Premium
Upper crustal resistivity structure of the East Pacific Rise near 13°N
Author(s) -
Evans R. L.,
Constable S. C.,
Sinha M. C.,
Cox C. S.,
Unsworth M. J.
Publication year - 1991
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 - 10.1029/91gl02305
Subject(s) - geology , electrical resistivity and conductivity , depth sounding , crest , crust , seafloor spreading , geophysics , ridge , upper crust , amplitude , seismology , paleontology , oceanography , physics , quantum mechanics
An active source electromagnetic (EM) sounding has been conducted on the axis of the East Pacific Rise (EPR) at 13° 10′N. 1D inversion and modelling techniques, seeking resistivity as a function of depth, have been applied to 8 Hz amplitude data collected along the ridge crest. Resistivity is seen to increase monotonically between 50 m and 1 km below the seafloor, increasing from ∼1Ωm to around 90Ωm. We observe no intrinsic difference in upper crustal resistivity structure between the rise axis and 100,000 year old crust. Inferred surface porosities of 20% are larger than those recorded in 5.9 my old crust in DSDP hole 504B. Our data do not require, and lack sufficient information for, the reliable inclusion of a conductive termination to the model below 1.2 km.