Subriver Solution Cavities in the Tennessee Valley

Moneymaker, Berlen C.

doi:10.1086/624945

Cited by 9 publications

(3 citation statements)

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“…Consequently, aquifers closely associated with the river system would have been heavily impacted by such events (Creuzé des Châtelliers et al 1994). Drill cores from the lower Tennessee River identified Pleistocene valleys buried at least 21 m below the present valley depth, and groundwater levels were equally depressed during this time (Moneymaker 1941). Thus, groundwater habitats closely aligned with the Tennessee valley (Tuscumbia Limestone formation) may have been more heavily impacted during the Pleistocene, and those at higher elevations and further distance from the valley (Fort Payne Chert formation) may have served as refugia during times of instability.…”

Section: Extrinsic Contributions To Genetic Differentiation and Lineage Divergencementioning

confidence: 99%

The influence of life‐history strategy on genetic differentiation and lineage divergence in darters (Percidae: Etheostomatinae)

2014

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Recent studies determined that darters with specialized breeding strategies can exhibit deep lineage divergence over fine geographic scales without apparent physical barriers to gene flow. However, the extent to which intrinsic characteristics interact with extrinsic factors to influence population divergence and lineage diversification in darters is not well understood. This study employed comparative phylogeographic and population genetic methods to investigate the influence of life history on gene flow, dispersal ability, and lineage divergence in two sympatric sister darters with differing breeding strategies. Our results revealed highly disparate phylogeographic histories, patterns of genetic structure, and dispersal abilities between the two species suggesting that life history may contribute to lineage diversification in darters, especially by limiting dispersal among large river courses.Both species also showed striking differences in demographic history, indicating that extrinsic factors differentially affected each species during the Pleistocene. Collectively, our results indicate that intrinsic and extrinsic factors have influenced levels of gene flow among populations within both species examined. However, we suggest that life-history strategy may play a more important role in lineage diversification in darters than previously appreciated, a finding that has potentially important implications for understanding diversification of the rich North American freshwater fish fauna. K E Y W O R D S :Dispersal ability, genetic structure, microsatellites, phylogeography, sister species.

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Section: Extrinsic Contributions To Genetic Differentiation and Lineage Divergencementioning

confidence: 99%

The influence of life‐history strategy on genetic differentiation and lineage divergence in darters (Percidae: Etheostomatinae)

2014

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“…For instance, dramatic solution cavities beneath fiver beds in the Tennessee Valley, USA, (Moneymaker 1941) occur in an area which probably underwent Devensian (Wisconsian) periglaciation (cf. Washburn 1979, p. 305).…”

Section: Implications Of the New Modelmentioning

confidence: 99%

Devensian periglacial influences on the development of spatially variable permeability in the Chalk of southeast England

Younger

1989

QJEGH

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In unconfined parts of the Chalk aquifer in southeast England, permeability generally varies laterally with the lowest permeabilities occurring beneath interfluve areas, and the highest beneath river valleys and dry valleys. Furthermore, the Chalk in the river valleys is normally in excellent hydraulic continuity with the overlying highly permeable Quaternary gravels. However, recent field investigations in the Thames Valley have demonstrated the existence of zones of anomalously low Chalk permeability associated with the development of thin discontinuous confining layers of low permeability 'putty chalk' at the gravel-chalk interface. Hitherto putty chalk in the Middle Thames Valley has mostly been reported from interfluve areas where it can occur as a periglacially frost-weathered mantle on the upper surface of the Chalk. The true extent and hydraulic significance of putty chalk in valley bottom positions is only now being realised. Existing models for the lateral variation in Chalk permeability cannot explain these new observations. A new model is therefore proposed in which it is envisaged that, during the Devensian, carbonate dissolution in perennial taliks (unfrozen zones) beneath the major channels of the braided palaeo-Thames caused the high-permeability zones, while permafrost beneath the interfluves restricted dissolution at those sites. Freeze-thaw action in seasonal taliks beneath minor channels would account for the formation of putty chalk at the gravel-chalk interface, and the persistence of permafrost beneath these seasonal taliks would lead to a restriction of dissolution, and thus to a zone of low permeability. Form and process in modern periglacial braided river/aquifer systemsModem braided rivers in periglacial environments include the Scott Glacier Outwash River, Alaska, and the Donjek River, Yukon Territory (Miall 1977;Rust 1972), both of which have sediment assemblages

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“…To explore the effects weak points in a grout curtain used, a simplified model was set up in RS2 with the geologic context of the Kentucky Lock for an excavation. The context of this site was chosen because: 1) Kentucky Lock and Dam have previously explored significant ver tical karst features (Moneymaker, 1941) and (Moneymaker & Rhodes, 1945), 2) the current construction of the new lock has exposed large areas of part of the lock foundation and 3) grouting was successfully used in a vertical feature below the upstream cofferdam to prevent excessive water infiltration and 4) the lock foundation and cofferdams are placed on one unit of limestone. Figure 2 below on the right shows the vertical features that were located beneath the upstream cofferdam and where conventional and jet grouting were successfully used to provide seepage.…”

Section: Geology and Context Of The Kentucky Lock Sitementioning

confidence: 99%

The Evolution of Geotech - 25 Years of Innovation

Hammah¹,

Yacoub²,

McQuillan³

et al. 2021

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I have been teaching and researching rock engineering and practicing as a consultant since 1972. I have spent most of that time in underground mining. I have seen significant changes, both evolutionary and radical, in the sector. In this paper, I reflect on some of these changes in mining geomechanical practice. I will also comment on some of the positive and occasionally less positive impacts of these changes. One constant throughout my career is that geomechanical designs will always be fraught with uncertainty. As a result, we will discuss geomechanical design as being, in its essence, a risk management exercise. I will argue that, as impressive as modern numerical analysis techniques are, they do not on their own mitigate design risk; under worst-case scenarios, they make things worse. Empirical and simple models must be used as a check. The paper intends to provoke healthy skepticism in geomechanics practitioners, designers and managers regarding all the aspects of the geomechanical analysis and design process. A failure to recognize the risks in these processes can have catastrophic effects.

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Subriver Solution Cavities in the Tennessee Valley

Cited by 9 publications

References 0 publications

The influence of life‐history strategy on genetic differentiation and lineage divergence in darters (Percidae: Etheostomatinae)

The influence of life‐history strategy on genetic differentiation and lineage divergence in darters (Percidae: Etheostomatinae)

Devensian periglacial influences on the development of spatially variable permeability in the Chalk of southeast England

The Evolution of Geotech - 25 Years of Innovation

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