The Tamar conductivity anomaly

Abstract

The Tamar Lineament follows an approximately straight line from near the mouth of the Tamar River to near the Tasman Peninsula. The pre-Carboniferous geology is very different on the two sides of this line. On the north-east side Devonian sediments are of deep water facies, typified by the Mathinna Beds. On the south-west side Devonian and older sediments are of shallow water origin, such as the Owen conglomerates and Gordon limestone. The granites in the north-east side are slightly older than those on the south-west side. There are also geophysical differences. The magnetic anomaly structure is smoother in the north-east and earthquakes are less frequent. This paper reports a striking conductivity anomaly coinciding with the Tamar Lineament.