Computer Science
Scientific paper
Jul 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992metic..27s.264m&link_type=abstract
Meteoritics, vol. 27, no. 3, volume 27, page 264
Computer Science
Scientific paper
The Millbillillie eucrite has been intensively studied to determine its magnetic properties. Mutually oriented samples were measured for their Natural Remanent Magnetization (NRM), magnetic susceptibility (chi), and anisotropy of susceptibility. Chi is low (0.9+-0.7x10^-6 m^3 kg^-1), and anisotropy of susceptibility is unaligned and small. The magnetic carriers are identified as single domain/pseudo-single domain nickel-poor kamacite. A large proportion of the magnetic grains are paramagnetic kamacite that quickly decay to iron oxides on heating. There is an initial clustering of NRM directions, and alternating field (a.f.) demagnetization of the NRM show that a hard unidirectional primary component is overprinted by a softer secondary magnetization associated with the fusion crust. The weak but stable magnetization was measured using a cryogenic magnetometer. Due to clast-rich/clast-poor layering, it is believed that Millbillillie has suffered minimal shock since formation (Fitzgerald, 1980). The unidirectional magnetization supports this conclusion. Since the primary component is uniform in direction within the sample, palaeointensity experiments are expected to yield meaningful results. Without checking samples for internal uniformity of magnetization directions, results could be misleading. Three methods were used. Results using the ARM-NRM method average at ~27 microteslas, as do those from Thellier-Thellier dual heating. IRM normalization gives values of 6 microteslas and 25 microteslas; this method is considered the least accurate of the three. The palaeointensity results indicate that the rock cooled in a strong magnetic field; an internal dynamo-type magnetizing field is preferred over external fields (solar wind or impact- generated) for dynamical reasons. On the assumption that a body similar to 4 Vesta is the Howardite-Eucrite-Diogenite parent body, the high palaeointensity results could argue for an iron core for such a body. Fitzgerald, M.J. (1980) Trans. R. Soc. Aust., 104 (6), 201-207.
No associations
LandOfFree
The Magnetic Properties of the Millbillillie Eucrite: Palaeointensity Results and Evidence for a Dynamo-Type Magnetising Field does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Magnetic Properties of the Millbillillie Eucrite: Palaeointensity Results and Evidence for a Dynamo-Type Magnetising Field, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Magnetic Properties of the Millbillillie Eucrite: Palaeointensity Results and Evidence for a Dynamo-Type Magnetising Field will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1210137