CHALLENGES AND ANSWERS FOR ENVIRONMENTAL MAGNETISM IN THE NEW CENTURY

Current environmental magnetism research has utilized past results from fundamental studies of magnetic minerals as a function of grain-size. In the next decade and beyond, however, as data are acquired from complex sediment archives their accurate interpretation will require new research on two overlapping fronts. One relates the to successful discovery of grain-size mixtures, not merely the presence of a unique grain size, as frequently observed in lake sediments and loess records. The other challenge is to recognize the presence of weakly magnetic minerals such as goethite and siderite against the background of strongly magnetic minerals like magnetite. These weakly magnetic minerals provide critical redox information caused by time-dependent environmental change. Here we present selected data from our laboratory and elsewhere to demonstrate that given certain basic instrumentation to measure magnetic hysteresis and remanence properties, preferably at and below 300 K, valuable answers can be obtained to both the questions posed above.