Depth trends in magnetic properties in an area of prolonged cold seawater drawdown in uppermost Troodos-type oceanic crust

Study of the oxide minerals and measurements of the magnetic properties of about 100 samples distributed over a 475 m continuous drill-core section from the uppermost part of an extrusive sequence of the Troodos, Cyprus, ophiolite close to 35°02′N, 33°11′E, in the vicinity of Malounda, yields the following principal results: (1) Low-temperature alteration is intense to a depth of 260 m, below which it is relatively much subdued. (2) Saturation magnetization, natural remanence intensity, and initial susceptibility all increase continuously with depth throughout the section. (3) Curie temperature decreases with depth to 260 m, below which a change in the style of the thermal decay of magnetization behaviour takes place. (4) Pillowed and massive flows differ in their magnetic properties.The results are consistent with the downwards decrease in low-temperature alteration also noted by K. Gillis from the distribution of secondary minerals. The downwards variations in magnetic properties closely follow in both ...