Uranium to lead dating Free live amatuer web cam no sighn up
Metamorphic rocks represent alterations of precursor sedimentary, igneous, or other metamorphic rocks.Through the cycles of burial, folding, faulting, and subduction of crustal plates, rocks get pushed and dragged down to depths where - under heat and pressure - changes take place.One such individual is Robert Gentry, who holds a Master's degree in Physics (and an honorary doctorate from the fundamentalist Columbia Union College).For over thirteen years he held a research associate's position at the Oak Ridge National Laboratory where he was part of a team which investigated ways to immobilize nuclear waste.Sedimentary rocks are secondary in formation, being the product of precursor rocks (of any type).
The haloes are caused by radiation damage to the host mineral's crystalline structure.Gentry has spent most of his professional life studying the nature of very small discoloration features in mica and other minerals, and concluded that they are proof of a young Earth.Geologists classify rocks into three main categories - sedimentary, igneous, and metamorphic - based on the way in which they form.This was never fully successful as the size/intensity of an observed damage halo was also a function of the abundance of radionuclides present in the inclusion, and the crystalline structure of the host mineral. First is his contention that the granitic rocks from which samples reportedly came constitute the "primordial" crust of the Earth.Within these rocks are biotite (an iron-bearing form of mica) and fluorite crystals which bear a relatively uncommon class of tiny, concentric discoloration "haloes" (figure 2).
In metamorphic rocks, new minerals form that are more stable at higher temperatures and pressures.