Among the oldest examples of cave artwork within the US are on the partitions of Dunbar Collapse Clarksville, Tennessee—50 miles northwest of Nashville. Relationship again round 800 years, these embrace petroglyphs carved into the limestone and pictographs drawn in charcoal that have been recognized within the early 2000s. Some have geometric, summary varieties—corresponding to concentric round shapes—whereas others function human figures or probably signify beings associated to religious observe. The cave is believed to have been a sacred area for Indigenous folks in the course of the Mississippian interval, spanning from roughly 500 to 1,000 years in the past. Archaeological research have revealed indicators that the usage of the cave by people goes again even additional—going down over tens of 1000’s of years—from traces of the extraction of its mineral sources to proof of the care of the useless. The cave, stretching eight miles underground, is now a part of Dunbar Cave State Park.
In February, extreme flooding from heavy rains utterly submerged the cave artwork. Dunbar Cave State Park officers said that it was the best flooding within the cave on document, “a number of ft larger” than one other main flood in 2010 and “the third such occasion in lower than one yr”. Pictures they posted on-line confirmed the aftermath: mud was caked on all sides of the cave, together with the ceiling, with a number of bats discovered drowned. Restoration of the location’s broken infrastructure is now underway as a way to reopen the cave for public excursions. In the meantime, archaeologists have been assessing any harm to the cave artwork, as this was the primary recorded time it had been utterly coated throughout a flood.
Entrance to Dunbar Cave Photograph: David Duplessis © TennesseePhotographs.com
In accordance with data shared by the Tennessee Division of Surroundings and Conservation (TDEC), its Division of Archaeology (TDOA) has in contrast high-resolution pictures that have been taken of the artwork in 2014 to these taken after the flooding. This evaluation confirmed that there have been no indicators of the pigments having degraded or undergone structural harm from water and sediment speeding into the cave. TDOA additionally performed a non-destructive analysis of any modifications within the artwork’s elemental or mineralogical nature utilizing fibre-optic reflectance spectroscopy and transportable X-ray fluorescence spectroscopy. This examination was in comparison with research achieved in 2016, and it revealed no detectable modifications within the artwork’s chemical composition.
As above, so beneath
Though the cave artwork doesn’t seem to have been harmed, TDOA is planning common monitoring for the potential impression of flooding because it turns into a extra widespread prevalence. This might have oblique results on the artwork as properly, if the cave setting modifications resulting from issues like will increase in ambient moisture and humidity. As a part of this care, TDOA and Tennessee State Parks are persevering with their ongoing work with Indigenous descendant communities, together with the Jap Band of Cherokee, within the preservation of this archaeological website.
“Defending and stewarding irreplaceable archaeological options like that at Dunbar Cave is among the many most necessary work that we do,” says Phil Hodge, a state archaeologist and director of TDOA. “And it’s greater than merely preserving historical pigments on a limestone cave wall; it’s about preserving the voices of Indigenous individuals who used this cave and held it sacred for 1000’s of years, and who stay related to it within the current.”
Sacred shapes: the partitions of Dunbar Cave—believed to have functioned as a religious area for Indigenous folks 500-1,000 years in the past—are embellished with each geometric varieties and depictions of people
Photograph: TSP Advertising archives
Tennessee State Parks can also be partnering with the US Geological Survey and the TDEC Division of Water to review the hydrology of the watershed within the space in an try to find out long-term options. Dunbar Cave is only one function in a “karst” area—formed by the dissolution of its limestone bedrock into caves, sinkholes and different options. (Tennessee is among the most “karstified” areas of North America, and the state has 1000’s of identified caves.) This causes a definite relationship between water and a really porous floor; water has at all times been a part of Dunbar Cave, however by no means at such excessive ranges and so fast-moving.
How water is managed above influences every thing that occurs underground, and local weather change—in addition to improvement of the constructed setting—can have a major impression on not solely the way forward for the artwork at Dunbar Cave but additionally on its subterranean ecological habitat, a haven for uncommon animals like endangered gray bats, blind cave crayfish and southern cavefish. Restoring points of the setting surrounding the cave, like wetlands, might assist mitigate harm from future main storms. For instance, a latest proposal from state officers thought of returning a man-made lake at Dunbar Cave State Park to its pure and extra sustainable state as a free-flowing stream, which might higher handle an rising frequency of flash flooding. Nevertheless, the Clarksville Metropolis Council voted in January to protect the lake, which is used to irrigate an area golf course.
Inside Dunbar Cave Photograph: TSP Advertising archives
“We have now to ask: can we higher educate the native public in regards to the significance of watersheds and karst?” says David Britton, the park supervisor at Dunbar Cave State Park. “On this a part of the nation, our above-ground world is intrinsically related to the world beneath our ft. Good stewardship ensures concord and safety of not simply cultural treasures just like the cave artwork, but additionally the complete ecosystems that exist in caves. Our day by day actions on the bottom can have devastating penalties, even when we will’t instantly see the consequences.”
After the flooding earlier this yr, though some mud accrued in Dunbar Cave’s passageways, a lot of the impression was on its infrastructure. Two giant boardwalks have been broken after being dislodged by the floods. Considered one of them supplies customer security in a moist space of the cave, whereas the opposite prevents harm from foot site visitors in an archaeological space. These are being reconstructed by a restoration group, in a manner that’s sustainable and supposed to maintain them from breaking unfastened once more in future flooding.
The rebuilding of the boardwalks is being addressed earlier than guided excursions can restart. Excursions are often held seasonally from Might to September and have included the cave artwork. They’re the one such alternative for the general public to see Mississippian cave artwork on this uncommon place, the place an underground cultural historical past and ecology are each cared for collectively.
