|WikiProject Geology||(Rated Start-class, High-importance)|
|To-do list for Paleomagnetism:|
Significant use of paleomagnetic data
The most significant use of paleomagnetic data is three-fold: it is a proof of the movement of the tectonic plate; its data can be used to plot and map the movements of the tectonic plates, and thus the movements of the supercontinents as they broke up; and its data shows that the poles have reversed several time over the earth's lifetime. It was an early proof of Wegener's theory of continental drift, moving it into a more accurately described plate techtonic structure. Basically palemagnetism measures the strength and direction of magnetic fields in ferrous metal patterns on the earth's crust showing plate movement, where naturally magnetically induced ferrous crystals align themselves along the N-S plain during the solidifying of the ferrous crystals within the ignious rock as it hardens. The mapping of these directional data of the ferrous crystals set in solidifying magma. the mapping shows where the continental remnant/techtonic plate has been ans where it finally ended up. In combination with comparative fossil analyses and even a compartison of typical living birds, animals, insects, plants and fish the paleomagnetic data gives a crear view of what happened over the billions of years of continental Drift, and as it continues today.
with paleomagnetism, theres always been one thing that has confused me somewhat. I wonder what causes the magnetic field to change, and when it does "flip", is it an immediate thing, or is it a gradual thing. wouldnt this also have some sort of a profound effect on nature aswell. im not sure but dont birds have somthing in them that helps them align with north (magnetic) and thus migrate? would be grateful if anyone could answer these questions :)
- I don't know about biological effects but the duration of the "flip" is 2 to 10 thousand years (this is an extremely short time with regards to the geological time scale but a long time when it comes to humans). The cause of the "flip" lies in the liquid outer core (the geodynamo process) and is very much debated. --Octupole
Trying to find some info about paleomagnetism I stumbled over the cleanup-tag and obliged. I noticed several points:
- although the different remnant magnetisations are described quite well, there are no informations about the method of measuring it. I laid down the outlines in the source, but I'm only a poor, lonesome geologist
- there was some strange info on early misgivings of the methods, which I tried to change into a section about the historical development of the method and its application
- there are no real examples of the application of paleomagnetic measurements
- there is no word about the geophysical theories about the reasons for the magnetic field to change
- there is no word about apparent directional change, i.e. due to plate tectonic movements.
Those are all good points, Jo - and two years later, I'm going to do something about them. I am an expert in this field, and this looks like a good opportunity for outreach: this page is the top Google hit for "paleomagnetism". Apparently none of my colleagues have been involved yet. I will try to add these things in the next few months. There is a pretty good page on apparent polar wander, by the way. There is also a dynamo page, but it says little about the geodynamo - even though the latter is redirected to the former! RockMagnetist (talk) 14:55, 1 September 2010 (UTC)
I unilaterally decided to raise the importance of this article to High. Paleomagnetism is one of the main branches of geophysics, and should be ranked above articles like "Ignacy Domeyko" and "Fichtelgebirge". RockMagnetist (talk) 13:14, 3 September 2010 (UTC)