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Regional shortening fabrics in eastern North America: Far‐field stress transmission from the Appalachian‐Ouachita Orogenic Belt
Author(s) -
Craddock John P.,
Jackson Mike,
Pluijm Ben A.,
Versical Robert T.
Publication year - 1993
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/92tc01106
Subject(s) - geology , foreland basin , paleozoic , differential stress , sedimentary rock , calcite , thrust fault , tectonics , paleontology , geochemistry , seismology , petrology , geomorphology , deformation (meteorology) , oceanography
Paleozoic carbonates of cratonic eastern North America comprise the footwall of the Appalachian‐Ouachita fold‐and‐thrust belt and contain a layer‐parallel shortening (lps) fabric that is preserved by mechanically twinned calcite. Shortening directions are generally parallel to the Appalachian‐Ouachita thrust‐transport direction in carbonates of the thrust belt proper (restored width ∼400 km) and within carbonates up to 1700 km into the foreland, giving a pre‐thrusting sedimentary prism ∼2100 km wide through which compressive orogenic stresses were transmitted. The shortening strain magnitudes (<6%) and the inferred calcite twinning differential stress magnitudes (<90 MPa) decrease exponentially away from the orogenic front. Calcite twinning strain patterns in other adjacent tectonic provinces, such as the Grenville, Laramide, Keweenawan Rift, and Newark Basin, are distinct from the twinning strains preserved in the cratonic Paleozoic carbonates. (Appalachian orogen, far‐field stresses, calcite microstructures).