Crosby Garrett Helmet, "not fizzing away in a field"

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Yesterday I briefly commented on the remarks of Julian Evan-Hart giving the detectorists' take on the Crosby Garrett helmet fiasco where he aggressively criticises those who think the object should have gone to a museum:

[...] those who bleat constantly about where it should be stored totally miss the point that whatever its now no longer fizzing away and corroding in a field...[...]

That is quite an interesting comment isn't it? It's part of the tekkies' empirically untested assertion that they are "rescuing" objects from destruction by hoiking them out from below ploughsoil level (as expressed here by Rod Blunt for example). This is in my opinion total nonsense, but never mind that now, let's look at this single case of the application of the argument.

Mr Evan-Hart has (it says on his website) 30 years of detecting experience in Britain. On the basis of that experience he would expect to find evidence that something that had been lying in a Cumbrian field for nigh-on two thousand years would be " fizzing away and corroding". The state of preservation of metal detected finds from adjacent areas of Cumbria (including Crosby Garrett itself) visible on the PAS database was discussed here earlier. They are indeed heavily corroded. I'm not sure I see any evidence that they were "fizzing away" in the process, but the point is that a certain amount of crustier corrosion would be expected on a find made here. Mr Evan-Hart apparently agrees with this assessment.

It seems however that Mr Evan-Hart has not in fact looked too closely at the photos that have been published of this find, none of which (and now some of us have seen the photos in the conservation report not released to the public). If he had he would be puzzled by the fact that on none of them are any corrosion products anything like those he obviously expects to find. No real evidence of the metal "corroding in a field" and certainly none of it " fizzing away in a field". So why not? The corrosion products form under the specific conditions of the burial environment. Why did the precise spot where that object was found have a burial environment which was so atypical of the area around? What was the burial environment of that object that led to this effect? If Mr Evan-Hart was to buy some dug-up coins on V-coins, how would the seller be describing that 'patina'? Would it be "typical dug up British detector find patina"? Would it be "Cumbrian Fell patina"? Or would it be named suggesting it had come from an entirely different geographical location and burial environment? (Gentle Reader: do a search of coin selling sites and see what it would be called).

Evan-Hart co-wrote a book about beginning artefact hunting. It is summarised on the NCMD website where we find the following passage:

For example, copper alloy - that develops a certain patina - will eventually become familiar in terms of age and colour in your search areas. Some of us have got pretty good at this recognition, and when a fellow Pastfinder shows a coin etc to fellow members, we can state where it was found with reasonable accuracy.

Really? So maybe a "PAStfinder" can tell us where in Cumbria one would find objects with the somewhat specific corrosion products like this.

The whole point is that the Crosby Garrett helmet does not have corrosion products on it which are entirely consistent with the story that it is a find from the region of Cumbria that is stated to have been the findspot. No evidence of that "fizzing away and corroding in a [Cumbrian] field". Why not?

[This question is not discussed in the "restorer's report" which does not describe the state of the object upon receipt in more than general terms].

Photo: Inside the Crosby Garrett helmet showing the corrosion products and state of the metal (photo by Caballo on Roman Army Talk).