Hulot et al., 2002 Magnetic field including all terms

Ternary diagram of the iron- titanium oxide solid solution magnetic minerals Magnetic minerals: Ferromagnetism

Two most useful natural rock magnetizations (NRM, J r ) for paleomagnetism Detrital Remanent Magnetization (DRM) formed during or soon after deposition of sediments locked in by compaction and lithification to sedimentary rock relatively weak Thermo-remanent Magnetization (TRM) formed in basic igneous rocks (e.g., basalt) upon cooling through Curie temperature locked in upon further cooling very strong

thermo-remanent magnetization, TRM

Detrital remanent magnetization DRM

Paleomagnetic measurements  Collect many suitable samples (e.g. basalt) with in situ orientation determined

2001 Paleomag trip to Grand Canyon In August, 2001 I was one of about 12 student slaves on a 2 week rafting trip down the Grand canyon to collect paleomag samples. Led by Joe Kirschvink, Caltech We drilled the Tapeats sandstone from the Cambrian; involved lots of water to cool the drill (me at top, Dave Evans, Yale below) Because we were in a national park, we had to patch the drill holes once the samples were removed. Here I am mixing some concete with local rocks

Good result Bad result thermal demag (°C) AC demag (mT)

Isolation from environmental and geomagnetic fields cage Mu metal encased room

corrections for structure

Blocks rotated during Neogene Mojave extension (Miocene)

Paleomagnetic declinations

Declination vrs age for the western Transverse Block Samples from this area

Europe rotated by 38 degrees about rotation pole at 88.5N, 27.7E Closing the North Atlantic Ordovician to Jurassic ( Ma) “Apparent polar wander” (APW) paths for North America and Europe

Errors (  95 cones of confidence)