Damage to the Archaeological Record Caused by Collection-Driven Exploitation of Archaeological Sites (A Typology of Hoik Holes)

Metal detecting hole

Having just read a Bangor professor's account of traces of Collection-driven artefact hunting on published Austrian sites, and knowing (as he has admitted), he does not take part in it himself, he and his readers might benefit from an account of how it is generally done and its effects on the archaeological record. There are basically seven types of hole dug in this process, and I'll present them briefly below:

Dangerous digging

Hoik hole type A (otherwise known as the 'effingbighole method'), huge hole of varying shapes and sizes, generally big enough to stand in, dug blindly down into the invisible archaeological record and the loose upcast searched through for any collectable items (may involve metal detector use). In this process the upcast is spread about and mixed. Even after weathering and natural bioturbation, if filled in, this will likely register as a 'pit' in subsequent excavation (example, holes dug the hole dug in collection-driven extraction of non-metallic artefacts in UK, or in similar looting in S. America, MENA region and so on)

Bellingham hoard hoik in progress (Facebook)

 
Hoik hole type B (otherwise known as the 'nuvverbit over-ere' method), huge hole of varying shapes and sizes, dug blindly down into the invisible archaeological record with the use of a detecting device driving the expansion of the hole by detecting successive targets to dig out. Often in the heat of the search the upcast is spread about or heaped, in the process mixing it. These holes can be dug by hand (Holborough) or machine. Even when infilled, after weathering and natural bioturbation, this will likely register as a 'pit' in subsequent excavation (example, the hole dug to retrieve the Bellingham Hoard) 

Lenborough chaos

Hoik hole type C, fairly large and irregular vertical-sided hole, dug blindly down deep  into the invisible archaeological record on either grassland or into firmer layers below the ploughsoil where directed by a metal detector signal. In such a hole, stratigraphical observation, let alone documentation, is very difficult to achieve, if not totally impossible. In the digging of such holes, the upcast is often scattered around and mixed. Even after weathering and natural bioturbation, infilled, holes like this will probably register as a 'pit' in subsequent excavation (example, the hole dug to hastily retrieve the Lenborough Hoard). Holes like this are typically employed where Treasure hunters have strong signal from archaeological layers under the ploughsoil.

Scattered 'axe hoard' hole (5:52)

Hoik hole type D, moderate size and  relatively shallow, dug into loose soil (such as ploughsoil, garden soil) due to which the hole is amorphous. Dug blindly down into and often through a patterned artefact scatter contained in the upper layers of a site (in other words the archaeological record  - see also here and here on the ploughsoil evidence destroyed by artefact hunting). This is usually done on detecting a hidden buried metal artefact with a metal detector. Dug with various types of spade. The depth of the hole is determined by the depth of penetration of the metal detector used and teh characteristics of the (generally small) target item. After the find has been found in the upcast or sides of the hole the loose upcast is shoved back in the hole. Unless there are other, detailed records, and the hole has not penetrated the subsoil, the disturbance to the site (and the patterned artefact scatter that is one of its manifestations) will be undetectable in any subsequent investigation.  
 

Scene from Series 3 of 'Detectorists'

Hoik hole type E, moderate size and fairly regular, dug blindly down into the invisible archaeological record on detecting a hidden buried metal artefact with a metal detector by using a digging tool to cut a large (spade size) 'plug'. Usually employed on pasture sites and permanent grassland. The size of the hole is determined by the ease of lifting the plug whole. After the find has been located with minimal disturbance of the plug by use of a pinpointer, the plug can be ire-inserted and stamped down. Depending on the type of soil and the way the plug is handled and reinserted, the traces in plan may be a few thin spadecuts that could largely disappear during weathering and natural bioturbation.

Hoik hole type F, Small and fairly regular, often vertical. These holes are dug blindly down into the invisible archaeological record on detecting a hidden buried metal artefact with a metal detector by using a digging tool like a small narrow trowel or posthole digging spade (sold by metal detector suppliers) to cut a small narrow plug. The size of the hole means that the earth of different deposits may not get mixed much (and often a dropcloth is used), so in general what goes into the hole is what came out. After the soil is replaced and firmly stamped down the trace in plan may be a narrow zone of slightly discoloured soil that, could look like a small postjhole or stakehole, or may largely disappear during subsequent weathering and natural bioturbation.

Leverage for dummies

Hoik hole type G (aka the 'leverage method'), Here the hole dug and soil disturbance are minimal. having located the buried object a thin blade or probe is gently pushed blindly down into the invisible archaeological record and the object levered up through a narrow cut in the overlying material. The small size of the disturbance means that the traces in the soil of the site are barely visible and will largely disappear during weathering and natural bioturbation. (Here's a video of shallow usage and another one). Used where possible by treasure hunters who don't want people to know they've been there.

Artefact Hunting type H, eyes only, no hole is dug, artefacts collected directly from surface exposures such as ploughed surfaces, pipeline wayleaves, or stream banks. 

Despite a lot of 'liaison', it is unclear what proportion of the various methods of collectable-acquisition are used on British sites.  What can be said however is that given the depth of penetration of most metal detectors in the case of single items, hole digging of types A, B and C, generally associated with hoards, graves and other such concentrations of metal objects  would be in the minority. In England and Wales, when we have annually about 800-1000 Treasure items reported (many - but not all - of which came from such holes dug by the finder), the number of (reported and unreported) finds from shallower hoiking (types D, E, F and G as well as deeper holes) may reach as many as 800 000 items a year. Thus the traces of artefact hunting that are reflected in holes dug into the underlying archaeological layers recognised in subsequent excavation - even if the slight traces of some of these techniques are actually being looked for, is in no way a reflection of the scale, scope and type of  depletion and damage to the archaeological record of a region by Collection-Driven Exploitation of the archaeological record.