Portable Magnetic Susceptibility
Magnetic susceptibility properties vary widely and are not solely lithology-linked. For example, in siliciclastic sediments, some sandstones are more susceptible than most shales, whereas some shales can be more susceptible than many sandstones. While there are no global rules for interpreting susceptibility data, the natural variability of siliciclastic sediments allows magnetic susceptibility data to be used as a correlation tool. In carbonate systems, magnetic susceptibility data will reflect increased terrigenous influx, data that can then be used to identify sequence boundaries and system tracts.
One key to magnetic susceptibility interpretation however is the need for a large data set and the best way to obtain that is using a handheld susceptibility meter. The Bartington MS2K Magnetic Susceptibility Scanner is readily transportable and can be used for measurement of magnetic susceptibility in any solid material. It is ideal for direct measurement of core or for use in the field and is entirely non-destructive. There are no HSE issues, the only caution required is if steel (nails, trestle tables) are in close proximity, since that can provide false readings. Typically, 500-600 hundred readings can be made in a working day.
The log shows magnetic susceptibility values in a section from an isolated carbonate platform. Cyclical patterns magnetic response correspond to the tops of the sigmoids and sigmoid sets. In terms of sequence stratigraphy, the Magnetic susceptibility values reach Maxima where the sequences are at their shallowest.