Full vector low-temperature magnetic measurements of geologic materials

The magnetic properties of geologic materials offer insights into an
enormous range of important geophysical phenomena ranging from inner core
dynamics to paleoclimate. Often it is the low-temperature behavior
(<300 K) of magnetic minerals that provides the most useful and
highest sensitivity information for a given problem. Conventional
measurements of low-temperature remanence are typically conducted on
instruments that are limited to measuring one single-axis component of the
magnetization vector and are optimized for measurements in strong fields.
These instrumental limitations have prevented fully optimized applications
and have motivated the development of a low-temperature probe that can be
used for low-temperature remanence measurements between 17 and 300 K along
three orthogonal axes using a standard 2G Enterprises SQuID rock
magnetometer. In this contribution, we describe the design and
implementation of this instrument and present data from five case studies
that demonstrate the probe's considerable potential for future
research: a polycrystalline hematite sample, a polycrystalline hematite
and magnetite mixture, a single crystal of magnetite, a single crystal of
pyrrhotite, and samples of Umkondo Large Igneous Province diabase sills.