Post-glacial sea level rise, Wikipedia.
The idea for his column originated with the concept of rising coastal water levels as global ice-melting caused by climate change continues. Some shoreline rock art will be lost as water levels rise. This has been happening for many millennia with gradual warming of the earth, but the newly emerged phenomenon of human-cause climate change has accelerated the problem significantly. According to Wikipedia, “since the last glacial maximum about 20,000 years ago, the sea level has risen by more than 125 metres (410 ft), with rates varying from less than a mm/year to 40+ mm/year, as a result of melting ice sheets over Canada and Eurasia. Rapid disintegration of ice sheets led to so called ‘meltwater pulses’, periods during which sea level rose rapidly. The rate of rise started to slow down about 8,200 years before present; the seal level was almost constant the last 2,500 years, before the present rising trend that started at the end of the 19th century or the beginning of the 20th." (Wikipedia)
The implication of this is that many rock art sites that were originally on dry land are now submerged. Or, to restate this from the other way, because of past sea level rise there are possibly now huge numbers of rock art sites to be discovered offshore, underwater.
Traverse Bay, Michigan. Internet photo, Public Domain.
One, which has been reported at Grand Traverse Bay (Michigan), in Lake Michigan, is called the “Stonehenge of the Great Lakes.” There, some forty feet underwater are a number of upright stones forming a partial circle, with what appears to be a mammoth carved on one of the stones (Puiu 2017). The discovery was made in 2007 and reported by Mark Holley, a professor at Northwestern Michigan College in Traverse City (Hardy 2015).
Some examples have been published in Tiwary’s 2014 paper “Underwater Rock Art: In Global Context” (see references). Tirwary’s paper deals with the aspect of Marine Archaeology that he calls ‘underwater rock art.’ “It refers to those rock art sites which had existed on the coastal plains or on the fringes of water bodies which in due course of time got submerged into the waters due to various reasons, the cause of which may be natural such as changes in the earth’s crust and the subsequent raise of the water level or even Man-made such as due to modern developmental projects. So this specialized field of Rock Art Studies deal with those paintings which already got submerged or on the verge of submersion and analysis its various problems such as the causes of submersion (if natural), it’s preservation and conservation problems, methods adopted for its exploration and documentation, etc.” (Tiwary 2014)
Tirwary’s first example is a gridlike pattern found on a rock underwater in the Farne Islands, Northumberland, UK, by a diver named Ben Burville. “During February, 2007 Mr. Ben Burville noticed some interesting carving on the rock about 20ft (7m) underwater off the Farne Islands in Northumberland. - One thing should be noticed is that the site is a few miles off shore and no sign of human activity can be seen in the area. It is at the base of a rock formation that forms part of the Outer Farnes. The rock seems to be the same as the local rock in the same vicinity. - An explanation for the absence of patina marks on it has been given in the following way. As the rock has been covered by sand for most of the time, the sand may have scoured the stone and if the marks had been buried in enough sand, it might have stopped oxygen getting to the stone to cause patination. It mbe possible during glacial episodes sea levels were up to more than 139m below present day sea level. Most of the southern North Sea was dry land so it is feasible that rock art could have been done on land and now it is below sea level. It all depends on the date of the work.” (Tiwary 2014) (A short video of this can be seen at https://www.youtube.com/watch?v=kP7BeNVVBM0)
One famous location where we can assumed there once was rock art but it is now underwater is the entrance to Cosquer Cave. “In July 1991 Dr. Jean Clottes, an English teacher (Honorary President of the French Prehistoric Society, Scientific Advisor for Prehistoric Art, Director of Prehistoric Antiquities) and a deep sea diver Henri Cosquer discovered paintings and engravings in a cave beneath the sea near Marseilles (France) on the Mediterranean coast. The gallery slopes up for about 360 feet under water before reaching a huge chamber that partly remained above the sea where many prehistoric paintings and engravings are preserved on the walls.” (Tiwary 2014) Based upon our knowledge of other Paleolithic painted caves I think we can assume that rock art would have originally been distributed throughout the whole of the original cave, meaning that much rock art was probably located in the 360 foot sloping gallery before it was flooded by rising sea levels.
Another location of rock art that had been apparently created on the shore but is now submerged in the sea is found in the South Pacific. “Recently most archaeological research program in Island Melanesia had been concerned with first settlement sites having rock art. About 3000 engravings had been noticed on the sea shore and some are now submerged in the sea.” (Tiwary 2014)
These are only a few in what must be a much larger number of submerged rock art sites, with many waiting to be discovered. Not only has rock art been submerged by sea-level rise, some rock art has been inundated by human hydrological projects. Dams, in particular, have covered large numbers of pictographs and petroglyphs under water. This will be the subject in part two of this exploration.
NOTE: Some images in this posting were retrieved from the internet with a search for public domain photographs. If any of these images are not intended to be public domain, I apologize, and will happily provide the picture credits if the owner will contact me with them. For further information on these reports you should read the original reports at the sites listed below.
Additionally - I wish to express my gratitude to Dr. Sachin Tiwary for his permission to quote his study as well as reproduce images from it.
REFERENCES:
Hardy, Mike, 2015 Great Lakes Stonehenge, November 27, 2015, https://thumbwind.com
Puiu, Tibi, 2017 Stonehenge-Like Structure Found Under Lake Michigan, January 26, 2017, https://www.smescience.com
Tiwary, Sachin Dr., 2014 Underwater Rock Art: In Global Context, En Rupestreweb, http://www.rupestreweb.info/underwaterrockart.html
Wikipedia, Past Changes in Sea Level, https://en.wikipedia.org/wiki/Sea_level_rise
Posts
I am inspired with this article. I felt that while writing the article in 2014 i was unfortunate to contact the author of this article. Many things need to do for the future work. There are many more sites in yhe world should be under study. I would like to join the next projects.
ReplyDelete