Free-air gravity maps suggest that, rather than having been a rectilinear feature, the subducted portion of the D’Entrecasteaux ridge, which impacts the Vanuatu Trench at a high angle, was curvilinear. The entire region is reminiscent, in size and the disposition of subduction -related volcanics and collision orogens, to the Banda Sea region of eastern Indonesia.

Modern airborne gravity relies largely on measurements of gravity gradients. Given how very small the signal will inevitably be, it is clear that measuring it is bound to be very, very difficult. Nevertheless, it was being done in Australia in the late 1920s with some success.

In the Preface to the report in the Imperial Geophysical Experimental Survey in Australia in the late 1920s and early 1930s, a few unforgettable names were listed. Attached to the survey was ‘J. M. Rayner, of the New South Wales  Department of Mines’, and moving to the lower echelons, the Electrical Section had a field assistant called R. F. Thyer, while designated as a Temporary Assistant was one N.H Fisher.

It is not given to many people to be recognised as the most important figure in the geological history of an entire country, but Hugh Davies, who died on April 26 this year, had that distinction.

In late 2022, Bill Hinze published, through the Minnesota Geological Survey, a book entitled From Compass to Drone: The Evolving Role of Magnetics in Mapping the Geology and Ore Deposits of the Lake Superior Region: 1830-2022.

Coincidentally, two recent threads on LinkedIn brought Assynt to mind. And one of those threads concerned Janet Watson, geological queen of the Northwest Highlands

In the instructions Joseph Gaimard copied into the diary before he left Toulon, there is a long section on field geology. Despite being written in 1817, it could very usefully be given as a guide to first-year geology students in our universities. Amongst other things, it has some very nice sketches and some wise words on the importance of context, but it also has comments on the importance of rocks that are not in situ

It took a few years for the significance of the linear magnetic anomalies discovered by Ron Mason and Arthur Raff to be realised, but they were key factors in the development of Plate Tectonics. This development might have been considerably delayed if their work, arguably the first systematic magnetic survey of a large area of oceanic crust, had instead been carried out over the seas east of Queensland. Even today the uniform data set that provides the best approach to study of this region is gravitational, not magnetic.

Back in the mid-1960s, plate tectonics was still in its infancy but the origin of the shallow rises in the Tasman Sea, as strips of Australia peeled away like layers on an onion, was already pretty obvious. Inevitably, there was speculation on possible links between ophiolites in eastern Papua and New Caledonia.

Giving a talk in the AGH university building in Krakow was memorable, as far as I was concerned, because it was the building where Eddie Polak, one of my first geophysical mentors, studied during the four years that preceded the invasion of Poland and the start of the Second World War. I was able to imagine him in his time there all the better because he had left me with a typescript of his memoirs.