HR: 15:00h
AN: GP23A-05 INVITED     [Abstracts]
TI: Paleomagnetism and Tectonics: Latin American Perspectives
AU: * MacDonald, W D
EM: wdmacdon@binghamton.edu
AF: Dept. Geological Sciences, State University of New York, Vestal Parkway East, Binghamton, NY 13902-6000, United States
AB: Since the early paleomagnetic studies in Latin America by K. Creer in the 50s, many hundreds of paleomagnetic studies in this region have been carried out. Because plate tectonic movements induce structural displacements in the crust near plate boundaries, remanent magnetizations therefore carry information about both types of displacements: plate displacements and structural displacements. The challenge for paleomagnetic researchers is to distinguish the structural ('local') effects from the plate-tectonic ('global') effects. On a global scale, plate motions are recorded in geomagnetic polar wander paths, and structural movements induce scatter about that path. On a local scale, structural displacements can be deciphered from the patterns of scatter of the paleomagnetic directions, leading to inferences about diverse structural and tectonic processes. Progressing from a local (i.e. near-site) to a regional scale, paleomagnetic patterns reveal structural events involving rotation on folds and faults, distortion in plate-boundary zones, accretion of allochthonous terranes, oblique subduction and strike-slip effects, tilting of large crustal blocks, and 'oroclinal' bending. Examples of such mixed signals are presented from the Latin American region, and some outstanding problems for paleomagnetic studies in Latin America are summarized.
DE: 1525 Paleomagnetism applied to tectonics: regional, global
DE: 1527 Paleomagnetism applied to geologic processes
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Joint Assembly