In situ temperature and heat flow were determined in 1994 at 159 sites, grouped into 66 clusters between latitude 65 N and 67 30' N at water depths from 669 m to 1464 m. The mean of all cluster heat-flow measurements conducted in this survey was 58.5 mW m 2 , with a standard error of 4.40 mW m 2 . The mean heat flow from IKU well data for the Trøndelag Platform is 56.2 6.65 mW m 2 . Shorter wavelength heat-flow variations appear to be controlled structurally and can be explained by sedimentation and thermal refraction effects. High heat flow associated with faulted structural highs such as the Nyk High and Vema Dome-Rym Fault Zone may also result from hydrothermal convection. Relatively isolated high (106.6 mW m 2 ) heat flow observed at 846 m water depth may be an artefact of bottom water disturbances; however, virtually identical deep-water heat-flow anomalies, believed to be of hydrothermal origin, also exist. While heat-flow measurements made at water depths less than 1000 m should be regarded with caution, there is presently no justification for eliminating those exhibiting linear heat flow with depth. Submarine avalanches seem unimportant in the survey area. Neither crustal thinning, underplating nor sill intrusion, within the last 50 Ma, would have a measurable effect on present-day heat flow. The net effect of crustal thinning may be a reduction of the crustal heat generation potential, depending on the degree of thinning of the upper crust, since the accumulating sediments cannot compensate fully for the lost heat generation from a crystalline basement.

Doherty Earth Observatory. He spent 6 years at Gulf Research and Development (Harmarville Lab), where he studied measurement and modeling of hydrocarbon thermal regimes. He continued this work at Brookhaven National Laboratory as visiting research associate at Lamont-Doherty and (1989-present) as a director at Omegalink International Ltd.

A computer model of sea floor spreading is presented. This time‐dependent thermal model, which includes the presence of an adjacent continent, simulates not only the evolution of an oceanic region but also the thermal evolution of an Atlantic‐type continental margin. Incorporation of the adjacent continent into a sea floor spreading model allows one to utilize geological and geophysical data from the continent and continental margin as constraints. In terms of the model parameters a more complete picture of the early spreading history and its relation to the initial rifting of the continent is provided. While vertical heat flow dominates in both the ocean and the continent proper, several effects of lateral heat flow across the ocean‐continent boundary are seen. They are reflected in the surface heat flow and topography computed from the model. Owing to lateral heat flow, subsidence of the continental margin can be more rapid than has been estimated from previous models and is a strong function of horizontal position. Applied to the Norwegian‐Greenland Sea, the model satisfies all available geophysical data for that area and produces oceanic depths nearly 1 km shallower than for other oceans of comparable age. It is consistent with the idea that thermal expansion is responsible for the unusually shallow depths and positive free air gravity observed in the Norwegian‐Greenland Sea. These results may be applicable to parts of other oceans where large regions depart from the normal age‐depth curve. Thermal depth anomalies are not necessarily indicative of increased heat input from below but may more generally reflect differences in the ratio of the heat entering the lithosphere to the spreading rate. If it is correct, this concept may provide an origin for some of the shorter‐wavelength relief (10–100 km) seen in oceanic basement. The heat flow distribution across the Norwegian continental margin is consistent with a thermal model in which the Vøring Plateau Escarpment is concident with the ocean‐continent boundary.

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ABSTRACT. We report 55 new measurements of heat flow in the Norwegian-Greenland Sea and 29 new measurements on the flanks of the Reykjanes Ridge. Interpretations of the data are based only on the most reliable measurements in areas with a low probability of environment disturbance to the.heat flow. The results in the Norwegian-Greenland Sea show the expected decrease in heat flow with distance from the presently active spreading center. Based on a simple thermal model of sea-floor spreading, the average heat flow in the Norwegian-Greenland Sea over areas of the sea floor that can be dated is 2.7 HFU, which is anomalously high compared to other oceans of comparable age. Measurements at distances greater than 100 km from the Reykjanes Ridge axis show a steady decrease with age, and when age is taken into account the heat flow is also anomalously high relative to other spreading centers.