Comments on “The cut and recorrelated gravity map of the United States”



G. L. Kinsland (Eos, August 28, 1984, p. 490) proposed that a late Proterozoic transcontinental right-lateral strike-slip fault system with approximately 600 km of offset exists in the United States, striking northwest from southeastern Alabama to northwestern Montana. After Kinsland corrected the proposed displacement, two aligned gravity features were noted: first, the Central North American Rift System (CNARS) and the Hartville Uplift and second, the Late Proterozoic rift passive margins of the Ouachita Mountains and the Appalachian Mountains. However, significant displacement along the proposed trace of the fault is precluded by the disruption of various terranes that would result (Figures 1a and lb). Some of these terranes include

  • The northwestern corner of the Wyoming province (feature 4 in the figures; Dutch [1983]).
  • The North American Central Plains conductive anomaly (NACPCA)-Mullen Creek-Nash Fork shear zone (feature 3; Camfield and Gough [1977]).
  • The CNARS (feature 2), which Yarger and Lam [1983] and Yarger [1982] extended through Kansas to the Oklahoma border. Danbom et al. [1980] found gravity and magnetic evidence for a probable extension of the CNARS into northern Oklahoma.