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A gravity model for the Sudbury Structure along the Lithoprobe seismic line
Author(s) -
McGrath P. H.,
Broome H. J.
Publication year - 1994
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/93gl02247
Subject(s) - bouguer anomaly , geology , mafic , gravity anomaly , density contrast , basement , anomaly (physics) , seismology , geophysics , petrology , paleontology , physics , civil engineering , condensed matter physics , astronomy , oil field , engineering
Previous gravity models of the Sudbury Structure (1850 Ma) were constrained by surface geology, and by density measurements of surface and borehole rock samples. Recent high‐resolution seismic reflection data provide additional constraints for modeling new gravity observations made along the Sudbury Lithoprobe transect. Results indicate, 1) density distributions constrained by the seismic data yield calculated gravity values matching the Bouguer gravity data, 2) the main sources of gravitational disturbance are external to the Sudbury Structure, 3) the positive gravity anomaly trend south of the Sudbury Structure is associated with mafic rocks of Proterozoic age, and 4) the large, ramplike, gravity anomaly paralleling the northwest margin of the Sudbury Structure is an expression of a northward dipping boundary within the Archean basement. The presence of a hidden mafic layer beneath the Sudbury Structure is not required to model the Bouguer gravity data. An enigma is an 8 mGal, positive, gravity anomaly over the south central Sudbury Structure.