Recognising rock art Natural or not?
I’m sorry, I haven’t a clue!
Weathering Location, slope, exposure, vegetation etc Geology and archaeology CURRENT APPEARANCE Appearance of original ca...
Does it matter? <ul><li>Did Neolithic and Bronze Age people distinguish between carved and natural marks? </li></ul><ul>...
But it matters to recorders… <ul><li>Recording natural features as rock art could potentially: </li></ul><ul><ul><li>infla...
I found it so it must be rock art! <ul><li>Bias noted in volunteers ‘discovering’ their own new rock art…whilst discoun...
When is a cup-mark not a cup-mark? <ul><li>Solution hollow? </li></ul><ul><li>Eroded concretion? </li></ul><ul><li>Fossil?...
Peck marks <ul><li>Peck marks are evidence of carving but absence of peck marks is not evidence of natural cupules! </li><...
Size <ul><li>Isn’t that important… </li></ul><ul><li>Cup marks vary from micro-cups to ‘basins’ but most carved cups are ...
Shape <ul><li>Most cups are circular but ovals do sometimes occur </li></ul><ul><li>Need to consider how erosion may have ...
Depth <ul><li>Dia. usually 2-5 x depth </li></ul><ul><li>Very deep or very shallow features are more likely to be natural ...
Profile 1 In this sample of 111 cups the majority are 4-5 times wider than they are deep.
Profile 2 <ul><li>Carved cups tend towards </li></ul><ul><li>hemispherical or conical, </li></ul><ul><li>and are symmetri...
Context 1 <ul><li>Need to look around at local geology </li></ul><ul><ul><li>Any similar features on other rocks? </li></u...
Context 2 <ul><li>Is the cup part of a composition? </li></ul><ul><ul><li>Are there other, more diagnostic motifs on the p...
Context 3 <ul><li>Is the cup mark on a stone in a prehistoric monument? </li></ul>
Your turn! Using only visual clues…
 

 
X Natural erosion
 
X Natural erosion
Copt Howe – natural ‘cups’ on the panel…
Copt Howe – natural ‘cups’ on the panel… ? Natural erosion?
 
? Natural erosion + carving?
 
X Natural erosion
 

 
X Natural erosion
 

 
X Natural erosion
 

 
Chisel marks from quarrying X
 
X Natural erosion
 

 

 
X Natural erosion
 

 
X Natural erosion
 
Iron inclusions X
 

 
X Natural erosion
 
Bullet strike X
 
Marine molluscs X
 
?
Marine molluscs?
Marine molluscs? X
Conclusions <ul><li>Lots of grey areas between natural and artificial marks </li></ul><ul><li>Very difficult to determine ...
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Natural or Not?

Published on: Mar 3, 2016
Published in: Technology      
Source: www.slideshare.net


Transcripts - Natural or Not?

  • 1. Recognising rock art Natural or not?
  • 2. I’m sorry, I haven’t a clue!
  • 3. Weathering Location, slope, exposure, vegetation etc Geology and archaeology CURRENT APPEARANCE Appearance of original carving Tools and techniques used, length of exposure Original form of carving Presence of geological features – e.g. vesicles, bedding planes, fissures Original form of rock surface
  • 4. Does it matter? <ul><li>Did Neolithic and Bronze Age people distinguish between carved and natural marks? </li></ul><ul><li>Perhaps unusual natural features had just as much meaning… </li></ul>
  • 5. But it matters to recorders… <ul><li>Recording natural features as rock art could potentially: </li></ul><ul><ul><li>inflate numbers </li></ul></ul><ul><ul><li>skew distribution maps </li></ul></ul><ul><ul><li>deflect resources </li></ul></ul>
  • 6. I found it so it must be rock art! <ul><li>Bias noted in volunteers ‘discovering’ their own new rock art…whilst discounting similar examples recorded by other researchers… </li></ul><ul><li>Experience helps…or does it? – The more you become familiar with the local geology the better, but the more you see, the more you will realise how difficult it is! </li></ul>
  • 7. When is a cup-mark not a cup-mark? <ul><li>Solution hollow? </li></ul><ul><li>Eroded concretion? </li></ul><ul><li>Fossil? </li></ul><ul><li>Molluscs? </li></ul><ul><li>Bullet ricochet? </li></ul><ul><li>Historical origin? </li></ul>
  • 8. Peck marks <ul><li>Peck marks are evidence of carving but absence of peck marks is not evidence of natural cupules! </li></ul>
  • 9. Size <ul><li>Isn’t that important… </li></ul><ul><li>Cup marks vary from micro-cups to ‘basins’ but most carved cups are 3-10cm in diameter </li></ul>
  • 10. Shape <ul><li>Most cups are circular but ovals do sometimes occur </li></ul><ul><li>Need to consider how erosion may have affected the shape </li></ul>
  • 11. Depth <ul><li>Dia. usually 2-5 x depth </li></ul><ul><li>Very deep or very shallow features are more likely to be natural </li></ul><ul><li>Shallow ‘saucers’ may be the result of spalling of the rock surface </li></ul>
  • 12. Profile 1 In this sample of 111 cups the majority are 4-5 times wider than they are deep.
  • 13. Profile 2 <ul><li>Carved cups tend towards </li></ul><ul><li>hemispherical or conical, </li></ul><ul><li>and are symmetrical. </li></ul><ul><li>Non-symmetrical cups or </li></ul><ul><li>those with occluded internal </li></ul><ul><li>surfaces are more likely to be </li></ul><ul><li>natural. </li></ul>Occluded surfaces Water erosion in sloping cups  
  • 14. Context 1 <ul><li>Need to look around at local geology </li></ul><ul><ul><li>Any similar features on other rocks? </li></ul></ul><ul><ul><li>Are the ‘cups’ aligned along a bedding plane? </li></ul></ul>
  • 15. Context 2 <ul><li>Is the cup part of a composition? </li></ul><ul><ul><li>Are there other, more diagnostic motifs on the panel? </li></ul></ul><ul><ul><li>Is the cup part of a ‘domino’ or ‘rosette’ pattern? </li></ul></ul>
  • 16. Context 3 <ul><li>Is the cup mark on a stone in a prehistoric monument? </li></ul>
  • 17. Your turn! Using only visual clues…
  • 19. 
  • 21. X Natural erosion
  • 23. X Natural erosion
  • 24. Copt Howe – natural ‘cups’ on the panel…
  • 25. Copt Howe – natural ‘cups’ on the panel… ? Natural erosion?
  • 27. ? Natural erosion + carving?
  • 29. X Natural erosion
  • 31. 
  • 33. X Natural erosion
  • 35. 
  • 37. X Natural erosion
  • 39. 
  • 41. Chisel marks from quarrying X
  • 43. X Natural erosion
  • 45. 
  • 47. 
  • 49. X Natural erosion
  • 51. 
  • 53. X Natural erosion
  • 55. Iron inclusions X
  • 57. 
  • 59. X Natural erosion
  • 61. Bullet strike X
  • 63. Marine molluscs X
  • 65. ?
  • 66. Marine molluscs?
  • 67. Marine molluscs? X
  • 68. Conclusions <ul><li>Lots of grey areas between natural and artificial marks </li></ul><ul><li>Very difficult to determine using only photographs </li></ul><ul><li>Need to consider physical form + context (geological and archaeological) </li></ul><ul><li>Local experience helps, but self-bias doesn’t! </li></ul>

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