Gravity measurements in eclogite mapping, Naustdal, Sogn og Fjordane.

Abstract

Gravity measurements have been carried out along 10 profiles in the region in between Naustdal and Engebø. The objective of the measurements was to detect new heavy bodies of eclogite and to map the extension to the depth of the known eclogite at Bygdahaugen. To confirm the ability of the gravity method, two profiles were measured across the known eclogite deposit in Naustdal. The size (depth) of this deposit should be estimated. The results show that the gravity method is well suited for such investigations and the Naustdal deposit was clearly indicated bye a strong anomaly. To the east of Bygdahaugen a new body with a possible density of around 3400 kg\/m3 (eclogite) was indicated body. The depth extent is estimated to 600 m in the model. The size of the body is probably in the same range as the Engbø deposit, approximately 400 mill. tons. More detailed investigations, both geophysical and geological, have to be carried out before drilling can start. At least four gravity profiles should be measured which will confirm the anomalies and lead to an improved estimate of the size of the indicated deposits.