Appalachian stress study. 2. Analysis of Devonian shale core: some implications for the nature of contemporary stress variations and Alleghanian deformation in Devonian rocks

K. F. Evans, G. Oertel, James Terry Engelder

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

Detailed stress measurements in three boreholes penetrating horizontally bedded Devonian siltstones, sandstones, and limestones above a prominent salt decollement in the Appalachian Plateau of western New York have revealed variations in horizontal stress magnitudes which correlate with lithologic and stratigraphic units in all wells. High differential stress levels (up to 20MPa) were found in shales of very high clay content, contrary to the proposition that such materials have negligible long-term strength. Elastic modulus data show that stiffer beds generally host higher stress levels and suggest that sand/shale stress contrasts result in large part from elastic shortening of the section in response to regional ENE compression. No correlation between stress and Poisson's ratio was found. However, a major systematic drop in stress level within the generally massive shales, which occurs across a group of sand beds near the base of the Rhinestreet formation, appears to be of different origin. The stress offset corresponds to the top of a section which we conclude, on the basis of local and regional total strain data derived from chlorite fabric measurements, once hosted abnormally high pore pressures. -from Authors

Original languageEnglish (US)
Pages (from-to)7155-7170
Number of pages16
JournalJournal of Geophysical Research
Volume94
Issue numberB6
DOIs
StatePublished - Jan 1 1989

Fingerprint

Alleghanian
Appalachian region
shale
Shale
rocks
Rocks
sand
chlorites
sandstone
strength (mechanics)
modulus of elasticity
limestone
shortenings
rock
plateaus
shales
clay
salts
sands
beds

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences (miscellaneous)
  • Palaeontology

Cite this

@article{f489239d538d445ba6fad62b8deb34da,
title = "Appalachian stress study. 2. Analysis of Devonian shale core: some implications for the nature of contemporary stress variations and Alleghanian deformation in Devonian rocks",
abstract = "Detailed stress measurements in three boreholes penetrating horizontally bedded Devonian siltstones, sandstones, and limestones above a prominent salt decollement in the Appalachian Plateau of western New York have revealed variations in horizontal stress magnitudes which correlate with lithologic and stratigraphic units in all wells. High differential stress levels (up to 20MPa) were found in shales of very high clay content, contrary to the proposition that such materials have negligible long-term strength. Elastic modulus data show that stiffer beds generally host higher stress levels and suggest that sand/shale stress contrasts result in large part from elastic shortening of the section in response to regional ENE compression. No correlation between stress and Poisson's ratio was found. However, a major systematic drop in stress level within the generally massive shales, which occurs across a group of sand beds near the base of the Rhinestreet formation, appears to be of different origin. The stress offset corresponds to the top of a section which we conclude, on the basis of local and regional total strain data derived from chlorite fabric measurements, once hosted abnormally high pore pressures. -from Authors",
author = "Evans, {K. F.} and G. Oertel and Engelder, {James Terry}",
year = "1989",
month = "1",
day = "1",
doi = "10.1029/JB094iB06p07155",
language = "English (US)",
volume = "94",
pages = "7155--7170",
journal = "Journal of Geophysical Research",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "B6",

}

Appalachian stress study. 2. Analysis of Devonian shale core : some implications for the nature of contemporary stress variations and Alleghanian deformation in Devonian rocks. / Evans, K. F.; Oertel, G.; Engelder, James Terry.

In: Journal of Geophysical Research, Vol. 94, No. B6, 01.01.1989, p. 7155-7170.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Appalachian stress study. 2. Analysis of Devonian shale core

T2 - some implications for the nature of contemporary stress variations and Alleghanian deformation in Devonian rocks

AU - Evans, K. F.

AU - Oertel, G.

AU - Engelder, James Terry

PY - 1989/1/1

Y1 - 1989/1/1

N2 - Detailed stress measurements in three boreholes penetrating horizontally bedded Devonian siltstones, sandstones, and limestones above a prominent salt decollement in the Appalachian Plateau of western New York have revealed variations in horizontal stress magnitudes which correlate with lithologic and stratigraphic units in all wells. High differential stress levels (up to 20MPa) were found in shales of very high clay content, contrary to the proposition that such materials have negligible long-term strength. Elastic modulus data show that stiffer beds generally host higher stress levels and suggest that sand/shale stress contrasts result in large part from elastic shortening of the section in response to regional ENE compression. No correlation between stress and Poisson's ratio was found. However, a major systematic drop in stress level within the generally massive shales, which occurs across a group of sand beds near the base of the Rhinestreet formation, appears to be of different origin. The stress offset corresponds to the top of a section which we conclude, on the basis of local and regional total strain data derived from chlorite fabric measurements, once hosted abnormally high pore pressures. -from Authors

AB - Detailed stress measurements in three boreholes penetrating horizontally bedded Devonian siltstones, sandstones, and limestones above a prominent salt decollement in the Appalachian Plateau of western New York have revealed variations in horizontal stress magnitudes which correlate with lithologic and stratigraphic units in all wells. High differential stress levels (up to 20MPa) were found in shales of very high clay content, contrary to the proposition that such materials have negligible long-term strength. Elastic modulus data show that stiffer beds generally host higher stress levels and suggest that sand/shale stress contrasts result in large part from elastic shortening of the section in response to regional ENE compression. No correlation between stress and Poisson's ratio was found. However, a major systematic drop in stress level within the generally massive shales, which occurs across a group of sand beds near the base of the Rhinestreet formation, appears to be of different origin. The stress offset corresponds to the top of a section which we conclude, on the basis of local and regional total strain data derived from chlorite fabric measurements, once hosted abnormally high pore pressures. -from Authors

UR - http://www.scopus.com/inward/record.url?scp=0024927879&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0024927879&partnerID=8YFLogxK

U2 - 10.1029/JB094iB06p07155

DO - 10.1029/JB094iB06p07155

M3 - Article

AN - SCOPUS:0024927879

VL - 94

SP - 7155

EP - 7170

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - B6

ER -