The Magnetic properties of the Cleveland Dyke
In this post i will attempt to produce an accurate report into my findings, regarding the magnetic
properties of the Cleveland dyke, in the south west area of Cleveland
I would like to start by saying i became involved in this subject accidentally, ie my research at the time was focused on the superficial geological deposits covering this area, i would regularly cross the path of the Cleveland dyke without giving it a lot of thought, until i started to wonder whether it could have played a part in forming the landscape we now walk upon.
I had been excavating what Ive named the Stanton gravel beds, for over two years in an attempt to prove that the superficial deposits of the South West area of Cleveland, were in fact not the documented glacial mess they were said to be, i had started to find that there was no signe of the bolder clay- till that i should have been finding in my excavations, but instead i was finding well sorted separated alluvial deposits, sat upon an equally well sorted gravel bed. The simple diagram below shows my findings either side of the Cleveland dyke.
The alluvial deposits above the Stainton gravel beds i found were all but stoneless, just hard packed friable clay, i found no evidence of lamination's- varved clay. These deposits as documented on my blog reports at historyofabeck.blogspot.com cover the entire South West Cleveland area, and strangely seem to begin and end at the boundaries of the Mercia mudstone bedrock zones of this area.
In my excavations i started to notice a lot of what looked like whinstone, mostly angular towards the bottom of the gravel beds, that in the Stainton area average about 300 mm thick. The gravels becoming smaller toward the top, again i did not give it much thought, but then the thought as to how the whin stone had become part of this thin uniformed gravel bed, containing organic material including the bones of animals and humans, that was then buried beneath up to three metres of separate almost stoneless alluvial deposits started to really puzzle me.
I then noticed that the whinstone attracted a none rare earth magnet as can be seen below at my main excavation at Stainton, i reported these findings to the local Riggs group who i had recently had a visit from members Andy Cooper and Allen Simkins, Andy replied with great interest and initial surprise at my reports, and arranged a date for a visit to view and test the samples i had excavated from the Stainton gravel beds.
I decided to test the whinstone left over from the nearby Stainton quarry, i found that all samples i tested attracted the same none rare earth magnets quite easily. I reported this to Andy and Allen and they visited not long after and tested the samples themselves, finding my reports as being correct.
Andy took some samples to test himself and pass on to a Geologist at Durham university, he later sent me the reply from the Geologist, who i would rather not name without his permission, the report stated that he thought the samples were not Whinstone from the Cleveland dyke in the Stainton quarry area but must be whin sill that had been transported here via glacial movements, as the whinn sill stone had been found to have a higher magnetic content.
( A statement i will soon show to be wrong! )
This had me puzzled as most of the whinstone found in the Stainton gravel beds is angular and this to me points to the rock not travelling to far, and is it just a big coincidence that the dyke is very close by !?. I then remembered i had come accross old cobbles at the site of the old whinstone quarry, i tested all of the cobbles i could find at the quarry site, each one easily attracted a none rare earth magnet.
The Cleveland dyke was created by the then molten rock squeezing through older rock, one thing i found very interesting was that the dyke was created about 59 mya and that the planet at that time was in a period of reversed polarisation, as can be seen on the chart above the white segments marking periods of reversed polarisation.
Above a partially washed out whinnstone bolder at Stainton beck, with a none rare earth magnet attached with a thin piece of paper between, to rule out any mud or other material causing the magnet to stick.
Simple experiment showing a compass needles deflection by the dyke stone at Stainton
I took a cobble home cleaned it and re tested it with the same results, i conducted a simple experiment using a compass. pictured above, the results i found quite amazing, again i reported the findings to Andy Cooper ( tvriggs ) he too was more than surprised, i had placed the whinstone cobble that was shaped from the whistone of the Cleveland dyke at Stainton quarry, on a plastic wheelie bin well away from any metallic object, i then approached the cobble holding the compass in front of me, the compass needle was deflected 180 degrees.
I repeated the process with a similar sized piece of Whinn sill from high force at Tees dale, then a piece of Laverkite from the Staithes sea wall , then a piece of Whin stone taken from an outcrop of the Cleveland dyke at Codberry in upper Teesdale.
Results
Stainton whinstone 70 - 180 degrees
Whinn sill deflected 70-80 degrees ( High force)
Laverkiite deflected 20 degrees ( Staithes sea wall )
Coldberry ( Cleveland dyke ) 40-60 degrees
Tests carried out on an eight mile stretch of the dyke
I was asked by Andy Cooper of riggs group if i could test other parts of the dyke for the same Phenomena, i agreed to conduct the same tests as carried out at the Stainton quarry site. I decided to walk the length of the Cleveland dyke as best i could from Stainton quarry to Cliff rigg an old whinstone quarry on the edge of the Cleveland hills, aproxomatly 8 miles walking distance.
When there were no outcrops of insitue dyke to test i tested rock on the surface, i had little magnetic responce to a none rare earth magnet, until i reached the langhbargh ridge just east of old Nunthorpe, there i found a few surface pieces of whinstone that did attract the magnets, i then proceeded east towards a known Dyke outcrop near the Whinstone view caravan site, here i found an attraction but it did not mach that of the Stainton stone.
I carried on towards cliff rigg checking track stone that sometimes attracted the magnets, but as a whole did not come close to the attraction i was used to finding in the Stainton quarry location, as i reached the bottom of the Cleveland hills just north east of Great Ayton, i joined a track that leads up to the old whinstone workings at Cliff rigg, i decided to drop severall none rare earth magnets on the track, immediately i noticed the magnets were covered in small stone particles and dust, i came to the conclusion that the track must have originally been made using the same stone that was being quarried, and therefore the stone particles and dust were from worn down whinstone from the Cliff rigg mine.
I proceeded to climb up to the worked outcrop of the Cleveland dyke at Cliff rigg, pictured above from
the top looking out towards Teeside, there i tested both left over whinstone and the few insitue sections of the dyke but again i found a low attraction compared to the Stainton quarry site.
Stainsby beck Dyke outcrop at Thornaby on Tees.
The next ourcrop i decided to test was at Stainsby beck Thornaby on tees Cleveland, again i found either no attraction to the same none rare earth magnets used at both Stainton and cliff rigg, or a far weaker magnetic responce on a few samples, than at the Stainton quarry location, i checked a lot of whinstone at this location and can say as at cliff rigg, the whinstone here has a far less magnetic attraction than that of the stone from the Stainton quarry site, although i did test a branch of the dyke between the two sites ie Stainton and Stainsby, and did find stone of the same level of attraction as at Stainton just south of Stainton vale farm.
