Tolstoy M, Harding A J, Orcutt J A
Science. 1993 Oct 29;262(5134):726-9. doi: 10.1126/science.262.5134.726.
Spreading segments of the Mid-Atlantic Ridge show negative bull's-eye anomalies in the mantle Bouguer gravity field. Seismic refraction results from 33 degrees S indicate that these anomalies can be accounted for by variations in crustal thickness along a segment. The crust is thicker in the center and thinner at the end of the spreading segment, and these changes are attributable to variations in the thickness of layer 3. The results show that accretion is focused at a slow-spreading ridge, that axial valley depth reflects the thickness of the underlying crust, and that along-axis density variations should be considered in the interpretation of gravity data.
大西洋中脊的扩张段在地幔布格重力场中显示出负的靶心异常。南纬33度处的地震折射结果表明，这些异常可以用沿某一段地壳厚度的变化来解释。在扩张段的中部地壳较厚，末端较薄，这些变化归因于第3层厚度的变化。结果表明，增生作用集中在慢速扩张脊，轴谷深度反映了下伏地壳的厚度，并且在重力数据解释中应考虑沿轴密度变化。
