Open AccessAdmittance signatures of rifted and transform margins: examples from eastern Canada
Author(s) -
Verhoef J.,
Jackson H. R.
Publication year - 1991
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1991.tb03458.x
Subject(s) - geology , margin (machine learning) , ridge , bathymetry , admittance , seismology , geodesy , paleontology , oceanography , physics , machine learning , computer science , electrical impedance , quantum mechanics
SUMMARY Examination of the gravity and bathymetry data across the rifted Scotian margin and the sheared Grand Banks margin, off the Canadian east coast, using a spectral analysis or admittance approach. yielded different results. The admittance for the Scotian margin best fitted a regional compensation model; in contrast, a local compensation mechanism reproduced the transfer function for the Grand Banks margin. The results for the longer wavelengths were verified using satellite altimetry data. The effect of a hidden or subsurface load was investigated for both margins and this was also found to differ. The differences in the compensation mechanism between rifted and sheared margins was attributed to their formation mechanisms. Rifted margins are formed by upper crustal faulting and lower crustal flow parallel to the spreading centre. These characteristics are compatible with thin plate flexure compensation. In contrast, transform margins are formed perpendicular to the spreading ridge and the isotherms are only slightly raised as the spreading centre migrates along the margin producing a weak suture which accommodates local compensation.