Thellier-type paleointensity experiments were conducted on welded ash matrix or pumice from the 1912 Novarupta (NV) and 1980 Mt. St. Helens (MSH) pyroclastic density currents (PDCs) with the intention of evaluating their suitability for geomagnetic paleointensity studies. PDCs are common worldwide, but can have complicated thermal and alteration histories. We attempt to address the role that em...

A magnetic signature of tree rings was tested as a potential paleo-climatic indicator. We examined wood from sequoia tree, located in Mountain Home State Forest, California, whose tree ring record spans over the period 600 - 1700 A.D. We measured low and high-field magnetic susceptibility, the natural remanent magnetization (NRM), saturation isothermal remanent magnetization (SIRM), and stabili...

In the natural case of an hypervelocity impact on a planetary or asteroidal surface, two competing phenomena occur: partial or complete shock demagnetizat on of preexisting remanence and acquisition of shock remanent magnetization (SRM). In this paper, to better understand the effects of shock on the magnetic history of rocks, we simulate this natural case through laser shock experiments in con...

Introduction: The burst of early work on the magnetism of the Apollo samples was followed by a quiescent period until recently. It had been thought that the strong magnetization in samples, whose ages ranged from approximately 3.65 to 3.9 Ga, was evidence of a lunar dynamo at that time. New results have yielded evidence for a possible early dynamo at ~4.2 Ga giving surface fields of the order o...

This article presents magnetic data of a 300-m-thick Mio-Pliocene red clay and Quaternary loess-paleosol sequence near Chaona town in the Central Chinese Loess Plateau. Detailed magnetostratigraphy shows that the aeolian red clay began to accumulate at ca. 8.1 Ma. Here, we presented a high-resolution rock magnetic data at 20-40 cm intervals within 4.5-8 ka span per sample of this section, which...

We report on the generation of large inverse remanent magnetizations in nano-sized core/shell structure of Au/Ni by turning off the applied magnetic field. The remanent magnetization is very sensitive to the field reduction rate as well as to the thermal and field processes before the switching off of the magnetic field. Spontaneous reversal in direction and increase in magnitude of the remanen...

2014 A brief review is given of some calculations of the remanent magnetization of fine particles. The remanence after previous saturation has been calculated for a number of different types of anisotropy. A discussion is also given of remanence curves attained after application of D. C. or A. C. fields, and relations between such curves are pointed out. LE JOURNAL DE PIIYSIQUE ET LE RADIUM TOM...