What are the main proofs for continental drift? matching geologic strata ? observation of subduction? fault lines measured? paleologia?
No. Today, you place a set of differential GPS receivers and actually WATCH them drift at up to centimeters per year. The rest are still good though, but not the "Main" proofs.
Slightly off topic, but how many know that GPS receivers have also detected land masses 'rising' when a low pressure front is over the area, and 'falling' when a high pressure weather system is over the same land mass area? It only amounts to a few millimeters, but I found it interesting.
Here is a cut & paste and link to one site that mentions atmospheric pressure loading, but I could not find the more detailed paper I read. Perhaps it was part of the vanDam and Herring paper. This site has some good information also. "Horizontal Atmospheric Gradients and Air Pressure Loading Effects In the data processing the atmosphere is normally considered to be spherically stratified. We assume that one equivalent zenith wet delay value determines the wet delay in any direction, given a certain elevation angle. More advanced models, using more parameters to describe the atmosphere, have been proposed as alternatives to this very simplified model (Davis et al., 1993; Macmillan, 1995). Several groups are now implementing possibilities to estimate horizontal gradients in the software Bar-Sever and Kroger (1996); Chen and Herring (1996). The lack of pressure data available during the GPS analysis can be the reason for different errors. During the entire GPS processing we have to model many external and internal effects on the crust of the earth. One effect currently not modeled is the pressure loading. The vertical position of the GPS receiver changes due to different atmospheric pressure loading the Earth (vanDam and Herring, 1994). Extreme values could affect the vertical component of the GPS estimates on the cm level. These effects are of course related more to the general pressure field in the region rather than to a specific site. To properly model this effect a grid of pressure data has to be available." http://www.gfy.ku.dk/~iag/Travaux_99/ssg1158.htm
Basically all of these plus the GPS system is enough to prove continental drift. Geologic strata: Pretty much matched up between ancient coastlines of non-volcanic continents such as S. Australia/S.Africa and Antarctica (latter is somewhat volcanic, but that's in another place) Observation of Subduction: Indian Ocean quake is an example. The Java plate slipped northeast by several centimeters all at once. Fault lines measured? Done for well over a hundred years by the USGS, and especially here in California. Paleontology? This is the earliest convincing evidence to earth scientists after Wegner first proposed the idea, with fossils in Brazil and West Africa matching up exactly.
I think continental drift probably exists, otherwise how do you explain the spread of flora across all the contintents?! This leaves the question of how long the Earth has actually been here!
