CONTRIBUTIONS OF FINE-PARTICLE MAGNETISM TO READING THE GLOBAL PALEOCLIMATE RECORD

Paleoclimate changes are recorded by proxy as variations in concentration, composition, and grain size of magnetic minerals, principally magnetite (Fe3O4), in the sediments deposited in lakes, oceans, and continental eolian deposits. Cross-validated multiple-parameter magnetic measurements of such sediment cores provide global change data of high temporal resolution, useful for constructing a base-line record against which anthropogenic modifications may be discerned. Theories of superparamagnetism and magnetic domains are used to explain the physical basis of magnetic proxy recording. Examples of applications to validation of Milankovitch theory of climate change and delineation of the glacial and interglacial stages of the last 1 000 000 years are provided.