GEOL 106 Chapter Notes - Chapter 2: Seafloor Spreading, Geomagnetic Reversal, Outer Core

• School: Queen's University
• Department: Geological Sciences and Geological Engineering
• Course: GEOL 106
• Professor: John Hanes

Document Summary

Harry h. hess: suggested that continental drift was result of process of seafloor spreading along mid- oceanic ridges. Paleomagnetism: study of magnetism of rocks at time their magnetic signature formed. Earth"s te(cid:373)perature of (cid:272)ore is too high to sustai(cid:374) per(cid:373)a(cid:374)e(cid:374)t (cid:373)ag(cid:374)etizatio(cid:374) will decay magnetic field. What produces magnetic stripes rocks on floor of ocean were found to have irregularities in magnetic field called anomalies or pertur(cid:271)atio(cid:374)s of earth"s (cid:373)ag(cid:374)eti(cid:272) field (cid:272)aused (cid:271)y lo(cid:272)al field of (cid:373)ag(cid:374)etized ro(cid:272)ks o(cid:374) seafloor. When mapped, the stripes form quasi-linear patterns parallel to oceanic ridges stripe width patterns matched sequences established by land geologists for polarity reversals in land volcanic rocks. Merging magnetic anomalies with numerical ages of rocks produced record of seafloor spreading could explain magnetic stripe patterns. Most recent magnetic reversal occurred 0. 7 million years ago. When field is reversed, cooling rocks preserve a reverse magnetic signature and a brown stripe is preserved.