EARTH CRUST IN OCEANS AND STRIP ANOMALIES OF MAGNETIC FIELD

Abstract

Examples of the isolation and interpretation of the strip anomalies of the magnetic field of the oceans are considered. Data were used on the eastern edge of the Pacific Ocean over most of the western coast of North America and on the Knipovich Ridge at the transition from the Atlantic Ocean to the Arctic. It is shown that they do not correspond to the ideas of the plate tectonics hypothesis about deepseated processes in the tectonosphere of these regions. In both cases, all or many of the signs indicating spreading of the oceanic crust are absent. The impossibility of determining the age of the oceanic crust from magnetic data is substantiated. This applies both to complicated models of the origin of anomaly sources and to the results obtained. The sequence of anomalies in the North Pacific indicates plate movement along or away from the deep trench. Ancient rocks, including Precambrian rocks, were found on the MidAtlantic Ridge and secant faults. A model of the Earth’s crust of the oceans is proposed according to the advectionpolymorphic hypothesis. This is the result of the oceanization of the crust of the margins of the continents. It has a few reduced power and increased basicity. During the restructuring, the crust lost the upper part, the lower one was transformed into a crustmantle mixture. The speed of seismic waves in it corresponds to such a composition and temperature of oceanic plates. Data on the magnetization of rocks of different layers of the crust and its changes with age are analyzed. The significant role of the middle and lower parts of the oceanic crust in creating anomalies in the magnetic field of various parts of the oceans is shown. Models of magnetic field sources corresponding to different parts of the oceans are constructed. They explain the observed anomalies. An assumption is made about the nature of magnetic anomalies on the outskirts of the midocean ridges.

Keywords

• ocean magnetic field
• deepseated processes
• sources of anomalies