A comment on: 'A detailed rock magnetic and opaque mineralogy study of the basalts from the Nazca Plate' by H. P. Johnson and J. M. Hall

Abstract

Johnson & Hall (1978) have discussed the results of magnetic measurements and reflected light microscopy of basalts from Legs 34 and 16 of the Deep Sea Drilling Project. Their data form two main groups: (1) Samples from unoxidized or slightly oxidized massive flows tend to be associated with low Curie points (T, < 200°C) and small median demagnetizing fields and with relatively high values of intensity of natural remanence (Jn), of saturation magnetization (J"), of low-field susceptibility ( k ) and of overall ferromagnetic grain size and grain concentration. (2) In the fine-grained pillow lavas T, is in the range 225-40Ooc.