08/01/2018 · Development of tectonic theory Precursors

The claimed special resemblance of South American and Australian marsupials does not, in any zoölogist's opinion, extend to identity of species or genera but consists at the very most of the possession in common of one family, Dasyuridae or Thylacinidae, and one advanced suborder, Diprotodontia. My own opinion (e.g. Simpson, 1939, 1941) is that even this degree of affinity is not supported by the evidence, which is entirely consistent with affinity only through the little-differentiated Holarctic marsupial stock. For the purpose of argument, however, the evidence may tentatively be granted this maximum possible weight. At this evaluation, it still does not support but on the contrary opposes the idea of a direct, practicable land route between Australia and South America. That such a route should exist and should produce only this rather distant resemblance in only two groups among faunas otherwise so completely different is so improbable as to be almost inconceivable. If any southern connection is indicated, this cannot be continental or a practicable, fully emerged land-bridge, but something on the order of discontinuous, evanescent island chains. Even granting extreme value to these facts, they still favor the hypothesis of stable continents and not those of drift or transoceanic continents as has so often been claimed.

Time | Internet Encyclopedia of Philosophy

Paleomagnetism, the study of Earth’s magnetic field over time by looking at rocks, was first used to verify the theories of continental drift and plate tectonics; however, it can also be used to support the Snowball Earth hypothesis (12). Essentially, magnetic minerals within a sedimentary rock will align with Earth’s magnetic field. By looking at this alignment over time, it is apparent that this magnetic field has changed. This allows paleomagnetists to estimate the latitude of a rock when it was formed. Macouin et al. looked at isotopic signatures and the paleomagnetism of Doushantou carbonates in South China and found that the likely location for these was 3±4.5°N (26). Other studies have found that rocks from Late Neoproterozoic would also have been situated at low latitudes. The finding of glacial deposits at these latitudes lends evidence to support the theory of global Neoproterozoic glaciations. Opponents of this data, however, question the accuracy of the reconstruction because it is hard to determine if a magnetic signature is original, or if it was reset by later geologic activity, such as mountain building orogeny.

Time has been studied for thousands of years

Nevertheless, many issues remain to be resolved