Structural geology of North America

Eardley, A. J.

doi:10.5962/bhl.title.62079

Cited by 214 publications

(84 citation statements)

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“…The Sierra Nevada Mountains (Curtis et al , 1958) and the Colorado Plateau (Eardley, 1962) are features which came into existence long before Miocene time. Also, the Gulf of California did not exist at this time (Larson et al .…”

mentioning

confidence: 99%

The impact of tectonic activity in the development of Monterey Submarine Canyon

Allen¹

1982

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mentioning

confidence: 99%

The impact of tectonic activity in the development of Monterey Submarine Canyon

Allen¹

1982

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“…Reference [51] also documents Grenville-age inversion on the Mid-Continent Rift System, and cross-sections after [52] and [36] show significant deformation in the Cambrian-Mississippian section, overlain by a base Pennsylvanian unconformity. A major tectonic event, making the proto-Nemaha Uplift emergent, is documented in the Ordovician [37,53,54].…”

Section: Methodsmentioning

confidence: 99%

“…Inversion via compression of Mid-Continent Rift System structures is documented from calcite strain analysis in the Lake Superior Region, ranging in age from Grenvillian-age transpressive strain to Permian age contraction [50]. Reference [51] also documents Grenville-age inversion on the Mid-Continent Rift System, and cross-sections after [52] and [36] show significant deformation in the Cambrian-Mississippian section, overlain by a base Pennsylvanian unconformity. A major tectonic event, making the proto-Nemaha Uplift emergent, is documented in the Ordovician [37,53,54].…”

Section: Figurementioning

confidence: 99%

Joint and Lineament Patterns across the Midcontinent Indicate Repeated Reactivation of Basement-Involved Faults

et al. 2018

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Joint networks hosted in successively younger rocks, developing as a result of forced (trishear) folding of a rock mass above a deep-seated fault, can be used to infer the reactivation history of that deep-seated fault. This study aims to use joint networks in Pennsylvanian, Permian and Cretaceous rocks to document evidence of reactivation on basement faults during the Paleozoic and Mesozoic of Nebraska and Kansas. The most prominent basement features in southeast Nebraska and northeast Kansas are oriented NE-SW, likely related to the Midcontinent Rift System and Nemaha Uplift, and oriented NW-SE, likely related to fabrics from the Central Plains Orogeny. These features are well defined in the potential fields data. Joint patterns in the study area show an E-W oriented trend, as well as clearly discernable NE-SW and subsidiary N-S and NW-SE trends. The E-W trend is interpreted to be related to far-field stresses from Laramide and Ancestral Rocky Mountain orogenic events, whilst the NE-SW trend is interpreted to be related to subtle reactivation on the Mid-continent rift and related faults, observed in basement data. These movements produced stresses of sufficient magnitude to produce joints in the post-rift rock units, but not sufficient to generate shear fractures. Similarly, the~N-S and NW-SE joint trends are taken as evidence of subtle reactivation on the Nemaha Uplift and Central Plains Orogeny systems, generating joints by the formation of forced folds. This contribution therefore provides a convincing case study of the value of coupled potential fields and surface feature studies in discerning buried tectonic trends and subtle reactivation thereon.

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“…1996;Vecchioli et a1. 1969); they developed early in the history of basin evolution while rifting continued and the more competent, coarser-grained beds responded brittlely to extensional stress (Eardley 1962). The numerous steeply dipping fractures identified by Morin et a1.…”

Section: Deep Wellmentioning

confidence: 96%

Fractured‐Aquifer Hydrogeology from Geophysical Logs: Brunswick Group and Lockatong Formation, Pennsylvania

2000

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The Brunswick Group and the underlying Lockatong Formation are composed of lithified Mesozoic sediments that constitute part of the Newark Basin in southeastern Pennsylvania. These fractured rocks form an important regional aquifer that consists of gradational sequences of shale, siltstone, and sandstone, with fluid transport occurring primarily in fractures. An extensive suite of geophysical logs was obtained in seven wells located at the borough of Lansdale, Pennsylvania, in order to better characterize the areal hydrogeologic system and provide guidelines for the refinement of numerical ground water models. Six of the seven wells are approximately 120 m deep and the seventh extends to a depth of 335 m. Temperature, fluid conductivity, and flowmeter logs are used to locate zones of fluid exchange and to quantify transmissivities. Electrical resistivity and natural gamma logs together yield detailed stratigraphic information, and digital acoustic televiewer data provide magnetically oriented images of the borehole wall from which almost 900 fractures are identified.Analyses of the geophysical data indicate that the aquifer penetrated by the deep well can be separated into two distinct structural domains, which may, in turn, reflect different mechanical responses to basin extension by different sedimentary units:1. In the shallow zone (above 125 m), the dominant fracture population consists of gently dipping bedding plane partings that strike N46°E and dip to the northwest at about 11 degrees. Fluid flow is concentrated in the upper 80 m along these subhorizontal fractures, with transmissivities rapidly diminishing in magnitude with depth.2. The zone below 125 m marks the appearance of numerous high-angle fractures that are orthogonal to the bedding planes, striking parallel but dipping steeply southeast at 77 degrees.This secondary set of fractures is associated with a fairly thick (approximately 60 m) high-resistivity, low-transmissivity sandstone unit that is abruptly terminated by a thin shale bed at a depth of 190 m. This lower contact effectively delineates the aquifer's vertical extent at this location because no detectable evidence of ground water movement is found below it. Thus, fluid flow is controlled by fractures, but fracture type and orientation are related to lithology. Finally, a transient thermal-conduction model is successfully applied to simulate observed temperature logs, thereby confirming the effects of ground-surface warming that occurred in the area as a result of urbanization at the turn of the century. The systematic warming of the upper 120 m has increased the transmissivity of this aquifer by almost 10%, simply due to changes in fluid viscosity and density.

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Structural geology of North America

Cited by 214 publications

References 0 publications

The impact of tectonic activity in the development of Monterey Submarine Canyon

The impact of tectonic activity in the development of Monterey Submarine Canyon

Joint and Lineament Patterns across the Midcontinent Indicate Repeated Reactivation of Basement-Involved Faults

Fractured‐Aquifer Hydrogeology from Geophysical Logs: Brunswick Group and Lockatong Formation, Pennsylvania

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