Abstract:Stusdy of the oxide minerals and measurement of the megnetic properties of about 100 samples distributed over a 475m continuous drillcore section from the uppermost part of extrusive sequence of the Troodos, Cyprus, ophiolite close to 35°03´N, 33°10´ E in the vicinity of Malounda yields the following major results: -Low temperature alteration is intense to a depth of 260 m, below which it is relatively much subdued. -Saturation magnetization, natural remanence intensity and initial suscep- }ibility all increase continuously with depth throughout the section. -Curie temperature decreases with depth to 260 m, below which a change in the style in the thermal decay of magnetization behaviour takes place. -Pillowed and massive flows differ in their magnetic properties. The rdsults are consistent with the downwards decrease in low temperature alteration previously noted from the distribution of secondary minerals. The downwards variations in magnetic properties closely follow in both sense a.nd magnitude of the trends observed in DSDP Hole 417A. This supports the inter- pratation of the upper, reddened facies of the Troodos extrusive sequence as being due to prolonged drawdown of cold sea water, and suggests that the magnetization of at least the upper part of the Troodos ophiolite is a reliable guide to ocean crust magnetization.