Intersections of remanence small circles: new tools to improve data processing and interpretation in palaeomagnetism

摘要: SUMMARY Intersections of remanence small circles are increasingly used in palaeomagnetism to determine the palaeofield direction from synfolding remanences. The approach [‘small circle intersection (SCI) method’] presupposes that sites tilted different directions intersect a common point, which is assumed represent direction. SCI method not restricted It can be applied also derive pre-folding remanences, addition tilt correction and as cross-check for fold tests. However, has specific requirements does work all cases. suitability data sets reliability estimates have assessed carefully always against background local geology. This paper examines occurrence distribution tool judgement: first, set most suitable estimate by reliable, when theoretically possible intersections realized and, addition, clearly grouping narrow region. Second, greatly result SCI, identified highest number they with others. These criteria allow systematic investigation upon stability dependencies. Moreover, SCIs an indicator irregular, unexpected tectonic settings. When disperse strongly although significant bedding strike differences given, relative rotations or other displacements likely occurred. If so, will invalid probably biased, however, Fisher mean calculation tests affected. In this case, help separate into subsets valid statistics methods. possibility use tentative reconstructions infer true sequence tilts correct adequately.