking groundwater in Lombardy Region (Italy)

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Chiara Sbarbati ◽  
Maurizio Gorla ◽  
Alessandro Lacchini ◽  
Agata Cristaldi ◽  
Davide Lo Monaco ◽  
...  
Keyword(s):  
Dissolved Inorganic Carbon ◽  
Groundwater Age ◽  
Groundwater Resources ◽  
Regional Scale ◽  
Ion Concentration ◽  
Aquifer Recharge ◽  
Lombardy Region ◽  
Drinking Purposes ◽  
Aquifer Systems ◽  
The Impact

Groundwater is the main and safest source of water used for drinking purposes in many urban and rural communities worldwide. A deep knowledge of aquifer systems in terms of quality, vulnerability and renewability is fundamental to preserving groundwater resources. Thanks to contributions by different members of Water Alliance in synergy with Sapienza University, during November 2019 a multiisotopic regional scale analysis was carried out on groundwater tapped for drinking purposes in a wide area of the Lombardy Region. The study aimed to improve knowledge of recharge mechanisms, the groundwater’s relative age, and the impact of human activities on groundwater quality. Each Water Alliance supplier selected some wells and springs drawing water from different aquifer groups and distributed from north to south, for a total of 121 samples. Groundwater stable isotope analyses were performed on all the monitoring points, while tritium, nitrogen isotopes (15N and 18O in nitrates), sulphate isotopes (34S and 18O) and 13C isotope in Dissolved Inorganic Carbon (DIC) were analysed in selected monitoring wells based on previous data and major ion concentration results. The results confirm the key role of a multi-isotopic approach in defining aquifer recharge processes, relative groundwater age and the origin of pollutants, offering a useful tool to highlight local issues which could be investigated in depth by each water supplier.

Allegiance, Identities, and National Scientific Communities

2018 ◽  
pp. 162-207
Author(s):  
Cameron B. Strang
Keyword(s):  
United States ◽  
Case Studies ◽  
Scientific Community ◽  
The United States ◽  
Mississippi Valley ◽  
Scientific Communities ◽  
Territorial Expansion ◽  
Lower Mississippi Valley ◽  
William Dunbar

This chapter studies how individuals in the lower Mississippi Valley fashioned identities as men of science. It focuses on the 1790s to the 1810s, an era when several empires and other groups competed for power in the region. Local experts tried to benefit from circulating information among a variety of actual and potential patrons, and, in the process, they manipulated and blurred the boundaries between the United States’ scientific community and those of other polities competing for the borderlands. The chapter includes case studies of the Spanish naturalist and spy Thomas Power, the Scottish planter and astronomer William Dunbar, and the French engineer and slave trader Barthélémy Lafon. Their stories reveal how territorial expansion both added to, and exacerbated deep tensions within, the United States’ scientific community.

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