Did the Middlesboro, Kentucky, bolide impact event influence coal rank?

Hower, James C.; Greb, Stephen F.; Kuehn, K.; Eble, Cortland F.

doi:10.1016/j.coal.2009.05.003

Cited by 8 publications

(4 citation statements)

References 18 publications

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“…Adding these components together results in a total erosion of the Middlesboro impact structure of about 1.5 km. This is in contrast to the measured coal rank that indicates erosion of up to 4 km (Hower et al, 2009).…”

Section: Cratering Mechanicscontrasting

confidence: 83%

“…Three constraints can be placed on timing of the impact structure: (i) Impact timing appears to postdate the Alleghanian orogeny “because the Middlesboro basin structure does not seem to be deformed and appears to deform preexisting structure” (Rice & Ping, 1989). Based on Rodgers (1970), impact timing can be constrained to late Pennsylvanian and/or Permian age; (ii) a second constraint is given by the occurrence of Quaternary sediments overlying the basin; (iii) a third constraint was derived from burial depth calculations based on coal rank measurements, constraining timing of the impact to a minimum post‐early Permian age (Hower et al., 2009). Burial depth of the exposed strata is estimated to be roughly 4 km (Hower et al., 2009).…”

Section: Introductionmentioning

confidence: 99%

“…Based on Rodgers (1970), impact timing can be constrained to late Pennsylvanian and/or Permian age; (ii) a second constraint is given by the occurrence of Quaternary sediments overlying the basin; (iii) a third constraint was derived from burial depth calculations based on coal rank measurements, constraining timing of the impact to a minimum post‐early Permian age (Hower et al., 2009). Burial depth of the exposed strata is estimated to be roughly 4 km (Hower et al., 2009).…”

Section: Introductionmentioning

confidence: 99%

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Geophysical and structural analyses of the Middlesboro impact structure, Kentucky, USA: Reactivation of a thrust detachment of the Appalachian foreland fold‐and‐thrust belt

Wihanto,

Kenkmann

2023

Meteorit & Planetary Scien

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This paper reports on the Middlesboro impact structure (36°37′03″ N; 83°43′39″ W), a complex impact structure located in the Appalachian foreland fold‐and‐thrust belt of southeast Kentucky, USA. The structure forms a basin approximately 5.5 km in diameter exposing intensely deformed Pennsylvanian sediments. Based on field data, microstructural observation, and geophysical analyses we qualitatively assess degree and distribution of fragmentation of target rocks within the impact structure. Shock deformation features, especially feather features, are reported for the impact structure. Shallow seismic refraction data were acquired along a radial profile from outside the impact structure to the center of the structure. Seismic (P‐wave) velocity trends indicate that fracture intensity increases toward the center, reducing the overall seismic velocity. However, intense rock sealing in some parts of the central uplift increases the strength of rock samples and locally increases seismic velocities. We present a modified geologic map of the Middlesboro impact structure based on high‐resolution lineament analysis, field work, and reevaluation of existing structural data from geologic maps. The modified map suggests that crater circularity at Middlesboro is skewed by the reactivation of pre‐existing zones of structural anisotropy in the target. We propose that due to an oblique impact from northerly direction the sub‐horizontal Pine Mountain thrust plane beneath the impact structure became reactivated with a top‐to‐the south shear component. The impact‐induced formation/reactivation of the Doublings Fault Zone as a thrust ramp appears to have deflected the otherwise straight strike of the Cumberland Mountains southward. The Rocky Face fault approaches the crater rim fault, and we propose that this sinistral strike‐slip fault was formed, or at least reactivated, by the impact and accommodated the oblique impact's horizontal momentum.

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Section: Cratering Mechanicscontrasting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Geophysical and structural analyses of the Middlesboro impact structure, Kentucky, USA: Reactivation of a thrust detachment of the Appalachian foreland fold‐and‐thrust belt

Wihanto,

Kenkmann

2023

Meteorit & Planetary Scien

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“…Faults associated with the structure result in a degree of unpredictability regarding the continuity of coal beds, with the sudden loss of coal, changes in dip and brecciation. Although not an unequivocal conclusion, the local rise in the rank of the coal at Middlesboro by some 20% could be from local post-impact heating (Hower et al, 2009). …”

Section: Gold and Uranium Of Vredefortmentioning

confidence: 99%