Recent heat flow measurements in the Indian Ocean

Abstract

Forty-one new heat flow measurements were made in the Indian Ocean by Lamont Geological Observatory ships. Three measurements were made in the Red Sea and indicated a higher than average heat flow. Six heat flow values in the axis of the mid-Indian Ocean ridge at 21°30′S indicate a local region of very high heat flow. On the basis of recent geophysical observations in the Indian Ocean, the trend of the axis of the mid-Indian Ocean ridge is reinterpreted. The zone of rough topography between the equator and 35°S and longitude 64° and 68°E is interpreted as a fracture zone that displaces the Carlsberg ridge from the southeast branch of the mid-Indian Ocean ridge. At two stations in the southern Indian Ocean, the temperature gradients measured at each station changed greatly with depth in the sediment. These changes are thought to result from recent changes in the bottom water temperature. The average of all measurements to date in the Indian Ocean is 1.46 μcal/cm² sec. The average of 135 measurements in the deep basins with thick sediment is 1.32 μcal/cm² sec and may better represent the average heat flow through the floor of the Indian Ocean.