GEOL 1001 Lecture : GEOLOGY NOTES
Document Summary
It is the movement of plates and the forces acting between them. It explains the distribution of volcanoes, earthquakes, folded mountain chains, rock assemblages, and seafloor structures. The forces that drive plate motions arise from the mantle convection system. ~evolution of theory continental drift francis bacon (1620)-noted parallelism of the shorelines across the atlantic ocean. Eduard suess (late 1800s) proposed joining the southern continents to form a supercontinent (gondwanaland) Alfred wegener (1915)-similarity of geologic structures and rocks across continents suggested a single major supercontinent (pangaea) at one time. Rock type and structural similarities appalachian mountains and. Suggest driving mechanism might be mantle thermal convection. Dragged the two halves of the continents apart-seafloor spreading. Prposed idea of seafloor spreading : new formation at the cracks in the ridges followed by lateral spreading. Some minerals are naturally magnetic, e. g. magnetite common in basalt. Lava: ~1000c records direction of magnetic pole upon cooling. Normal polarity: rocks have same magnetism as present magnetic field.
