Palaeomagnetic Observations

The primary aim of this palaeomagnetic data modelling study is to use ancient site latitude to quantify the established climate zones on each small Earth model. In theory, each colour coded site sample should fall within its respective designated climate zone. In practice, this quantification is highly dependent on the structural correction and magnetic screening applied to each sample. The validity of these corrections is beyond this study. There are many examples within this study to suggest that site data are being manipulated—overzealous structural correction and magnetic screening—to force the data into a preconceived location that coincides with plate tectonic modelling. Polar latitudes within Eastern Australia are a prime example:

The limitations of palaeomagnetic data are also exemplified by this study. A good example of these limitations are highlighted on the Late Triassic models for North America and Europe. Here, both equatorial (red) and temperate zone (green) site samples occur together, plus polar zone (blue) site samples shown within Eastern Australia and New Zealand. Other examples include mismatching site data for adjoining continents, for example site data for Australia located adjacent to North America, and Chinese data adjacent to Australia and Antarctica during the Permian.

This, of course, could be used to negate the small Earth models, but, in general, the data plotted on each of the younger Mesozoic and Cenozoic models agree in principle with the identified climate zones, in particular when the 5 degree latitude error factors for each zone are taken into consideration. For example: ,

In contrast, the older Palaeozoic and Precambrian data become progressively more disorientated moving back in time. This is due to the increasing degree of tectonic and metamorphic disruption to these older rocks, and hence the increase in uncertainty with regard to structural correction and magnetic screening of the site samples. Where multiple magnetic vectors are present in a site sample it is envisaged that correction and screening is likely to continue until such time as the data "fit" the required plate tectonic assemblage. For example, the contradictory Asian and Russian data for the Carboniferous and Ordovician North Pole assemblage: , For plate tectonic assemblages see: https://paleobiodb.org/navigator/

Data for the Precambrian models is shown to be inconsistent, even for Plate Tectonic models, with all three climate zones overlapping, for example the Early Proterozoic: In general, palaeolatitudes plotted on Expansion Tectonic small Earth models agree in principle with the climate zone data, regardless of the potential for mathematical manipulation of the primary palaeomagnetic data.