Abstract
The natural remanent magnetisation (NRM) of basalt lava containing (oxidised) magnetic phases is usually assumed to be proportional to the weight percent of magnetic phases. It is shown here that olivine basalt has a different behaviour. The NRM intensity increases at an increasing rate with the amount of magnetic phases. This is attributed to the oxidation of olivine during cooling of the basalt that leads to the exsolution of magnetite in a single domain state. In this way, olivine basalt is found to become an order of magnitude more magnetic than basalt that does not contain olivine. A simple explanation for the magnetic anomalies on Mars is offered, based upon these findings and Mössbauer spectroscopy data from Gusev crater on Mars.
| Original language | English |
|---|---|
| Pages (from-to) | 276-289 |
| Number of pages | 14 |
| Journal | Physics of the Earth and Planetary Interiors |
| Volume | 154 |
| Issue number | 3-4 |
| DOIs | |
| Publication status | Published - 16 Mar 2006 |
Bibliographical note
Funding Information:H.P. Gunnlaugsson acknowledges support from the Danish Natural Science Foundation (2006-01-0030). The late J.M. Knudsen and R.B. Hargraves are acknowledged for fruitful discussions. J. Chevallier at Aarhus University is acknowledged for experimental help.
Other keywords
- Icelandic basalt
- Magnetic anomalies
- Mars
- Mössbauer spectroscopy
- NRM
- Olivine basalt