Upper Crustal Resistivity Structure of the East Pacific Rise near 13 N
نویسندگان
چکیده
_Abstract. An active source electromagnetic (EM) sounding has been conducted on the axis of the East Pacific Rise (EPR) at 13 ø 10 •N. 1D inversion and modelling techniques, seeking resistivity as a function of depth, have been applied to 8 Ilz amplitude data collected along the ridge crest. Resistivity is seen to increase monotonically between 50 m and 1 km below the seafloor, increasing from •lf•m to around 90Ftm. 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 kin.
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