Compilers: Frederick J. Davey and Anthony B. Watts
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One color sheet, 36" x 44", scale 1:3,000,000 at 47.7 °S. From abstract: A new free-air anomaly map has been produced for the New Zealand region using marine and land gravity measurements. The main features of the free-air anomaly field are associated with the Indian-Pacific plate boundary which passes through New Zealand. Linear belts of large amplitude positive and negative free-air anomalies, typical of island arc-trench systems, are associated with the Tonga-Kermadec and the Macquarie Ridge sectors of the plate boundary. The gravity expression of the plate boundary is far more complex where it passes through New Zealand. At the northern end of New Zealand the large negative anomaly belt is displaced westwards over the continental area and the positive anomaly is greatly reduced. Towards central New Zealand a second negative anomaly occurs at the continental margin. Over central New Zealand, where continental lithosphere occurs on both sides of the plate boundary, the gravity anomalies are subdued. The Louisville ridge is defined by a positive anomaly belt with flanking gravity lows. Positive free-air anomalies occur over the marginal plateaus of New Zealand, but the Pacific Ocean basin is associated with generally negative anomalies.
Published: 4/01/1983
Pages: 8 plus 1 sheet
Product Category: Maps and Charts