THE DEEP STRUCTURE OF THE EARTH INFERRED FROM A SATELLITE'S ORBIT. PART 1. THE DENSITY ANOMALY
NAVAL WEAPONS LAB DAHLGREN VA
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A model of a fluid mantle is described which retains the significant features of the earths interior and is adjustable to the outside gravity field. It is shown that the density anomaly is within the order of approximation governed by Laplaces equation regardless of a fluid or solid mantle hypothesis. The density anomaly is numerically evaluated on the basis of the most recently available satellite-sensed gravity data. While it is virtually impossible to interpret the computed world density maps in terms of tectonic features of the earths crust on the grounds of a solid mantle assumption, the fluid mantle theory permits such an interpretation which is consistent up to many small details. Since every density anomaly computed seems to have played some role in the evolution of the crustal tectonics of today and, vice versa, because every major tectonic feature appears to be explainable by just the computed density anomalies, it is concluded that the gravity data used yielded a resolution of all essential density anomalies of the mantle.